阅读说明：本技术 用于耗尽cd117+细胞的组合物和方法 (Compositions and methods for depleting CD117+ cells ) 是由 布拉德利·R·皮尔斯 安东尼·博伊坦诺 拉胡尔·帕尔乔杜里 肖恩·麦克唐纳 拉吉夫·潘瓦尔 于 2018-10-23 设计创作，主要内容包括：本发明提供了组合物和方法,该组合物和方法可用于耗尽CD117+细胞,以及用于治疗尤其是多种造血疾病、代谢紊乱、癌症和自身免疫性疾病。本文描述了抗体、其抗原结合片段、及缀合物,它们可以被应用于通过例如耗尽患者诸如人类的CD117+细胞的群体来实现对这些状况的治疗。本文描述的组合物和方法可以用于通过例如耗尽CD117+癌细胞或自身免疫性细胞的群体来直接治疗紊乱。本文描述的组合物和方法还可以用于准备患者以便于造血干细胞移植疗法,并且通过在移植程序之前选择性地耗尽内源性造血干细胞来改善造血干细胞移植物的植入。(The present invention provides compositions and methods useful for depleting CD117+ cells, and for treating, inter alia, a variety of hematopoietic diseases, metabolic disorders, cancer, and autoimmune diseases. Described herein are antibodies, antigen-binding fragments thereof, and conjugates that can be applied to achieve treatment of these conditions by, for example, depleting a population of CD117+ cells in a patient, such as a human. The compositions and methods described herein can be used to directly treat a disorder by, for example, depleting a population of CD117+ cancer cells or autoimmune cells. The compositions and methods described herein can also be used to prepare patients for hematopoietic stem cell transplantation therapy and to improve engraftment of hematopoietic stem cell grafts by selectively depleting endogenous hematopoietic stem cells prior to the transplantation procedure.)

1. An isolated anti-CD 117 antibody or antigen-binding fragment thereof, comprising:

(a) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 31, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 32, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 33; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 34, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 35, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 36;

(b) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 21, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 22, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 23; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 24, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 25, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 26;

(c) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:41, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:42, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 43; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 44, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 45, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 46;

(d) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 51, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 52, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 53; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:54, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:55, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 56;

(e) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 61, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 62, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 63; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:64, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:65, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 66;

(f) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:71, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:72, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 73; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:74, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:75, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 76;

(g) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 81, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 82, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 83; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:84, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:85, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 86;

(h) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 11, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 12, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 13; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 14, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 15, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 16;

(i) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 91, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 92, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 93; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:94, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:95, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 96; or

(j) A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 101, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 102, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 103; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 104, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 105, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 106.

2. An isolated anti-CD 117 antibody or antigen-binding fragment thereof, comprising

A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:127, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:128, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 129; and comprising a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:130, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:131, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO:132, wherein the antibody or antigen-binding fragment thereof is an antagonist antibody.

3. An isolated anti-CD 117 antibody or antigen-binding fragment thereof, comprising

a) A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 133, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 134, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 135; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 136, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 137, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 138; or

b) A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 139, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 140, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 141; and comprises a light chain variable region comprising the CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 142, the CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 143, and the CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 144,

wherein the antibody or antigen-binding fragment thereof is a neutral antibody.

4. An anti-CD 117 antibody or antigen-binding fragment thereof, comprising:

(a) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 29 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 30;

(b) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 19 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 20;

(c) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO:39 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 40;

(d) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 49 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 50;

(e) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 59 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 60;

(f) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO:69 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 70;

(g) (ii) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID No. 79 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID No. 80;

(h) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 9 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 10;

(i) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 89 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 90; or

(j) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 99, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 100.

5. The anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-4, wherein the antibody or antigen-binding fragment has 1x10 as measured by biolayer interferometry (BLI)^-2To 1x10^-3、1 x 10^-3To 1x10^-4、1 x 10^-5To 1x10^-6、1 x 10^-6To 1x10^-7Or 1x10^-7To 1x10^-8Dissociation rate (K) of_OFF)。

6. The anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-4, wherein the antibody or antigen-binding fragment is defined by a biolayer interferometry (BLI) assay with a K_DBinding to CD 117: about 100nM or less, about 90nM or less, about 80nM or less, about 70nM or less, about 60nM or less, about 50nM or less, about 40nM or less, about 30nM or less, about 20nM or less, about 10nM or less, about 8nM or less, about 6nM or less, about 4nM or less, about 2nM or less, about 1nM or less.

7. The anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-6, wherein the antibody or antigen-binding fragment thereof is human.

8. The anti-CD 117 antibody of any one of claims 1-7, wherein the antibody is an intact antibody.

9. The anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-8, wherein the antibody is an IgG.

10. The anti-CD 117 antibody or antigen-binding fragment thereof of claim 9, wherein the IgG is IgG1 or IgG 4.

11. The anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-10, wherein the antibody or antigen-binding fragment thereof is a monoclonal antibody.

12. The anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-11, comprising a heavy chain constant region having the amino acid sequence set forth in SEQ ID No. 122 and/or a light chain constant region comprising the amino acid sequence set forth in SEQ ID No. 121.

13. The anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-11, comprising an Fc region comprising at least one amino acid substitution selected from the group consisting of: D265C, H435A, L234AA and L235A (numbered according to EU index).

14. The anti-CD 117 antibody or antigen-binding fragment thereof of claim 13, wherein the Fc region comprises the amino acid substitutions D265C, L234A, and L235A (numbering according to the EU index).

15. An intact anti-CD 117 human antibody, comprising a light chain comprising the amino acid sequence set forth in SEQ ID NO:109 and a heavy chain comprising an amino acid sequence selected from the group consisting of: 110, 111, 112, 113, and 114.

16. An intact anti-CD 117 human antibody, comprising a light chain comprising the amino acid sequence set forth in SEQ ID No. 115 and a heavy chain comprising an amino acid sequence selected from the group consisting of: 116, 117, 118, 119, and 120.

17. A method of depleting a population of CD117+ cells of a human patient, the method comprising administering the antibody of any one of claims 1-16 to the human patient.

18. The method of claim 17, wherein the human patient is in need of hematopoietic stem cell transplantation.

19. A method of treating a human subject having a hematologic cancer, comprising administering to the human subject having a hematologic cancer the anti-CD 117 antibody or antigen-binding fragment thereof of any one of claims 1-16.

20. The method of claim 19, wherein the hematologic cancer is leukemia.

21. A pharmaceutical composition comprising the antibody or antigen-binding portion thereof of any one of claims 1-16 and a pharmaceutically acceptable carrier.

22. A conjugate comprising an anti-CD 117 antibody conjugated to a cytotoxin via a linker, wherein the antibody comprises the antibody or antigen-binding portion thereof of any one of claims 1-16.

23. The conjugate of claim 22, wherein the cytotoxin is selected from the group consisting of: amatoxin, pseudomonas exotoxin A, deBouganin, diphtheria toxin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicin, irinotecan, SN-38, duocarmycins, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolophenyldiazepines, and indolophenyldiazepine dimers.

24. The conjugate of claim 23, wherein the amanitin is selected from the group consisting of: alpha-amanitin, beta-amanitin, gamma-amanitin, amanitin amide, amanitin nontoxic cyclic peptide, amanitin carboxylic acid, and amanitin nontoxic cyclic peptide.

25. A conjugate represented by the formula Ab-Z-L-Am, wherein Ab is an antibody or antigen-binding fragment thereof that specifically binds to CD117, L is a linker, Z is a chemical moiety, and Am is amatoxin, wherein the antibody or antigen-binding fragment thereof is a neutral antibody that is internalized when bound to CD 117-expressing cells and has a 1x10 as determined by biolayer interferometry (BLI)^-3s^-1To 1x10^-6s^-1Human CD117 off rate (K)_OFF)。

26. The conjugate of claim 25, wherein the neutral antibody comprises

a) A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 133, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 134, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 135; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 136, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 137, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 138; or

b) A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 139, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 140, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 141; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 142, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 143, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 144.

27. A conjugate represented by the formula Ab-Z-L-Am, wherein Ab is an antibody or antigen-binding fragment thereof that binds CD117, L is a linker, Z is a chemical moiety, and Am is amatoxin, wherein the antibody or antigen-binding fragment thereof comprises:

(a) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 31, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 32, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 33; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 34, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 35, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 36;

(b) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 21, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 22, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 23; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 24, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 25, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 26;

(c) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 41, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 42, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 43; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 44, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 45, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 46;

(d) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 51, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 52, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 53; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:54, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:55, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 56;

(e) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 61, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 62, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 63; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:64, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:65, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 66;

(f) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:71, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:72, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 73; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:74, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:75, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 76;

(g) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 81, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 82, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 83; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:84, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:85, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 86;

(h) an anti-CD 117 antibody or antigen-binding fragment thereof comprising a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 11, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 12, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 13; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 14, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 15, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 16;

(i) a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 91, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 92, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 93; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:94, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:95, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 96; or

(j) A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 101, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 102, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 103; the light chain variable region comprises a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO 104, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO 105, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO 106.

28. A conjugate represented by the formula Ab-Z-L-Am, wherein Ab is an antibody or antigen-binding fragment thereof that binds CD117, L is a linker, Z is a chemical moiety, and Am is amatoxin, wherein the antibody or antigen-binding fragment thereof comprises:

(a) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 29 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 30;

(b) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 19 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 20;

(c) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO:39 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 40;

(d) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 49 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 50;

(e) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 59 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 60;

(f) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO:69 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 70;

(g) (ii) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID No. 79 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID No. 80;

(h) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 9 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 10;

(i) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 89 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 90; or

(j) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO 99, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO 100.

29. The conjugate of any one of claims 25-28, wherein the amatoxin-linker conjugate is represented by formula (I)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄、R₅、R₆And R₇Each independently is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted C₁-C₆Alkyl, optionally substituted C₁-C₆Heteroalkyl, optionally substituted C₂-C₆Alkenyl, optionally substituted C₂-C₆Heteroalkenyl, optionally substituted C₂-C₆Alkynyl, optionally substituted C₂-C₆(ii) heteroalkynyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is optionally substituted C₁-C₆Alkylene, optionally substituted C₁-C₆Heteroalkylene, optionally substituted C₂-C₆Alkenylene, optionally substituted C₂-C₆Heteroalkenylene, optionally substituted C₂-C₆Alkynylene, optionally substituted C₂-C₆(ii) a heteroalkynylene group, an optionally substituted cycloalkylene group, an optionally substituted heterocycloalkylene group, an optionally substituted arylene group, an optionally substituted heteroarylene group, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within the antibody or antigen-binding fragment thereof,

wherein Am contains exactly one R_CAnd (4) a substituent.

30. The conjugate of claim 29, wherein L-Z is

Or

31. The conjugate of any one of claims 25-28, wherein Am-L-Z is represented by formula (IA)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄、R₅、R₆And R₇Each independently is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted C₁-C₆Alkyl, optionally substituted C₁-C₆Heteroalkyl, optionally substituted C₂-C₆Alkenyl, optionally substituted C₂-C₆Heteroalkenyl, optionally substituted C₂-C₆Alkynyl, optionally substituted C₂-C₆(ii) heteroalkynyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is optionally substituted C₁-C₆Alkylene, optionally substituted C₁-C₆Heteroalkylene, optionally substituted C₂-C₆Alkenylene, optionally substituted C₂-C₆Heteroalkenylene, optionally substituted C₂-C₆Alkynylene, optionally substituted C₂-C₆(ii) a heteroalkynylene group, an optionally substituted cycloalkylene group, an optionally substituted heterocycloalkylene group, an optionally substituted arylene group, an optionally substituted heteroarylene group, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within the antibody or antigen-binding fragment thereof,

wherein Am contains exactly one R_CAnd (4) a substituent.

32. The conjugate of claim 31, wherein L-Z is

33. The conjugate of any one of claims 25-28, wherein Am-L-Z is represented by formula (IB)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄、R₅、R₆And R₇Each independently is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted C₁-C₆Alkyl, optionally substituted C₁-C₆Heteroalkyl, optionally substituted C₂-C₆Alkenyl, optionally substituted C₂-C₆Heteroalkenyl, optionally substituted C₂-C₆Alkynyl, optionally substituted C₂-C₆(ii) heteroalkynyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is optionally substituted C₁-C₆Alkylene, optionally substituted C₁-C₆Heteroalkylene, optionally substituted C₂-C₆Alkenylene, optionally substituted C₂-C₆Heteroalkenylene, optionally substituted C₂-C₆Alkynylene, optionally substituted C₂-C₆(ii) a heteroalkynylene group, an optionally substituted cycloalkylene group, an optionally substituted heterocycloalkylene group, an optionally substituted arylene group, an optionally substituted heteroarylene group, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within the antibody or antigen-binding fragment thereof,

wherein Am contains exactly one R_CAnd (4) a substituent.

34. The conjugate of claim 33, wherein L-Z is

35. The conjugate of any one of claims 25-28, wherein the conjugate is one of:

wherein X is-S-, -S (O) -or-SO₂-。

36. The conjugate of any one of claims 25-28, wherein the conjugate is:

37. the conjugate of any one of claims 25-28, wherein the conjugate is:

38. the conjugate of any one of claims 25-28, wherein the conjugate is:

39. the conjugate of any one of claims 25-28, wherein Am-L-Z is represented by formula (II), formula (IIA), or formula (IIB)

Wherein X is S, SO or SO₂；

R₁Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof; and is

R₂Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof;

wherein when R is₁When is H, R₂Is said linker, and when R₂When is H, R₁Is the said joint.

40. The conjugate of claim 39, wherein X is SO, R₁Is said linker, and R₂Is H.

41. The conjugate of claim 40, wherein L-Z is

42. The conjugate of any one of claims 25-28, wherein the antibody or antigen-binding fragment thereof is conjugated to the amanitin through a cysteine residue in the Fc domain of the antibody or antigen-binding fragment thereof.

43. The conjugate of claim 42, wherein the cysteine residue is selected from the group consisting of: cys118, Cys239 and Cys265 (numbering according to the EU index).

44. The conjugate of any one of claims 29, 31, or 33, wherein R is₁Is H, OH OR OR_A；

R₂Is H, OH OR OR_B；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃、R₄、R₆and R₇Each is H;

R₅is OR_C；

R₈Is OH or NH₂(ii) a And is

R₉Is H or OH.

45. The conjugate of any one of claims 29, 31, or 33, wherein R is₁And R₂Each independently is H or OH;

R₃is R_C；

R₄、R₆And R₇Each is H;

R₅is H, OH or OC₁-C₆An alkyl group;

R₈is OH or NH₂(ii) a And is

R₉Is H or OH.

46. The conjugate of any one of claims 29, 31, or 33, wherein R is₁And R₂Each independently is H or OH;

R₃、R₆and R₇Each is H;

R₄is OR_COr R_C；

R₅Is H, OH or OC₁-C₆An alkyl group;

R₈is OH or NH₂(ii) a And is

R₉Is H or OH.

47. The conjugate of any one of claims 29, 31, or 33, wherein R is₁And R₂Each independently isH or OH;

R₃、R₆and R₇Each is H;

R₄and R₅Each independently is H or OH;

R₈is OR_COr NHR_C(ii) a And is

R₉Is H or OH.

48. The conjugate of any one of claims 25-28, wherein the conjugate is:

or

49. The conjugate of any one of claims 29-48, wherein the antibody or antigen-binding fragment thereof is internalized by CD117+ cells.

50. The conjugate of any one of claims 29-48, wherein the antibody or antigen-binding fragment thereof has a K of about 0.1pM to about 1 μ M, as determined by BLI_dBinds to CD 117.

51. The conjugate of any one of claims 29-48, wherein the antibody or antigen-binding fragment thereof is bound by the following K, as determined by a biolayer interferometry (BLI) assay_DBinding to CD 117: about 100nM or less, about 90nM or less, about 80nM or less, about 70nM or less, about 60nM or less, about 50nM or less, about 40nM or less, about 30nM or less, about 20nM or less, about 10nM or less, about 8nM or less, about 6nM or less, about 4nM or less, about 2nM or less, about 1nM or less.

52. The patch of any of claims 29-48A compound, wherein the antibody or antigen-binding fragment thereof is at about 1x10 as determined by BLI^-3s^-1To about 1x10⁶s^-1K of_OFFBinds to CD 117.

53. The conjugate of any one of claims 29-48, wherein the antibody or antigen-binding fragment thereof is bound by the following K, as measured by biolayer interferometry (BLI)_OFFBinding to CD 117: 1x10^-2To 1x10^-3、1 x 10^-3To 1x10^-4、1 x 10^-5To 1x10^-6、1 x 10^-6To 1x10^-7Or 1x10^-7To 1x10^-8。

54. The conjugate of any one of claims 25-50, wherein the antibody or antigen-binding fragment thereof is human.

55. The conjugate of any one of claims 25-51, wherein the antibody is an intact antibody.

56. The conjugate of any one of claims 25-52, wherein the antibody is an IgG.

57. The conjugate of claim 53, wherein the IgG is IgG1 or IgG 4.

58. The conjugate of any one of claims 25-54, wherein the antibody or antigen-binding fragment thereof is a monoclonal antibody.

59. The conjugate of any one of claims 25-55, wherein the antibody or antigen-binding fragment thereof comprises a heavy chain constant region having the amino acid sequence set forth in SEQ ID NO 122 and/or a light chain constant region comprising the amino acid sequence set forth in SEQ ID NO 121.

60. The conjugate of any one of claims 25-55, wherein the antibody or antigen-binding fragment thereof comprises an Fc region comprising at least one amino acid substitution selected from the group consisting of: D265C, H435A, L234AA and L235A (numbered according to EU index).

61. The conjugate of claim 57, wherein the Fc region comprises D265C, L234A, and L235A (numbering according to the EU index).

62. The conjugate of any one of claims 25-50, wherein the antibody is an intact antibody comprising a light chain comprising the amino acid sequence set forth in SEQ ID NO:109 and a heavy chain comprising an amino acid sequence selected from the group consisting of SEQ ID NO:110, 111, 112, 113 and 114.

63. A method of depleting a population of CD117+ cells in a human patient, the method comprising administering to the patient an effective amount of the conjugate of any one of claims 25-62.

64. A method of depleting a population of CD117+ cells of a human patient in need of a hematopoietic stem cell transplant, the method comprising administering to the patient an effective amount of the conjugate of any one of claims 25-62 prior to the patient receiving a transplant comprising hematopoietic stem cells.

65. A method, the method comprising:

a. administering to a human patient the conjugate of any one of claims 25-62 in an amount sufficient to deplete the patient's population of CD117+ cells; and

b. the patient is then administered a graft comprising hematopoietic stem cells.

66. The method of any one of claims 63-65, wherein the CD117 is GNNK + CD 117.

67. The method of any one of claims 63-66, wherein the conjugate is internalized by a cancer cell, an autoimmune cell, or a hematopoietic stem cell after being administered to the patient.

68. The method of any one of claims 63-67, wherein the transplant comprising hematopoietic stem cells is administered to the patient after the concentration of the conjugate is substantially cleared from the patient's blood.

69. The method of any one of claims 63-67, wherein the hematopoietic stem cells or progeny thereof maintain hematopoietic stem cell functional potential two or more days after the hematopoietic stem cells are transplanted into the patient.

70. The method of any one of claims 63-69, wherein said hematopoietic stem cells or progeny thereof are capable of being localized to hematopoietic tissue and/or reconstituting hematopoiesis after said hematopoietic stem cells are transplanted into said patient.

71. The method of any one of claims 63-70, wherein upon transplantation into the patient, the hematopoietic stem cells cause recovery of a population of cells selected from the group consisting of: megakaryocytes, thrombocytes, platelets, erythrocytes, mast cells, myeloblasts, basophils, neutrophils, eosinophils, microglia, granulocytes, monocytes, osteoclasts, antigen presenting cells, macrophages, dendritic cells, natural killer cells, T lymphocytes, and B lymphocytes.

72. The method of any one of claims 63-71, wherein the patient suffers from a stem cell disorder.

73. The method of any one of claims 63-71, wherein the patient suffers from a hemoglobin abnormality disorder, a myeloproliferative abnormality disorder, an immunodeficiency disorder, or a metabolic disorder.

74. The method of claim 73, wherein the hemoglobin abnormality disorder is selected from the group consisting of: sickle cell anemia, thalassemia, fanconi's anemia, aplastic anemia, and wiskott-aldrich syndrome.

75. The method of claim 73, wherein the immunodeficiency disorder is congenital immunodeficiency or acquired immunodeficiency.

76. The method of claim 75, wherein the acquired immunodeficiency is a human immunodeficiency virus or an acquired immunodeficiency syndrome.

77. The method of claim 73, wherein the metabolic disorder is selected from the group consisting of: glycogen storage disease, mucopolysaccharidosis, gaucher's disease, herler's disease, sphingolipid storage disease and metachromatic leukodystrophy.

78. The method of any one of claims 63-71, wherein the patient is suffering from cancer.

79. The method of claim 78, wherein the cancer is selected from the group consisting of: leukemia, lymphoma, multiple myeloma, and neuroblastoma.

80. The method of claim 78, wherein the cancer is a hematological cancer.

81. The method of claim 80, wherein the hematologic cancer is acute myelogenous leukemia, acute lymphatic leukemia, chronic myelogenous leukemia, chronic lymphatic leukemia, or multiple myeloma.

82. The method of claim 78, wherein the cancer is diffuse large B-cell lymphoma or non-Hodgkin's lymphoma.

83. The method of any one of claims 63-71, wherein the patient suffers from a disorder selected from the group consisting of: adenosine deaminase deficiency and severe combined immunodeficiency disease, hyper-immunoglobulin M syndrome, eastern incisional disease, hereditary lymphocytosis, osteopetrosis, osteogenesis imperfecta, storage disease, thalassemia major, systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, and juvenile rheumatoid arthritis.

84. The method of any one of claims 63-71, wherein the patient has an autoimmune disorder.

85. The method of claim 84, wherein the autoimmune disorder is selected from the group consisting of: multiple sclerosis, human systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, treatment of psoriasis, type 1diabetes, acute disseminated encephalomyelitis, Edison's disease, alopecia universalis, ankylosing spondylitis, antiphospholipid antibody syndrome, aplastic anemia, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome, autoimmune oophoritis, Barlow disease, Behcet's disease, bullous pemphigoid, cardiomyopathy, Chagas 'disease, chronic fatigue immune dysfunction syndrome, chronic inflammatory demyelinating polyneuropathy, Crohn's disease, cicatricial pemphigoid, celiac-herpetiform dermatitis, cold agglutinin disease, CREST syndrome, malignant atrophic papulosis, discoid lupus erythematosus, autonomic nerve dysfunction, endometriosis, Primary mixed cryoglobulinemia, fibromyalgia-fibromyositis, goodpasture's syndrome, graves' disease, guillain-barre syndrome, hashimoto's thyroiditis, hidradenitis suppurativa, idiopathic and/or acute thrombocytopenic purpura, idiopathic pulmonary fibrosis, IgA neuropathy, interstitial cystitis, juvenile arthritis, kawasaki disease, lichen planus, lyme disease, meniere disease, mixed connective tissue disease, myasthenia gravis, neuromyotonia, strabismus myoclonus syndrome, optic neuritis, alder's thyroiditis, pemphigus vulgaris, pernicious anemia, polychondritis, polymyositis and dermatomyositis, primary biliary cirrhosis, polyarteritis nodosa, polyglandular syndrome, polymyalgia rheumatica, primary agammaglobulinemia, raynaud's phenomenon, reiter's syndrome, morbus, gilles disease, salpingitis, vernal glomerulonephritis, and vernal glomerulonephritis, Rheumatic fever, sarcoidosis, scleroderma, sjogren's syndrome, stiff person syndrome, Takayasu's arteritis, temporal arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, vulvodynia, and Wegener's granulomatosis.

Technical Field

The present invention relates to anti-CD 117 antibodies and Antibody Drug Conjugates (ADCs) thereof, and to the treatment of patients suffering from a variety of pathologies such as, inter alia, hematological diseases, metabolic disorders, cancer and autoimmune diseases, by administering antibodies or ADCs capable of binding to CD117 expressed by hematopoietic cells such as hematopoietic stem cells.

Background

Despite advances in the medical field, there remains a need for the treatment of hematopoietic pathologies, such as diseases, especially of specific blood cells, metabolic disorders, cancer and autoimmune conditions. Although hematopoietic stem cells have significant therapeutic potential, a limitation that has prevented their use in the clinic is the difficulty associated with ensuring engraftment of hematopoietic stem cell grafts in the host.

Currently, there is a need for compositions that can be used as modulators that target specific endogenous stem cells to facilitate the engraftment of exogenous hematopoietic stem cell implants such that the pluripotency and hematopoietic functionality of these cells are retained in the patient after implantation.

CD117 (also known as c-kit or stem cell factor receptor (SCRF)) is a single transmembrane receptor tyrosine kinase that binds to the ligand Stem Cell Factor (SCF). SCF induces homodimerization of cKIT, which activates tyrosine kinase activity of cKIT and signals through PI3-AKT and MAPK pathways (Kindblom et al, Am J. Path.1998152 (5): 1259).

CD117 was originally discovered as an oncogene and was studied in the field of oncology (see, e.g., Stankov et al (2014) Curr Pharm Des.20(17): 2849-80). Antibody drug conjugates against CD117 (KTN0158) are currently being investigated for the treatment of refractory gastrointestinal stromal tumors (GISTs) (e.g., "KTN 0158, a humanized-KIT monoclonal antibody, monoclonal biological activity against viral infection and monoclonal antibody cells" London et al (2016) Clin Cancer DOI:10.1158/1078-0432. CCR-16-2152).

CD117 is highly expressed on Hematopoietic Stem Cells (HSCs). This pattern of expression makes CD117a potential target for the regulation of a wide variety of diseases. However, there remains a need for anti-CD 117-based therapies that effectively modulate patients to facilitate transplantation, such as bone marrow transplantation.

Summary of The Invention

Described herein are antibodies and antigen-binding portions thereof that specifically bind to human CD117 (also referred to as c-kit), as well as compositions of and methods of using the antibodies. In particular, the antibodies and fragments described herein may be used in anti-CD 117 Antibody Drug Conjugates (ADCs).

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 10 and a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO. 9.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a light chain variable region comprising the CDR1 domain as set forth in SEQ ID NO. 14, the CDR2 domain as set forth in SEQ ID NO. 15, the CDR3 domain as set forth in SEQ ID NO. 16; and comprises a heavy chain variable region comprising the CDR1 domain as set forth in SEQ ID NO. 11, the CDR2 domain as set forth in SEQ ID NO. 12, the CDR3 domain as set forth in SEQ ID NO. 13.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:31, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:32, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 33; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 34, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 35, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 36.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:21, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:22, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 23; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 24, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 25, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 26.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:41, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:42, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 43; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 44, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 45, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 46.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:51, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:52, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 53; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:54, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:55, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 56.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 61, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 62, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 63; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:64, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:65, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 66.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 71, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 72, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 73; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:74, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:75, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 76.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:81, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:82, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 83; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:84, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:85, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 86.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 11, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 12, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 13; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 14, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 15, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 16.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:91, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:92, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 93; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO. 94, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO. 95, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO. 96.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:101, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:102, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 103; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:104, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:105, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 106.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:127, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:128, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 129; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:130, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:131, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 132.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID No. 133, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID No. 134, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID No. 135; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:136, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:137, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 138.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:139, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:140, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 141; and comprises a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:142, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:143, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 144.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO. 29 and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO. 30.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO 19 and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO 20.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO:39 and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO: 40.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO. 49, and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO. 50.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO 59 and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO 60.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID No. 69, and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID No. 70.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO:79 and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO: 80.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO.9, and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO. 10.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID NO. 89, and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID NO. 90.

In one embodiment, the anti-CD 117 antibody or antigen-binding portion thereof comprises a heavy chain variable region comprising an amino acid sequence as set forth in SEQ ID No. 99, and a light chain variable region comprising an amino acid sequence as set forth in SEQ ID No. 100.

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises an Fc region comprising amino acid substitution D265C (numbered according to the EU index).

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises an Fc region comprising amino acid substitutions D265C, L234A, and L2345A (numbered according to the EU index).

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises an Fc region comprising amino acid substitutions D265C and H435A (numbered according to the EU index).

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises an Fc region comprising amino acid substitutions D265C, L234A, L2345A, and H435A (numbered according to the EU index).

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises (i) a light chain constant region comprising an amino acid sequence as set forth in SEQ ID NO:121, and (ii) a heavy chain constant region comprising an amino acid sequence as set forth in SEQ ID NO: 122.

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises (i) a light chain constant region comprising an amino acid sequence as set forth in SEQ ID NO:121, and (ii) a heavy chain constant region comprising an amino acid sequence as set forth in SEQ ID NO: 123.

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises (i) a light chain constant region comprising an amino acid sequence as set forth in SEQ ID NO:121, and (ii) a heavy chain constant region comprising an amino acid sequence as set forth in SEQ ID NO: 124.

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises (i) a light chain constant region comprising an amino acid sequence as set forth in SEQ ID NO:121, and (ii) a heavy chain constant region comprising an amino acid sequence as set forth in SEQ ID NO: 125.

In some embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises (i) a light chain constant region comprising an amino acid sequence as set forth in SEQ ID NO:121, and (ii) a heavy chain constant region comprising an amino acid sequence as set forth in SEQ ID NO: 126.

In one embodiment, the anti-CD 117 antibody or antigen-binding fragment thereof is internalized by the CD117+ cell.

In another embodiment, the antibody or antigen-binding fragment thereof has a K of about 0.1pM to about 1 μ M as determined by BLI_dBinds to CD 117. In one embodiment, the antibody or antigen-binding fragment thereof is bound by the following K as determined by a biolayer interferometry (BLI) assay_DBinding to CD 117: about 100nM or less, about 90nM or less, about 80nM or less, about 70nM or less, about 60nM or less, about 50nM or less, about 40nM or less, about 30nM or less, about 20nM or less, about 10nM or less, about 8nM or less, about 6nM or less, about 4nM or less, about 2nM or less, about 1nM or less. In yet another embodiment, the antibody or antigen-binding fragment thereof is administered at about 1x10 as determined by BLI^-3s^-1To about 1x10⁶s^-1K of_OFFBinds to CD 117. In yet another embodiment, the antibody or antigen-binding fragment thereof is represented by the following K, as measured by biolayer interferometry (BLI)_OFFBinding to CD 117: 1x10^-2To 1x10^-3、1x10^-3To 1x10^-4、1x10^-5To 1x10^-6、1x10^-6To 1x10^-7Or 1x10^-7To 1x10^-8。

In certain embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof is human.

In certain embodiments, the anti-CD 117 antibody is an intact antibody.

In certain embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof is an IgG, e.g., IgG1 or IgG 4.

In certain embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof is a monoclonal antibody.

In certain embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises a heavy chain constant region having an amino acid sequence as set forth in SEQ ID NO. 122 and/or a light chain constant region comprising an amino acid sequence as set forth in SEQ ID NO. 121.

In certain embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof comprises a light chain comprising an amino acid sequence as set forth in SEQ ID No. 109 and a heavy chain comprising an amino acid sequence selected from the group consisting of SEQ ID NO:110, 111, 112, 113 and 114.

The antibodies, fragments, and ADCs described herein, including antibody 54(Ab54), antibody 55(Ab55), antibody 56(Ab56), antibody 57(Ab57), antibody 58(Ab58), antibody 61(Ab61), antibody 66(Ab66), antibody 67(Ab67), antibody 68(Ab68), or antibody 69(Ab69), may be used in compositions and methods for treating, inter alia, a variety of hematopoietic disorders, metabolic disorders, cancer, and autoimmune diseases. The invention additionally features methods for conditioning a patient, such as a human patient, prior to receiving hematopoietic stem cell transplantation therapy to facilitate the engraftment of a hematopoietic stem cell implant. The patient may be a patient suffering from one or more blood disorders such as haemoglobin abnormalities or other haematopoietic pathologies and thus requiring haematopoietic stem cell transplantation. As described herein, hematopoietic stem cells are capable of differentiating into numerous cell types in the hematopoietic lineage, and can be administered to a patient for engraftment (engraftment) or reimplantation (re-engraftment) of cell types that are deficient in the patient.

The invention features methods of treating a patient with an antibody and ADC capable of binding to a protein expressed by hematopoietic cells, such as CD117 (including, e.g., GNNK + CD117), to (i) directly treat a disease, such as, inter alia, a blood disorder, a metabolic disease, a cancer, or an autoimmune disease described herein, by selectively depleting a population of CD 117-expressing cells, such as abnormal blood cells, cancer cells, or autoimmune cells, and/or (ii) deplete a population of endogenous hematopoietic stem cells in the patient. The former activity enables the direct treatment of a wide variety of disorders associated with cells of the hematopoietic lineage, as CD117 can be expressed by cancerous cells, such as leukemia cells, autoimmune lymphocytes, such as T cells expressing T cell receptors that cross-react with self-antigens, and other cell types. The latter activity, i.e., selective depletion of hematopoietic stem cells, in turn creates a void which can subsequently be filled by transplantation of an exogenous (e.g., autologous, allogeneic or syngeneic) hematopoietic stem cell implant. Accordingly, the present invention provides methods of treating a variety of hematopoietic conditions, such as, inter alia, sickle cell anemia, thalassemia, fanconi anemia, Wiskott-Aldrich syndrome, adenosine deaminase deficiency-severe combined immunodeficiency disease, metachromatic leukodystrophy, Diamond-Blackfan anemia and Schwachman-Diamond syndrome, human immunodeficiency virus infection and acquired immunodeficiency syndrome, and cancer and autoimmune diseases.

In a first aspect, the invention provides a method of depleting a population of CD117+ cells in a human patient by administering an effective amount of an antibody or antigen-binding fragment thereof capable of binding to CD117, wherein the antibody or antigen-binding fragment is conjugated to a cytotoxin.

In another aspect, the invention provides a method of depleting a population of CD117+ cells of a human patient in need of a hematopoietic stem cell graft by administering an effective amount of an antibody or antigen-binding fragment thereof capable of binding to CD117 prior to receiving the hematopoietic stem cell-containing graft, wherein the antibody or antigen-binding fragment is conjugated to a cytotoxin.

In another aspect, the invention features, for example, a method of treating a human patient in need of hematopoietic stem cell transplantation, the method including administering to the human patient a graft comprising hematopoietic stem cells, wherein the patient has previously been administered an antibody or antigen-binding fragment thereof capable of binding to CD117, wherein the antibody or antigen-binding fragment is conjugated to a cytotoxin and is administered in an amount sufficient to deplete the patient's population of CD117+ cells.

In additional aspects, the invention features, for example, a method of treating a human patient in need of a hematopoietic stem cell graft, the method including: administering to a human patient an antibody or antigen-binding fragment thereof capable of binding to CD117, wherein the antibody or antigen-binding fragment is conjugated to a cytotoxin and is administered in an amount sufficient to deplete a population of CD117+ cells of the patient, and subsequently administering to the patient a graft comprising hematopoietic stem cells.

In some embodiments of any of the foregoing aspects of the invention, the antibody or antigen-binding fragment thereof is conjugated to a cytotoxin.

In one embodiment, the anti-CD 117 conjugate is represented by the formula Ab-Z-L-Am, wherein Ab is an antibody or antigen-binding fragment thereof that specifically binds to CD117, L is a linker, Z is a chemical moiety, and Am is amatoxin, wherein the antibody or antigen-binding fragment thereof is a neutral antibody that is internalized when bound to CD 117-expressing cells and has 1x10 as determined by biolayer interferometry (BLI)^-3s^-1To 1x10^-6s^-1Human CD117 off rate (K)_OFF)。

In any of the above aspects, the cytotoxin may be, for example, pseudomonas exotoxin A, deBouganin, diphtheria toxin, amanitins such as alpha-amanitin, saporin (saporin), maytansine, maytansinoids (maytansinoids), auristatins (auristatins), anthracyclines, calicheamicins (calicheamicins), irinotecan, SN-38, duocarmycins (duocarmycins), pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolopendrazines, or indolopendrazine dimers, or variants thereof.

In some embodiments of any of the above aspects, CD117 is GNNK + CD 117.

In another aspect, the invention provides a method of depleting a population of CD117+ cells in a human patient in need of a hematopoietic stem cell transplant by administering an effective amount of an antibody or fragment thereof capable of binding to CD117 prior to receiving the hematopoietic stem cell-containing transplant.

In another aspect, the invention features, for example, a method of treating a human patient in need of a hematopoietic stem cell transplant, the method including administering to the human patient a transplant comprising hematopoietic stem cells, wherein the patient has previously been administered an antibody or fragment thereof capable of binding CD117 in an amount sufficient to deplete the patient's population of CD117+ cells.

In additional aspects, the invention features, for example, a method of treating a human patient in need of a hematopoietic stem cell graft, the method including: administering to a human patient an amount of an antibody or fragment thereof capable of binding to CD117 sufficient to deplete the patient's population of CD117+ cells; and subsequently administering to the patient a graft comprising hematopoietic stem cells.

In some embodiments of any of the foregoing aspects, an antibody or fragment thereof that binds CD117 (e.g., GNNK + CD117) is covalently bound to an Fc domain, such as a dimeric Fc domain isolated from a human antibody (e.g., isolated from an IgG1, IgG2, IgG3, or IgG4 isotype human antibody). In some embodiments, the Fc domain is a monomeric Fc domain comprising a single polypeptide chain. In some embodiments, the N-terminus of the antibody or fragment thereof binds to an Fc domain. In some embodiments, the C-terminus of the antibody or fragment thereof binds to an Fc domain. The Fc domain may be conjugated to one or more copies of the antibody or fragment thereof. For example, conjugates useful in the methods described herein include a dimeric Fc domain, wherein each polypeptide chain of the Fc domain is conjugated to an antibody or fragment thereof. The Fc domain, in turn, can be conjugated to a cytotoxin, such as a cytotoxin described herein (e.g., pseudomonas exotoxin A, deBouganin, diphtheria toxin, amanitins such as alpha-amanitin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicin, irinotecan, SN-38, duocarmycins, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolopendrazines, and indolopendrazine dimers, or variants thereof).

In some embodiments of the foregoing aspect, the antibody or fragment thereof is covalently bound to a cytotoxin (forming an ADC), such as a cytotoxin described herein (e.g., pseudomonas exotoxin a, debaugenin, diphtheria toxin, amatoxin such as alpha-amatoxin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicin, irinotecan, SN-38, duocarmycin, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolopendrin and indolopendrin dimers, or variants thereof). In some embodiments, the N-terminus of the antibody or fragment thereof binds to a cytotoxin. In some embodiments, the C-terminus of the antibody or fragment thereof binds to a cytotoxin. The cytotoxin may then be conjugated to the Fc domain of an anti-CD 117 antibody.

In some embodiments, the antibody or fragment thereof is covalently bound to the cytotoxin at one site of the antibody or fragment thereof (e.g., the N-terminus or C-terminus of the antibody or fragment thereof) and covalently bound to the Fc domain at another site on the antibody or fragment thereof (e.g., the opposite end of the antibody or fragment thereof).

In some embodiments, the Fc domain is a human IgG1 isotype Fc domain. In some embodiments, the Fc domain is a human IgG2 isotype Fc domain. In some embodiments, the Fc domain is a human IgG3 isotype Fc domain. In some embodiments, the Fc domain is a human IgG4 isotype Fc domain.

In some embodiments of any of the above aspects, the cytotoxin is amatoxin or a derivative thereof, such as α -amanitin, β -amanitin, γ -amanitin, amanitin amide (amaninamide), amanitin nontoxic cyclic peptide (amacullin), amanitin carboxylic acid (amaculinic acid), and proapolin nontoxic cyclic peptide (proamullin). In some embodiments of any of the above aspects, the cytotoxin is amatoxin, and the antibody or antigen-binding fragment thereof conjugated to the cytotoxin is represented by the formula Ab-Z-L-Am, wherein Ab is the antibody or antigen-binding fragment thereof, L is a linker, Z is a chemical moiety, and Am is amatoxin. In some embodiments, the amatoxin is conjugated to a linker. In some embodiments, Am-L-Z is represented by formula (I)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, optionally substituted heteroarylA group;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene), optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof; and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD 117).

In some embodiments, Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

Wherein S is a sulfur atom, which represents a reactive substituent (e.g., an-SH group from a cysteine residue) present within an antibody or antigen-binding fragment thereof that binds CD 117.

In some embodiments, L-Z is

In some embodiments, L-Z is

In some embodiments, Am-L-Z-Ab is

In some embodiments, Am-L-Z-Ab is

In some embodiments, Am-L-Z-Ab is

In some embodiments, Am-L-Z is represented by formula (IA)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene), optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD 117); and is

Wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, L-Z is

In some embodiments, L-Z is

In some embodiments, Am-L-Z is represented by formula (IB)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (E.g. C₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene), optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD 117); and is

Wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, R_AAnd R_BCombine with the oxygen atom to which they are bound to form a 5-membered heterocycloalkyl group of the formula:

wherein Y is- (C ═ O) -, - (C ═ S) -, - (C ═ NR_E) -or-(CR_ER_E’) -; and is

R_EAnd R_E’Each independently is optionally substituted C₁-C₆alkylene-R_COptionally substituted C₁-C₆Heteroalkylene-R_COptionally substituted C₂-C₆alkenylene-R_COptionally substituted C₂-C₆Heteroalkenylene-R_COptionally substituted C₂-C₆alkynylene-R_COptionally substituted C₂-C₆Heteroalkynylene-R_COptionally substituted cycloalkylene-R_COptionally substituted heterocycloalkylene-R_COptionally substituted arylene-R_COr optionally substituted heteroarylene-R_C。

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB), wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃is H or R_C；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_COr NHR_C；

R₉Is H or OH; and is

Wherein R is_CAnd R_DEach as defined above.

In some embodiments, Am is represented by formula (IA) or formula (IB),

wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃is H or R_C；

R₄And R₅Each independently is H, OH, OR_C、R_COR OR_D；

R₆And R₇Each is H;

R₈is OH, NH₂、OR_COr NHR_C；

R₉Is H or OH; and is

Wherein R is_CAs defined above.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁Is H, OH OR OR_A；

R₂Is H, OH OR OR_B；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃、R₄、R₆and R₇Each is H;

R₅is OR_C；

R₈Is OH or NH₂；

R₉Is H or OH; and is

Wherein R is_CAs defined above.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁And R₂Each independently is H or OH;

R₃is R_C；

R₄、R₆And R₇Each is H;

R₅is H, OH or OC₁-C₆An alkyl group;

R₈is OH or NH₂；

R₉Is H or OH; and is

Wherein R is_CAs defined above.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁And R₂Each independently is H or OH;

R₃、R₆and R₇Each is H;

R₄and R₅Each independently is H, OH, OR_COr R_C；

R₈Is OH or NH₂；

R₉Is H or OH; and is

Wherein R is_CAs defined above.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁And R₂Each independently is H or OH;

R₃、R₆and R₇Each is H;

R₄and R₅Each independently is H or OH;

R₈is OH, NH₂、OR_COr NHR_C；

R₉Is H or OH; and is

Wherein R is_CAs defined above.

In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, L-Z is

In some embodiments, Am-L-Z is represented by formula (II), formula (IIA), or formula (IIB),

wherein X is S, SO or SO₂；R₁Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof; and R is₂Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof; wherein when R is₁When is H, R₂Is a linker, and when R₂When is H, R₁Is a joint. In one embodiment, X is SO and R₁Is a linker, and R₂Is H.

In some embodiments, R₁Is a linker and R₂Is H and the linker and chemical moiety together are L-Z, is

In some embodiments, Am-L-Z-Ab is:

in some embodiments, Am-L-Z-Ab is:

in some embodiments, the conjugate is represented by formula (IV). In some embodiments, the conjugate is represented by formula (IVA). In some embodiments, the conjugate is represented by formula (IVB).

In some embodiments, the Am-L-Z precursor is

Wherein the maleimide reacts with a thiol group present on a cysteine in the antibody.

In some embodiments, the Am-L-Z precursor is

Wherein the maleimide reacts with a thiol group present on a cysteine in the antibody.

In some embodiments of any of the above aspects, the cytotoxin is a maytansine alkaloid selected from the group consisting of: DM1 and DM 4. In some embodiments, the cytotoxin is an auristatin selected from the group consisting of: monomethyl auristatin E and monomethyl auristatin F. In some embodiments, the cytotoxin is an anthracycline selected from the group consisting of: daunorubicin, doxorubicin, epirubicin, and idarubicin.

In another aspect, the invention features a method of depleting a population of CD117+ cells in a human patient by administering an effective amount of an antibody or antigen-binding fragment thereof or ADC that is capable of binding to GNNK + CD 117.

In addition, the invention features a method of depleting a population of CD117+ cells in a human patient in need of a hematopoietic stem cell transplant by administering an effective amount of an antibody or antigen-binding fragment thereof or ADC capable of binding to GNNK + CD117 prior to receiving the hematopoietic stem cell-containing transplant.

In another aspect, the invention features, for example, a method of treating a human patient in need of a hematopoietic stem cell transplant, the method including administering to the human patient a transplant containing hematopoietic stem cells, wherein the patient has previously been administered an antibody or antigen-binding fragment thereof or ADC capable of binding to GNNK + CD117 in an amount sufficient to deplete the patient's population of CD117+ cells.

In additional aspects, the invention features, for example, a method of treating a human patient in need of a hematopoietic stem cell graft, the method including: administering to a human patient an antibody or antigen-binding fragment thereof or ADC capable of binding to GNNK + CD117 in an amount sufficient to deplete the patient's population of CD117+ cells, and subsequently administering to the patient a transplant comprising hematopoietic stem cells.

In some embodiments of any of the above aspects, the antibody or antigen-binding fragment thereof is selected from the group consisting of: monoclonal antibody or antigen-binding fragment thereof, polyclonal antibody or antigen-binding fragment thereof, humanized antibody or antigen-binding fragment thereof, bispecific antibody or antigen-binding fragment thereof, dual variable immunoglobulin domains, single chain Fv molecules (scFv), diabodies (diabodies), triabodies (triabodies), nanobodies (nanobodies), antibody-like protein scaffolds, Fv fragments, Fab fragments, F (ab')₂Molecules and tandem di-scFv (tandem di-scFv). In some embodiments, the antibody has an isotype selected from the group consisting of: IgG, IgA, IgM, IgD and IgE.

In some embodiments of any of the above aspects, the antibody or antigen-binding fragment thereof or ADC is internalized by a hematopoietic cell, such as a hematopoietic stem cell, a cancer cell, or an autoimmune cell, upon administration to the patient. For example, an antibody or antigen-binding fragment thereof or ADC may be internalized by hematopoietic stem cells, cancer cells, or autoimmune cells via receptor-mediated endocytosis (e.g., upon binding to cell surface CD117, such as GNNK + CD 117). In some embodiments, the cytotoxin covalently bound to the antibody or antigen-binding fragment thereof can be released intracellularly by chemical cleavage (e.g., enzymatic or non-specific cleavage by a linker described herein). The cytotoxin can then access its intracellular targets (such as especially mitotic spindle antiparatus, nuclear DNA, ribosomal RNA or topoisomerase, etc.) in order to promote the death of endogenous hematopoietic cells such as especially the death of endogenous hematopoietic stem cells, endogenous cancer cells or endogenous autoimmune cells prior to transplantation therapy.

In some embodiments of any of the above aspects, the antibody or antigen-binding fragment thereof or ADC is capable of promoting necrosis of hematopoietic cells such as, inter alia, hematopoietic stem cells, cancer cells, or autoimmune cells. In some embodiments, the antibody or antigen-binding fragment thereof can promote death of endogenous hematopoietic stem cells, death of endogenous cancer cells, or death of endogenous autoimmune cells, particularly prior to transplantation therapy, by recruiting one or more complement proteins, Natural Killer (NK) cells, macrophages, neutrophils, and/or eosinophils to a cell, such as a hematopoietic stem cell, after being administered to a patient.

In some embodiments of any of the above aspects, the hematopoietic stem cell-containing graft is administered to the patient after the concentration of the antibody, or antigen-binding fragment thereof, or ADC, has been substantially cleared from the blood of the patient.

In some embodiments of any of the above aspects, the hematopoietic stem cells or progeny thereof still maintain hematopoietic stem cell functional potential after two or more days (e.g., from about 2 days to about 5 days, from about 2 days to about 7 days, from about 2 days to about 20 days, from about 2 days to about 30 days, such as 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, 21 days, 22 days, 23 days, 24 days, 25 days, 26 days, 27 days, 28 days, 29 days, 30 days, or more) after the hematopoietic stem cells are transplanted into the patient.

In some embodiments of any of the above aspects, the hematopoietic stem cells or progeny thereof are capable of being localized to a hematopoietic tissue, such as bone marrow, and/or reconstituting hematopoiesis, after the hematopoietic stem cells are transplanted into the patient.

In some embodiments of any of the above aspects, the hematopoietic stem cells, upon transplantation into the patient, cause recovery of a population of cells selected from the group consisting of: megakaryocytes, thrombocytes, platelets, erythrocytes, mast cells, myeloblasts, basophils, neutrophils, eosinophils, microglia, granulocytes, monocytes, osteoclasts, antigen presenting cells, macrophages, dendritic cells, natural killer cells, T lymphocytes, and B lymphocytes.

In some embodiments of any of the above aspects, the methods are used to treat one or more disorders, such as by depleting a population of patient's hematopoietic stem cells prior to hematopoietic stem cell transplantation therapy in order to provide a niche (niche) to which the transplanted hematopoietic stem cells can home. After transplantation, hematopoietic stem cells can establish productive hematopoiesis to replenish deficient cell types in the patient or cell types actively killed or already killed, e.g., by chemotherapy. For example, the patient may be a patient suffering from a stem cell disorder. In some embodiments, the patient suffers from a hemoglobin abnormality disorder, such as sickle cell anemia, thalassemia, fanconi's anemia, aplastic anemia, and Wiskott-Aldrich syndrome. Patients may be afflicted with an immunodeficiency disorder, such as an congenital immunodeficiency disorder or an acquired immunodeficiency disorder (e.g., human immunodeficiency virus or acquired immunodeficiency syndrome). In some embodiments, the patient suffers from a metabolic disorder, such as glycogen storage Disease, mucopolysaccharidosis, Gaucher's Disease, hurler Disease, sphingolipid storage Disease, and metachromatic leukodystrophy. In some embodiments, the patient suffers from a disorder selected from the group consisting of: adenosine deaminase deficiency and severe combined immunodeficiency Disease, hyper-immunoglobulin M syndrome, Chediak-Higashi Disease, hereditary lymphocytosis, osteopetrosis, osteogenesis imperfecta, storage Disease, thalassemia major, systemic sclerosis, systemic lupus erythematosus and juvenile rheumatoid arthritis. In some embodiments, the patient suffers from an autoimmune disease, such as scleroderma, multiple sclerosis, ulcerative colitis, crohn's disease, and type 1 diabetes. In some embodiments, the patient is suffering from cancer or a myeloproliferative disease, such as a hematological cancer. In some embodiments, the patient is suffering from acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia, chronic lymphoid leukemia, multiple myeloma, diffuse large B-cell lymphoma, or non-hodgkin's lymphoma. In some embodiments, the patient suffers from a myelodysplastic disease, such as myelodysplastic syndrome.

In some embodiments of any of the above aspects, the method is for directly treating a cancer, such as a cancer characterized by CD117+ cells (e.g., a leukemia characterized by CD117+ cells), by administering an antibody or antigen-binding fragment thereof that depletes a population of CD117+ cancer cells of a patient and/or by administering an antibody or antigen-binding fragment thereof so as to deplete a population of endogenous hematopoietic stem cells prior to hematopoietic stem cell transplantation. In the latter case, transplantation can then reconstitute a population of cells that are depleted, for example, during the process of eliminating cancer cells. The cancer may be a hematologic cancer, such as acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia, chronic lymphoid leukemia, multiple myeloma, diffuse large B-cell lymphoma or non-hodgkin's lymphoma.

In some embodiments of any of the above aspects, the method is used to treat an autoimmune disease, such as by administering the antibody or antigen-binding fragment thereof or ADC so as to deplete a population of CD117+ autoimmune cells and/or by administering the antibody or antigen-binding fragment thereof so as to deplete a population of endogenous hematopoietic stem cells prior to hematopoietic stem cell transplantation. In the latter case, transplantation can then reconstitute the population of cells that are depleted, for example, during the process of eliminating autoimmune cells. The autoimmune disease can be, for example, scleroderma, Multiple Sclerosis (MS), human Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA), Inflammatory Bowel Disease (IBD), treatment of psoriasis, Type 1diabetes mellitus (Type 1diabetes mellitus), Acute Disseminated Encephalomyelitis (ADEM), Edison's disease, alopecia universalis, ankylosing spondylitis, antiphospholipid antibody syndrome (APS), aplastic anemia, autoimmune hemolytic anemia, autoimmune hepatitis, Autoimmune Inner Ear Disease (AIED), autoimmune lymphoproliferative syndrome (ALPS), autoimmune oophoritis, Barlow disease, Behcet's disease, bullous pemphigoid, cardiomyopathy, Chagas disease, Chronic Fatigue Immune Dysfunction Syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, psoriasis, multiple sclerosis (IBD), psoriasis, diabetes mellitus, Chronic Fatigue Immune Dysfunction Syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, Crohn's disease, cicatricial pemphigoid, celiac disease-dermatitis herpetiformis, cold agglutinin disease, CREST syndrome, malignant atrophic papulopathy (degoss disease), discoid lupus erythematosus, autonomic nerve dysfunction, endometriosis, primary mixed cryoglobulinemia (refractory mixed cryoglobulinemia), fibromyalgia-fibromyositis, Goodpasture's syndrome, graves disease, guillain-barre syndrome (GBS), hashimoto's thyroiditis, hidradenitis suppurativa, idiopathic and/or acute thrombocytopenic purpura, idiopathic pulmonary fibrosis, IgA neuropathy, interstitial cystitis, juvenile arthritis, kawasaki disease, lichen planus, lyme disease, meniere disease, Mixed Connective Tissue Disease (MCTD), myasthenia gravis, neuromyoclonic myotonia, oblique eye clonic syndrome (OMS), omd syndrom disease (omd), neurolemma, and acute myelogenous sclerosis, Optic neuritis, alder's thyroiditis, pemphigus vulgaris, pernicious anemia, polychondritis, polymyositis and dermatomyositis, primary biliary cirrhosis, polyarteritis nodosa, polyglandular syndrome, polymyalgia rheumatica, primary agammaglobulinemia, raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, sjogren's syndrome, stiff person's syndrome, Takayasu's arteritis, temporal arteritis (also known as "giant cell arteritis"), ulcerative colitis, uveitis, vasculitis, vitiligo, vulvodynia ("vulvar vestibulitis"), and Wegener granulomatosis.

Thus, in some embodiments of any of the above aspects, the invention features methods of treating a hemoglobin abnormality disorder, such as sickle cell anemia, thalassemia, fanconi's anemia, aplastic anemia, and wiskott-aldrich syndrome. In some embodiments, the invention features methods of treating an immunodeficiency disorder, such as an congenital immunodeficiency disorder or an acquired immunodeficiency disorder (e.g., human immunodeficiency virus or acquired immunodeficiency syndrome). In some embodiments, the invention features methods of treating metabolic disorders, such as glycogen storage disease, mucopolysaccharidosis, gaucher's disease, heller disease, sphingolipid storage disease, and metachromatic leukodystrophy. In some embodiments, the invention features a method of treating a disorder selected from the group consisting of: adenosine deaminase deficiency and severe combined immunodeficiency disease, hyper-immunoglobulin M syndrome, eastern incisional disease, hereditary lymphocytosis, osteopetrosis, osteogenesis imperfecta, storage disease, thalassemia major, systemic sclerosis, systemic lupus erythematosus and juvenile rheumatoid arthritis. In some embodiments, the invention features methods of treating an autoimmune disease, such as scleroderma, multiple sclerosis, ulcerative colitis, crohn's disease, or type 1 diabetes. In some embodiments, the invention features methods of treating cancer or myeloproliferative diseases, such as hematologic cancer. In some embodiments, the invention features methods of treating acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia, chronic lymphoid leukemia, multiple myeloma, diffuse large B-cell lymphoma, or non-hodgkin's lymphoma. In some embodiments, the patient suffers from a myelodysplastic disease, such as myelodysplastic syndrome. In these embodiments, the methods may comprise the step of administering an antibody or antigen-binding fragment thereof that binds CD117 (e.g., GNNK + CD117) or ADC and/or hematopoietic stem cell graft according to the methods of any of the above-described aspects and embodiments of the invention.

Similarly, in some embodiments of any of the above aspects, the invention provides methods of directly treating cancer, such as cancer characterized by CD117+ cells (e.g., leukemia characterized by CD117+ cells). In these embodiments, the methods comprise administering an antibody or antigen-binding fragment thereof that binds CD117 (e.g., GNNK + CD 117). The cancer may be a hematologic cancer, such as acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia, chronic lymphoid leukemia, multiple myeloma, diffuse large B-cell lymphoma or non-hodgkin's lymphoma.

In addition, in some embodiments of any of the above aspects, the invention provides a method of treating an autoimmune disease, such as Multiple Sclerosis (MS), human Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA), Inflammatory Bowel Disease (IBD), psoriasis, Type 1diabetes mellitus (Type 1diabetes mellitus) (Type 1diabetes), Acute Disseminated Encephalomyelitis (ADEM), edison's disease, alopecia universalis, ankylosing spondylitis, antiphospholipid antibody syndrome (APS), aplastic anemia, autoimmune hemolytic anemia, autoimmune hepatitis, Autoimmune Inner Ear Disease (AIED), autoimmune lymphoproliferative syndrome (ALPS), autoimmune oophoritis, barlow disease, behcet's disease, bullous pemphigoid, cardiomyopathy, chagas ' disease, psoriasis, Chronic Fatigue Immune Dysfunction Syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, crohn's disease, cicatricial pemphigoid, celiac-dermatitis herpetiformis, cold agglutinin disease, CREST syndrome, malignant atrophic papulopathy, discoid lupus erythematosus, autonomic dysfunction, endometriosis, primary mixed cryoglobulinemia, fibromyalgia-fibromyositis, goodpasture's syndrome, graves disease, guillain-barre syndrome (GBS), hashimoto's thyroiditis, hidradenitis suppurativa, idiopathic and/or acute thrombocytopenic purpura, idiopathic pulmonary fibrosis, IgA neuropathy, interstitial cystitis, juvenile arthritis, kawasaki disease, lichen planus, lyme disease, meniere disease, Mixed Connective Tissue Disease (MCTD), myasthenia gravis, neuromyotonia, sarcopenia, bruise's disease, and/or a, Strabismus myoclonus syndrome (OMS), optic neuritis, alder's thyroiditis, pemphigus vulgaris, pernicious anemia, polychondritis, polymyositis and dermatomyositis, primary biliary cirrhosis, polyarteritis nodosa, polyglandular syndrome, polymyalgia rheumatica, primary agammaglobulinemia, raynaud's phenomenon, reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, sjogren's syndrome, stiff man's syndrome, takayasu's arteritis, temporal arteritis (also known as "giant cell arteritis"), ulcerative colitis, uveitis, vasculitis, vitiligo, vulvar pain ("vulvodynia"), and wegener's granulomatosis. In these embodiments, the methods comprise administering an antibody or antigen-binding fragment thereof that binds CD117 (e.g., GNNK + CD 117).

In another aspect, the invention features a method of depleting a population of CD117+ (e.g., GNNK + CD117) cells by contacting the population with an effective amount of a conjugate (or ADC) represented by the formula Ab-Z-L-Am, wherein Ab is an antibody or antigen-binding fragment thereof that binds to CD117, Z is a chemical moiety, L is a linker, and Am is amatoxin. Am-L-Z may be represented by formula (IA)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄、R₅、R₆And R₇Each independently is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene), optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof,

wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, L-Z is

In some embodiments, L-Z is

In some embodiments, Am-L-Z is represented by formula (IB)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene), optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD 117); and is

Wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, L-Z is

In some embodiments, Am-L-Z-Ab is one of:

wherein X is S, SO or SO₂。

In some embodiments, Ab-Z-L-Am is

In some embodiments, Ab-Z-L-Am is

In another aspect, the invention features a conjugate represented by the formula Ab-Z-L-Am, where Ab is an antibody or antigen-binding fragment thereof that binds CD117 (e.g., GNNK + CD117), and Am is amatoxin. In some embodiments, Am-L-Z is represented by formula (I), (IA), (IB), (II), (IIA), or (IIB) above.

In some embodiments, the linker-chemical moiety of the conjugate, amanitin moiety (Am-L-Z), is represented by formula (IA)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄、R₅、R₆And R₇Each independently is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted C₁-C₆Alkyl, optionally substituted C₁-C₆Heteroalkyl, optionally substituted C₂-C₆Alkenyl, optionally substituted C₂-C₆Heteroalkenyl, optionally substituted C₂-C₆Alkynyl, optionally substituted C₂-C₆(ii) heteroalkynyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is optionally substituted C₁-C₆Alkylene, optionally substituted C₁-C₆Heteroalkylene, optionally substituted C₂-C₆Alkenylene, optionally substituted C₂-C₆Heteroalkenylene, optionally substituted C₂-C₆Alkynylene, optionally substituted C₂-C₆(ii) a heteroalkynylene group, an optionally substituted cycloalkylene group, an optionally substituted heterocycloalkylene group, an optionally substituted arylene group, an optionally substituted heteroarylene group, a dipeptide, - (C ═ O) -, a peptide, or a combination thereof; and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof,

wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, L-Z is

In some embodiments, L-Z is

In some embodiments, Am-L-Z is represented by formula (IB)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄、R₅、R₆And R₇Each independently is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted C₁-C₆Alkyl, optionally substituted C₁-C₆Heteroalkyl, optionally substituted C₂-C₆Alkenyl, optionally substituted C₂-C₆Heteroalkenyl, optionally substituted C₂-C₆Alkynyl, optionally substituted C₂-C₆(ii) heteroalkynyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is optionally substituted C₁-C₆Alkylene, optionally substituted C₁-C₆Heteroalkylene, optionally substituted C₂-C₆Alkenylene, optionally substituted C₂-C₆Heteroalkenylene, optionally substituted C₂-C₆Alkynylene, optionally substituted C₂-C₆(ii) a heteroalkynylene group, an optionally substituted cycloalkylene group, an optionally substituted heterocycloalkylene group, an optionally substituted arylene group, an optionally substituted heteroarylene group, a dipeptide, - (C ═ O) -, a peptide, or a combination thereof; and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof,

wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, L-Z is

In some embodiments, L-Z is

In some embodiments, Am-L-Z is represented by formula (II), formula (IIA), or formula (IIB),

wherein X is S, SO or SO₂；

R₁Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof; and is

R₂Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof;

wherein when R is₁When is H, R₂Is a linker, and when R₂When is H, R₁Is a joint.

In one embodiment, X is SO and R₁Is a linker, and R₂Is H.

In some embodiments, L-Z is

In some embodiments of the foregoing two aspects, the antibody or antigen-binding fragment thereof is conjugated to amanitin through a cysteine residue in the Fc domain of the antibody or antigen-binding fragment thereof. In some embodiments, the cysteine residue is introduced by mutation in the Fc domain of the antibody or antigen-binding fragment thereof. For example, the cysteine residue may be selected from the group consisting of: cys118, Cys239, and Cys265 (e.g., D265C).

In some embodiments of these aspects, the cysteine residue is naturally occurring in the Fc domain of the antibody or antigen-binding fragment thereof. For example, the Fc domain may be an IgG Fc domain, such as a human IgG1 Fc domain, and the cysteine residue may be selected from the group consisting of: cys261, Csy321, Cys367 and Cys 425.

Some embodiments in these aspectsIn the scheme, R₁Is H, OH OR OR_A；

R₂Is H, OH OR OR_B；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃、R₄、R₆and R₇Each is H;

R₅is OR_C；

R₈Is OH or NH₂；

R₉Is H or OH; and is

X is-S-, -S (O) -or-SO₂-。

In some embodiments, R₁And R₂Each independently is H or OH;

R₃is R_C；

R₄、R₆And R₇Each is H;

R₅is H, OH or OC₁-C₆An alkyl group;

R₈is OH or NH₂；

R₉Is H or OH; and is

X is-S-, -S (O) -or-SO₂-. In some embodiments, R₁And R₂Each independently is H or OH;

R₃、R₆and R₇Each is H;

R₄is OR_COr R_C；

R₅Is H, OH or OC₁-C₆An alkyl group;

R₈is OH or NH₂；

R₉Is H or OH; and is

X is-S-, -S (O) -or-SO₂-. In some embodiments, R₁And R₂Each independently is H or OH;

R₃、R₆and R₇Each is H;

R₄and R₅Each independently is H or OH;

R₈is OR_COr NHR_C；

R₉Is H or OH; and is

X is-S-, -S (O) -or-SO₂-. In some embodiments of these aspects, the antibody or antigen-binding fragment thereof is internalized by CD117+ cells.

In some embodiments, Am-L-Z-Ab is:

in some embodiments, Am-L-Z-Ab is:

in some embodiments of these aspects, the antibody or antigen-binding fragment thereof has a K below_dBinding to CD 117: less than 1 μ M, less than 750nM, less than 500nM, less than 250nM, less than 200nM, less than 150nM, less than 100nM, less than 75nM, less than 50nM, less than 10nM, less than 1nM, less than 0.1nM, less than 10pM, less than 1pM, or less than 0.1 pM. In some embodiments, K_dFrom about 0.1pM to about 1. mu.M.

In some embodiments of these aspects, the antibody or antigen-binding fragment thereof is from about 9x10^-2M^-1s^-1To about 1x10²M^-1s^-1K of (a)_onBinds to CD 117.

In some embodiments of these aspects, the antibody or antigen-binding fragment thereof competitively inhibits binding of CD117 to a second antibody or antigen-binding fragment thereof or binds to the same epitope as the second antibody, wherein the second antibody or antigen-binding fragment thereof has the following Complementarity Determining Regions (CDRs): CDR-H1 having the amino acid sequence SYWIG (SEQ ID NO: 1); CDR-H2 having amino acid sequence IIYPGDSDTRYSPSFQG (SEQ ID NO: 2); CDR-H3 having amino acid sequence HGRGYNGYEGAFDI (SEQ ID NO: 3); CDR-L1 having amino acid sequence RASQGISSALA (SEQ ID NO: 4);

CDR-L2 having the amino acid sequence DASSLES (SEQ ID NO: 5); and

CDR-L3 having amino acid sequence CQQFNSYPLT (SEQ ID NO: 6).

In some embodiments of these aspects, the antibody or antigen-binding fragment thereof competitively inhibits binding of CD117 to a second antibody or antigen-binding fragment thereof or binds to the same epitope as the second antibody, wherein the second antibody or antigen-binding fragment thereof has the following Complementarity Determining Regions (CDRs): CDR-H1 having the amino acid sequence set forth in SEQ ID NO. 11; CDR-H2 having the amino acid sequence set forth in SEQ ID NO. 12; CDR-H3 having the amino acid sequence set forth in SEQ ID NO. 13; CDR-L1 having the amino acid sequence set forth in SEQ ID NO. 14; CDR-L2 having the amino acid sequence set forth in SEQ ID NO. 15; and CDR-L3 having the amino acid sequence set forth in SEQ ID NO 16.

In one embodiment, the compositions and methods disclosed herein include an anti-CD 117 antibody Ab 67.

In one embodiment, the compositions and methods disclosed herein include an anti-CD 117 antibody comprising a variable heavy chain amino acid sequence as set forth in SEQ ID No.9, and a light chain variable region comprising a light chain amino acid sequence as set forth in SEQ ID No. 10.

In some embodiments of these aspects, the antibody or antigen-binding fragment thereof is selected from the group consisting of: monoclonal antibodies or antigen-binding fragments thereof, polyclonal antibodies or antigen-binding fragments thereof, humanized antibodies or antigen-binding fragments thereof, bispecific antibodies or antigen-binding fragments thereof, dual variable immunoglobulin domains, single chain Fv molecules (scFv), diabodies, triabodies, nanobodies, antibody-like protein scaffolds, Fv fragments, Fab fragments, F (ab')₂Molecules and tandem di-scfvs.

In another aspect, the invention features a conjugate represented by the formula Ab-Cy, wherein Ab is an antibody or antigen-binding fragment thereof that binds CD117 (e.g., GNNK + CD117), and Cy is a cytotoxin. In some embodiments of this aspect, the cytotoxin is pseudomonas exotoxin A, deBouganin, diphtheria toxin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicins, irinotecan, SN-38, duocarmycins, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolophenyldiazepines, or indolophenyldiazepine dimers, or a variant of any of the foregoing cytotoxins.

In some embodiments of this aspect, the antibody or antigen-binding fragment thereof is selected from the group consisting of: monoclonal antibodies or antigen-binding fragments thereof, polyclonal antibodies or antigen-binding fragments thereof, humanized antibodies or antigen-binding fragments thereof, bispecific antibodies or antigen-binding fragments thereof, dual variable immunoglobulin domains, single chain Fv molecules (scFv), diabodies, triabodies, nanobodies, antibody-like protein scaffolds, Fv fragments, Fab fragments, F (ab')₂Molecules and tandem di-scfvs. In some embodiments, the antibody has an isotype selected from the group consisting of: IgG, IgA, IgM, IgD and IgE.

In another aspect, the invention features an antibody or fragment thereof that binds CD117 (e.g., GNNK + CD117) covalently bound to an Fc domain, such as a dimeric Fc domain isolated from a human antibody (e.g., isolated from an IgG1, IgG2, IgG3, or IgG4 isotype human antibody). In some embodiments of this aspect, the Fc domain is a monomeric Fc domain comprising a single polypeptide chain. In some embodiments of this aspect, the N-terminus of the antibody or fragment thereof binds to an Fc domain. In some embodiments of this aspect, the C-terminus of the antibody or fragment thereof is bound to an Fc domain. The Fc domain may be conjugated to one or more copies of the antibody or fragment thereof. For example, the conjugates described herein include a dimeric Fc domain, wherein each polypeptide chain of the Fc domain is conjugated to an antibody or fragment thereof. The Fc domain, in turn, can be conjugated to a cytotoxin, such as a cytotoxin described herein (e.g., pseudomonas exotoxin A, deBouganin, diphtheria toxin, amanitins such as alpha-amanitin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicin, irinotecan, SN-38, duocarmycins, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolopendrazines, and indolopendrazine dimers, or variants thereof).

In some embodiments of this aspect, the antibody or fragment thereof is covalently bound to a cytotoxin, such as a cytotoxin described herein (e.g., pseudomonas exotoxin a, debaugenin, diphtheria toxin, amatoxin such as alpha-amatoxin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicin, irinotecan, SN-38, duocarmycin, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimer, indolopendrin, and indolopendrin dimer, or a variant thereof). In some embodiments of this aspect, the N-terminus of the antibody or fragment thereof is conjugated to a cytotoxin. In some embodiments of this aspect, the C-terminus of the antibody or fragment thereof is conjugated to a cytotoxin. The cytotoxin may then be conjugated to an Fc domain.

In some embodiments of this aspect, the antibody or fragment thereof is covalently bound to the cytotoxin at one site on the antibody or fragment thereof (e.g., the N-terminus or C-terminus of the antibody or fragment thereof) and covalently bound to the Fc domain at another site on the antibody or fragment thereof (e.g., the opposite end of the antibody or fragment thereof).

In some embodiments of this aspect, the Fc domain is a human IgG1 isotype Fc domain. In some embodiments of this aspect, the Fc domain is a human IgG2 isotype Fc domain. In some embodiments of this aspect, the Fc domain is a human IgG3 isotype Fc domain. In some embodiments of this aspect, the Fc domain is a human IgG4 isotype Fc domain.

In certain embodiments, the foregoing methods and compositions include an anti-CD 117 antibody or antigen-binding fragment thereof comprising the CDRs listed in the heavy and light chain amino acid sequences of any one of Ab54, Ab55, Ab56, Ab57, Ab58, Ab61, Ab66, Ab67, Ab68, or Ab69, listed in table 10. In certain embodiments, the foregoing methods and compositions include an anti-CD 117 antibody or antigen-binding fragment thereof comprising the variable regions listed in the heavy and light chain amino acid sequences of any one of Ab54, Ab55, Ab56, Ab57, Ab58, Ab61, Ab66, Ab67, Ab68, or Ab69 listed in table 10. In certain embodiments, the foregoing methods and compositions include an IgG1 anti-CD 117 antibody or antigen-binding fragment thereof comprising the variable regions listed in the heavy and light chain amino acid sequences of any one of Ab54, Ab55, Ab56, Ab57, Ab58, Ab61, Ab66, Ab67, Ab68, or Ab69 listed in table 10.

Brief Description of Drawings

FIG. 1 shows binding of the indicated purified IgG (sensor associated) to purified human CD117 ectodomain (R & D Systems #332-SR) at concentrations of 33.3nM and 11nM as measured by biolayer interferometry (BLI) over time.

Fig. 2A and 2B graphically depict the results of in vitro cell proliferation assays showing the dose-dependent effect of each of the indicated antibodies on Stem Cell Factor (SCF) -dependent proliferation of human CD34+ bone marrow cells. Depicted is the total viable cell count (FIG. 2A) or viable CD34+ CD90+ cell count (FIG. 2B) (y-axis) as determined by flow cytometry in the presence of 3100mAb, HC-67/LC-67 (i.e., Ab67) IgG or control as a function of the concentration (x-axis) of 3100mAb, HC-67/LC-67 (i.e., Ab67) IgG or control.

Fig. 3A and 3B graphically depict the results of in vitro cell killing assays showing the dose-dependent effect of each of the ADCs shown on the viability of human CD34+ bone marrow cells. The total viable cell count (FIG. 3A) or viable CD34+ CD90+ cell count (FIG. 3B) (y-axis) is plotted as a function of the concentration (x-axis) of HC-67/LC-67ADC (i.e., Ab67 ADC) or control in the presence of HC-67/LC-67ADC (i.e., Ab67 ADC) or control.

FIG. 4 shows binding of the indicated purified IgG (sensor associated) to purified human CD117 ectodomain (R & D Systems #332-SR) at concentrations of 33.3nM and 11nM as measured by biolayer interferometry (BLI) over time.

Fig. 5A and 5B graphically depict the results of in vitro cell proliferation assays showing the dose-dependent effect of each of the indicated antibodies on Stem Cell Factor (SCF) -dependent proliferation of human CD34+ bone marrow cells. The total viable cell count (FIG. 5A) or viable CD34+ CD90+ cell count (FIG. 5B) (y-axis) as determined by flow cytometry in the presence of 3100mAb, HC-55/LC-55IgG (Ab55 IgG) or control is depicted as a function of the concentration (x-axis) of 3100mAb, HC-55/LC-55IgG (Ab55 IgG) or control.

Fig. 6A and 6B graphically depict the results of in vitro cell killing assays showing the dose-dependent effect of each of the ADCs shown on the viability of human CD34+ bone marrow cells. The total viable cell count (FIG. 6A) or viable CD34+ CD90+ cell count (FIG. 6B) (y-axis) is plotted as a function of the concentration (x-axis) of HC-55/LC-55ADC (Ab55ADC) or control in the presence of HC-55/LC-55ADC (Ab55ADC) or control.

FIGS. 7A and 7B show binding of the purified IgG (sensor associated) shown to purified human CD117 ectodomain (R & D Systems #332-SR) at concentrations of 33.3nM and 11nM over time as measured by biolayer interferometry (BLI). The results for Ab54, Ab55, Ab56, Ab57, Ab68, and Ab61 are shown in fig. 7A. The results for Ab66, Ab67, Ab68, and Ab69 are shown in fig. 7B.

Fig. 8A and 8B graphically depict the results of an in vitro cell killing assay showing the variation of Kasumi-1 cell viability as measured by cellterglo in luminescence (RLU) with the indicated anti-CD 117ADC or control concentration. The results for Ab54, Ab55, Ab56, Ab57, Ab58, and Ab61 are shown in fig. 8A. The results for Ab66, Ab67, Ab68, and Ab69 are shown in fig. 8B.

Fig. 9 graphically depicts quantification of the area under the killing curve for the in vitro cell killing assay depicted in fig. 8A and 8B.

Fig. 10A and 10B graphically depict the results of in vitro cell proliferation assays showing the effect of each of the antibodies shown on Stem Cell Factor (SCF) -dependent proliferation of human CD34+ bone marrow cells. The total count of viable cells (y-axis) as a function of antibody concentration (x-axis) determined by flow cytometry in the presence of the indicated antibody or control (CK6) is depicted. The results for Ab54, Ab55, Ab56, Ab57, Ab58, and Ab61 are shown in fig. 10A. The results for Ab66, Ab67, Ab68, and Ab69 are shown in fig. 10B.

Fig. 11A and 11B graphically depict the results of in vitro cell proliferation assays showing the effect of each of the antibodies shown on Stem Cell Factor (SCF) -dependent proliferation of human CD34+ bone marrow cells. The viable CD34+ CD90+ cell count (y-axis) as determined by flow cytometry as a function of antibody concentration (x-axis) in the presence of the indicated antibody or control (CK6) is depicted. The results for Ab54, Ab55, Ab56, Ab57, Ab58, and Ab61 are shown in fig. 11A. The results for Ab66, Ab67, Ab68, and Ab69 are shown in fig. 11B.

Fig. 12 graphically depicts the results of an in vitro cross-blocking assay in which the binding (y-axis) of CK6 or human SCF to Ab55 or Ab67 associated CD117 was evaluated as a function of time (x-axis).

Figure 13A shows the binding of human or murine SCF to human CD117 extracellular domain as determined by BLI (y-axis) as a function of time (x-axis). Subsequently, as shown in fig. 13B, the in vitro cross-blocking assay showed changes in binding of human or murine SCF to Ab67 associated CD117 (y-axis) over time (x-axis).

Fig. 14A and 14B graphically depict the results of in vitro internalization assays. The percentage of surface CD117 on human bone marrow CD34+ cells was evaluated after 24 hours incubation with hIgG1, antagonist antibody, neutral antibody, or SCF (fig. 14A). The corresponding percentage of surface IgG was also evaluated as a function of time (fig. 14B).

Fig. 15A-15C graphically depict the results of in vitro cell killing assays of Ab67 ADC and Ab55ADC on Kasumi-1 cells (fig. 15A) or primary human stem cells (fig. 15B and 15C). FIG. 15A graphically depicts the results of an in vitro cell killing assay showing Kasumi-1 cell viability as measured by Celltiter Glo in luminescence (RLU) as a function of concentration of HC-55/LC-55ADC (Ab55ADC), HC-67/LC-67ADC (Ab67 ADC), or control. Fig. 15B and 15C graphically depict the results of an in vitro cell killing assay showing the dose-dependent effect of each of the ADCs shown on the viability of human CD34+ bone marrow cells in the presence of HC-55/LC-55ADC (Ab55ADC), HC-67/LC-67ADC (Ab67 ADC), or a control, based on the total viable cell count (fig. 15B) or the viable CD34+ CD90+ cell count (fig. 15C) (y-axis) as a function of antibody concentration (x-axis).

FIGS. 16A-16F depict chromatograms showing elution profiles of the indicated antibodies after 7 days (CK6 control (FIG. 16A), HC-55/LC-55(Ab 55; FIG. 16B) or HC-67/LC-67(Ab 67; FIG. 16C)) or after 15 days (CK6 control (FIG. 16D), HC-55/LC-55(Ab 55; FIG. 16E) or HC-67/LC-67(Ab 67; FIG. 16F)) under the indicated incubation conditions, as analyzed by hydrophobic interaction chromatography.

Fig. 17A and 17B graphically depict the results of in vitro cell killing assays showing the change in viable CD34+ CD90+ cell count as a function of Ab67(WT) -ADC (i.e., WT half-life) or Ab67(H435A) -ADC (i.e., rapid half-life).

Figure 18 depicts a graphical representation of an electropherogram showing the charge heterogeneity profile of the acidic variants present in the indicated antibodies under the indicated incubation conditions (x-axis) determined by capillary electrophoresis.

Fig. 19A and 19B graphically depict the results of in vivo cell depletion assays showing that Ab67(H435A) -ADC (i.e., fast half-life) or Ab67(WT) -ADC (i.e., WT half-life) at a dose of 0.1mg/kg selectively depletes human HSCs in humanized NSG mice. The absolute number of CD34+ cells in bone marrow of Ab67(H435A) -ADC, Ab67(WT) -ADC, or control-treated mice after a single administration of 0.03mg/kg, 0.1mg/kg, or 0.3mg/kg of ADC21 days is shown in fig. 19A. Also shown is the percentage of human bone marrow cells present in peripheral blood of Ab67(H435A) -ADC, Ab67(WT) -ADC, or control-treated mice for each condition, expressed as the percentage of this cell population before treatment (normalized to baseline) (fig. 19B).

Figure 20 graphically depicts the results of in vivo cell depletion assays showing that Ab67(H435A) -ADC (i.e., rapid half-life) at a single dose of 0.3mg/kg or a fractionated dose of 0.2mg/kg Q3Dx2 selectively depletes cynomolgus HSCs in cynomolgus monkeys. The absolute number (mean +/-SEM) of CD34+ CD90+ CD45RA- (phenotypic HSC) isolated from bone marrow of male cynomolgus monkeys dosed with the indicated dosing regimen is shown.

Fig. 21A and 21B depict multiple sequence alignments of the heavy chain variable region (VH; fig. 21A) and light chain variable region (LH; fig. 21B) of antagonistic antibodies Ab54, Ab55, Ab66, and Ab 67. The CDRs of each variable region are indicated.

FIGS. 22A and 22B depict multiple sequence alignments of the heavy chain variable region (VH; FIG. 22A) and the light chain variable region (LH; FIG. 22B) of neutral antibodies Ab58 and Ab 61. The CDRs of each variable region are indicated.

Fig. 23A and 23B depict multiple sequence alignments of the heavy chain variable region (VH; fig. 23A) and light chain variable region (LH; fig. 23B) of neutral antibodies Ab66, Ab67, Ab68, and Ab 69. The CDRs of each variable region are indicated.

Detailed Description

Described herein are isolated anti-CD 117 human antibodies that bind to human CD 117. The antibodies provided herein have a number of features that make them advantageous for therapy, including methods of modulating human patients to facilitate stem cell transplantation. For example, the antibodies disclosed herein cross-react with rhesus monkey CD117 and are capable of internalization. These two features also make them advantageous for use in conjugates for delivering cytotoxins to CD 117-expressing cells.

The antibodies described herein include both antagonistic and neutral antibodies. Specifically, provided herein are the following anti-CD 117 antibodies: antibody 54(Ab54), antibody 55(Ab55), antibody 56(Ab56), antibody 57(Ab57), antibody 58(Ab58), antibody 61(Ab61), antibody 66(Ab66), antibody 67(Ab67), antibody 68(Ab68), and antibody 69(Ab69), each of which is a human anti-CD 117 antibody that specifically binds to the extracellular domain of human CD 117. Binding regions for Ab54, Ab55, Ab56, Ab57, Ab58, Ab61, Ab66, Ab67, Ab68, and Ab69 are described below, including in table 10. The anti-CD 117 antibodies disclosed herein can be included in an anti-CD 117 antibody drug conjugate (ADC; also referred to herein as a conjugate).

The anti-CD 117 antibodies and conjugates described herein can be used in methods of treating a variety of disorders, such as diseases of cell types in the hematopoietic lineage, cancer, autoimmune diseases, metabolic disorders, and stem cell disorders, among others. The compositions and methods described herein can (i) directly deplete a population of pathology-causing cells, such as a population of cancer cells (e.g., leukemia cells) and autoimmune cells (e.g., autoreactive T cells), and/or (ii) deplete a population of endogenous hematopoietic stem cells, in order to facilitate engraftment of the transplanted hematopoietic stem cells by providing a niche into which the transplanted cells can home. The foregoing activity may be achieved by administering an ADC, antibody or antigen-binding fragment thereof capable of binding to an antigen (CD117) expressed by endogenous pathogenic cells or hematopoietic stem cells. In the case of direct treatment of the disease, this administration may cause a reduction in the number of cells that cause the pathology of interest. In the case of preparing a patient for hematopoietic stem cell transplantation therapy, this administration can result in the selective depletion of a population of endogenous hematopoietic stem cells, thereby creating a void in hematopoietic tissue, such as bone marrow, which can then be filled by transplanted exogenous hematopoietic stem cells. This selective depletion is also known as conditioning. The present invention is based in part on the following findings: ADCs, antibodies, or antigen-binding fragments thereof that are capable of binding to CD117 (such as GNNK + CD117) may be administered to a patient to achieve both activities or as a modulator. ADCs, antibodies, or antigen-binding fragments thereof that bind to CD117 may be administered to patients suffering from cancer, such as leukemia or autoimmune diseases, to directly deplete populations of cancerous cells or autoimmune cells, and may also be administered to patients in need of hematopoietic stem cell transplantation therapy to promote survival and engraftment potential of transplanted hematopoietic stem cells.

Engraftment of hematopoietic stem cell grafts can be manifested in a variety of empirical measurements as a result of administration of an anti-CD 117 antibody or antigen-binding fragment thereof. For example, engraftment of transplanted hematopoietic stem cells can be assessed by assessing the number of Competitive Repopulating Units (CRUs) present in the bone marrow of a patient following administration of an antibody or antigen-binding fragment thereof capable of binding CD117 and subsequent administration of a hematopoietic stem cell graft. In addition, one can observe engraftment of a hematopoietic stem cell graft by incorporating a reporter gene (such as an enzyme that catalyzes a chemical reaction that produces a fluorescent, chromogenic, or luminescent product) into a vector by which the donor hematopoietic stem cells are transfected, and then monitoring the corresponding signal in the tissue, such as bone marrow, into which the hematopoietic stem cells have home. One can also observe hematopoietic stem cell engraftment by assessing the number and survival of hematopoietic stem and progenitor cells, e.g., as determined by Fluorescence Activated Cell Sorting (FACS) analysis methods known in the art. Implantation may also be determined by measuring the white blood cell count in the peripheral blood during the post-transplant period, and/or by measuring the recovery of bone marrow cells by the donor cells in a sample of bone marrow aspirate.

The following section provides a description of conjugates, antibodies, or antigen-binding fragments thereof, which can be administered to a patient, such as a patient suffering from cancer or an autoimmune disease, or a patient in need of hematopoietic stem cell transplantation therapy, in order to facilitate the engraftment of a hematopoietic stem cell implant, as well as methods of administering such therapeutic agents to a patient (e.g., prior to hematopoietic stem cell transplantation).

Definition of

As used herein, the term "about" refers to a value within 10% above or below the value described. For example, the term "about 5 nM" refers to the range from 4.5nM to 5.5 nM.

As used herein, the term "amatoxin" refers to a member of the amanitin peptide family produced by the mushroom of Amanita pharioides (Amanita pharioides), or a variant or derivative thereof, such as a variant or derivative thereof capable of inhibiting RNA polymerase II activity. Amanitins useful for use in conjunction with the compositions and methods described herein include compounds according to, but not limited to, the following formula (III), including α -amanitin, β -amanitin, γ -amanitin, amanamide, amanitin nontoxic cyclic peptide, amanitin carboxylic acid, or amanitin nontoxic cyclic peptide. As described herein, amatoxin can be conjugated to an antibody or antigen-binding fragment thereof (thereby forming a conjugate (i.e., ADC)) through, for example, a linker moiety (L). Exemplary methods of amanitin conjugation and linkers useful in such processes are described below. Also described herein are exemplary linker-containing amatoxins useful for conjugation to antibodies or antigen-binding fragments according to the compositions and methods.

The formula (III) is as follows:

wherein R is₁Is H, OH OR OR_A；

R₂Is H, OH OR OR_B；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H or R_D；

R₄Is H, OH, OR_DOr R_D；

R₅Is H, OH, OR_DOr R_D；

R₆Is H, OH, OR_DOr R_D；

R₇Is H, OH, OR_DOr R_D；

R₈Is OH, NH₂OR OR_D；

R₉Is H, OH OR OR_D；

X is-S-, -S (O) -or-SO₂-; and is

R_DIs optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl.

For example, amanitins useful in combination with the compositions and methods described herein include compounds according to the following formula (IIIA):

wherein R is₁Is H, OH OR OR_A；

R₂Is H, OH OR OR_B；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H or R_D；

R₄Is H, OH, OR_DOr R_D；

R₅Is H, OH, OR_DOr R_D；

R₆Is H, OH, OR_DOr R_D；

R₇Is H, OH, OR_DOr R_D；

R₈Is OH, NH₂OR OR_D；

R₉Is H, OH OR OR_D；

X is-S-, -S (O) -or-SO₂-; and is

R_DIs optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl.

Amanitin useful in combination with the compositions and methods described herein also includes compounds according to the following formula (IIIB):

wherein R is₁Is H, OH OR OR_A；

R₂Is H, OH OR OR_B；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H or R_D；

R₄Is H, OH, OR_DOr R_D；

R₅Is H, OH, OR_DOr R_D；

R₆Is H, OH, OR_DOr R_D；

R₇Is H, OH, OR_DOr R_D；

R₈Is OH, NH₂OR OR_D；

R₉Is H, OH OR OR_D；

X is-S-, -S (O) -or-SO₂-; and is

R_DIs optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl.

As described herein, amatoxin can be conjugated to an antibody or antigen-binding fragment thereof (thereby forming a conjugate) through, for example, a linker moiety. Exemplary methods of amanitin conjugation and linkers useful in such processes are described in the section entitled "linkers for chemical conjugation" and in table 1 below. Exemplary linker-containing amatoxins useful for conjugation to antibodies or antigen-binding fragments according to the compositions and methods described herein are shown in structural formulae (I), (IA), (IB), (II), (IIA), and (IIB) recited herein.

As used herein, the term "antibody" refers to an immunoglobulin molecule that specifically binds to or is immunoreactive with a particular antigen and includes monoclonal, genetically engineered, and otherwise modified forms of antibodies, including but not limited to chimeric, humanized, heteroconjugate antibodies (e.g., bispecific, trispecific, and tetraspecific, diabody, triabody, and tetrabody) and antigen-binding fragments of antibodies, including, for example, Fab ', F (ab')₂Fab, Fv, rIgG and scFv fragments. Unless otherwise indicated, the term "monoclonal antibody" (mAb) is intended to include intact molecules as well as antibody fragments (including, e.g., Fab and F (ab')₂Fragments) are added. As used herein, Fab and F (ab')₂Fragments refer to antibody fragments lacking the Fc fragment of an intact antibody. Examples of such antibody fragments are described herein.

The antibodies of the invention are typically isolated or recombinant. "isolated", as used herein, refers to a polypeptide, such as an antibody, that has been identified and isolated and/or recovered from a cell or cell culture in which it is expressed. Typically, the isolated antibody will be prepared by at least one purification step. Thus, an "isolated antibody" refers to an antibody that is substantially free of other antibodies having different antigenic specificities. For example, an isolated antibody that specifically binds to CD117 is substantially free of antibodies that specifically bind to antigens other than CD 117.

As used herein, the term "antigen-binding fragment" refers to one or more fragments of an antibody that retain the ability to specifically bind to a target antigen. The antigen binding function of an antibody may be performed by fragments of a full-length antibody. The antibody fragment may be, for example, Fab, F (ab')₂scFv, diabody, triabody, affibody (affibody), nanobody, aptamer, or domain antibody. Included are the knots of the term "antigen-binding fragments" of an antibodyExamples of synthetic fragments include, but are not limited to: (i) fab fragment from V_L、V_H、C_LAnd C _H1 domain; (ii) f (ab')₂A fragment, a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) from V_HAnd C _H1 domain; (iv) v with one arm consisting of antibody_LAnd V_H(iv) an Fv fragment consisting of a domain, (V) comprising V_HAnd V_LA dAb of a domain; (vi) from V_HdAb fragments consisting of domains (see, e.g., Ward et al, Nature 341:544-546, 1989); (vii) from V_HOr V_LA domain constituting dAb; (viii) an isolated Complementarity Determining Region (CDR); and (ix) a combination of two or more (e.g., two, three, four, five, or six) isolated CDRs, which may optionally be joined by a synthetic linker. Furthermore, despite the two domains V of the Fv fragment_LAnd V_HEncoded by separate genes, but they can be joined using recombinant methods by linkers that enable them to be single protein chains, where V_LAnd V_HThe regions pair to form monovalent molecules (known as single chain fv (scFv); see, e.g., Bird et al, Science 242: 423-. These antibody fragments can be obtained using conventional techniques known to those skilled in the art, and these fragments can be screened for utility in the same manner as intact antibodies. Antigen-binding fragments can be produced by recombinant DNA techniques, enzymatic or chemical cleavage of intact immunoglobulins, or, in some cases, by chemical peptide synthesis procedures known in the art.

As used herein, the term "anti-CD 117 antibody" or "antibody that binds to CD 117" refers to an antibody that is capable of binding to CD117 with sufficient affinity such that the antibody is useful as a diagnostic and/or therapeutic agent targeting CD 117. The amino acid sequences of the two major isoforms of human CD117 are provided in SEQ ID NO 145 (isoform 1) and SEQ ID NO 146 (isoform 2).

The term "bispecific antibody" as used herein refers, for example, to a monoclonal antibody, typically a human or humanized antibody, which is capable of binding to at least two different antigens. For example, one binding specificity may be for the hematopoietic stem cell surface antigen CD117 (e.g., GNNK + CD117), and another may specifically bind a different hematopoietic stem cell surface antigen or another cell surface protein, such as a receptor or receptor subunit involved in, inter alia, a signal transduction pathway that enhances cell growth.

As used herein, the term "complementarity determining region" (CDR) refers to a hypervariable region found in both the light chain and heavy chain variable domains of an antibody. The more highly conserved portions of the variable domains are called Framework Regions (FR). The amino acid positions depicting the hypervariable regions of an antibody can vary according to the background and various definitions known in the art. Some positions within a variable domain may be considered mixed hypervariable positions in that these positions may be considered within a hypervariable region according to one set of criteria, while being considered outside the hypervariable region according to a different set of criteria. One or more of these positions may also be found in an extended hypervariable region. The antibodies described herein may contain modifications in these mixed hypervariable positions. The variable domains of native heavy and light chains each contain four framework regions, largely adopting a β -sheet configuration, connected by three CDRs, which form loops connecting, and in some cases forming part of, the β -sheet structure. The CDRs in each chain are in close proximity in the order FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4 through the framework regions and, together with the CDRs from the other antibody chains, contribute to the formation of the target binding site for the antibody (see Kabat et al, Sequences of Proteins of immunological Interest, National Institute of Health, Bethesda, MD., 1987). In certain embodiments, the numbering of immunoglobulin amino acid residues is according to the immunoglobulin amino acid residue numbering system of Kabat et al, unless otherwise indicated (although any antibody numbering scheme may be used, including but not limited to IMGT and Chothia).

As used herein, the terms "conditioning" and "conditioning" refer to the process by which a patient is prepared for receiving a transplant containing hematopoietic stem cells. Such procedures facilitate the engraftment of hematopoietic stem cell grafts (e.g., as inferred from a continuing increase in the number of hematopoietic stem cells that survive within a blood sample isolated from a patient following a conditioning procedure and subsequent hematopoietic stem cell transplantation). According to the methods described herein, a patient can be modulated for hematopoietic stem cell transplantation therapy by administering to the patient an ADC, antibody, or antigen-binding fragment thereof capable of binding to an antigen expressed by hematopoietic stem cells, such as CD117 (e.g., GNNK + CD 117). As described herein, an antibody can be covalently conjugated to a cytotoxin to form a drug-antibody conjugate. Administration of an ADC, antibody, antigen-binding fragment thereof, or drug-antibody conjugate capable of binding one or more of the foregoing antigens to a patient in need of hematopoietic stem cell transplantation therapy can facilitate the engraftment of a hematopoietic stem cell implant by, for example, selectively depleting endogenous hematopoietic stem cells to create a void filled by an exogenous hematopoietic stem cell graft.

As used herein, the term "conjugate" refers to a compound formed by chemically bonding a reactive functional group of one molecule (such as an antibody or antigen-binding fragment thereof) with an appropriate reactive functional group of another molecule (such as a cytotoxin described herein). The conjugate may comprise a linker between two molecules bound to each other. Examples of linkers that can be used to form conjugates include peptide-containing linkers, such as linkers containing naturally occurring or non-naturally occurring amino acids, such as D-amino acids. Linkers can be prepared using a variety of strategies described herein and known in the art. Depending on the reactive components therein, the linker may be cleaved as follows: for example, enzymatic hydrolysis, photolysis, hydrolysis under acidic conditions, hydrolysis under basic conditions, oxidation, disulfide reduction, nucleophilic cleavage, or organometallic cleavage (see, e.g., Lerich et al, bioorg. Med. chem.,20: 571-. Notably, the term "conjugate" (when referring to a compound) may also be interchangeably referred to herein as a "drug conjugate", "antibody drug conjugate" or "ADC".

As used herein, the term "coupling reaction" refers to a chemical reaction in which two or more substituents that are suitable for reacting with each other react to form a chemical moiety that links (e.g., covalently) the molecular fragments to which each substituent is bound. Coupling reactions include those in which a reactive substituent bound to a fragment that is a cytotoxin (such as a cytotoxin known in the art or described herein) is reacted with an appropriate reactive substituent bound to a fragment that is an antibody or antigen-binding fragment thereof (such as an antibody that binds CD117 (such as GNNK + CD117), antigen-binding fragment thereof, or a specific anti-CD 117 antibody known in the art or described herein). Examples of suitable reactive substituents include nucleophile/electrophile pairs (such as, inter alia, thiol/haloalkane pairs, amine/carbonyl pairs, or thiol/α, β -unsaturated carbonyl pairs), diene/dienophile pairs (such as, inter alia, azide/alkyne pairs), and the like. Coupling reactions include, but are not limited to, thiol alkylation, hydroxyl alkylation, amine condensation, amidation, esterification, disulfide formation, cycloaddition (e.g., [4+2] Diels-Alder cycloaddition, [3+2] Huisgen cycloaddition, among others), nucleophilic aromatic substitution, electrophilic aromatic substitution, and other reaction forms known in the art or described herein.

As used herein, "CRU (competitive reimplantation unit)" refers to a unit of measure of chronically implanted stem cells that can be detected after in vivo transplantation.

As used herein, the term "donor" refers to a human or animal from which cells are isolated prior to administration of one or more cells or their progeny to a recipient. The one or more cells may be, for example, a population of hematopoietic stem cells.

The term "diabody" as used herein refers to a bivalent antibody comprising two polypeptide chains, wherein each polypeptide chain comprises a V connected by a linker_HAnd V_L(ii) a domain whose linker is too short (e.g., a linker comprising five amino acids) to allow V on the same peptide chain_HAnd V_LIntramolecular association of domains. This configuration forces each domain to pair with a complementary domain on the other polypeptide chain to form a homodimeric structure. Accordingly, the term "trisomy" refers to a trivalent antibody comprising three peptide chains, each peptide chain comprising one V linked by a linker_HDomains and a V_L(ii) a domain which is,the linker is extremely short (e.g., a linker comprising 1-2 amino acids) and does not allow for V within the same peptide chain_HAnd V_LIntramolecular association of domains. Peptides configured in this manner are typically trimerized in order to fold into their native structure, so as to convert V of adjacent peptide chains_HAnd V_LThe domains are located in close spatial proximity to each other (see, e.g., Holliger et al, Proc. Natl. Acad. Sci. USA 90: 6444-.

As used herein, "drug-to-antibody ratio" or "DAR" refers to the number of drugs, e.g., amatoxin, attached to the antibody of the conjugate. The DAR of the ADC may range from 1 to 8, although higher loadings are also possible depending on the number of attachment sites on the antibody. In certain embodiments, the conjugate has a DAR of 1,2,3, 4, 5,6,7, or 8.

As used herein, "dual variable domain immunoglobulin" ("DVD-Ig") refers to the combination of target binding variable domains of two monoclonal antibodies via a linker to produce a tetravalent, dual-targeted single-dose antibody (see, e.g., Gu et al, meth.enzymol.,502:25-41,2012).

As used herein, the term "endogenous" describes a substance, such as a molecule, cell, tissue, or organ, that naturally occurs in a particular organism, such as a human patient (e.g., a hematopoietic stem cell or hematopoietic lineage cell, such as a megakaryocyte, thrombocyte, platelet, erythrocyte, mast cell, myeloblast, basophil, neutrophil, eosinophil, microglia, granulocyte, monocyte, osteoclast, antigen presenting cell, macrophage, dendritic cell, natural killer cell, T lymphocyte, or B lymphocyte).

As used herein, the term "engraftment potential" is used to refer to the ability of hematopoietic stem and progenitor cells to re-engraft tissue, whether such cells are naturally circulating or provided by transplantation. The term encompasses all events surrounding or resulting in implantation, such as tissue homing of cells and colonization of cells within the tissue of interest. The progression of the subject can be assessed or quantified using any clinically acceptable parameter known to those skilled in the art or by disease progression, survival of hematopoietic stem and progenitor cells or survival of the recipient, and the engraftment efficiency or engraftment rate can include, for example, assessing the incorporation or expression of Competitive Reimplantation Units (CRUs), markers in one or more tissues into which stem cells home, engraft or become engrafted (tissue (s)). Implantation can also be determined by measuring the white blood cell count in the peripheral blood during the post-transplant period. Engraftment can also be assessed by measuring the recovery of bone marrow cells by donor cells in a sample of bone marrow aspirate.

As used herein, the term "exogenous" describes a substance, such as a molecule, cell, tissue, or organ (e.g., a hematopoietic stem cell or hematopoietic lineage cell, such as a megakaryocyte, thrombocyte, platelet, erythrocyte, mast cell, myeloblast, basophil, neutrophil, eosinophil, microglia, granulocyte, monocyte, osteoclast, antigen presenting cell, macrophage, dendritic cell, natural killer cell, T lymphocyte, or B lymphocyte) that does not naturally occur in a particular organism, such as a human patient. Exogenous materials include those provided to the organism from an external source or cultured materials extracted from an external source.

As used herein, the terms "Fc," "Fc region," and "Fc domain" refer to the portion of an IgG antibody that is associated with a crystallizable fragment obtained by papain digestion of an IgG molecule. The Fc region comprises the C-terminal halves of the two heavy chains of an IgG molecule linked by disulfide bonds. It has no antigen binding activity, but contains a carbohydrate moiety and a binding site for complement and Fc receptors, including the FcRn receptor. The Fc region contained a second constant domain CH2 (e.g., residues at EU positions 231-340 of IgG 1) and a third constant domain CH3 (e.g., residues at EU positions 341-447 of human IgG 1). As used herein, the Fc region includes a "lower hinge region" (e.g., residues at EU positions 233 and 239 of IgG 1). Fc may refer to this region in isolation, or in an antibody, antibody fragment, or Fc fusion protein. Polymorphisms have been observed at a number of positions in the Fc domain, including but not limited to EU positions 270, 272, 312, 315, 356, and 358, and thus there may be minor differences between the sequences presented herein and those known in the art. Thus, a "wild-type IgG Fc domain" or a "WT IgG Fc domain" refers to any naturally occurring IgG Fc region (i.e., any allele). The sequences of the heavy chains of HUMAN IgG1, IgG2, IgG3 and IgG4 can be found in many sequence databases, for example, in the Uniprot database (www.uniprot.org), under accession numbers P01857(IGHG1_ HUMAN), P01859(IGHG2_ HUMAN), P01860(IGHG3_ HUMAN) and P01861(IGHG1_ HUMAN), respectively. An example of a "WT" Fc region is provided in SEQ ID NO:122 (which provides a heavy chain constant region comprising an Fc region).

The term "modified Fc region" or "variant Fc region" as used herein refers to an IgG Fc domain comprising one or more amino acid substitutions, deletions, insertions, or modifications introduced at any position within the Fc region.

The terms "full-length antibody" and "intact antibody" are used interchangeably herein to refer to an antibody in its substantially intact form, rather than an antibody fragment as defined herein. Thus, for an IgG antibody, a complete antibody comprises two heavy chains, each heavy chain comprising a variable region, a constant region, and an Fc region, and two light chains, each light chain comprising a variable region and a constant region. More specifically, a complete IgG comprises two light chains, each light chain comprising a light chain variable region (VL) and a light chain constant region (CL), and two heavy chains, each heavy chain comprising a heavy chain variable region (VH) and three heavy chain constant regions (CH1, CH2, and CH 3). CH2 and CH3 represent the Fc region of the heavy chain.

As used herein, the term "framework region" or "FW region" includes amino acid residues adjacent to the CDRs of an antibody or antigen-binding fragment thereof. The FW region residues may be present, for example, in, inter alia, human antibodies, humanized antibodies, monoclonal antibodies, antibody fragments, Fab fragments, single chain antibody fragments, scFv fragments, antibody domains and bispecific antibodies.

As used herein, the term "hematopoietic stem cell" ("HSC") refers to immature blood cells that have the ability to self-renew and differentiate into mature blood cells containing cells of different lineages, including but not limited to cells of the lineageRestricted to granulocytes (e.g., promyelocytes, neutrophils, eosinophils, basophils), erythrocytes (e.g., reticulocytes, erythrocytes), thrombocytes (e.g., promegakaryocytes, platelet-producing megakaryocytes, platelets), monocytes (e.g., monocytes, macrophages), dendritic cells, microglia, osteoclasts, and lymphocytes (e.g., NK cells, B cells, and T cells). Such cells may include CD34⁺A cell. CD34⁺The cells are immature cells expressing CD34 cell surface markers. In humans, CD34+ cells are considered to comprise a subpopulation of cells having the above defined stem cell characteristics, whereas in mice, HSCs are CD 34-. In addition, HSC also refers to long term reconstituted HSCs (LT-HSCs) and short term reconstituted HSCs (ST-HSCs). LT-HSC and ST-HSC are differentiated based on functional potential and cell surface marker expression. For example, human HSCs are CD34+, CD38-, CD45RA-, CD90+, CD49F +, and lin- (negative for mature lineage markers (including CD2, CD3, CD4, CD7, CD8, CD10, CD11B, CD19, CD20, CD56, CD 235A)). In mice, bone marrow LT-HSCs are CD34-, SCA-1+, C-kit +, CD135-, Slamfl/CD150+, CD48-, and lin- (negative for mature lineage markers (including Ter119, CD11B, Gr1, CD3, CD4, CD8, B220, IL7 ra)), while ST-HSCs are CD34+, SCA-1+, C-kit +, CD135-, Slamfl/CD150+, and lin- (negative for mature lineage markers (including Ter119, CD11B, Gr1, CD3, CD4, CD8, B220, IL7 ra)). In addition, ST-HSCs are less quiescent and proliferate more than LT-HSCs under homeostatic conditions. However, LT-HSCs have greater self-renewal potential (i.e., they survive throughout adulthood and can be transplanted continuously by continuous recipients), whereas ST-HSCs have limited self-renewal (i.e., they survive only for a limited period of time and do not have continuous transplantation potential). Any of these HSCs can be used in the methods described herein. ST-HSCs are particularly useful because they are highly proliferative and therefore can produce differentiated progeny more quickly.

As used herein, the term "hematopoietic stem cell functional potential" refers to a functional characteristic of a hematopoietic stem cell that includes 1) pluripotency (which refers to the ability to differentiate into a variety of different blood lineage cells including, but not limited to, granulocytes (e.g., promyelocytes, neutrophils, eosinophils, basophils), erythrocytes (e.g., reticulocytes, erythrocytes), thrombocytes (e.g., promegakaryocytes, platelet-producing megakaryocytes, platelets), monocytes (e.g., monocytes, macrophages), dendritic cells, microglia, osteoclasts, and lymphocytes (e.g., NK cells, B cells, and T cells)), 2) self-renewal (which refers to the ability of a hematopoietic stem cell to produce daughter cells with equivalent potential as the mother cell, and further this ability can occur repeatedly without failure throughout the life of the individual), and 3) the ability of hematopoietic stem cells or their progeny to be reintroduced into the transplant recipient, at which time they home to the hematopoietic stem cell niche and reconstitute productive and sustained hematopoiesis.

As used herein, the term "human antibody" is intended to include antibodies having variable and constant regions derived from human germline immunoglobulin sequences. Human antibodies can include amino acid residues that are not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random mutation or site-specific mutagenesis in vitro or during gene rearrangement or by somatic mutation in vivo). However, the term "human antibody" as used herein is not intended to include such antibodies: wherein CDR sequences derived from the germline of another mammalian species (such as a mouse) have been grafted onto human framework sequences. Human antibodies can be produced in human cells (e.g., by recombinant expression) or from non-human animals or prokaryotic or eukaryotic cells capable of expressing functionally rearranged human immunoglobulin (such as heavy and/or light chain) genes. When the human antibody is a single chain antibody, it may include a linker peptide that is not present in the native human antibody. For example, the Fv can contain a linker peptide, such as two to about eight glycine or other amino acid residues, that links the variable region of the heavy chain and the variable region of the light chain. Such linker peptides are considered to be of human origin. Human antibodies can be prepared by a variety of methods known in the art, including phage display methods using antibody libraries derived from human immunoglobulin sequences. Human antibodies can also be produced using transgenic mice that do not express functional endogenous immunoglobulins but can express human immunoglobulin genes (see, e.g., PCT publication Nos. WO 1998/24893; WO 1992/01047; WO 1996/34096; WO 1996/33735; U.S. Pat. No. 5,413,923; 5,625,126; 5,633,425; 5,569,825; 5,661,016; 5,545,806; 5,814,318; 5,885,793; 5,916,771; and 5,939,598).

"humanized" antibodies refer to antibodies that contain minimal sequence derived from non-human immunoglobulins. Thus, a "humanized" form of a non-human (e.g., murine) antibody is a chimeric antibody that contains minimal sequence derived from the non-human antibody. All or substantially all of the FW regions may also be those having human immunoglobulin sequences. The humanized antibody may also contain at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin consensus sequence. Methods for humanizing antibodies are known in the art and have been described, for example, in Riechmann et al, Nature 332: 323-E7, 1988; U.S. Pat. nos. 5,530,101; U.S. Pat. No. 5,585,089; nos. 5,693,761; nos. 5,693,762; and U.S. Pat. No. 6,180,370.

As used herein, patients "in need of" a hematopoietic stem cell graft include patients exhibiting a deficiency or deficiency in one or more blood cell types, as well as patients suffering from stem cell disorders, autoimmune diseases, cancer, or other pathologies described herein. Hematopoietic stem cells typically exhibit: 1) multipotent and thus can differentiate into a variety of different blood lineage cells, including but not limited to granulocytes (e.g., promyelocytes, neutrophils, eosinophils, basophils), erythrocytes (e.g., reticulocytes, erythrocytes), thrombocytes (e.g., promegakaryocytes, platelet-producing megakaryocytes, platelets), monocytes (e.g., monocytes, macrophages), dendritic cells, microglia, osteoclasts, and lymphocytes (e.g., NK cells, B cells, and T cells), 2) self-renewal and thus can generate daughter cells with equivalent potential to the mother cell, and 3) the ability to be reintroduced into the transplant recipient, at which time they home to the hematopoietic stem cell niche and reconstitute productive and sustained hematopoiesis. Thus, hematopoietic stem cells can be administered to a patient deficient or defective in one or more cell types of cells of the hematopoietic lineage in order to reconstitute a population of defective or deficient cells in vivo. For example, a patient may suffer from cancer, and the deficiency may be caused by administration of chemotherapeutic agents or other drugs that selectively or non-specifically deplete the population of cancerous cells. Additionally or alternatively, the patient may suffer from a hemoglobin abnormality (e.g., a non-malignant hemoglobin abnormality), such as sickle cell anemia, thalassemia, fanconi's anemia, aplastic anemia, and wiskott-aldrich syndrome. The subject may be a subject suffering from: adenosine deaminase severe combined immunodeficiency disease (ADA SCID), HIV/AIDS, metachromatic leukodystrophy, Diamond-Blackfan anemia, and Schwachman-Diamond syndrome. The subject may have or be affected by: hereditary blood disorders (e.g., sickle cell anemia) or autoimmune disorders. Additionally or alternatively, the subject may have or be affected by: malignant tumors, such as neuroblastoma or hematological cancers. For example, the subject may have leukemia, lymphoma, or myeloma. In some embodiments, the subject has acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia, chronic lymphoid leukemia, multiple myeloma, diffuse large B-cell lymphoma, or non-hodgkin's lymphoma. In some embodiments, the subject has myelodysplastic syndrome. In some embodiments, the subject has an autoimmune disease, such as scleroderma, multiple sclerosis, ulcerative colitis, crohn's disease, type 1diabetes, or another autoimmune pathology described herein. In some embodiments, the subject is in need of chimeric antigen receptor T Cell (CART) therapy. In some embodiments, the subject has or is otherwise affected by a metabolic storage disorder. The subject may suffer from or otherwise be affected by a metabolic disorder selected from the group consisting of: glycogen storage disease, mucopolysaccharide storage disease, gaucher's disease, Heller disease, sphingolipid storage disease, metachromatic leukodystrophy, or any other Disease or disorder that may benefit from the treatments and therapies disclosed herein, including, but not limited to, severe combined immunodeficiency Disease, Wiscott-Aldrich syndrome, hyper-immunoglobulin M (IgM) syndrome, Cheers' Disease, hereditary lymphohistiocytosis, osteopetrosis, osteogenesis imperfecta, storage Disease, thalassemia major, sickle cell Disease, systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, juvenile rheumatoid arthritis, and those described in "Bone Marrow transplantation for Non-Maligrant Disease," ASH Edutation Book,1:319-338(2000) ", the disclosure of which is incorporated herein by reference in its entirety as it relates to pathologies that can be treated by administration of hematopoietic stem cell transplantation therapy. Additionally or alternatively, a patient "in need of" a hematopoietic stem cell graft may be a patient who has or has not suffered one of the aforementioned pathologies but still exhibits: reduced levels of one or more endogenous cell types within the hematopoietic lineage (e.g., compared to levels in other healthy subjects), such as megakaryocytes, thrombocytes, platelets, erythrocytes, mast cells, myeloblasts, basophils, neutrophils, eosinophils, microglia, granulocytes, monocytes, osteoclasts, antigen presenting cells, macrophages, dendritic cells, natural killer cells, T lymphocytes, and B lymphocytes. For example, one skilled in the art can readily determine whether the levels of one or more of the foregoing cell types or other blood cell types are reduced in a person relative to other healthy subjects by, among other procedures, flow cytometry and Fluorescence Activated Cell Sorting (FACS) methods known in the art.

As used herein, the term "monoclonal antibody" refers to an antibody derived from a single clone, including any eukaryotic, prokaryotic, or phage clone, rather than the method by which it is produced.

As used herein, "neutral antibody" refers to an antibody or antigen-binding fragment thereof that does not significantly neutralize, block, inhibit, eliminate, reduce, or interfere with the activity of a specific or specific target (e.g., CD117), including binding of a receptor to a ligand or interaction of an enzyme with a substrate. In one embodiment, the neutral anti-CD 117 antibody or fragment thereof is an anti-CD 117 antibody that does not substantially inhibit SCF-dependent cell proliferation and does not cross-block binding of SCF to CD 117. An example of a neutral antibody is Ab67 (or an antibody having a binding region of Ab 67). In contrast, "antagonist" anti-CD 117 antibodies inhibit SCF-dependent proliferation and are capable of cross-blocking SCF binding to CD 117. An example of an antagonistic antibody is Ab55 (or an antibody with a binding region for Ab 55).

As used herein, the term "recipient" refers to a patient who receives a transplant, such as a transplant containing a population of hematopoietic stem cells. The transplanted cells administered to the recipient may be, for example, autologous cells, syngeneic cells, or allogeneic cells.

As used herein, the term "sample" refers to a sample (e.g., blood components (e.g., serum or plasma), urine, saliva, amniotic fluid, cerebrospinal fluid, tissue (e.g., placenta or dermis), pancreatic juice, chorionic villus sample, and cells) taken from a subject.

As used herein, the term "scFv" refers to a single chain Fv antibody in which the variable domains from the heavy and light chains of the antibody have joined to form one chain. scFv fragments comprise a single polypeptide chain comprising the variable region of the antibody light chain (V) separated by a linker_L) (e.g., CDR-L1, CDR-L2 and/or CDR-L3) and antibody heavy chain variable region (V)_H) (e.g., CDR-H1, CDR-H2, and/or CDR-H3). V linking scFv fragments_LAnd V_HThe linker of the region may be a peptide linker comprising proteinogenic (proteinogenic) amino acids. Alternative linkers may be used to increase the resistance of the scFv fragment to proteolytic degradation (e.g., linkers containing D-amino acids) to enhance the solubility of the scFv fragment (e.g., hydrophilic linkers such as linkers containing polyethylene glycol or polypeptides containing repeating glycine and serine residues) to improve the molecular propertiesBiophysical stability (e.g., a linker containing cysteine residues that form intramolecular or intermolecular disulfide bonds), or to reduce the immunogenicity of the scFv fragment (e.g., a linker containing glycosylation sites). It will also be appreciated by those of ordinary skill in the art that the variable regions of the scFv molecules described herein may be modified such that their amino acid sequences differ from the amino acid sequence of the antibody molecule from which they are derived. For example, nucleotide or amino acid substitutions that result in conservative substitutions or changes may be made at amino acid residues (e.g., in CDRs and/or framework residues) in order to retain or enhance the ability of an scFv to bind to an antigen recognized by a corresponding antibody.

As used herein, the term "specific binding" or "specifically binds" refers to the ability of an antibody to recognize and bind to a particular protein structure (epitope) rather than to broadly recognize and bind to a protein. If the antibody is specific for epitope "A", then in the reaction of labeled "A" with the antibody, the presence of the molecule containing epitope A (or free, unlabeled A) will reduce the amount of labeled A bound to the antibody. For example, an antibody "specifically binds" to a target if, when labeled, the antibody can compete away from its target by a corresponding unlabeled antibody. In one embodiment, if the antibody is directed against a target such as CD117, it has at least about 10^-4M、10^-5M、10^-6M、10^-7M、10^-8M、10^-9M、10^-10M、10^-11M、10^-12M or less (less means less than 10)^-12Number of (2), e.g. 10^-13) K of_DThe antibody then binds specifically to the target. In one embodiment, as used herein, the term "specifically binds to CD 117" or "specifically binds to CD 117" refers to an antibody or antibody fragment that binds to CD117 and has 1.0x10^-7Dissociation constant (K) of M or less_D) As determined by surface plasmon resonance. In one embodiment, K_D(M) is determined according to standard biolayer interferometry (BLI). In one embodiment, K_off(1/s) determined according to standard biolayer interferometry (BLI). It is understood, however, that antibodies may be capable ofCapable of specifically binding to two or more antigens associated with the sequences. For example, in one embodiment, the antibody can specifically bind to both human and non-human (e.g., mouse or non-human primate) orthologs of CD 117.

As used herein, the terms "subject" and "patient" refer to an organism, such as a human, that receives treatment for a particular disease or condition as described herein. For example, a patient, such as a human patient, may be treated prior to hematopoietic stem cell transplantation therapy in order to facilitate the engraftment of exogenous hematopoietic stem cells.

As used herein, the phrase "substantially cleared from the blood" refers to a point in time after administration of a therapeutic agent (such as an anti-CD 117 antibody or antigen-binding fragment thereof) to a patient at which the concentration of the therapeutic agent in a blood sample isolated from the patient is such that the therapeutic agent cannot be detected by conventional means (e.g., such that the therapeutic agent cannot be detected above a noise threshold of a device or assay used to detect the therapeutic agent). A variety of techniques known in the art can be used to detect the antibody or antibody fragment, such as ELISA-based detection assays known in the art or described herein. Additional assays that can be used to detect antibodies or antibody fragments include, inter alia, immunoprecipitation techniques and immunoblotting assays known in the art.

As used herein, the phrase "stem cell disorder" broadly refers to any disease, disorder or condition that can be treated or cured by modulating a target tissue of a subject and/or by ablating an endogenous stem cell population in the target tissue (e.g., ablating an endogenous hematopoietic stem cell or progenitor cell population from a bone marrow tissue of the subject) and/or by implanting or transplanting stem cells in the target tissue of the subject. For example, type 1diabetes has been shown to be cured by hematopoietic stem cell transplants and may benefit from modulation according to the compositions and methods described herein. Additional disorders that may be treated using the compositions and methods described herein include, but are not limited to, sickle cell anemia, thalassemia, fanconi's anemia, aplastic anemia, wiskott-aldrich syndrome, ADA SCID, HIV/AIDS, metachromatic leukodystrophy, Diamond-Blackfan anemia, and Schwachman-Diamond syndrome. Additional diseases that may be treated using the patient-regulated and/or hematopoietic stem cell graft methods described herein include genetic blood disorders (e.g., sickle cell anemia) and autoimmune disorders, such as scleroderma, multiple sclerosis, ulcerative colitis, and crohn's disease. Additional diseases that may be treated using the modulation and/or transplantation methods described herein include malignancies, such as neuroblastoma or hematological cancers, such as leukemia, lymphoma and myeloma. For example, the cancer may be acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia, chronic lymphoid leukemia, multiple myeloma, diffuse large B-cell lymphoma or non-hodgkin's lymphoma. Additional diseases treatable using the modulation and/or transplantation methods described herein include myelodysplastic syndrome. In some embodiments, the subject has or is otherwise affected by a metabolic storage disorder. For example, the subject may suffer from or otherwise be affected by a metabolic disorder selected from the group consisting of: glycogen storage disease, mucopolysaccharide storage disease, gaucher's disease, Heller disease, sphingolipid storage disease, metachromatic leukodystrophy, or any other Disease or disorder that may benefit from the treatments and therapies disclosed herein, and which include, but are not limited to, severe combined immunodeficiency Disease, Wiscott-Aldrich syndrome, hyper-immunoglobulin M (IgM) syndrome, Cheers' Disease, hereditary lymphocytosis, osteopetrosis, osteogenesis imperfecta, storage Disease, severe thalassemia, sickle cell Disease, systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, juvenile rheumatoid arthritis, and those described in "Bone Marrowtransplantation for Non-Malignant Disease," ASH efficacy Book,1:319-, the disclosure of which is incorporated herein by reference in its entirety as it relates to pathologies that can be treated by administration of hematopoietic stem cell transplantation therapy.

As used herein, the term "transfection" refers to any of a variety of techniques commonly used to introduce foreign DNA into prokaryotic or eukaryotic host cells, such as electroporation, lipofection, calcium phosphate precipitation, DEAE-dextran transfection, and the like.

As used herein, the term "treatment" or "treatment" refers to reducing the severity and/or frequency of disease symptoms, eliminating disease symptoms and/or underlying causes of the symptoms, reducing the frequency or likelihood of disease symptoms and/or underlying causes thereof, and improving or remedying damage caused directly or indirectly by disease. Beneficial or desired clinical results include, but are not limited to, facilitating the engraftment of exogenous hematopoietic cells in a patient following antibody-modulating therapy and subsequent hematopoietic stem cell transplantation therapy as described herein. Additional beneficial results include an increase in the cell count or relative concentration of hematopoietic stem cells in a patient in need of hematopoietic stem cell transplantation following regulatory therapy and subsequent administration of an exogenous hematopoietic stem cell implant to the patient. Beneficial results of the therapies described herein may also include an increase in cell count or relative concentration of one or more of hematopoietic lineage cells, such as megakaryocytes, thrombocytes, platelets, erythrocytes, mast cells, myeloblasts, basophils, neutrophils, eosinophils, microglia, granulocytes, monocytes, osteoclasts, antigen presenting cells, macrophages, dendritic cells, natural killer cells, T lymphocytes, or B lymphocytes, following the regulatory therapy and subsequent hematopoietic stem cell transplantation therapy. Additional beneficial results may include a reduction in the number of pathogenic cell populations, such as populations of cancer cells (e.g., CD117+ leukemia cells) or autoimmune cells (e.g., CD117+ autoimmune lymphocytes, such as CD117+ T cells that express T cell receptors that cross-react with self-antigens). To the extent that the methods of the invention are directed to preventing a disorder, it is understood that the term "preventing" does not require that the disorder state be completely prevented. Rather, as used herein, the term prophylaxis refers to the ability of the skilled person to identify a population susceptible to a disorder such that administration of a compound of the invention can be performed prior to onset of the disease. The term does not imply that the disease state is completely avoided.

As used herein, the terms "variant" and "derivative" are used interchangeably and refer to naturally occurring, synthetic and semi-synthetic analogs of the compounds, peptides, proteins or other substances described herein. Variants or derivatives of the compounds, peptides, proteins, or other substances described herein may retain or improve the biological activity of the original material.

As used herein, the term "vector" includes nucleic acid vectors, such as plasmids, DNA vectors, plasmids, RNA vectors, viruses, or other suitable replicons. The expression vectors described herein may contain polynucleotide sequences as well as additional sequence elements, e.g., for expressing proteins and/or integrating these polynucleotide sequences into the genome of a mammalian cell. Some vectors that may be used to express the antibodies and antibody fragments of the invention include plasmids containing regulatory sequences (such as promoter and enhancer regions) that direct the transcription of genes. Other useful vectors for expressing antibodies and antibody fragments contain polynucleotide sequences that enhance the rate of translation of these genes or improve the stability or nuclear export of mRNA produced by gene transcription. These sequence elements may include, for example, 5 'and 3' untranslated regions and polyadenylation signal sites to direct the efficient transcription of genes carried on expression vectors. The expression vectors described herein may also contain polynucleotides encoding markers for selecting cells containing such vectors. Examples of suitable markers include genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, kanamycin, and nourseothricin.

The term "acyl" as used herein refers to-C (═ O) R, where R is hydrogen ("aldehyde"), alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heteroaryl, or heterocyclyl, as defined herein. Non-limiting examples include formyl, acetyl, propionyl, benzoyl and acryloyl.

As used herein, the term "alkyl" refers to a straight or branched chain alkyl group having, for example, from 1 to 20 carbon atoms in the chain. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, tert-pentyl, hexyl, isohexyl, and the like.

As used herein, the term "alkylene" refers to a straight or branched chain divalent alkyl group. The divalent sites may be on the same or different atoms within the alkyl chain. Examples of alkylene groups include methylene, ethylene, propylene, isopropylene, and the like.

As used herein, the term "heteroalkyl" refers to a straight or branched alkyl group having, for example, from 1 to 20 carbon atoms in the chain and also containing one or more heteroatoms (e.g., oxygen, nitrogen, or sulfur atoms, among others) in the chain.

As used herein, the term "heteroalkylene" refers to a straight or branched chain divalent heteroalkyl group. The divalent sites may be on the same or different atoms within the heteroalkyl chain. The divalent position may be one or more heteroatoms.

As used herein, the term "alkenyl" refers to a straight or branched chain alkenyl group having, for example, from 2 to 20 carbon atoms in the chain. Examples of alkenyl groups include ethenyl, propenyl, isopropenyl, butenyl, tert-butenyl, hexenyl, and the like.

As used herein, the term "alkenylene" refers to a straight or branched chain divalent alkenyl group. The divalent positions may be on the same or different atoms within the alkenyl chain. Examples of alkenylene include vinylene, propenylene, isopropenylene, butenylene, and the like.

As used herein, the term "heteroalkenyl" refers to a straight or branched chain alkenyl group having, for example, from 2 to 20 carbon atoms in the chain and also containing one or more heteroatoms (such as, inter alia, oxygen, nitrogen, or sulfur atoms) in the chain.

As used herein, the term "heteroalkenylene" refers to a straight or branched divalent heteroalkenylgroup. The divalent positions may be on the same or different atoms within the heteroalkenyl chain. The divalent position may be one or more heteroatoms.

As used herein, the term "alkynyl" refers to straight or branched chain alkynyl groups having, for example, from 2 to 20 carbon atoms in the chain. Examples of alkynyl groups include propargyl, butynyl, pentynyl, hexynyl, and the like.

As used herein, the term "alkynylene" refers to a straight or branched chain divalent alkynyl group. The divalent positions may be on the same or different atoms within the alkynyl chain.

As used herein, the term "heteroalkynyl" refers to a straight or branched chain alkynyl group having, for example, from 2 to 20 carbon atoms in the chain and also containing one or more heteroatoms (such as, inter alia, oxygen, nitrogen or sulfur atoms) in the chain.

As used herein, the term "heteroalkynylene" refers to a straight or branched chain divalent heteroalkynyl group. The divalent positions may be on the same or different atoms within the heteroalkynyl chain. The divalent position may be one or more heteroatoms.

As used herein, the term "cycloalkyl" refers to a monocyclic, or fused, bridged, or spiro polycyclic ring structure that is saturated and has, for example, from 3 to 12 carbon ring atoms. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicyclo [3.1.0] hexane, and the like.

As used herein, the term "cycloalkylene" refers to a divalent cycloalkyl group. The divalent positions may be on the same or different atoms within the ring structure. Examples of cycloalkylene include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, and the like.

As used herein, the term "heterocycloalkyl" refers to a monocyclic ring, or a fused, bridged or spiro polycyclic ring structure, which is saturated and has, for example, from 3 to 12 ring atoms per ring structure, selected from carbon atoms and heteroatoms, such as, inter alia, nitrogen atoms, oxygen atoms and sulfur atoms. The ring structure may contain one or more oxo groups, for example on a carbon, nitrogen or sulphur ring member. Examples of heterocycloalkyl groups include, by way of example and not limitation, dihydropyridinyl, tetrahydropyridinyl (piperidinyl), tetrahydrothienyl, piperidinyl, 4-piperidinonyl, pyrrolidinyl, 2-pyrrolidinonyl, tetrahydrofuranyl, tetrahydropyranyl, bistetrahydropyranyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, octahydroisoquinolinyl, piperazinyl, quinuclidinyl, and morpholinyl.

As used herein, the term "heterocycloalkylene" refers to a divalent heterocycloalkyl group. The divalent positions may be on the same or different atoms within the ring structure.

As used herein, the term "aryl" refers to a monocyclic or polycyclic aromatic ring system containing, for example, from 6 to 19 carbon atoms. Aryl groups include, but are not limited to, phenyl, fluorenyl, naphthyl, and the like. The divalent position may be one or more heteroatoms.

As used herein, the term "arylene" refers to a divalent aryl group. The divalent positions may be on the same or different atoms.

As used herein, the term "heteroaryl" refers to a monocyclic heteroaryl, or a bicyclic or tricyclic fused ring heteroaryl, wherein one or more ring atoms is a heteroatom, such as nitrogen, oxygen, or sulfur. Heteroaryl groups include pyridyl, pyrrolyl, furyl, thienyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, 1,2, 3-triazolyl, 1,2, 4-triazolyl, 1,2, 3-oxadiazolyl, 1,2, 4-oxadiazolyl, 1,2, 5-oxadiazolyl, 1,3, 4-triazinyl, 1,2, 3-triazinyl, benzofuranyl, [2, 3-dihydro ] benzofuranyl, isobenzofuranyl, benzothienyl, benzotriazolyl, isobenzothienyl, indolyl, isoindolyl, 3H-indolyl, benzimidazolyl, imidazo [1,2-a ] pyridyl, benzothiazolyl, benzoxazolyl, quinolizinyl, quinazolinyl, pyrazolyl, 1,2, 4-triazinyl, 1-triazinyl, and the like, Phthalazinyl, quinoxalinyl, cinnolinyl, naphthyridinyl, pyrido [3,4-b ] pyridyl, pyrido [3,2-b ] pyridyl, pyrido [4,3-b ] pyridyl, quinolyl, isoquinolyl, tetrazolyl, 5,6,7, 8-tetrahydroquinolyl, 5,6,7, 8-tetrahydroisoquinolyl, purinyl, pteridinyl, carbazolyl, xanthenyl, benzoquinolyl and the like.

As used herein, the term "heteroarylene" refers to a divalent heteroaryl group. The divalent positions may be on the same or different atoms. The divalent position may be one or more heteroatoms.

Unless otherwise limited by the definition of individual substituents, the foregoing chemical moietiesFor example, a group such as "alkyl", "alkylene", "heteroalkyl", "heteroalkylene", "alkenyl", "alkenylene", "heteroalkenylene", "alkynyl", "alkynylene", "heteroalkynyl", "heterocycloalkylene", "cycloalkylene", "heterocycloalkyl", "heterocycloalkylene", "aryl", "arylene", "heteroaryl", and "heteroarylene" may be optionally substituted, for example, with from 1 to 5 substituents selected from the group consisting of: alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkylaryl, alkylheteroaryl, alkylcycloalkyl, alkylheterocycloalkyl, amino, ammonium, acyl, acyloxy, acylamino, aminocarbonyl, alkoxycarbonyl, ureido, carbamate, aryl, heteroaryl, sulfinyl, sulfonyl, alkoxy, sulfanyl, halogen, carboxyl, trihalomethyl, cyano, hydroxyl, mercapto, nitro and the like. Typical substituents include, but are not limited to, -X, -R, -OH, -OR, -SH, -SR, NH₂、-NHR、-N(R)₂、-N⁺(R)₃、-CX₃、-CN、-OCN、-SCN、-NCO、-NCS、-NO、-NO₂、-N₃、-NC(＝O)H、-NC(＝O)R、-C(＝O)H、-C(＝O)R、-C(＝O)NH₂、-C(＝O)N(R)₂、-SO₃-、-SO₃H、-S(＝O)₂R、-OS(＝O)₂OR、-S(＝O)₂NH₂、-S(＝O)₂N(R)₂、-S(＝O)R、-OP(＝O)(OH)₂、-OP(＝O)(OR)₂、-P(＝O)(OR)₂、-PO₃、-PO₃H₂、-C(＝O)X、-C(＝S)R、-CO₂H、-CO₂R、-CO₂-、-C(＝S)OR、-C(＝O)SR、-C(＝S)SR、-C(＝O)NH₂、-C(＝O)N(R)₂、-C(＝S)NH₂、-C(＝S)N(R)₂、-C(＝NH)NH₂and-C (═ NR) N (R)₂(ii) a Wherein each X is independently selected in each occurrence from F, Cl, Br, and I; and each R is independently selected at each occurrence from alkyl, aryl, heterocycloalkyl or heteroaryl, a protecting group, and a prodrug moiety. In all cases where a group is described as "optionally substituted", that group is in each caseMay be independently substituted with one or more of the above substituents.

In all instances where a group is described as "optionally substituted," the group can, independently at each instance, be substituted with one or more substituents above. Substitution may include situations where adjacent substituents undergo ring closure, such as ring closure of ortho-functional substituents to form lactams, lactones, cyclic anhydrides, acetals, hemiacetals, thioacetals, aminals, and hemiaminals formed by, for example, ring closure to provide a protecting group.

It is understood that, depending on the context, certain radical naming conventions may include mono-radicals or di-radicals. For example, where a substituent requires two points of attachment to the rest of the molecule, it is understood that the substituent is a diradical. For example, substituents identified as alkyl groups requiring two attachment points include diradicals, such as-CH₂-、-CH₂CH₂-、-CH₂CH(CH₃)CH₂-and the like. Other radical naming conventions clearly indicate that the radical is a diradical, such as "alkylene," "alkenylene," "arylene," "heterocycloalkylene," and the like.

In all cases where a substituent is described as a diradical (i.e., two points of attachment to the rest of the molecule), it is understood that the substituent can be attached in any directional configuration unless otherwise indicated.

anti-CD 117 antibodies

The present invention is based in part on the following findings: antibodies or antigen-binding fragments thereof capable of binding to CD117, such as GNNK + CD117, can be used as therapeutic agents, either alone or as conjugates (ADCs), to, for example, (i) treat cancers and autoimmune diseases characterized by CD117+ cells, and (ii) facilitate the engraftment of transplanted hematopoietic stem cells in patients in need of transplantation therapy. These therapeutic activities may be induced by: for example, the binding of an isolated anti-CD 117 antibody, antigen-binding fragment thereof, that binds to CD117 (e.g., GNNK + CD117) expressed on the surface of a cell, such as a cancer cell, an autoimmune cell, or a hematopoietic stem cell, and subsequently induces cell death. Depletion of endogenous hematopoietic stem cells can provide a niche towards which transplanted hematopoietic stem cells can home and subsequently establish productive hematopoiesis. In this manner, the transplanted hematopoietic stem cells can be successfully transplanted into a patient, such as a human patient, suffering from the stem cell disorders described herein.

Antibodies and antigen-binding fragments capable of binding to human CD117 (also known as c-Kit, mRNA NCBI reference sequence: NM-000222.2, protein NCBI reference sequence: NP-000213.1), including those capable of binding to GNNK + CD117, can be used in conjunction with the compositions and methods described herein to modulate a patient to facilitate hematopoietic stem cell transplantation therapy. Polymorphisms affecting the coding region or extracellular domain of CD117 in a large percentage of the population are not well known at present in non-oncology indicators (indications). At least four isoforms of CD117 have been identified, and it is possible to express additional isoforms in tumor cells. Two of the CD117 isoforms are located on the intracellular domain of the protein, and two are present in the outer membrane proximal region. The two extracellular isoforms GNNK + and GNNK-differ in the presence (GNNK +) or absence (GNNK-) of the 4 amino acid sequence. These isoforms are reported to have the same affinity for ligand (SCF), but binding of ligand to GNNK-isoforms is reported to increase internalization and degradation. GNNK + isoforms can be used as immunogens to generate antibodies capable of binding CD117, as antibodies raised against the isoforms will include GNNK + and GNNK-proteins. The amino acid sequences of human CD117 isoforms 1 and 2 are described in SEQ ID NO 145 and SEQ ID NO 146, respectively. In certain embodiments, the anti-human CD117(hCD117) antibodies disclosed herein are capable of binding to both isoform 1 and isoform 2 of human CD 117.

Yeast library screening of human antibodies was performed to identify novel anti-CD 117 antibodies and fragments thereof having diagnostic and therapeutic uses, as described below. Antibodies 54(Ab54), 55(Ab55), 56(Ab56), 57(Ab57), 58(Ab58), 61(Ab61), 66(Ab66), 67(Ab67), 68(Ab68) and 69(Ab69) are human antibodies identified in this screen. These antibodies cross-react with human CD117 and rhesus monkey CD 117. Furthermore, these antibodies disclosed herein are capable of binding to two isoforms of human CD117, namely isoform 1(SEQ ID NO:145) and isoform 2(SEQ ID NO: 146).

The amino acid sequences of the different binding regions of anti-CD 117 antibodies Ab54, Ab55, Ab56, Ab57, Ab58, Ab61, Ab66, Ab67, Ab68 and Ab69 are described in table 10. The invention includes human anti-CD 117 antibodies comprising CDRs as set forth in table 10, as well as human anti-CD 117 antibodies comprising variable regions as set forth in table 10.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 55. The heavy chain variable region (VH) amino acid sequence of antibody 55 (i.e., Ab55) is set forth in SEQ ID NO:19 (see Table 10). The VH CDR domain amino acid sequences of antibody 55 are set forth in SEQ ID NO:21(VH CDR1), SEQ ID NO:22(VH CDR2), and SEQ ID NO:23(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 55 is depicted in SEQ ID NO:20 (see Table 10). The VL CDR domain amino acid sequences of antibody 55 are set forth in SEQ ID NO:24(VLCDR1), SEQ ID NO:25(VL CDR2) and SEQ ID NO:26(VL CDR 3). The heavy chain constant region of antibody 55 is set forth in SEQ ID NO. 122. The light chain constant region of antibody 55 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:21, SEQ ID NO:22, and SEQ ID NO:23, and the light chain variable region CDR sets as set forth in SEQ ID NO:24, SEQ ID NO:25, and SEQ ID NO: 26. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO. 20, and a heavy chain variable region as set forth in SEQ ID NO. 19.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 54. The heavy chain variable region (VH) amino acid sequence of antibody 54 (i.e., Ab54) is set forth in SEQ ID NO:29 (see Table 10). The VH CDR domain amino acid sequences of antibody 54 are set forth in SEQ ID NO:31(VH CDR1), SEQ ID NO:32(VH CDR2), and SEQ ID NO:33(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 54 is depicted in SEQ ID NO:30 (see Table 10). The VL CDR domain amino acid sequences of antibody 54 are set forth in SEQ ID NO:34(VL CDR1), SEQ ID NO:35(VL CDR2) and SEQ ID NO:36(VL CDR 3). The heavy chain constant region of antibody 54 is set forth in SEQ ID NO. 122. The light chain constant region of antibody 54 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:31, SEQ ID NO:32, and SEQ ID NO:33, and the light chain variable region CDR sets as set forth in SEQ ID NO:34, SEQ ID NO:35, and SEQ ID NO: 36. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO. 30, and a heavy chain variable region as set forth in SEQ ID NO. 29.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 56. The heavy chain variable region (VH) amino acid sequence of antibody 56 (i.e., Ab56) is set forth in SEQ ID NO:39 (see Table 10). The VH CDR domain amino acid sequences of antibody 56 are set forth in SEQ ID NO 41(VH CDR1), SEQ ID NO 42(VH CDR2), and SEQ ID NO 43(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 56 is depicted in SEQ ID NO:40 (see Table 10). The VL CDR domain amino acid sequences of antibody 56 are set forth in SEQ ID NO:44(VL CDR1), SEQ ID NO:45(VL CDR2) and SEQ ID NO:46(VL CDR 3). The heavy chain constant region of antibody 56 is set forth in SEQ ID NO. 122. The light chain constant region of antibody 56 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:41, SEQ ID NO:42, and SEQ ID NO:43, and the light chain variable region CDR sets as set forth in SEQ ID NO:44, SEQ ID NO:45, and SEQ ID NO: 46. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO. 40, and a heavy chain variable region as set forth in SEQ ID NO. 39.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 57. The heavy chain variable region (VH) amino acid sequence of antibody 57 (i.e., Ab57) is set forth in SEQ ID NO:49 (see Table 10). The VH CDR domain amino acid sequences of antibody 57 are set forth in SEQ ID NO:51(VH CDR1), SEQ ID NO:52(VH CDR2), and SEQ ID NO:53(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 57 is depicted in SEQ ID NO:50 (see Table 10). The VL CDR domain amino acid sequences of antibody 57 are set forth in SEQ ID NO:54(VL CDR1), SEQ ID NO:55(VL CDR2) and SEQ ID NO:56(VL CDR 3). The heavy chain constant region of antibody 57 is set forth in SEQ ID NO. 122. The light chain constant region of antibody 57 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:51, SEQ ID NO:52, and SEQ ID NO:53, and the light chain variable region CDR sets as set forth in SEQ ID NO:54, SEQ ID NO:55, and SEQ ID NO: 56. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO. 50, and a heavy chain variable region as set forth in SEQ ID NO. 49.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 58. The heavy chain variable region (VH) amino acid sequence of antibody 58 (i.e., Ab58) is set forth in SEQ ID NO:59 (see Table 10). The VH CDR domain amino acid sequences of antibody 58 are set forth in SEQ ID NO:61(VH CDR1), SEQ ID NO:62(VH CDR2), and SEQ ID NO:63(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 58 is depicted in SEQ ID NO:60 (see Table 10). The VL CDR domain amino acid sequences of antibody 58 are set forth in SEQ ID NO:64(VL CDR1), SEQ ID NO:65(VL CDR2) and SEQ ID NO:66(VL CDR 3). The heavy chain constant region of antibody 58 is set forth in SEQ ID NO: 122. The light chain constant region of antibody 58 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:61, SEQ ID NO:62, and SEQ ID NO:63, and the light chain variable region CDR sets as set forth in SEQ ID NO:64, SEQ ID NO:65, and SEQ ID NO: 66. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO:60, and a heavy chain variable region as set forth in SEQ ID NO: 59.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 61. The heavy chain variable region (VH) amino acid sequence of antibody 61 (i.e., Ab61) is set forth in SEQ ID NO:69 (see Table 10). The VH CDR domain amino acid sequences of antibody 61 are set forth in SEQ ID NO:71(VH CDR1), SEQ ID NO:72(VH CDR2), and SEQ ID NO:73(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 61 is depicted in SEQ ID NO:70 (see Table 10). The VL CDR domain amino acid sequences of antibody 61 are set forth in SEQ ID NO:74(VLCDR1), SEQ ID NO:75(VL CDR2) and SEQ ID NO:76(VL CDR 3). The heavy chain constant region of antibody 61 is set forth in SEQ ID NO: 122. The light chain constant region of antibody 61 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:71, SEQ ID NO:72, and SEQ ID NO:73, and the light chain variable region CDR sets as set forth in SEQ ID NO:74, SEQ ID NO:75, and SEQ ID NO: 76. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO. 70, and a heavy chain variable region as set forth in SEQ ID NO. 69.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 66. The heavy chain variable region (VH) amino acid sequence of antibody 66 (i.e., Ab66) is set forth in SEQ ID NO:79 (see Table 10). The VH CDR domain amino acid sequences of antibody 66 are set forth in SEQ ID NO:81(VH CDR1), SEQ ID NO:82(VH CDR2), and SEQ ID NO:83(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 66 is depicted in SEQ ID NO:80 (see Table 10). The VL CDR domain amino acid sequences of antibody 66 are set forth in SEQ ID NO:84(VL CDR1), SEQ ID NO:85(VL CDR2) and SEQ ID NO:86(VL CDR 3). The heavy chain constant region of antibody 66 is set forth in SEQ ID NO. 122. The light chain constant region of antibody 66 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:81, SEQ ID NO:82, and SEQ ID NO:83, and the light chain variable region CDR sets as set forth in SEQ ID NO:84, SEQ ID NO:85, and SEQ ID NO: 86. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO:80, and a heavy chain variable region as set forth in SEQ ID NO: 79.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 67. The heavy chain variable region (VH) amino acid sequence of antibody 67 is set forth in SEQ ID NO:9 (see Table 2). The VH CDR domain amino acid sequences of antibody 67 are set forth in SEQ ID NO:11(VH CDR1), SEQ ID NO:12(VH CDR2), and SEQ ID NO:13(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 67 is depicted in SEQ ID NO:10 (see Table 2). The VL CDR domain amino acid sequences of antibody 67 are set forth in SEQ ID NO:14(VL CDR1), SEQ ID NO:15(VL CDR2) and SEQ ID NO:16(VL CDR 3). The full length Heavy Chain (HC) of antibody 67 is set forth in SEQ ID NO:110, and the full length heavy chain constant region of antibody 67 is set forth in SEQ ID NO: 122. The Light Chain (LC) of antibody 67 is set forth in SEQ ID NO: 109. The light chain constant region of antibody 67 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:11, SEQ ID NO:12, and SEQ ID NO:13, and the light chain variable region CDR sets as set forth in SEQ ID NO:14, SEQ ID NO:15, and SEQ ID NO: 16. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable heavy chain comprising the amino acid residues set forth in SEQ ID NO.9, and a heavy chain variable region as set forth in SEQ ID NO. 10. In additional embodiments, the anti-CD 117 antibody comprises a heavy chain comprising SEQ ID NO 110 and a light chain comprising SEQ ID NO 109.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 68. The heavy chain variable region (VH) amino acid sequence of antibody 68 (i.e., Ab68) is set forth in SEQ ID NO:89 (see Table 10). The VH CDR domain amino acid sequences of antibody 68 are set forth in SEQ ID NO:91(VH CDR1), SEQ ID NO:92(VH CDR2), and SEQ ID NO:93(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 68 is depicted in SEQ ID NO:90 (see Table 10). The VL CDR domain amino acid sequences of antibody 68 are set forth in SEQ ID NO:94(VL CDR1), SEQ ID NO:95(VL CDR2) and SEQ ID NO:96(VL CDR 3). The heavy chain constant region of antibody 68 is set forth in SEQ ID NO. 122. The light chain constant region of antibody 68 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO:91, SEQ ID NO:92, and SEQ ID NO:93, and the light chain variable region CDR sets as set forth in SEQ ID NO:94, SEQ ID NO:95, and SEQ ID NO: 96. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID NO. 90, and a heavy chain variable region as set forth in SEQ ID NO. 89.

In one embodiment, the invention provides anti-CD 117 antibodies or antigen-binding fragments thereof comprising binding regions, e.g., CDRs, variable regions, corresponding to those of antibody 69. The heavy chain variable region (VH) amino acid sequence of antibody 69 (i.e., Ab69) is set forth in SEQ ID NO:99 (see Table 10). The VH CDR domain amino acid sequences of antibody 69 are set forth in SEQ ID NO 101(VH CDR1), SEQ ID NO 102(VH CDR2) and SEQ ID NO 103(VH CDR 3). The light chain variable region (VL) amino acid sequence of antibody 69 is depicted in SEQ ID NO:100 (see Table 10). The VL CDR domain amino acid sequences of antibody 69 are set forth in SEQ ID NO 104(VL CDR1), SEQ ID NO 105(VL CDR2) and SEQ ID NO 106(VL CDR 3). The heavy chain constant region of antibody 69 is set forth in SEQ ID NO: 122. The light chain constant region of antibody 69 is set forth in SEQ ID NO. 121. Thus, in certain embodiments, the anti-CD 117 antibody or antigen-binding portion thereof comprises the variable heavy chain CDR sets (CDR1, CDR2, and CDR3) as set forth in SEQ ID NO 101, SEQ ID NO 102, and SEQ ID NO 103, and the light chain variable region CDR sets as set forth in SEQ ID NO 104, SEQ ID NO 105, and SEQ ID NO 106. In other embodiments, the anti-CD 117 antibody, or antigen-binding portion thereof, comprises a variable light chain comprising the amino acid residues set forth in SEQ ID No. 100, and a heavy chain variable region as set forth in SEQ ID No. 99.

Certain anti-CD 117 antibodies described herein are neutral antibodies in that these antibodies do not substantially inhibit CD117 activity on CD 117-expressing cells. Neutral antibodies can be identified using, for example, an in vitro Stem Cell Factor (SCF) -dependent cell proliferation assay (see, e.g., example 11 described herein). In an SCF-dependent cell proliferation assay, neutral CD117 antibodies will not kill CD34+ cells that are dependent on SCF division, as neutral antibodies will not block SCF binding to CD117 such as inhibit CD117 activity.

Neutral antibodies can be used for diagnostic purposes because they have the ability to specifically bind to human CD117, but are also effective in killing CD 117-expressing cells when conjugated with cytotoxins such as those described herein. Generally, the antibody used in the conjugate has agonistic or antagonistic activity specific to the antibody. However, a unique conjugation approach is described herein, particularly where the stem cell graft prodrug is used as a modulator. While antagonistic antibodies alone or in combination with cytotoxins may be effective as conjugates in view of the killing ability of the antibody alone in addition to the cytotoxin, modulation with conjugates comprising neutral anti-CD 117 antibodies provides an alternative strategy in which the activity of the antibody is inferior to the effect of the cytotoxin, but the internalization and affinity characteristics of the antibody, such as the rate of dissociation, are important for effective delivery of the cytotoxin.

Examples of neutral anti-CD 117 antibodies include Ab58, Ab61, Ab66, Ab67, Ab68, and Ab 69. Comparison of the amino acid sequences of the CDRs of the neutral anti-CD 117 antibodies revealed consensus sequences between the two groups of neutral antibodies identified. A comparison of the heavy and light chain variable regions of Ab58 and Ab61 is depicted in fig. 22a and 22b, respectively. Ab58 and Ab61 share the same light chain CDR and HC CDR3, with slight differences in HC CDR1 and HC CDR 2. The consensus sequences of HC CDR1 and HC CDR2 are depicted in SEQ ID NO 133 and SEQ ID NO 134. Ab66, Ab67, Ab68 and Ab69 are also neutral antibodies. The heavy and light chain variable regions of these antibodies are depicted in fig. 23A and 23B, respectively. Although Ab66, Ab67, Ab68, and Ab69 share the same light chain CDRs and the same HC CDR3, these antibodies have variability in their HC CDR1 and HC CDR2 regions. The consensus sequences of these antibodies in the HC CDR1 and HC CDR2 regions are provided in SEQ ID NO:139 and SEQ ID NO:140, respectively.

Also provided herein are antagonistic antibodies, including Ab54, Ab55, Ab56, and Ab 57. A comparison of the variable heavy and light chain amino acid sequences of these antibodies is provided in fig. 21A and 22B, respectively. Although Ab54, Ab55, Ab56, and Ab57 share the same light chain CDRs and the same HC CDR3, these antibodies have variability in their HC CDR1 and HC CDR2 regions. The consensus sequences of these antibodies in the HC CDR1 and HC CDR2 regions are provided in SEQ ID NO:127 and SEQ ID NO:128, respectively.

The anti-CD 117 antibodies described herein can be in the form of: full length antibodies, bispecific antibodies, double variable domain antibodies, multi-chain or single chain antibodies, and/or binding fragments that specifically bind to human CD117, including but not limited to Fab, Fab ', (Fab')₂Fv, scFv (single chain Fv), surrogate antibody(s) (including surrogate light chain constructs), single domain antibody, camelized antibody(s), and the like. They may also be of or derived from any isotype including, for example, IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., IgG1, IgG2, IgG3 or IgG4) or IgM. In some embodiments, the anti-CD 117 antibody is an IgG (e.g., IgG1, IgG2, IgG3, or IgG 4).

Antibodies for use in conjunction with the methods described herein include variants of those antibodies described above, such as antibody fragments that contain or lack an Fc domain, as well as humanized variants of the non-human antibodies described herein and antibody-like protein scaffolds that contain one or more or all CDRs or equivalent regions thereof of the antibodies or antibody fragments described herein (e.g.,¹⁰fn3 domain). Exemplary antigen-binding fragments of the foregoing antibodies include, inter alia, dual variable immunoglobulin domains, single chain Fv molecules (scFv), diabodies, triabodies, nanobodies, antibody-like protein scaffolds, Fv fragments, Fab fragments, F: (ab')₂Molecules and tandem di-scfvs.

In one embodiment, anti-CD 117 antibodies comprising one or more radiolabeled amino acids are provided. Radiolabeled anti-CD 117 antibodies can be used for both diagnostic and therapeutic purposes (conjugation to radiolabeled molecules is another possible feature). Non-limiting examples of labels for polypeptides include, but are not limited to³H、¹⁴C、¹⁵N、³⁵S、⁹⁰Y、⁹⁹Tc and¹²⁵I、¹³¹i and¹⁸⁶re. Methods for preparing radiolabeled amino acid and related peptide derivatives are known in the art (see, e.g., Junghans et al Cancer chemother and Biotherapy 655-686 (2 nd edition, Chafner and Longo, eds., Lippincott Raven (1996)) and U.S. Pat. No. 4,681,581, U.S. Pat. No. 4,735,210, U.S. Pat. No. 5,101,827, U.S. Pat. No. 5,102,990 (U.S. re35,500), U.S. Pat. No. 5,648,471, and U.S. Pat. No. 5,697,902. for example, radioisotopes can be conjugated by the chloramine T method.

The anti-CD 117 antibodies or binding fragments described herein may also include modifications and/or mutations that alter the properties of the antibodies and/or fragments, such as, for example, modifications and/or mutations that increase half-life, increase or decrease ADCC, and the like, as are known in the art.

In one embodiment, the anti-CD 117 antibody or binding fragment thereof comprises a variant Fc region, wherein the variant Fc region comprises at least one amino acid modification relative to a wild-type Fc region such that the molecule has altered affinity for fcyr. It is known from crystallographic studies that certain amino acid positions within the Fc region are in direct contact with Fc γ R. In particular amino acids 234-. (see Sondermann et al, 2000Nature,406: 267-273). Thus, the anti-CD 117 antibodies described herein may comprise a variant Fc region comprising a modification at least one residue that is in direct contact with an fcyr based on structural and crystallographic analysis. In one embodiment, the Fc region of an anti-CD 117 antibody (or fragment thereof) comprises an amino acid substitution at amino acid 265 according to the EU index as in Kabat et al, Sequences of Proteins of Immunological Interest,5th ed. The "EU index in Kabat" refers to the numbering of the human IgG1 EU antibody. The EU index or EU index as in Kabat or EU numbering scheme refers to the numbering of EU antibodies (Edelman et al, 1969, Proc Natl Acad Sci USA 63:78-85, herein incorporated by reference in its entirety.) in one embodiment, the Fc region comprises a D265A mutation. In one embodiment, the Fc region comprises the D265C mutation. In some embodiments, the Fc region of the anti-CD 117 antibody (or fragment thereof) comprises an amino acid substitution at amino acid 234 according to the EU index as in Kabat. In one embodiment, the Fc region comprises the L234A mutation. In some embodiments, the Fc region of the anti-CD 117 antibody (or fragment thereof) comprises an amino acid substitution at amino acid 235 according to the EU index as in Kabat. In one embodiment, the Fc region comprises the L235A mutation. In yet another embodiment, the Fc region comprises the L234A and L235A mutations. In another embodiment, the Fc region comprises the D265C, L234A, and L235A mutations.

In certain aspects, a variant IgG Fc domain comprises one or more amino acid substitutions resulting in a reduction or elimination of binding affinity to fcyr and/or C1q as compared to a wild-type Fc domain that does not comprise the one or more amino acid substitutions. Fc binding interactions are critical for a variety of effector functions and downstream signaling events, including but not limited to antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Accordingly, in certain aspects, antibodies comprising modified Fc regions (e.g., comprising L234A, L235A, and D265C mutations) have significantly reduced or eliminated effector function.

Affinity for the Fc region can be determined using a variety of techniques known in the art, such as, but not limited to, equilibrium methods (e.g., enzyme-linked immunosorbent assay (ELISA); KinExA, analytical biochemistry, Vol.373:52-60,2008; Rathanawami et al; or Radioimmunoassay (RIA)) or by surface plasmon resonance assay or other kinetic-based assay mechanisms (e.g., BIACORE)^TMAnalysis or Octet^TMAnalysis of(forteBIO)) and other methods such as indirect binding assays, competitive binding assays, Fluorescence Resonance Energy Transfer (FRET), gel electrophoresis, and chromatography (e.g., gel filtration). These and other methods may utilize labels on one or more of the components being examined and/or employ a variety of detection methods including, but not limited to, chromogenic, fluorescent, luminescent, or isotopic labeling. A detailed description of binding affinity and kinetics can be found in Paul, W.E., eds., Fundamental Immunology,4th Ed., Lippincott-Raven, Philadelphia (1999), which focuses on antibody-immunogen interactions. One example of a competitive binding assay is a radioimmunoassay comprising incubating a labeled antigen with an antibody of interest in the presence of increasing amounts of unlabeled antigen, and detecting the antibody bound to the labeled antigen. The affinity and the binding off-rate of the antibody of interest for a particular antigen can be determined from the data by Scatchard plot analysis. Competition with the second antibody can also be determined using radioimmunoassay. In this case, the antigen is incubated with the antibody of interest conjugated to a labeling compound in the presence of increasing amounts of unlabeled secondary antibody.

The antibodies of the invention may be further engineered to further modulate antibody half-life by introducing additional Fc mutations such as those described in: for example (Dall' Acqua et al (2006) J Biol Chem 281:23514-24), (Zalevsky et al (2010) Nat Biotechnol 28:157-9), (Hinton et al (2004) J Biol Chem 279:6213-6), (Hinton et al (2006) J Immunol 176:346-56), (Shields et al (2001) J Biol Chem 276:6591-604), (Petkova et al (2006) Int Immunol 18:1759-69), (Datta-Mannan et al (2007) Drug Metab Dispos 35:86-94), (Vaccaro et al (2005) Nattechnol 23:1283-8), (Yeung et al (2010) Cancer Res 70:3269-77), and (1999) Eur Kimunol 29:2819-25, and including the following positions: 250. 252, 253, 254, 256, 257, 307, 376, 380, 428, 434 and 435. Exemplary mutations that may be made, alone or in combination, are the T250Q, M252Y, I253A, S254T, T256E, P257I, T307A, D376V, E380A, M428L, H433K, N434S, N434A, N434H, N434F, H435A, and H435R mutations.

Thus, in one embodiment, the Fc region comprises a mutation that results in a decrease in half-life. An antibody with a short half-life may be advantageous in certain circumstances where it is expected that the antibody will function as a short-lived therapeutic agent, e.g., the modulation steps described herein, wherein HSCs are administered after administration of the antibody. Ideally, the antibody will be substantially cleared prior to delivery of HSCs, which typically also express CD117, but are not targets of anti-CD 117 antibodies, unlike endogenous stem cells. In one embodiment, the Fc region comprises a mutation at position 435 (EU index according to Kabat). In one embodiment, the mutation is the H435A mutation.

In one embodiment, the anti-CD 117 antibodies described herein have a half-life equal to or less than 24 hours, a half-life equal to or less than 22 hours, a half-life equal to or less than 20 hours, a half-life equal to or less than 18 hours, a half-life equal to or less than 16 hours, a half-life equal to or less than 14 hours, a half-life equal to or less than 13 hours, a half-life equal to or less than 12 hours, or a half-life equal to or less than 11 hours. In one embodiment, the half-life of the antibody is 11 hours to 24 hours, 12 hours to 22 hours, 10 hours to 20 hours, 8 hours to 18 hours, or 14 hours to 24 hours.

In some aspects, the Fc region comprises two or more mutations that confer a reduced half-life and that substantially reduce or completely eliminate the effector function of the antibody. In some embodiments, the Fc region comprises a mutation that results in a reduction in half-life and a mutation of at least one residue that can be in direct contact with an fcyr (e.g., as based on structural and crystallographic analysis). In one embodiment, the Fc region comprises the H435A mutation, the L234A mutation, and the L235A mutation. In one embodiment, the Fc region comprises the H435A mutation and the D265C mutation. In one embodiment, the Fc region comprises the H435A mutation, the L234A mutation, the L235A mutation, and the D265C mutation.

In some embodiments, the antibody or antigen-binding fragment thereof is conjugated to a cytotoxin (e.g., amatoxin) through a cysteine residue in the Fc domain of the antibody or antigen-binding fragment thereof. In some embodiments, the cysteine residue is introduced by mutation in the Fc domain of the antibody or antigen-binding fragment thereof. For example, the cysteine residue may be selected from the group consisting of: cys118, Cys239 and Cys 265. In one embodiment, the Fc region of the anti-CD 117 antibody (or fragment thereof) comprises an amino acid substitution at amino acid 265 according to the EU index as in Kabat. In one embodiment, the Fc region comprises the D265C mutation. In one embodiment, the Fc region comprises the D265C and H435A mutations. In one embodiment, the Fc region comprises the D265C, L234A, and L235A mutations. In one embodiment, the Fc region comprises the D265C, L234A, L235A, and H435A mutations.

In some embodiments of these aspects, the cysteine residue is naturally occurring in the Fc domain of the antibody or antigen-binding fragment thereof. For example, the Fc domain may be an IgG Fc domain, such as a human IgG1 Fc domain, and the cysteine residue may be selected from the group consisting of: cys261, Csy321, Cys367 and Cys 425.

For example, in one embodiment, the Fc region of antibody 67 is modified to include the D265C mutation (e.g., SEQ ID NO: 111). In another embodiment, the Fc region of antibody 67 is modified to include the D265C, L234A, and L235A mutations (e.g., SEQ ID NO: 112). In yet another embodiment, the Fc region of antibody 67 is modified to include the D265C and H435A mutations (e.g., SEQ ID NO: 113). In another embodiment, the Fc region of antibody 67 is modified to include the D265C, L234A, L235A, and H435A mutations (e.g., SEQ ID NO: 114).

With respect to antibody 55, in one embodiment, the Fc region of antibody 55 is modified to include the D265C mutation (e.g., SEQ ID NO: 117). In another embodiment, the Fc region of antibody 55 is modified to include the D265C, L234A, and L235A mutations (e.g., SEQ ID NO: 118). In yet another embodiment, the Fc region of antibody 55 is modified to include the D265C and H435A mutations (e.g., SEQ ID NO: 119). In another embodiment, the Fc region of antibody 55 is modified to include the D265C, L234A, L235A, and H435A mutations (e.g., SEQ ID NO: 120).

The Fc region of any one of antibody 54, antibody 55, antibody 56, antibody 57, antibody 58, antibody 61, antibody 66, antibody 67, antibody 68, or antibody 69 may be modified to include a D265C mutation (e.g., as in SEQ ID NO: 123); the D265C, L234A, and L235A mutations (e.g., as in SEQ ID NO: 124); the D265C and H435A mutations (e.g., as in SEQ ID NO: 125); or D265C, L234A, L235A, and H435A mutations (e.g., as in SEQ ID NO: 126).

The variant Fc domains described herein are defined in terms of the amino acid modifications that make up them. For all amino acid substitutions discussed herein in relation to the Fc region, the numbering is always according to the EU index. Thus, for example, D265C is an Fc variant having an aspartic acid (D) at EU position 265 replaced with a cysteine (C) relative to the parent Fc domain. Similarly, for example, D265C/L234A/L235A defines variant Fc variants having substitutions at EU positions 265(D to C), 234(L to a), and 235(L to a) relative to a parent Fc domain. Variants may also be specified according to the final amino acid composition of the EU amino acid position at which they are mutated. For example, the L234A/L235A mutant may be referred to as LALA. It should be noted that the order in which the substitutions are provided is arbitrary.

In one embodiment, the anti-CD 117 antibody or antigen-binding fragment thereof comprises a variable region having an amino acid sequence at least 95%, 96%, 97%, or 99% identical to SEQ ID NO disclosed herein. Alternatively, the anti-CD 117 antibody or antigen-binding fragment thereof comprises CDRs comprising SEQ ID NOs disclosed herein, and the framework regions of the variable regions described herein have an amino acid sequence at least 95%, 96%, 97%, or 99% identical to the SEQ ID NOs disclosed herein.

In certain embodiments, the anti-CD 117 antibody or antigen-binding fragment thereof has an off-rate, which is particularly advantageous when used as part of a conjugate. For example, in certain embodiments, the anti-CD 117 antibody has the following off-rate constants (K) for human CD117 and/or rhesus CD117 as measured by biolayer interferometry (BLI)_off)：1x10^-2To 1x10^-3、1x10^-3To 1x10^-4、1x10^-5To 1x10^-6、1x10^-6To 1x10^-7Or 1x10^-7To 1x10^-8. In some embodiments of the present invention, the substrate is,the antibody or antigen-binding fragment thereof is represented by the following K as determined by a biolayer interferometry (BLI) assay_DBinding to CD117 (e.g., human CD117 and/or rhesus CD 117): about 100nM or less, about 90nM or less, about 80nM or less, about 70nM or less, about 60nM or less, about 50nM or less, about 40nM or less, about 30nM or less, about 20nM or less, about 10nM or less, about 8nM or less, about 6nM or less, about 4nM or less, about 2nM or less, about 1nM or less.

As described in more detail below, the antibodies and binding fragments thereof disclosed herein can be used in conjugates.

Antibodies can be produced using recombinant methods and compositions, for example, as described in U.S. Pat. No. 4,816,567. In one embodiment, isolated nucleic acids encoding the anti-CD 117 antibodies described herein are provided. Such nucleic acids may encode an amino acid sequence of an antibody comprising a VL and/or an amino acid sequence comprising a VH (e.g., a light chain and/or a heavy chain of an antibody). In another embodiment, one or more vectors (e.g., expression vectors) comprising such nucleic acids are provided. In another embodiment, host cells comprising such nucleic acids are provided. In one such embodiment, the host cell comprises (e.g., has been transformed with): (1) a vector comprising a nucleic acid encoding an amino acid sequence comprising a VL of an antibody and an amino acid sequence comprising a VH of an antibody, or (2) a first vector comprising a nucleic acid encoding an amino acid sequence comprising a VL of an antibody, and a second vector comprising a nucleic acid encoding an amino acid sequence comprising a VH of an antibody. In one embodiment, the host cell is a eukaryotic cell, e.g., a Chinese Hamster Ovary (CHO) cell or a lymphocyte (e.g., Y0, NS0, Sp20 cell). In one embodiment, a method of making an anti-CLL-1 antibody is provided, wherein the method comprises culturing a host cell comprising a nucleic acid encoding the antibody as provided above under conditions suitable for expression of the antibody, and optionally recovering the antibody from the host cell (or host cell culture medium).

For recombinant production of anti-CD 117 antibodies, nucleic acids encoding, for example, antibodies as described above are isolated and inserted into one or more vectors for further cloning and/or expression in host cells. Such nucleic acids can be readily isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of specifically binding to genes encoding the heavy and light chains of an antibody).

Suitable host cells for cloning or expressing antibody-encoding vectors include prokaryotic or eukaryotic cells as described herein. For example, antibodies can be produced in bacteria, particularly when glycosylation and Fc effector function are not required. For expression of antibody fragments and polypeptides in bacteria, see, e.g., U.S. Pat. nos. 5,648,237, 5,789,199, and 5,840,523. (see also: Charlton, Methods in Molecular Biology, Vol.248(B.K.C.Lo, eds., Humana Press, Totowa, N.J.,2003), pp.245-254, describing the expression of antibody fragments in E.coli (E.coli.). After expression, the antibody can be isolated from the soluble fraction of the bacterial cell mass (past) and can be further purified.

Vertebrate cells can also be used as hosts. For example, mammalian cell lines suitable for growth in suspension may be useful. Other examples of useful mammalian host cell lines are the monkey kidney CV1 cell line (COS-7) transformed by SV40, the human embryonic kidney cell line (293 or 293 cells as described in Graham et al, J.Gen Virol.36:59 (1977)), baby hamster kidney cells (BHK), mouse support cells (TM4 cells as described in, for example, Mather, biol.Reprod.23: 243-; human lung cells (W138), human liver cells (Hep G2), mouse breast tumor (MMT 060562), TRI cells (as described, for example, in Mather et al, AnnalsN.Y.Acad.Sci.383:44-68 (1982)), MRC 5 cells, and FS4 cells. Other useful mammalian host cell lines include Chinese Hamster Ovary (CHO) cells, including DHFR-CHO cells (Urlaub et al, Proc. Natl. Acad. Sci. USA 77:4216(1980)) and myeloma cell lines such as Y0, NS0 and Sp 2/0. For a review of certain mammalian host cell lines suitable for antibody production, see, e.g., Yazaki and Wu, Methods in molecular Biology, Vol.248(B.K.C.Lo, eds., Humana Press, Totowa, N.J.), pp.255-268 (2003).

In one embodiment, the anti-CD 117 antibody or antigen-binding fragment thereof comprises a variable region having an amino acid sequence that is at least 95%, 96%, 97%, or 99% identical to SEQ ID NO disclosed herein. Alternatively, the anti-CD 117 antibody or antigen-binding fragment thereof comprises CDRs comprising the SEQ ID NOs disclosed herein, and the framework regions of the variable regions described herein have an amino acid sequence that is at least 95%, 96%, 97%, or 99% identical to the SEQ ID NOs disclosed herein.

In one embodiment, the anti-CD 117 antibody or antigen-binding fragment thereof comprises a heavy chain variable region and a heavy chain constant region having the amino acid sequences disclosed herein. In another embodiment, the anti-CD 117 antibody or antigen-binding fragment thereof comprises a light chain variable region and a light chain constant region having the amino acid sequences disclosed herein. In yet another embodiment, the anti-CD 117 antibody or antigen-binding fragment thereof comprises a heavy chain variable region, a light chain variable region, a heavy chain constant region, and a light chain constant region having the amino acid sequences disclosed herein.

Method for identifying anti-CD 117 antibodies

Provided herein are novel anti-CD 117 antibodies that can be used in, for example, regulatory methods for stem cell transplantation. In view of the disclosure herein, other anti-CD 117 antibodies, e.g., neutral antibodies, can be identified.

Methods for high-throughput screening of antibodies or antibody fragments, molecular libraries capable of binding to CD117 (e.g., GNNK + CD117) can be used to identify affinity matured antibodies that can be used to treat cancer, autoimmune diseases, and modulate patients (e.g., human patients) in need of hematopoietic stem cell therapy as described herein. Such methods include in vitro display techniques known in the art, such as, inter alia, phage display, bacterial display, yeast display, mammalian cell display, ribosome display, mRNA display and cDNA display. The use of phage display to isolate ligands that bind biologically relevant molecules has been reviewed in: for example, Felici et al, Biotechnol. Annual Rev.1:149-183, 1995; katz, AnnualRev.Biophys.Biomol.Structure.26: 27-45, 1997; and Hoogenboom et al, Immunotechnology 4:1-20,1998, the disclosure of each of which is incorporated herein by reference as they relate to in vitro display technology. Randomized combinatorial peptide libraries have been constructed to select polypeptides that bind to cell surface antigens as described in Kay, Perspect. drug discovery Des.2:251-268,1995 and Kay et al, mol. Divers.1:139-140,1996, the disclosure of each of which is incorporated herein by reference as it relates to the discovery of antigen binding molecules. Proteins such as multimeric proteins have been successfully phage displayed as functional molecules (see, e.g., EP 0349578; EP 4527839 and EP0589877, and Chiswell and McCafferty, Trends biotechnol.10: 80-841992, the disclosure of each of which is incorporated herein by reference as they relate to the use of in vitro display techniques for discovery of antigen binding molecules). In addition, functional antibody fragments such as Fab and scFv fragments have been expressed in vitro display formats (see, e.g., McCafferty et al, Nature 348:552-554, 1990; Barbas et al, Proc. Natl. Acad. Sci. USA 88:7978-7982, 1991; and Clackson et al, Nature 352:624-628,1991, the disclosure of each of which is incorporated herein by reference as it relates to an in vitro display platform for the discovery of antigen binding molecules). In particular, these techniques can be used to identify and improve the affinity of antibodies that bind to CD117 (e.g., GNNK + CD117), which in turn can be used to deplete endogenous hematopoietic stem cells of a patient (e.g., a human patient) in need of hematopoietic stem cell transplantation therapy.

In addition to in vitro display techniques, computer modeling techniques can be used to design and identify antibodies and antibody fragments that bind to CD117 (e.g., GNNK + CD117) in silico. For example, using computer modeling techniques, one skilled in the art can screen libraries of antibodies and antibody fragments in silico for molecules capable of binding to a particular epitope, such as an extracellular epitope of the antigen. Antibodies and antigen-binding fragments thereof identified by these computational techniques may be used in conjunction with the therapeutic methods described herein, such as the cancer and autoimmune disease therapeutic methods described herein and the patient-regulatory procedures described herein.

Antibodies and antigen-binding fragments thereof that bind to CD117 (e.g., GNNK + CD117) on the surface of a cell (e.g., a cancer cell, an autoimmune cell, or a hematopoietic stem cell) and are internalized by the cell through, for example, receptor-mediated endocytosis can be identified using additional techniques. For example, the in vitro display techniques described above can be modified to screen for antibodies and antigen-binding fragments thereof that bind to CD117 (e.g., GNNK + CD117) on the surface of cancer cells, autoimmune cells, or hematopoietic stem cells and are subsequently internalized. Phage display represents one such technique that can be used in conjunction with this screening paradigm. To identify antibodies and fragments thereof that bind to CD117 (e.g., GNNK + CD117) and are subsequently internalized by cancer cells, autoimmune cells, or hematopoietic stem cells, one skilled in the art can modify the phage display technique described, for example, in Williams et al, Leukemia 19:1432-1438,2005, the disclosure of which is incorporated herein by reference in its entirety. For example, using mutagenesis methods known in the art, recombinant phage libraries can be generated that encode, inter alia, antibodies, antibody fragments, such as scFv fragments, Fab fragments, diabodies, triabodies, and triabodies, that contain randomized amino acid cassettes (e.g., in one or more or all of the CDRs or equivalent regions thereof, or antibodies or antibody fragments)¹⁰Fn3 domain or ligand. The framework regions, hinges, Fc domains, and other regions of an antibody or antibody fragment can be designed such that they are non-immunogenic in humans due to, for example, having human germline antibody sequences or sequences that exhibit only minor variations relative to human germline antibodies.

Phage libraries containing randomized antibodies or antibody fragments covalently bound to phage particles can be incubated with CD117 (e.g., GNNK + CD117) antigen using phage display techniques described herein or known in the art, e.g., by first incubating the phage library with a blocking agent such as, for example, milk protein, bovine serum albumin, and/or IgG in order to remove phage encoding antibodies or fragments thereof that exhibit non-specific protein binding and phage encoding antibodies or fragments thereof that bind Fc domains, and then incubating the phage library with a population of hematopoietic stem cells. The phage library can be incubated with a target cell, such as a cancer cell, an autoimmune cell, or a hematopoietic stem cell, for a time sufficient to allow the CD 117-specific antibody or antigen-binding fragment thereof (e.g., GNNK + CD 117-specific antibody or antigen-binding fragment thereof) to bind to a cell surface CD117 (e.g., cell surface GNNK + CD117) antigen and subsequently be internalized by the cancer cell, autoimmune cell, or hematopoietic stem cell (e.g., from 30 minutes to 6 hours at 4 ℃, such as 1 hour at 4 ℃). Phage containing antibodies or fragments thereof that do not exhibit sufficient affinity for one or more of these antigens to allow binding to and internalization by cancer cells, autoimmune cells, or hematopoietic stem cells can then be removed by washing the cells, for example, with cold (4 ℃) 0.1M glycine buffer at pH 2.8. Phage that bind to an antibody or fragment thereof that is internalized by a cancer cell, an autoimmune cell, or a hematopoietic stem cell can be identified by, for example, lysing the cell and recovering the internalized phage from the cell culture medium. The phage may then be amplified in the bacterial cell by incubating the bacterial cell with the recovered phage in 2xYT medium, for example, using methods known in the art. The phage recovered from the medium can then be characterized, for example, by determining the nucleic acid sequence of the gene encoding the antibody or fragment thereof inserted into the phage genome. The encoded antibody or fragment thereof can then be prepared de novo by chemical synthesis (e.g., chemical synthesis of an antibody fragment, such as an scFv fragment) or by recombinant expression (e.g., recombinant expression of a full-length antibody).

An exemplary method for in vitro evolution of anti-CD 117 (e.g., anti-GNNK + CD117) antibodies for use with the compositions and methods described herein is phage display. Phage display libraries can be generated by screening antibodies for similar regions in the CDRs or antibody-like scaffold of an antibody (e.g.,¹⁰loop BC, CD and DE of Fn3 domain) within the coding sequence. The template antibody coding sequence into which these mutations are introduced may be, for example, a native human germline sequence. These mutations can be made using standard mutagenesis techniques known in the art. Thus, each mutant sequence encodes in addition to one or more amino acidsAntibodies corresponding to the template outside the variation. Retroviral and phage display vectors can be engineered using standard vector construction techniques known in the art. The P3 phage display vector along with a compatible protein expression vector can be used to generate phage display vectors for antibody diversification.

The mutated DNA provides sequence diversity, and each transformant phage displays a variant of the original template amino acid sequence encoded by the DNA, resulting in a population of phage (library) displaying a large number of different but structurally related amino acid sequences. Due to the well-defined (well-defined) structure of the hypervariable regions of antibodies, amino acid variations introduced in phage display screens are expected to alter the binding properties of the binding peptides or binding domains without significantly altering their overall molecular structure.

In a typical screen, a phage library can be contacted with and allowed to bind to one of the aforementioned antigens or epitopes thereof. To facilitate separation of the binders (binders) and non-binders, it is convenient to immobilize the target on a solid support. Phage carrying a CD 117-binding moiety can form a complex with the target on the solid support, while non-binding phage remain in solution and can be washed away with excess buffer. Bound phage can then be released from the target by changing the buffer to extreme pH (pH 2 or pH 10), changing the ionic strength of the buffer, adding denaturants, or other known methods.

The recovered phage can then be amplified by infecting bacterial cells, and the screening process can be repeated with a new pool (pool) that is now depleted of non-binding antibodies and enriched for antibodies that bind CD117 (e.g., GNNK + CD 117). Even a few recovery of bound phage was sufficient to amplify the phage for subsequent screening iterations. After several rounds of selection, the gene sequences encoding the antibodies or antigen-binding fragments thereof derived from the phage clones selected in the binding pool are determined by conventional methods to reveal peptide sequences that confer binding affinity of the phage for the target. During the panning process, the sequence diversity of the population decreases with each round of selection until the desired peptide-bound antibody persists. The sequences may be concentrated on a small number of related antibodies or antigen-binding fragments thereof. An increase in the number of phage recovered in each round of selection indicates that convergence of the library has occurred in the screen (conversion).

Another method for identifying anti-CD 117 antibodies includes the use of humanized non-human antibodies that bind to CD117 (e.g., GNNK + CD117), e.g., according to the following procedure. Consensus Human antibody heavy and light chain Sequences are known in the art (see, e.g., "VBASE" Human germline sequence database; Kabat et al Sequences of Proteins of immunological Interest, fifth edition, U.S. department of Health and Human Services, NIHPubtilization No.91-3242,1991; Tomlinson et al, J.mol.biol.227:776-798, 1992; and Cox et al Eur.J.Immunol.24:827-836, 1994), the disclosure of each of which is incorporated herein by reference as it relates to consensus Human antibody heavy and light chain Sequences). One skilled in the art can use established procedures to identify variable domain framework residues and CDRs of a consensus antibody sequence (e.g., by sequence alignment). One can replace one or more CDRs of the heavy and/or light chain variable domains of a consensus human antibody with one or more corresponding CDRs of a non-human antibody that binds CD117 (e.g., GNNK + CD117) as described herein in order to generate a humanized antibody. This CDR exchange can be performed using gene editing techniques described herein or known in the art.

One example of a consensus human antibody that can be used to make humanized antibodies includes the heavy chain variable domain set forth in SEQ ID NO. 7: (SEQ ID NO:7) and the light chain variable domains listed in SEQ ID NO: 8:

in U.S. Pat. No. 6,054,297 (Genentech)The disclosure of which is incorporated herein by reference as it relates to human antibody consensus sequences. The CDRs in the above sequences are shown in bold.

To produce a humanized antibody, one may recombinantly express a polynucleotide encoding the above consensus sequences in which one or more variable region CDRs have been replaced with one or more variable region CDR sequences of a non-human antibody that binds CD117 (e.g., GNNK + CD 117). Since the affinity of an antibody for a hematopoietic stem cell antigen is mainly determined by CDR sequences, the resulting humanized antibody is expected to exhibit the same affinity for a hematopoietic stem cell antigen as that of a non-human antibody from which the humanized antibody is derived. Methods of determining the affinity of an antibody for a target antigen include, for example, ELISA-based techniques described herein and known in the art, among others, as well as surface plasmon resonance, fluorescence anisotropy, and isothermal titration calorimetry.

For example, the internalization ability of an anti-CD 117 antibody or fragment thereof can be assessed using radionuclide internalization assays known in the art. For example, an antibody or fragment thereof identified using in vitro display techniques described herein or known in the art can be functionalized by incorporating the following radioisotopes: such as¹⁸F、⁷⁵Br、⁷⁷Br、¹²²I、¹²³I、¹²⁴I、¹²⁵I、¹²⁹I、¹³¹I、²¹¹At、⁶⁷Ga、¹¹¹In、⁹⁹Tc、¹⁶⁹Yb、¹⁸⁶Re、⁶⁴Cu、⁶⁷Cu、¹⁷⁷Lu、⁷⁷As、⁷²As、⁸⁶Y、⁹⁰Y、⁸⁹Zr、²¹²Bi、²¹³Bi or²²⁵Ac, is used. For example, radioactive halogens such as polystyrene Beads (e.g., ionization Beads, Thermo Fisher Scientific, inc., Cambridge, MA) can be used with Beads containing electrophilic halogen reagents such as¹⁸F、⁷⁵Br、⁷⁷Br、¹²²I、¹²³I、¹²⁴I、¹²⁵I、¹²⁹I、¹³¹I、²¹¹At is incorporated into the antibody or fragment thereof. The radiolabeled antibody, fragment or ligand thereof may beIncubation with cancer cells, autoimmune cells, or hematopoietic stem cells for a time sufficient to allow internalization (e.g., from 30 minutes to 6 hours at 4 ℃, such as 1 hour at 4 ℃). The cells may then be washed to remove non-internalized antibody or fragment thereof (e.g., using cold (4 ℃) 0.1M glycine buffer at pH 2.8). By detecting the resulting emitted radiation (e.g., gamma radiation) of the cancer cells, autoimmune cells, or hematopoietic stem cells compared to the emitted radiation (e.g., gamma radiation) of the recovered wash buffer, internalized antibodies or fragments thereof can be identified.

Antibody Drug Conjugates (ADC)

Cytotoxins

The antibodies and antigen binding fragments thereof described herein can be conjugated (linked) to a cytotoxin via a linker. In some embodiments, the cytotoxic molecule is conjugated to a cell internalizing antibody or antigen binding fragment thereof as disclosed herein, such that upon uptake of the antibody or fragment thereof by a cell, the cytotoxin can access its intracellular target and mediate hematopoietic cell death. Any number of cytotoxins may be conjugated to the anti-CD 117 antibody, e.g., 1,2,3, 4, 5,6,7, or 8.

Cytotoxins suitable for use with the compositions and methods described herein include, among others known in the art, DNA intercalating agents (e.g., anthracyclines), agents capable of disrupting mitotic spindles (e.g., vinca alkaloids, maytansine alkaloids, and derivatives thereof), RNA polymerase inhibitors (e.g., amatoxins, such as α -amanitine and derivatives thereof), and agents capable of disrupting protein biosynthesis (e.g., agents exhibiting rRNA N-glycosidase activity, such as saporin and ricin a chains).

In some embodiments, the cytotoxin is a microtubule binding agent (e.g., a maytansine or maytansine alkaloid), amatoxin, pseudomonas exotoxin A, deBouganin, diphtheria toxin, saporin, auristatin, anthracycline, calicheamicin, irinotecan, SN-38, duocarmycin, Pyrrolobenzodiazepines (PBDs), pyrrolobenzodiazepine dimers, indolopendrons, and indolopendronazepine dimers, or a variant thereof, or another cytotoxic compound described herein or known in the art.

The antibodies or antigen-binding fragments thereof described herein (e.g., antibodies or antigen-binding fragments that recognize and bind CD117 (such as GNNK + CD117)) can be conjugated to a cytotoxin, such as pseudomonas exotoxin A, deBouganin, diphtheria toxin, amanitins such as alpha-amanitin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicin, irinotecan, SN-38, duocarmycins, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolopendrazines, and indolopendrazines dimers, or a variant thereof, or another cytotoxic compound described herein or known in the art, e.g., for the treatment of a cancer or autoimmune disease described herein, or promoting depletion of endogenous hematopoietic stem cells following administration to a patient in need of hematopoietic stem cell transplantation therapy (e.g., a human patient). In some embodiments, the cytotoxic molecule is conjugated to an internalizing antibody or antigen-binding fragment thereof, such that upon cellular uptake of the antibody or antigen-binding fragment, the cytotoxin can access its intracellular target and mediate endogenous hematopoietic cell death. Cytotoxins suitable for use with the compositions and methods described herein include, among others known in the art, DNA intercalating agents (e.g., anthracyclines), agents capable of disrupting mitotic spindles (e.g., vinca alkaloids, maytansines, maytansine alkaloids, and derivatives thereof), RNA polymerase inhibitors (e.g., amatoxins, such as α -amanitine and derivatives thereof), agents capable of disrupting protein biosynthesis (e.g., agents exhibiting rRNA N-glycosidase activity, such as saporin and ricin a chain).

Additional cytotoxins suitable for use with the compositions and methods described herein include, but are not limited to, among others, 5-ethynyluracil, abiraterone, acylfulvene (acylfulvene), adenosine, adodecylenol (adozelesin), aldesleukin, altretamine, ammostemin, amamaduox, amifostine, aminolevulinic acid (aminolevulinic acid), amrubicin (amrubicin), amsacrine, anagrelide (anagrelide), anastrozole (anastrozole), andrographolide, angiogenesis inhibitors, anagrex (antarelix), anti-dorsal morphogenetic protein-1, anti-androgens, prostate cancer, anti-estrogens, anti-neoperone (antanoplaston), antisense oligonucleotides, aphrodistin (aphrodistine), gene modulators, apoptosis modulators, purines (amastatin), metastatin (atastatin), antisense oligonucleotides (atastatin), and combinations thereof, Amoxicillin (atrimustine), apistatin 1 (axinstatin 1), apistatin 2 (axinstatin 2), apistatin 3 (axinstatin 3), azasetron (azasetron), azatropin (azatoxixin), diazotyrosine, baccatin III derivatives (baccatin IIIderivatives), banlangol (balanol), batimastat (batimastat), BCR/ABL antagonists, benzodihydrophin (benzochlorines), benzoylstaurosporine (benzostaurosporine), beta lactam derivatives, beta-alicine (beta-aletinine), beta-calicheamicin B (betacellamycinB), blignan acid, bI inhibitors, bicalutamide (calciramide), bizerine (biquetriene), dipyridamide (betahistidinyl-chloride), betanidine (betahistidinB), betadine B (betanidine), betanidine (biazospiramycin), betanidine (2), betanidine (betanidine), betanidine (blebetahistidinin B), betadine B (IBE), betanidine (IBE), betahistidinin B), betadine B (IBE), betadine B, beta-beta, Calcipotriol, calphostin C (calphostin C), camptothecin derivatives (e.g., 10-hydroxy-camptothecin), capecitabine (capecitabine), formamide-aminotriazole (carboxamide-amino-triazole), carboxyamidotriazole (carboxyyamidotriazole), capecitabine (carzelesin), casein kinase inhibitors, castanospermine, cecropin B (cecropin B), cetrorelix (cetrorelix), chlorin, chloroquinoxalinylsulfonamide, cicaprost (cicaprost), cisporphyrin, cladribine (clatribine), clomiphene and analogs thereof, clotrimazole, clarithromycin A (collismin A), clarithromycin B (collismin B), combretastatin A4 (bretastine A4), combretastatin analogs, canavanine (canavanine), bevaccin (816), nostoc acid A), candida albicans A (816), candida albicans A (monocalcin A), candida albicans A (A), candida albicans A, cyclopentaquinone, cyclopropanam, daptomycin (cyclopycin), cytarabine sodium octadecyl phosphate (cytarabine ocfosfate), cytolytic factor, hexaestrol phosphate (cytostatin), dacomizumab, decitabine, dehydromembraneosphingosine B, 2'deoxycoformycin (2' Deoxyoflomycin) (DCF), deslorelin (deslorelin), dexifosfamide (desfomamide), dexrazoxane (dexrazoxane), dexverapamil (dexverapamil), diazaquinone (diazizuoquone), hymexaspertisin B, dexdoxycycline (didox), diethylspermidine (didehydronornorgestamine), dihydro-5-azacytidine (dihydocytidine), dihydrotaxol (dioxoxin), dioxadoxycycline (dioxadoxycycline), spiramycin (dermolide), escolone, doxycycline (doxycycline), doxycycline (doxycycline), doxycycline (doxycycline), doxycycline, doxyc, Edelfosine, edrecolomab, eflornithine (eflornithine), elemene, efletifluoride, epothilone, epithilones, epristeride (epristeride), estramustine and its analogs, etoposide 4' -phosphate (also known as etopofoss), exemestane, fadrozole, fazabine, vefetamine (fenretinide), filgrastim, finasteride (fmasteride), fraxidil (flavopiridol), lefluzelastine (flezelastine), fursterone (fluasterone), fludarabine, fludroxydanamycin hydrochloride (fluodynolactomycin hydrochloride), fophenmetmex (forfenican), formestane (formestane), futricin (stricin), fotemustine (trospicine), flutemozine (fludioxonil), gazetidine (HH), gaboxadol (valproate, valcanine), glutathione (valcanine), gavagaridine (HHdiol), glutathione (valcanine), glutathione(s), glutathione (valcanidine), and glutathione (valcanidine), glutathione (HHnocirine), glutathione(s) inhibitors (valcanidine), valcanine), valcanidine), valcanine, valcanidine), and (HH-l, valcanidine (valcanine, valcanidine), and (valcanidine), or a (, Hypericin, ibandronic acid, idoxifene, idomenone, imofantrine, imofosfamine, ilomastat, imidazolacridone, imiquimod, immunostimulatory peptides, iobenguanide, idorubicin, Ipomoeal, irinotecan, ilolat, irsogladine, isobenzoguanazole, jelsbergide, cahaladrolide, F kakakakahalolide F, lamellarin-N (lamellarin-N triacetate), lanreotide, leinareomycin, letamifostin, leguminoxane, lentinan, sulbactin, lipocaline, lipophilic amide, platinum (7), meglumine, platinum (7) and its salts, Lutetium porphyrin (lutetium texaphyrin), lithophylline (lysofyline), maxolone (maspin), matrix metalloproteinase inhibitor, menoraril (menogaril), rnerbarone, metrelelin (meterin), methioninase, metoclopramide, MIF inhibitor, mifepristone (ifendrosine), miltefosine (miltefosine), mithramycin (mithracin), mitoguazone (mitoguazone), dibromodulcitol, mitomycin and its analogs, mitonaphthylamine (mitonafide), mitoxantrone (mitoxantrone), moffarotene (mofatrotene), molgramostim (molindone), mecarroline (mitoxantrone), melarsolone B (myloxide B), medroxyprogesterone ((acetyl-phenacline), nevirapine (neferin), neforin (neviradine), neviradine (nevirapine), nevirapine (nevirapine), naproxine (nevirapine), nevirapine (nevirapine), napine (naproxine), naproxine (naproxen), naproxine (e), naproxine (naproxine), naproxine (nap, Nemorubicin (nemorubicin), neridronic acid, nilutamide (nilutamide), lissamycin (nisamycin), ritulin (nitrulysin), octreotide (octreotide), oxkerne (okicenone), onapristone (onapristone), ondansetron (ondansetron), olanexin (oracin), ormaplatin (ormaplatin), oxaliplatin (oxaliplatin), enomycin (oxyaauromycin), taxol and its analogs, panomine (palauamine), palmitoyl rhizomycin (palmitylrhizoxin), pamidronic acid, panaxytriol, paminofene (pancoifene), pamabrastin (abamectin), papaverin (palliatine), asparaginase (pegararubicin), piceatannomycin (penoxerucin), pirfenidone (penoxsulosin), paradoxin (penoxsulosin), penoxepirubicin), penoxerucin (penoxsulin), penoxsulin (penoxsulin), penoxsulin (penoxsulin), penox, Purine nucleoside phosphorylase inhibitors, raltitrexed, rhizomycin, rogurimide, rohitudine, lubijiron B1(rubiginone B1), rupesil (ruboxyl), safrog (safingol), saint's plain (saintopin), myophyllol A (sarcophylol A), sargrastim (sargramostim), sobuzoxazone (sobuzoxazone), sonamine (sonermin), pamidronic acid (spifosic acid), spicamycin D (spicamycin D), spiromustine (spicerustine), stetimide (stipiamide), sulfinosine, tamoxifen (tallimustine), tegafur (tegafur), temozolomide, teniposide, tialisine (thibetastatin), thiocoraline (thiocoraline), tirapazamine (tirapazamine), topotecan (topotecan), toprostatin (topentin), triciribine (triciribine), trimetrexate (trimetrexate), veratramine (veramine), vinorelbine (vinorelbine), visatin (vinxaline), vorozole (vorozole), zeniplatin (zeniplatin) and benzalkonium C (lasicorb).

The anti-CD 117 antibodies and antigen binding fragments thereof described herein may be conjugated to a cytotoxin that is a microtubule binding agent. As used herein, the term "microtubule binding agent" refers to a compound that acts by disrupting the microtubule network, which is essential for mitotic and interphase cell function in a cell. Examples of microtubule binding agents include, but are not limited to, maytansine alkaloids and derivatives thereof, such as those described herein or known in the art, vinca alkaloids, such as vinblastine, vinblastine sulfate, vincristine sulfate, vindesine, and vinorelbine, taxanes, such as docetaxel and paclitaxel, macrolides, such as discodermolide (discodermolide), colchicine, and epothilones and derivatives thereof, such as epothilone B or derivatives thereof.

Maytansine alkaloids

In some embodiments, the microtubule binding agent is maytansine, a maytansine alkaloid, or an analog of a maytansine alkaloid. Maytansinoids are mitotic inhibitors that bind to microtubules and act by inhibiting tubulin polymerization. Maytansine was first isolated from the east African shrub Maytenus serrata (Maytenus serrata) (U.S. Pat. No. 3,896,111). Subsequently, it was discovered that certain microorganisms also produce maytansinoids, such as maytansinol and C-3 maytansinol esters (U.S. Pat. No. 4,151,042). Synthetic maytansinol and derivatives and analogs thereof are disclosed in, for example, U.S. Pat. nos. 4,137,230, 4,248,870, 4,256,746, 4,260,608, 4,265,814, 4,294,757, 4,307,016, 4,308,268, 4,308,269, 4,309,428, 4,313,946, 4,315,929, 4,317,821, 4,322,348, 4,331,598, 4,361,650, 4,364,866, 4,424,219, 4,450,254, 4,362,663 and 4,371,533. Maytansinoid drug moieties are attractive drug moieties in antibody drug conjugates because they: (i) is relatively easy to prepare by fermentation or chemical modification, derivatizes the fermentation product, (ii) is easy to derivatize with functional groups suitable for conjugation to antibodies via non-disulfide linkers, (iii) is stable in plasma, and (iv) is effective on a variety of tumor cell lines.

Examples of suitable maytansinoids include esters of maytansinol, synthetic maytansinol, and maytansinol analogs and derivatives. Included herein are any cytotoxins that inhibit microtubule formation and are highly toxic to mammalian cells, such as maytansine alkaloids, maytansinol, and maytansinol analogs and derivatives.

Examples of suitable maytansinol esters include those having a modified aromatic ring and those having modifications at other positions. Such suitable maytansinoids are disclosed in U.S. Pat. nos. 4,137,230, 4,151,042, 4,248,870, 4,256,746, 4,260,608, 4,265,814, 4,294,757, 4,307,016, 4,308,268, 4,308,269, 4,309,428, 4,313,946, 4,315,929, 4,317,821, 4,322,348, 4,331,598, 4,361,650, 4,362,663, 4,364,866, 4,424,219, 4,450,254, 4,322,348, 4,362,663, 4,371,533, 5,208,020, 5,416,064, 5,475,092, 5,585,499, 5,846,545, 6,333,410, 7,276,497 and 7,473,796, the disclosure of each being incorporated herein by reference as they relate to maytansine and its derivatives.

In some embodiments, the immunoconjugates of the invention utilize a thiol-containing maytansinoid (DM1), formally referred to as N²' -Deacetyl-N²' - (3-mercapto-1-oxopropyl) -maytansine as a cytotoxic agent. DM1 is represented by structural formula (VII):

in another embodiment, the conjugates of the invention utilize a thiol-containing maytansine alkaloid N²' -Deacetyl-N²' (4-methyl-4-mercapto-1-oxopentyl) -maytansine (e.g., DM4) as a cytotoxic agent. DM4 is represented by structural formula (V):

another maytansinoid comprising a side chain containing a sterically hindered thiol bond is N²' -Deacetyl-N²' (4-mercapto-1-oxopentyl) -maytansine (referred to as DM3), represented by structural formula (VI):

each of the maytansinoids taught in U.S. Pat. nos. 5,208,020 and 7,276,497 may also be used in the conjugates of the present invention. In this regard, the entire disclosures of 5,208,020 and 7,276,697 are incorporated herein by reference.

Many positions on maytansinoids can be used as sites for chemical linking of the linking moiety. For example, the C-3 position having a hydroxyl group, the C-14 position modified with a hydroxymethyl group, the C-15 position modified with a hydroxyl group, and the C-20 position having a hydroxyl group are all expected to be useful. In some embodiments, the C-3 position serves as the position of a chemical linking moiety, and in some particular embodiments, the C-3 position of maytansinol serves as the position of a chemical linking moiety. There are many linking groups known in the art for preparing antibody-maytansine alkaloid conjugates, including, for example, U.S. Pat. nos. 5,208,020, 6,441,163, and EP 0425235B 1; chari et al, Cancer Research 52: 127-; and those disclosed in us 2005/0169933 a1, the disclosures of which are expressly incorporated herein by reference. Additional linking groups are described and exemplified herein.

The present disclosure also includes various isomers and mixtures of maytansine alkaloids and conjugates. Certain compounds and conjugates of the invention can exist in a variety of stereoisomeric, enantiomeric, and diastereomeric forms. Several descriptions of the production of such antibody-maytansine alkaloid conjugates are provided in U.S. Pat. nos. 5,208,020, 5,416,064, 6,333,410, 6,441,163, 6,716,821, and 7,368,565, each of which is incorporated herein in its entirety.

The therapeutically effective number of maytansinoid molecules bound per antibody molecule can be determined by spectrophotometric measurements of the ratio of absorbance at 252nm and 280 nm. Conjugation of an average of 3 to 4 maytansinoid molecules per antibody molecule can enhance cytotoxicity to target cells without negatively affecting the function or solubility of the antibody, although one toxin molecule/antibody can enhance cytotoxicity over the antibody alone. The average number of maytansinoid molecules/antibodies or antigen-binding fragments thereof may be, for example, 1-10 or 2-5.

Anthracyclines

In other embodiments, the antibodies and antigen binding fragments thereof described herein may be conjugated to a cytotoxin that is an anthracycline molecule. Anthracyclines are antibiotic compounds that exhibit cytotoxicity. Research has shown that anthracyclines can operate to kill cells by a number of different mechanisms, including: 1) embedding drug molecules into the DNA of cells to inhibit DNA-dependent nucleiAcid synthesis; 2) free radicals are generated by the drug and then react with cellular macromolecules to cause damage to the cell, or 3) interactions of drug molecules with the cell membrane [ see, for example,Anthracycline Antibiotics In Cancer Therapypeterson et al, "Transport And Storage Of And acyclic cycle InExperimental Systems And Manual Leukamia"; bachur, Free radial Damage, supra, at pages 97-102]. Due to their cytotoxic potential, anthracyclines have been used to treat a number of cancers, such as leukemia, breast cancer, lung cancer, ovarian adenocarcinoma, and sarcoma. [ see for example,Anthracycline:Current Status And New DevelopmentsP.H-Wiernik, page 11]. Commonly used anthracyclines include doxorubicin, epirubicin, idarubicin and daunomycin.

The anthracycline Analog Doxorubicin (ADRIAMYCINO) is believed to interact with DNA by intercalation and inhibit the process of topoisomerase II, which unzips DNA for transcription. After the topoisomerase II complex breaks the DNA strand for replication, doxorubicin stabilizes the topoisomerase II complex, preventing the DNA double helix from being resealed, thereby stopping the replication process. Doxorubicin and Daunorubicin (DAUNOMYCIN) are prototypical cytotoxic natural product anthracycline chemotherapeutics (Sessa et al, (2007) cardiovasc. toxicol.7: 75-79).

Pyrrolobenzodiazepines (PBD)

In other embodiments, the anti-CD 117 antibodies or antigen-binding fragments thereof described herein can be conjugated to a cytotoxin that is a Pyrrolobenzodiazepine (PBD) or a cytotoxin comprising a PBD. PBDs are natural products produced by certain actinomycetes and have been shown to be sequence selective DNA alkylating compounds. PBD cytotoxins include, but are not limited to, anthracyclines, dimeric PBDs, and those disclosed, for example, in: hartley, J.A. (2011) "the level of pyrolobizodization as antiattumour agents," expert Opin. Inv. drug,20(6), "733-" 744; and Antonow, d.; thurston, D.E. (2011) "Synthesis of DNA-interactive pyrolo [2,1-c ] [1,4] benzodiazepines (PBDs)," chem.Rev.111:2815- "2864.

Calicheamicin

In other embodiments, the antibodies and antigen binding fragments thereof described herein may be conjugated to a cytotoxin that is a calicheamicin molecule. The antibiotics of the calicheamicin family are capable of generating double-stranded DNA breaks at sub-picomolar concentrations. For the preparation of conjugates of the calicheamicin family, see U.S. Pat. nos. 5,712,374, 5,714,586, 5,739,116, 5,767,285, 5,770,701, 5,770,710, 5,773,001, and 5,877,296 (all belonging to the American Cyanamid Company). Structural analogs of calicheamicin that may be used include, but are not limited to, those disclosed in, for example: hinman et al, Cancer Research 53: 3336-; lode et al, Cancer Research 58: 2925-; and the aforementioned American Cyanamid U.S. patent.

Auristatin

The anti-CD 117 antibodies and antigen-binding fragments thereof described herein can be conjugated to a cytotoxin that is an auristatin (U.S. patent nos. 5,635,483, 5,780,588). Auristatins are antimitotic agents that interfere with microtubule dynamics, GTP hydrolysis, and cell nucleus and cell division (Woyke et al (2001) antimicrob. Agents and Chemother.45(12):3580-3584), and have anti-cancer (U.S. Pat. No. 5,663,149) and antifungal activity (Pettit et al (1998) antimicrob. Agents Chemother.42: 2961-2965). (U.S. Pat. Nos. 5,635,483 and 5,780,588). The auristatin drug moiety may be attached to the antibody via the N- (amino) terminus or the C- (carboxyl) terminus of the peptide drug moiety (WO 02/088172).

Exemplary auristatin embodiments include the N-terminally linked monomethylauristatin drug moieties DE and DF, disclosed in Senter et al, Proceedings of the American association for Cancer Research, Volume 45, Abstract Number 623, filed 3/28/2004, the disclosure of which is expressly incorporated by reference in its entirety.

An exemplary auristatin embodiment is MMAE, where the wavy line represents the point of covalent attachment of the linker of the antibody-linker conjugate (-L-Z-Ab, as described herein).

Another exemplary auristatin embodiment is MMAF, where the wavy line represents the point of covalent attachment of the linker of an antibody-linker conjugate (-L-Z-Ab, as described herein), as disclosed in US 2005/0238649:

auristatins can be prepared according to the following method: U.S. Pat. nos. 5,635,483; U.S. Pat. nos. 5,780,588; pettit et al (1989) J.Am.chem.Soc.111: 5463-5465; pettit et al (1998) Anti-Cancer Drug Design 13: 243-277; pettit, G.R. et al Synthesis,1996, 719-725; pettit et al (1996) J.chem.Soc.Perkin Trans.15: 859-863; and Doronina (2003) nat. Biotechnol.21(7): 778-.

Amanitin shiitake venom

In some embodiments, the cytotoxin of the antibody-drug conjugate is an RNA polymerase inhibitor. In some embodiments, the RNA polymerase inhibitor is amatoxin or a derivative thereof.

In some embodiments, the cytotoxin is amatoxin or a derivative thereof, such as α -amanitin, β -amanitin, γ -amanitin, amanitin amide, amanitin nontoxic cyclic peptide, amanitin carboxylic acid, and amanitin nontoxic cyclic peptide. The structures of various naturally occurring amatoxins are represented by formula II and accompanying Table 1, and are disclosed, for example, in Zantotti et al, int.J. peptide Protein Res.30,1987, 450-459.

For example, the antibodies and antigen-binding fragments described herein may bind to amatoxin to form a conjugate represented by the formula Ab-Z-L-Am, wherein Ab is the antibody or antigen-binding fragment thereof, L is a linker, Z is a chemical moiety and Am is amatoxin. Many positions on amatoxin or its derivatives may be used as the position for covalently binding the linking moiety L, and thus the antibody or antigen-binding fragment thereof. In some embodiments, Am-L-Z is represented by formula (I)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substitutedHeteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene), optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

and is

Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD 117).

In some embodiments, Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, L-Z is

Wherein S is a sulfur atom, which represents a reactive substituent (e.g., an-SH group from a cysteine residue) present within an antibody or antigen-binding fragment thereof that binds CD 117.

In some embodiments, the conjugate is represented by one of formulae IV, IVA or IVB:

wherein X is S, SO orSO₂And Ab is shown to indicate the point at which Ab attaches. In some embodiments, Am-L-Z is

Where Ab is shown to indicate the point at which Ab attaches.

In some embodiments, Am-L-Z-Ab is

Where Ab is shown to indicate the point at which Ab attaches.

In some embodiments, Am-L-Z-Ab is

Where Ab is shown to indicate the point at which Ab attaches.

In some embodiments, the Am-L-Z precursor is

Wherein the maleimide reacts with a thiol group present on a cysteine in the antibody.

In some embodiments, the Am-L-Z precursor is

Wherein the maleimide reacts with a thiol group present on a cysteine in the antibody.

In some embodiments, Am-L-Z is represented by formula (IA)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene radical) Optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, - (C ═ O) -, or a combination thereof;

z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD 117); and is

Wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, L-Z is

In some embodiments, Am-L-Z is represented by formula (IB)

Wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine together with the oxygen atom to which they are bound to form an optionally substituted 5-membered heterocycloalkyl group;

R₃is H, R_COr R_D；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_C、OR_D、NHR_COr NR_CR_D；

R₉Is H, OH, OR_COR OR_D；

X is-S-, -S (O) -or-SO₂-；

R_Cis-L-Z;

R_Dis optionally substituted alkyl (e.g., C)₁-C₆Alkyl), optionally substituted heteroalkyl (e.g., C)₁-C₆Heteroalkyl), optionally substituted alkenyl (e.g., C)₂-C₆Alkenyl), optionally substituted heteroalkenyl (e.g., C)₂-C₆Heteroalkenyl), optionally substituted alkynyl (e.g., C)₂-C₆Alkynyl), optionally substituted heteroalkynyl (e.g., C)₂-C₆Heteroalkynyl), optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;

l is a linker, such as optionally substituted alkylene (e.g., C)₁-C₆Alkylene), optionally substituted heteroalkylene (C)₁-C₆Heteroalkylene), optionally substituted alkenylene (e.g., C)₂-C₆Alkenylene), optionally substituted heteroalkenylene (e.g., C)₂-C₆Heteroalkenylene), optionally substituted alkynylene (e.g., C)₂-C₆Alkynylene), optionally substituted heteroalkynylene (e.g., C)₂-C₆Heteroalkynylene), optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, peptide, diA peptide, - (C ═ O) -, or a combination thereof;

z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD 117); and is

Wherein Am contains exactly one R_CAnd (4) a substituent.

In some embodiments, L-Z is

In some embodiments, R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form a 5-membered heterocycloalkyl group of the formula:

wherein Y is- (C ═ O) -, - (C ═ S) -, - (C ═ NR_E) -or- (CR)_ER_E’) -; and is

R_EAnd R_E’Each independently is optionally substituted C₁-C₆alkylene-R_COptionally substituted C₁-C₆Heteroalkylene-R_COptionally substituted C₂-C₆alkenylene-R_COptionally substituted C₂-C₆Heteroalkenylene-R_COptionally substituted C₂-C₆alkynylene-R_COptionally substituted C₂-C₆Heteroalkynylene-R_COptionally substituted cycloalkylene-R_COptionally substituted heterocycloalkylene-R_COptionally substituted arylene-R_COr optionally substituted heteroarylene-R_C。

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃is H or R_C；

R₄Is H, OH, OR_C、OR_D、R_COr R_D；

R₅Is H, OH, OR_C、OR_D、R_COr R_D；

R₆Is H, OH, OR_C、OR_D、R_COr R_D；

R₇Is H, OH, OR_C、OR_D、R_COr R_D；

R₈Is OH, NH₂、OR_COr NHR_C；

R₉Is H or OH;

x is-S-, -S (O) -or-SO₂-; and is

Wherein R is_CAnd R_DEach as defined above.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁Is H, OH, OR_AOR OR_C；

R₂Is H, OH, OR_BOR OR_C；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃is H or R_C；

R₄And R₅Each independently is H,OH、OR_C、R_COR OR_D；

R₆And R₇Each is H;

R₈is OH, NH₂、OR_COr NHR_C；

R₉Is H or OH;

x is-S-, -S (O) -or-SO₂-; and is

Wherein R is_CAs defined above.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁Is H, OH OR OR_A；

R₂Is H, OH OR OR_B；

R_AAnd R_BWhen present, combine with the oxygen atom to which they are bound to form:

R₃、R₄、R₆and R₇Each is H;

R₅is OR_C；

R₈Is OH or NH₂；

R₉Is H or OH;

x is-S-, -S (O) -or-SO₂-; and is

Wherein R is_CAs defined above. Such amanitin conjugates are described, for example, in U.S. patent application publication No. 2016/0002298, the disclosure of which is incorporated herein by reference in its entirety.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁And R₂Each independently is H or OH;

R₃is R_C；

R₄、R₆And R₇Each is H;

R₅is H, OH or OC₁-C₆An alkyl group;

R₈is OH or NH₂；

R₉Is H or OH;

x is-S-, -S (O) -or-SO₂-; and is

Wherein R is_CAs defined above. Such amanitin conjugates are described, for example, in U.S. patent application publication No. 2014/0294865, the disclosure of which is incorporated herein by reference in its entirety.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁And R₂Each independently is H or OH;

R₃、R₆and R₇Each is H;

R₄and R₅Each independently is H, OH, OR_COr R_C；

R₈Is OH or NH₂；

R₉Is H or OH;

x is-S-, -S (O) -or-SO₂-; and is

Wherein R is_CAs defined above. Such amanitin conjugates are described, for example, in U.S. patent application publication No. 2015/0218220, the disclosure of which is incorporated herein by reference in its entirety.

In some embodiments, Am-L-Z is represented by formula (IA) or formula (IB),

wherein R is₁And R₂Each independently is H or OH;

R₃、R₆and R₇Each is H;

R₄and R₅Each independently is H or OH;

R₈is OH, NH₂、OR_COr NHR_C；

R₉Is H or OH;

x is-S-, -S (O) -or-SO₂-; and is

Wherein R is_CSuch as the aboveAs defined. Such amanitin conjugates are described, for example, in U.S. patent nos. 9,233,173 and 9,399,681 and US 2016/0089450, the disclosure of each of which is incorporated herein by reference in its entirety.

In some embodiments, Am-L-Z is

Additional amanitins that may be used for conjugation to antibodies or antigen-binding fragments thereof according to the compositions and methods described herein are described in, for example, WO 2016/142049; WO 2016/071856; WO 2017/149077; WO 2018/115466; and WO 2017/046658, the disclosure of each of which is incorporated herein by reference in its entirety.

In some embodiments, Am-L-Z is represented by formula (II), formula (IIA), or formula (IIB),

wherein X is S, SO or SO₂；R₁Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof; and R is₂Is H or a linker covalently bound to the antibody or antigen-binding fragment thereof via a chemical moiety Z formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within the antibody or antigen-binding fragment thereof; wherein when R is₁When is H, R₂Is a linker, and when R₂When is H, R₁Is a joint. In some embodiments, R₁Is a linker and R₂Is H and the linker and chemical moiety together are L-Z, is

In one embodiment, Am-L-Z-Ab is:

in one embodiment, Am-L-Z-Ab is:

in some embodiments, the cytotoxin is α -amanitin in some embodiments, α -amanitin is a compound of formula III in some embodiments, α -amanitin of formula III is attached to an anti-CD 117 antibody via linker L¹-R⁹Any of the above) with α -amanitin of formula III to provide α -amanitin-linker conjugates of formula I, IA, IB, II, IIA or IIB¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is β -amanitin in some embodiments, α -amanitin is a compound of formula III in some embodiments, β -amanitin of formula III is attached to an anti-CD 117 antibody via linker L¹-R⁹Any of the above) with β -amanitin of formula III to provide β -amanitin-linker conjugates of formula I, IA, IB, II, IIA or IIB¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises ═ O) (C)H₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is gamma amanitin. In some embodiments, the gamma amanitine is a compound of formula III. In some embodiments, the γ -amanitine of formula III is attached to the anti-CD 117 antibody via linker L. The linker L may be in several possible positions (e.g., R)¹-R⁹Any of (a) to gamma-amanitine of formula III) to provide gamma-amanitine-linker conjugates of formula I, IA, IB, II, IIA or IIB. In some embodiments, the linker is attached at position R¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, a joint packIncluding the PAB-Ala-Val portion. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is amanitin. In some embodiments, -amanitine is a compound of formula III. In some embodiments, the amanitin of formula III is attached to the anti-CD 117 antibody via linker L. The linker L may be in several possible positions (e.g., R)¹-R⁹Any of (a) to a-amanitin of formula III) to provide a-amanitin-linker conjugate of formula I, IA, IB, II, IIA or IIB. In some embodiments, the linker is attached at position R¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linkerIncluding the PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is amanitin. In some embodiments, the amanita is a compound of formula III. In some embodiments, the amanit of formula III is attached to the anti-CD 117 antibody via linker L. The linker L may be in several possible positions (e.g., R)¹-R⁹Any of) with an amanitol of formula III to provide an amanitol-linker conjugate of formula I, IA, IB, II, IIA or IIB. In some embodiments, the linker is attached at position R¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group(PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is an amanitin amide. In some embodiments, the amanitin amide is a compound of formula III. In some embodiments, the amanitin amide of formula III is attached to the anti-CD 117 antibody via linker L. The linker L may be in several possible positions (e.g., R)¹-R⁹Any of) with an amanitin amide of formula III to provide an amanitin amide-linker conjugate of formula I, IA, IB, II, IIA or IIB. In some embodiments, the linker is attached at position R¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a group selected from Val-Ala and Val-CitThe dipeptide of (1). In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is amanitin nontoxic cyclic peptide. In some embodiments, the amanitin nontoxic cyclic peptide is a compound of formula III. In some embodiments, the amanitin nontoxic cyclic peptide of formula III is attached to the anti-CD 117 antibody via linker L. The linker L may be in several possible positions (e.g., R)¹-R⁹Any of) is attached to the anserine nontoxic cyclic peptide of formula III at any one position to provide anserine nontoxic cyclic peptide-linker conjugates of formula I, IA, IB, II, IIA or IIB. In some embodiments, the linker is attached at position R¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises hydrazine, disulfideA thioether or a dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is amatoxin monohydroxyfop carboxylic acid. In some embodiments, the amanitin carboxylic acid is a compound of formula III. In some embodiments, the amanitin carboxylic acid of formula III is attached to the anti-CD 117 antibody via linker L. The linker L may be in several possible positions (e.g., R)¹-R⁹Any of the above) with a monohydroxyamatoxin carboxylic acid of formula III to provide a monohydroxyamatoxin carboxylic acid-linker conjugate of formula I, IA, IB, II, IIA or IIB. In some embodiments, the linker is attached at position R¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the linker is attached at position R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some casesIn an embodiment, the joint is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, the cytotoxin is a amanita nontoxic cyclic peptide. In some embodiments, the amanita nontoxic cyclic peptide is a compound of formula III. In some embodiments, the amanita nontoxic cyclic peptide of formula III is attached to the anti-CD 117 antibody via linker L. The linker L may be in several possible positions (e.g., R)¹-R⁹Any of (a) to a pro-anserine nontoxic cyclic peptide of formula III) to provide a pro-anserine nontoxic cyclic peptide-linker conjugate of formula I, IA, IB, II, IIA or IIB. In some embodiments, the linker is attached at position R¹To (3). In some embodiments, the linker is attached at position R²To (3). In some embodiments, the linker is attached at position R³To (3). In some embodiments, the linker is attached at position R⁴To (3). In some embodiments, the linker is attached at position R⁵To (3). In some embodiments, the linker is attached at position R⁶To (3). In some embodiments, the joint is attached in placePut R⁷To (3). In some embodiments, the linker is attached at position R⁸To (3). In some embodiments, the linker is attached at position R⁹To (3). In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

Synthetic methods for preparing amanitin are described in U.S. patent No. 9,676,702, which is incorporated herein by reference.

Antibodies and antigen-binding fragments for use with the compositions and methods described herein can be conjugated to amanitins such as alpha-amanitin or variants thereof using conjugation techniques known in the art or described herein. For example, antibodies and antigen-binding fragments thereof that recognize and bind CD117 (such as GNNK + CD117) may be conjugated to amanitins such as α -amanitin or variants thereof, as described in US 2015/0218220, the disclosure of which is incorporated herein by reference as it relates to, for example, amanitins such as α -amanitin and variants thereof, as well as covalent linkers that may be used for covalent conjugation.

Exemplary antibody-drug conjugates useful for binding with the methods described herein can be formed by reaction of an antibody or antigen-binding fragment thereof with amatoxin conjugated to a linker containing substituents suitable for reaction with reactive residues on the antibody or antigen-binding fragment thereof. Amatoxins conjugated with linkers containing substituents suitable for reaction with reactive residues on the antibodies or antigen-binding fragments thereof described herein include, but are not limited to, 7' C- (4- (6- (maleimido) hexanoyl) piperazin-1-yl) -amatoxin; 7' C- (4- (6- (maleimido) hexanamido) piperidin-1-yl) -amatoxin; 7' C- (4- (6- (6- (maleimido) hexanamido) hexanoyl) piperazin-1-yl) -amanitin; 7' C- (4- (4- ((maleimido) methyl) cyclohexanecarbonyl) piperazin-1-yl) -amatoxin; 7' C- (4- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanoyl) piperazin-1-yl) -amatoxin; 7' C- (4- (2- (6- (maleimido) hexanamido) ethyl) piperidin-1-yl) -amanitin; 7' C- (4- (2- (6- (6- (maleimido) hexanamido) ethyl) piperidin-1-yl) -amanitin; 7' C- (4- (2- (4- ((maleimido) methyl) cyclohexanecarboxamido) ethyl) piperidin-1-yl) -amatoxin; 7' C- (4- (2- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) ethyl) piperidin-1-yl) -amatoxin; 7' C- (4- (2- (3-carboxypropionylamino) ethyl) piperidin-1-yl) -amanitin; 7' C- (4- (2- (2-bromoacetamido) ethyl) piperidin-1-yl) -amanitin; 7' C- (4- (2- (3- (pyridin-2-yldisulfanyl) propionamido) ethyl) piperidin-1-yl) -amatoxin; 7' C- (4- (2- (4- (maleimido) butanamido) ethyl) piperidin-1-yl) -amatoxin; 7' C- (4- (2- (maleimido) acetyl) piperazin-1-yl) -amanitin; 7' C- (4- (3- (maleimido) propionyl) piperazin-1-yl) -amanitin; 7' C- (4- (4- (maleimido) butyryl) piperazin-1-yl) -amanitin; 7' C- (4- (2- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) ethyl) piperidin-1-yl) -amatoxin; 7' C- (3- ((6- (maleimido) hexanamido) methyl) pyrrolidin-1-yl) -amatoxin; 7' C- (3- ((6- (6- (maleimido) hexanamido) methyl) pyrrolidin-1-yl) -amatoxin; 7' C- (3- ((4- ((maleimido) methyl) cyclohexanecarboxamido) methyl) pyrrolidin-1-yl) -amatoxin; 7' C- (3- ((6- ((4- (maleimido) methyl) cyclohexanecarboxamido) hexanamido) methyl) pyrrolidin-1-yl) -amatoxin; 7' C- (4- (2- (6- (2- (aminooxy) acetamido) hexanamido) ethyl) piperidin-1-yl) -amanitin; 7' C- (4- (2- (4- (2- (aminooxy) acetamido) butyramido) ethyl) piperidin-1-yl) -amanitin; 7' C- (4- (4- (2- (aminooxy) acetamido) butyryl) piperazin-1-yl) -amanitin; 7' C- (4- (6- (2- (aminooxy) acetamido) hexanoylamino) piperazin-1-yl) -amanitin; 7' C- ((4- (6- (maleimido) hexanamido) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (maleimido) hexanamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (6- (maleimido) hexanamido) piperazin-1-yl) methyl) -amatoxin; (R) -7' C- ((3- ((6- (maleimido) hexanamido) methyl) pyrrolidin-1-yl) methyl) -amatoxin; (S) -7' C- ((3- ((6- (maleimido) hexanamido) methyl) pyrrolidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (6- (maleimido) hexanamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (4- ((maleimido) methyl) cyclohexanecarboxamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (maleimido) hexanamido) ethyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (6- (maleimido) hexanamido) ethyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (4- ((maleimido) methyl) cyclohexanecarboxamido) ethyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) ethyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((3- ((6- (6- (maleimido) hexanamido) -S-methyl) pyrrolidin-1-yl) methyl) -amatoxin; 7' C- ((3- ((6- (6- (maleimido) hexanamido) -R-methyl) pyrrolidin-1-yl) methyl) -amatoxin; 7' C- ((3- ((4- ((maleimido) methyl) cyclohexanecarboxamido) -S-methyl) pyrrolidin-1-yl) methyl) -amatoxin; 7' C- ((3- ((4- ((maleimido) methyl) cyclohexanecarboxamido) -R-methyl) pyrrolidin-1-yl) methyl) -amatoxin; 7' C- ((3- ((6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) methyl) pyrrolidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (3-carboxypropionylamino) ethyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (6- (6- (maleimido) hexanamido) hexanoyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanoyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (maleimido) acetyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (3- (maleimido) propionyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (4- (maleimido) butyryl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (2- (maleimido) acetamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (4- (maleimido) butyrylamino) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((3- ((6- (maleimido) hexanamido) methyl) azetidin-1-yl) methyl) -amatoxin; 7' C- ((3- (2- (6- (maleimido) hexanamido) ethyl) azetidin-1-yl) methyl) -amatoxin; 7' C- ((3- ((4- ((maleimido) methyl) cyclohexanecarboxamido) methyl) azetidin-1-yl) methyl) -amatoxin; 7' C- ((3- (2- (4- ((maleimido) methyl) cyclohexanecarboxamido) ethyl) azetidin-1-yl) methyl) -amatoxin; 7' C- ((3- (2- (6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) ethyl) azetidin-1-yl) methyl) -amatoxin; 7' C- (((2- (6- (maleimido) -N-methylhexanamido) ethyl) (methyl) amino) methyl) -amatoxin; 7' C- (((4- (6- (maleimido) -N-methylhexamido) butyl (methyl) amino) methyl) -amatoxin, 7' C- ((2- (2- (6- (maleimido) hexanamido) ethyl) azetidin-1-yl) methyl) -amatoxin, 7' C- ((2- (2- (6- (4- ((maleimido) methyl) cyclohexanamido) hexanamido) ethyl) azetidin-1-yl) methyl) -amatoxin, 7' C- ((4- (6- (2- (aminooxy) acetamido) hexanamido) hexanyl) piperazin-1-yl) methyl) -amatoxin, 7' C- ((4- (1- (6- (2- (aminooxy) acetamido) hexanamido) hexanoyl) methyl) -amatoxin - (aminoxy) -2-oxo-6, 9,12, 15-tetraoxa-3-azepane-17-acyl) piperazin-1-yl) methyl) -amanitin; 7' C- ((4- (2- (2- (aminooxy) acetamido) acetyl) piperazin-1-yl) methyl) -amanitin; 7' C- ((4- (3- (2- (aminooxy) acetamido) propionyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (4- (2- (aminooxy) acetamido) butyryl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (6- (2- (aminooxy) acetamido) hexanamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (2- (2- (aminooxy) acetamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (4- (2- (aminooxy) acetamido) butyrylamino) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (20- (aminooxy) -4, 19-dioxo-6, 9,12, 15-tetraoxa-3, 18-diazicosyl) piperidin-1-yl) methyl) -amatoxin; 7' C- (((2- (6- (2- (aminooxy) acetamido) -N-methylhexanamido) ethyl) (methyl) amino) methyl) -amanitin; 7' C- (((4- (6- (2- (aminooxy) acetamido) -N-methylhexanamido) butyl) (methyl) amino) methyl) -amanitin; 7' C- ((3- ((6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) methyl) pyrrolidin-1-yl) -S-methyl) -amatoxin; 7' C- ((3- ((6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexanamido) -R-methyl) pyrrolidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (2-bromoacetamido) ethyl) piperazin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (2-bromoacetamido) ethyl) piperidin-1-yl) methyl) -amatoxin; 7' C- ((4- (2- (3- (pyridin-2-yl-disulfanyl) propionylamino) ethyl) piperidin-1-yl) methyl) -amatoxin; 6' O- (6- (6- (maleimido) hexanamido) hexyl) -amatoxin; 6' O- (5- (4- ((maleimido) methyl) cyclohexanecarboxamido) pentyl) -amatoxin; 6' O- (2- ((6- (maleimido) hexyl) oxy) -2-oxoethyl) -amatoxin; 6' O- ((6- (maleimido) hexyl) carbamoyl) -amatoxin; 6' O- ((6- (4- ((maleimido) methyl) cyclohexanecarboxamido) hexyl) carbamoyl) -amatoxin; 6' O- (6- (2-bromoacetamido) hexyl) -amatoxin; 7' C- (4- (6- (azido) hexanamido) piperidin-1-yl) -amatoxin; 7' C- (4- (hex-5-ynylamido) piperidin-1-yl) -amatoxin; 7' C- (4- (2- (6- (maleimido) hexanamido) ethyl) piperazin-1-yl) -amanitin; 7' C- (4- (2- (6- (6- (maleimido) hexanamido) ethyl) piperazin-1-yl) -amanitin; 6' O- (6- (6- (11, 12-didehydro-5, 6-dihydro-dibenzo [ b, f ] azacycloocta (azocin) -5-yl) -6-oxohexanamido) hexyl) -amatoxin; 6' O- (6- (hex-5-alkynylamino) hexyl) -amanitin; 6' O- (6- (2- (aminooxy) acetylamido) hexyl) -amanitin; 6' O- ((6-aminooxy) hexyl) -amatoxin; and 6' O- (6- (2-iodoacetamido) hexyl) -amatoxin. The foregoing connectors that are useful for use in conjunction with the compositions and methods described herein are described, among other things, in, for example, U.S. patent application publication No. 2015/0218220, the disclosure of which is incorporated herein by reference in its entirety.

Additional cytotoxins that may be conjugated to antibodies or antigen-binding fragments thereof that recognize and bind CD117 (such as GNNK + CD117) for use in the direct treatment of cancer, autoimmune conditions, or for modulating a patient (e.g., a human patient) in preparation for hematopoietic stem cell transplantation therapy include, but are not limited to, among others, 5-ethynyluracil, abiraterone, acylfulvene (acylfulvene), acyclopentanol (adeprenol), adozelesin (adozelesin), aldesleukin, altretamine, ammustine, amidol (amidox), amifostine, aminolevulinic acid (aminolevulinic acid), amrubicin (amrubicin), amacridine, anagrelide (anagrelide), anastrozole (anastrozole), andrographolide, angiogenesis inhibitors, anaglix (arantix), anti-dorsal morphogenetic protein-1, antiandrogen, prostate cancer, anti-opioneomycin (anti-oncogenic) Antisense oligonucleotides, adriamycin glycine (aphrodillinlycine), apoptotic gene modulators, apoptotic modulators, depurination nucleic acids, oxanilin (asulamine), atamestane (atamestane), amoxastine (atrimustine), acitansine 1 (axinstatin 1), acitansine 2 (axinstatin 2), acitansine 3 (axinstatin 3), azasetron (azasetron), azatutin (azatoxxin), diazotyrosine, baccatin III derivatives (baccatin III derivatives), banlangonol (balanol), batimastat (batistat), BCR/ABL antagonists, benzodihydrophin (benzochlolins), benzoyl staurosporine (benzoguanadine), beta lactam derivatives, beta-alcalimide (betaxanthatin), betadine B (betanidine), betanidine (betanidine B), betanidine (betanidine, betahistidinin), betahistidinin (azacitine), betahistidinine (azastine), betahistidinine (betastatin, betahistidinine (betadine), betastatin (betahistidinine), betadine (betastatin, betahistidinine (betadine), betadine (betadine B, betahistidinine (beta-beta, bistratene A, bizelesin (bizelesin), bizelesin (breffllate), bleomycin A2, bleomycin B2, briprimine (bropirimine), butortititanium (budotitane), thionine sulfoximine, calcipotriol, calphostin C (calphostin C), camptothecin derivatives (e.g., 10-hydroxy-camptothecin), capecitabine (capecitabine), formamide-aminotriazole (carboxamide-amiodazole), carboxyamidotriazole (carboxamidotriazole), cabenzamide (carboxamidorizazole), carvedilin (carzelesin), casein kinase inhibitors, castanospermine, cecropin B (cecropin B), cetrorelix (cetrorelix), dihydrocolcotrinol, chloroquinoxaline, cetroritin (cicast), cis-protoporphyrin, clindamycin (clinoptidine), clotrimycin (clindamycin A), clotrimazole B, clotrimazole A, clindamycin A, 4, brevictimycin A, brevictimycin B, and their analogs, Conaginin (conaginin), canaxetine 816(crambescidin 816), crimsonitol (crisnatol), cryptophycin 8, cryptophycin A derivatives, kalafoxin A (curacin A), cyclopentaquinone, cyclopropanam (cycloplatam), cipomycin (cyclopycin), cytarabine sodium octadecyl phosphate (cytarabine octasfate), cytolytic factor, hexetil phosphate (cytostatin), daclizumab, decitabine, dehydrohymexathrin B, 2'deoxycoformycin (2' Deoxynofuromycin) (DCF), deslorelin (deslorelin), dexifosfamide (dexfosfamide), dexrazoxane (dexrazoxane), dexverapamil (dexverapamil), diazepine (diazepine B), dexrazoxane (doxazone), dexdidiamine (5-dihydrosphingosine), dihydrosphingosine (dihydrosphingosine), doxylamine (dihydrosphingosine (5), dihydrosphingosine (dihydrosphingosine), dihydrosphingosine (dihydrosphingosine, dihydrosphingosine (dihydrosphingosine) and doxycycline) as a derivative (doxycycline), and, Discodermolide, docosanol (docosanol), dolasetron, doxifluridine, droloxifene, dronabinol, duocarmycin SA (duocanycin SA), ebselen, etocarmustine, edelfosine, eflomuzumab, eflornithine (eflornithine), elemene, ethimidifluoride, epothilone, epithilones, epristeride (epristeride), estramustine and its analogs, etoposide 4' -phosphate (also known as etofosos), exemestane, fadrozole, fazarabine, vefetilide (fenretinide), filgrastimastine (filgrastimatine), finasteride (fmasteride), velvelvelvetravepirubidine (flupiridoxidol), fuyrerazine (eflavendum), fluzene), flutensegrin (flusterine), flusterine (doxorubine), gadoformorphine (gadolinium (gadoformatrofosfamine), gadoformatrovudine (gadolinium (gadoformatrovudine), flusterine (gadolinium (gadoformatrofossilxate), valtretin (gadine), flusterine (gadoformatrovudine), flusterine (gadofovir), tretin (gadoforestrine), tretin (gadoformycin), trex (gadoformycin), galocitabine (galocitabine), ganirelix (ganirelix), gelatinase inhibitor, gemcitabine, glutathione inhibitor, and prometham (hepsulfam), homoharringtonine (HHT), hypericin, ibandronic acid, idoxifene (idoxifene), itomenone (idramantone), imofosine (ilmofosine), ilomastat (ilomastat), imidazolacridones (imidazoacridones), imiquimod (imiquimod), immunocastrin, iobenzoguanide, idorubicin, Ipomoeatin, irinotecan, iractin (iroglatin), israquinone (isobenzoguanazole), Jeragulide (jacaraglitazolide), carhatriliff (karat), tricirisin (iritedirazone), lipophilic cysteine (lanoline), furilaginin (lanolate), furilacline (lanolate), furilazone), furilacline (lanolate), and its (lanolate), or its (lanolate), or a, and its (lanolate, or a, Lithoclinamide 7(lissoclinamide 7), lobaplatin, lometrexol (lomerexol), lonidamine (lonidamine), losoxantrone (losoxantrone), loxoribine (loxoribine), lurtotecan (lurotecan), lutetium porphyrin (lutetium texaphyrin), lisofenine (lysofylline), maxol, masafenib (maspin), matrix metalloproteinase inhibitors, melanolide (menogaril), rneberarone, metrelelin (meterelin), methionine, metoclopramide, MIF inhibitors, mifepristone (ifistrone), miltefosine (miltefosine), mithramycin (mithracin), mitoguazone (mitoguazone), mitomycin (mitomycin), mitomycin (oxymatrine), mitomycin (mitomycin B), milbemycin (mitomycin), milbemycin (milbemycin), milbemycin (luteolin (mitomycin), milbemycin (antimycin), milbemycin B), milbemycin (mitomycin), milbemycin (milbemycin), milbemycin (mitomycin (milbemycin), milbemycin (e) and analogs thereof, milbemycin (milbemycin), milbemycin (milbemycin, N-substituted benzamides, nafarelin (nafarelin), nagracetin (nagarestrip), naproxen (napavin), naftifine (napterin), narcotine (nartogastin), nedaplatin (nedaplatin), nemorubicin (nemorubicin), neridronic acid, nilutamide (nilutamide), lissamycin (nisamycin), riluzoline (nitrulyn), octreotide (octreotide), oxcarbazone (oknone), onapristone (ondanesetron), ondansetron (ondansetron), olacin (oracin), ormaplatin (oxaliplatin), oxaliplatin (oxprenomycin), taxol and analogues thereof, paminomine (lapatin), hexadecanoyl phosphonic acid (nafarestatin), penoxepin (flavopirtine), penoxpreneoxycarb (flavopirtine), pamidrin (penoxpreneoxycarb), pamidrin (penoxprenothricin (pentostatin), pamidrin (penoxprenothione (pentostatin), pamidronate (pentostatin), pamoate), pamidronate (pentostatin), pamoate (pentostatin (e), pamoate (pentostatin (e), pamoate (pentostatin (e), pamoate (e (pentostatin (pento, Pesphamide, phenylazamycin (phenylazinomomycin), saproline (picibanil), pirarubicin (pirarubicin), pirtroxine (pirritrexim), podophyllotoxin (podophylotoxin), podophyllotoxin (porfiromycin), purine nucleoside phosphorylase inhibitors, raltitrexed (ratrexed), rhizomycin, rogurimide (rogletimin), rhohemidine, rubiginone B1(rubiginone B1), rupeside (ruboxxyl), saflufenago (saflufenol), santoprene (saintoxin), myophyllitol A (sarchrysophanol A), sargrastim (sargramostim), sobuzosin (sobuzosin), sobuzosin (sobuzoxanine), sondamin (sormenein), paspalyphosphate (pamidrapamycin D), spicamycin D (spiculicidin), spiratin (murabutine), picatin (mycoprotein), picatine (mycophenolate), picatine (mycophenolate), picatine), piceatin (e), piceatannostatin (e, picatine), picatine, piceatannostatin (e), piceatannostatin (e, piceatin (e, picatine), piceatannostatin, Triciribine (triciribine), trimetrexate (trimetrexate), veratramine (veramine), vinorelbine (vinorelbine), vildagliptin (vinxatone), vorozole (vorozole), zeniplatin (zeniplatin) and benzalkob (zilascorb).

Linkers for chemical conjugation

A variety of linkers can be used to conjugate an antibody or antigen-binding fragment described herein (e.g., an antibody or antigen-binding fragment thereof that recognizes and binds CD117, such as GNNK + CD117) to a cytotoxic molecule.

The term "linker" as used herein refers to a divalent chemical moiety comprising a chain of covalent bonds or atoms that covalently attaches an antibody or fragment thereof (Ab) to a drug moiety (D) to form an antibody-drug conjugate of the present disclosure (ADC; Ab-Z-L-cytotoxin). Suitable linkers have two reactive ends, one for conjugation to an antibody and the other for conjugation to a cytotoxin. The antibody-conjugation reactive terminus (reactive moiety, Z') of the linker is typically a site capable of conjugation to the antibody via a cysteine thiol or lysine amine group on the antibody, and is thus typically a thiol-reactive group such as a double bond (as in maleimide) or a leaving group such as a chloro, bromo, iodo or R-sulfonyl group, or an amine-reactive group such as a carboxyl group; while the antibody-conjugating reactive end of the linker is typically a site capable of conjugating with a cytotoxin by forming an amide bond with a basic amine or carboxyl group on the cytotoxin, and is thus typically a carboxyl or basic amine group. When the term "linker" is used to describe a linker in conjugated form, one or both reactive termini will be absent (such as reactive moiety Z, which has been converted to chemical moiety Z) or incomplete (such as carbonyl of carboxylic acid only) due to the formation of bonds between the linker and/or cytotoxin and between the linker and/or antibody or antigen binding fragment thereof. Such conjugation reactions are described further below.

In some embodiments, the linker is cleavable under intracellular conditions such that cleavage of the linker releases the drug unit from the antibody in an intracellular environment. In still other embodiments, the linker unit is not cleavable, and the drug is released by, for example, antibody degradation. The linkers useful in the ADCs of the present invention are preferably stable extracellularly, preventing aggregation of the ADC molecules, and keeping the ADC readily soluble in the monomeric state in aqueous media. The ADC is preferably stable and remains intact, i.e. the antibody remains linked to the drug moiety, prior to transport or delivery into the cell. The linker is stable outside the target cell and can be cleaved at an effective rate inside the cell. The available linker will: (i) maintaining the specific binding characteristics of the antibody; (ii) allowing intracellular delivery of the conjugate or drug moiety; (iii) remain stable and intact, i.e., not cleaved, until the conjugate is delivered or transported to its target site; and (iv) maintaining the cytotoxic, cell killing or cytostatic effect of the cytotoxic moiety. The stability of the ADC can be measured by standard analytical techniques such as mass spectrometry, HPLC and separation/analysis techniques LC/MS. Covalent attachment of the antibody and drug moiety requires that the linker have two reactive functional groups, i.e., a bivalent in the sense of a reaction. Bivalent linking reagents useful for attaching two or more functional or biologically active moieties, such as peptides, nucleic acids, drugs, toxins, antibodies, haptens and reporter groups are known and methods for their resulting conjugates have been described (Hermanson, G.T, (1996) Bioconjugate Techniques; Academic Press: New York, p.234-242).

Linkers include those that can be cleaved by: for example, enzymatic hydrolysis, photolysis, hydrolysis under acidic conditions, hydrolysis under basic conditions, oxidation, disulfide reduction, nucleophilic cleavage, or organometallic cleavage (see, e.g., Lerich et al, bioorg.Med.chem.,20: 571-.

Linkers hydrolyzable under acidic conditions include, for example, hydrazones, semicarbazones, thiosemicarbazones, cis-aconitamides, orthoesters, acetals, ketals, and the like. (see, e.g., U.S. Pat. No. 5,122,368; No. 5,824,805; No. 5,622,929; Dubowchik and Walker,1999, pharm. therapeutics 83: 67-123; Neville et al, 1989, biol. chem.264:14653-14661, the disclosure of each of which is incorporated herein by reference in its entirety as it relates to a linker suitable for covalent conjugation). Such linkers are relatively stable under neutral pH conditions, such as in blood, but are unstable below pH 5.5 or pH 5.0 (the approximate pH of lysosomes).

Linkers cleavable under reducing conditions include, for example, disulfides. A variety of disulfide linkers are known in the art, including, for example, disulfide linkers formed as follows can be used: SATA (N-succinimidyl-S-acetylthioacetate), SPDP (N-succinimidyl-3- (2-pyridyldithio) propionate), SPDB (N-succinimidyl-3- (2-pyridyldithio) butyrate) and SMPT (N-succinimidyl-oxycarbonyl-alpha-methyl-alpha- (2-pyridyldithio) toluene), SPDB and SMPT (see, for example, Thorpe et al, 1987, Cancer Res.47: 5924-: antibodies Conjugates in radiodiagnosis and Therapy of cancer (c.w. vogel, ed. Oxford u.press, 1987. see also us patent No. 4,880,935, the disclosure of each of which is incorporated herein by reference in its entirety as it relates to linkers suitable for covalent conjugation).

Additional linkers suitable for use in the synthesis of drug-antibody conjugates as described herein include those capable of releasing cytotoxins through 1, 6-elimination processes (a "self-immolative" group), such as p-aminobenzyl alcohol (PABC), p-aminobenzyl (PAB), 6-maleimidocaproic acid, pH sensitive carbonates, and other reagents described in Jain et al, pharm. Res.32:3526-3540,2015, the disclosure of which is incorporated herein by reference in its entirety.

In some embodiments, the linker comprises an autodegradable group, such as the aforementioned PAB or PABC (p-aminobenzyloxycarbonyl), which is disclosed in: for example, Carl et al, J.Med.chem. (1981)24: 479-; chakravarty et al (1983) J.Med.chem.26: 638-; US 6214345; US 20030130189; US 20030096743; US 6759509; US 20040052793; US 6218519; US 6835807; US 6268488; US 20040018194; w098/13059; US 20040052793; US 6677435; US 5621002; US 20040121940; w02004/032828). Other such chemical moieties ("autocleavable linkers") capable of performing this process include methylene carbamates and heteroaryl groups such as aminothiazoles, aminoimidazoles, aminopyrimidines, and the like. Linkers containing such heterocyclic autodegradable groups are disclosed in the following: for example, U.S. patent publication nos. 20160303254 and 20150079114 and U.S. patent No. 7,754,681; hay et al (1999) bioorg.Med.chem.Lett.9: 2237; US 2005/0256030; de Groot et al (2001) J.org.chem.66: 8815-8830; and US 7223837.

The linker susceptible to enzymatic hydrolysis may be, for example, a peptide-containing linker that is cleaved by an intracellular peptidase or protease, including but not limited to lysosomal or endosomal proteases. One advantage of using intracellular proteolytic release of the therapeutic agent is that, when conjugated, the agent is generally impaired and the serum stability of the conjugate is generally higher. In some embodiments, the peptidyl linker is at least two amino acids in length or at least three amino acids in length. Exemplary amino acid linkers include dipeptides, tripeptides, tetrapeptides, or pentapeptides. Examples of suitable peptides include peptides comprising the following amino acids: such as valine, alanine, citrulline (Cit), phenylalanine, lysine, leucine, and glycine. Amino acid residues that constitute a component of an amino acid linker include naturally occurring amino acid residues, as well as small numbers of amino acids and non-naturally occurring amino acid analogs, such as citrulline. Exemplary dipeptides include valine-citrulline (vc or val-cit) and alanine-phenylalanine (af or ala-phe). Exemplary tripeptides include glycine-valine-citrulline (gly-val-cit) and glycine-glycine (gly-gly-gly). In some embodiments, the linker comprises a dipeptide such as Val-Cit, Ala-Val, or Phe-Lys, Val-Lys, Ala-Lys, Phe-Cit, Leu-Cit, Ile-Cit, Phe-Arg, or Trp-Cit. Linkers containing dipeptides such as Val-Cit or Phe-Lys are disclosed, for example, in U.S. patent No. 6,214,345, the disclosure of which is incorporated herein by reference in its entirety as it relates to linkers suitable for covalent conjugation. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the dipeptide is used in combination with an autolytic linker.

Linkers suitable for use herein may also include one or more groups selected from: c₁-C₆Alkylene radical, C₁-C₆Heteroalkylene group, C₂-C₆Alkenylene radical, C₂-C₆Heteroalkenylene, C₂-C₆Alkynylene, C₂-C₆Heteroalkynylene, C₃-C₆Cycloalkylene, heterocycloalkylene, arylene, heteroarylene, and combinations thereof, each of which may be optionally substituted. Non-limiting examples of such groups include (CH)₂)_n、(CH₂CH₂O)_nAnd- (C ═ O) (CH)₂)_n-a unit, where n is an integer from 1 to 6, independently selected for each case.

In some embodiments, the linker may comprise one or more of: hydrazine, disulfide, thioether, dipeptide, p-aminobenzyl (PAB) group, heterocyclic autodegradable group, optionally substituted C₁-C₆Alkyl, optionally substituted C₁-C₆Heteroalkyl, optionally substituted C₂-C₆Alkenyl, optionally substituted C₂-C₆Heteroalkenyl, optionally substituted C₂-C₆Alkynyl, optionally substituted C₂-C₆Heteroalkynyl, optionally substituted C₃-C₆Cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, solubility enhancing group, acyl, - (C ═ O) -, or- (CH)₂CH₂O)_n-a group, wherein n is an integer from 1 to 6. One skilled in the art will recognize that one or more of the groups listed may be in the form of a divalent (diradical) species such as C₁-C₆Alkylene, etc.

In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In one embodiment, the p-aminobenzyl group is placed between the cytotoxic drug and the protease cleavage site in the linker. In one embodiment, the p-aminobenzyl group is part of a p-aminobenzyloxycarbonyl unit. In one embodiment, the p-aminobenzyl group is part of a p-aminobenzyl amino unit.

In some embodiments, the linker comprises PAB, Val-Cit-PAB, Val-Ala-PAB, Val-Lys (Ac) -PAB, Phe-Lys (Ac) -PAB, D-Val-Leu-Lys, Gly-Gly-Arg, Ala-Ala-Asn-PAB, or Ala-PAB.

In some embodiments, the linker comprises a combination of one or more of: peptides, oligosaccharides, - (CH)₂)_n-、-(CH₂CH₂O)_n-, PAB, Val-Cit-PAB, Val-Ala-PAB, Val-Lys (Ac) -PAB, Phe-Lys (Ac) -PAB, D-Val-Leu-Lys, Gly-Gly-Arg, Ala-Ala-Asn-PAB or Ala-PAB.

In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6.

Linkers that may be used to conjugate an antibody or antigen-binding fragment thereof to a cytotoxic agent include those linkers that are covalently bound to the cytotoxic agent on one end of the linker and that contain a chemical moiety on the other end of the linker formed by a coupling reaction between a reactive substituent present on the linker and a reactive substituent present within an antibody or antigen-binding fragment thereof that binds CD117 (such as GNNK + CD 117). Reactive substituents that may be present within an antibody or antigen-binding fragment thereof that binds to CD117 (such as GNNK + CD117) include, but are not limited to, hydroxyl moieties of serine, threonine, and tyrosine residues; the amino moiety of a lysine residue; the carboxyl portion of aspartic and glutamic acid residues; and the thiol moiety of a cysteine residue, as well as the propargyl, azido, haloaryl (e.g., fluoroaryl), haloheteroaryl (e.g., fluoroheteroaryl), haloalkyl, and haloheteroalkyl moieties of a non-naturally occurring amino acid.

Examples of linkers useful in the synthesis of drug-antibody conjugates include those containing an electrophile suitable for reacting with nucleophilic substituents present within the antibody or antigen-binding fragment, such as amine and thiol moieties, such as Michael (Michael) acceptors (e.g., maleimides), activated esters, electron deficient carbonyl compounds, and aldehydes, among others. For example, linkers suitable for use in the synthesis of drug-antibody conjugates include, but are not limited to, succinimidyl 4- (N-maleimidomethyl) -cyclohexane-L-carboxylate (SMCC), N-Succinimidyl Iodoacetate (SIA), sulfo-SMCC, m-maleimidobenzoyl-N-hydroxysuccinimide ester (m-maleimidobenzoyl-N-hydroxysuccinimide ester) (MBS), sulfo-MBS and succinimidyl iodoacetate, among others, which are described, for example, in Liu et al, 18:690-697,1979, the disclosure of which is incorporated herein by reference as it relates to linkers for chemical conjugation. Additional linkers include non-cleavable maleimidocaproyl linkers, which are particularly useful for conjugation of microtubule disrupting agents such as auristatins, described by Doronina et al, Bioconjugate chem.17:14-24,2006, the disclosure of which is incorporated herein by reference as it relates to linkers for chemical conjugation.

One skilled in the art will recognize that any one or more of the chemical groups, moieties, and features disclosed herein can be combined in a variety of ways to form linkers useful for conjugating an antibody as disclosed herein to a cytotoxin. Other connectors that can be used in conjunction with the compositions and methods described herein are described, for example, in U.S. patent application publication No. 2015/0218220, the disclosure of which is incorporated herein by reference in its entirety.

Linkers that may be used in conjunction with the antibody-drugs described herein include, but are not limited to, linkers that contain chemical moieties formed by a coupling reaction as depicted in table 1 below. The curves represent the attachment points of the antibody or antigen-binding fragment, respectively, to the cytotoxic molecule.

TABLE 1 exemplary chemical moieties formed by conjugation reactions in the formation of antibody-drugs

One skilled in the art will recognize that the reactive substituent Z attached to the linker participates in a covalent coupling reaction with a reactive substituent on the antibody or antigen-binding fragment thereof to produce a chemical moiety Z, and will recognize the reactive substituent Z. Thus, antibody-drug conjugates that can be used in conjunction with the methods described herein can be formed by reacting an antibody or antigen-binding fragment thereof with a linker or cytotoxin-linker conjugate as described herein that includes a reactive substituent Z suitable for reacting with a reactive substituent on the antibody or antigen-binding fragment thereof to form a chemical moiety Z.

As depicted in table 1, examples of suitable reactive substituents on the linker and antibody or antigen-binding fragment thereof include nucleophile/electrophile pairs (e.g., thiol/haloalkane pairs, amine/carbonyl pairs, or thiol/α, β -unsaturated carbonyl pairs, etc.), diene/dienophile pairs (e.g., azide/alkyne pairs or diene/α, β -unsaturated carbonyl pairs, among others), and the like. Coupling reactions between reactive substituents that form chemical moiety Z include, but are not limited to, thiol alkylation, hydroxyalkylation, amine alkylation, amine or hydroxylamine condensation, hydrazine formation, amidation, esterification, disulfide formation, cycloaddition (e.g., [4+2] Diels-Alder cycloaddition, [3+2] Huisgen cycloaddition, among others), nucleophilic aromatic substitution, electrophilic aromatic substitution, and other reaction forms known in the art or described herein. Preferably, the linker comprises an electrophilic functional group to react with a nucleophilic functional group on the antibody or antigen-binding fragment thereof.

Reactive substituents that may be present within an antibody or antigen-binding fragment thereof as disclosed herein include, but are not limited to, nucleophilic groups such as (i) an N-terminal amine group, (ii) a pendant amine group, e.g., lysine, (iii) a pendant thiol group, e.g., cysteine, and (iv) a sugar hydroxyl or amino group, wherein the antibody is glycosylated. Reactive substituents that may be present within an antibody or antigen-binding fragment thereof as disclosed herein include, but are not limited to, hydroxyl moieties of serine, threonine, and tyrosine residues; the amino moiety of a lysine residue; the carboxyl portion of aspartic and glutamic acid residues; and the thiol moiety of a cysteine residue, as well as the propargyl, azido, haloaryl (e.g., fluoroaryl), haloheteroaryl (e.g., fluoroheteroaryl), haloalkyl, and haloheteroalkyl moieties of a non-naturally occurring amino acid. In some embodiments, the reactive substituent present within an antibody or antigen-binding fragment thereof as disclosed herein comprises an amine or thiol moiety. Some antibodies have reducible interchain disulfides, i.e., cysteine bridges. The antibody can be made reactive for conjugation to a linker reagent by treatment with a reducing agent such as DTT (dithiothreitol). Thus, in theory, each cysteine bridge will form two reactive thiol nucleophiles. Additional nucleophilic groups can be introduced into the antibody by reaction of lysine with 2-iminothiolane (2-iminothiolane) (Traut's reagent), resulting in conversion of the amine to a thiol. Reactive thiol groups can be introduced into an antibody (or fragment thereof) by introducing one, two, three, four, or more cysteine residues (e.g., making a mutant antibody comprising one or more non-natural cysteine amino acid residues). U.S. patent No. 7,521,541 teaches the engineering of antibodies by the introduction of reactive cysteine amino acids.

In some embodiments, the reactive moiety Z attached to the linker is a nucleophilic group that reacts with an electrophilic group present on the antibody. Useful electrophilic groups on antibodies include, but are not limited to, aldehyde and ketone carbonyl groups. The heteroatom of the nucleophilic group can react with an electrophilic group on the antibody and form a covalent bond with the antibody. Useful nucleophilic groups include, but are not limited to, hydrazide, oxime, amino, hydroxyl, hydrazine, thiosemicarbazone, hydrazide carboxylate, and aryl hydrazide.

In some embodiments, Z is the product of the reaction between reactive nucleophilic substituents (such as amine and thiol moieties) present within the antibody or antigen-binding fragment thereof and reactive electrophilic substituents Z. For example, Z may be, inter alia, a michael acceptor (e.g., maleimide), an activated ester, an electron deficient carbonyl compound, or an aldehyde.

In some embodiments, the ADC comprises an anti-CD 117 antibody conjugated via a linker and a chemical moiety Z to amanitin of any one of formulae I, IA, IB, II, IIA or IIB as disclosed herein. In some embodiments, the linker comprises a hydrazine, disulfide, thioether, or dipeptide. In some embodiments, the linker comprises a dipeptide selected from Val-Ala and Val-Cit. In some embodiments, the linker comprises a p-aminobenzyl group (PAB). In some embodiments, the linker comprises a PAB-Cit-Val moiety. In some embodiments, the linker comprises a PAB-Ala-Val moiety. In some embodiments, the linker comprises- (C ═ O) (CH)₂)_n-units, wherein n is an integer from 1 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-。

In some embodiments, the linker comprises — (CH)₂)_n-units, wherein n is an integer from 2 to 6. In some embodiments, the linker is-PAB-Cit-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is-PAB-Ala-Val- (C ═ O) (CH)₂)_n-. In some embodiments, the linker is- (CH)₂)_n-, where n is an integer of 2 to 6. In some embodiments, the linker is- (CH)₂)_n-, where n is 6.

In some embodiments, chemical moiety Z is selected from table 1. In some embodiments, the chemical moiety Z is

Wherein S is a sulfur atom, which represents a reactive substituent (e.g., an-SH group from a cysteine residue) present within an antibody or antigen-binding fragment thereof that binds CD 117.

In some embodiments, linker L and chemical moiety Z taken together are L-Z, is

In some embodiments, L-Z is

In some embodiments, L-Z is

One skilled in the art will recognize that the linker reactive substituent group structure includes maleimide as group Z prior to conjugation to the antibody or antigen-binding fragment thereof. The aforementioned linker moieties and amatoxin-linker conjugates that can be used in conjunction with the compositions and methods described herein are described, for example, in U.S. patent application publication No. 2015/0218220 and patent application publication No. WO2017/149077, the disclosures of which are incorporated herein by reference in their entirety, among others.

Preparation of antibody-drug conjugates

In the ADC of formula I as disclosed herein, the antibody or antigen binding fragment thereof is conjugated to one or more cytotoxic drug moieties (D), e.g., about 1 to about 20 drug moieties per antibody, through a linker L and a chemical moiety Z as disclosed herein. The ADCs of the present disclosure may be prepared by several routes, using organic chemical reactions, conditions and reagents known to those skilled in the art, including: (1) reacting the reactive substituent of the antibody or antigen-binding fragment thereof with a divalent linker reagent to form Ab-Z-L as described above, followed by reaction with drug moiety D; or (2) reacting a reactive substituent of the drug moiety with a divalent linker reagent to form D-L-Z, followed by reaction with a reactive substituent of an antibody or antigen-binding fragment thereof as described above to form an ADC of the formula D-L-Z-Ab, such as Am-Z-L-Ab. Additional methods for preparing ADCs are described herein.

In another aspect, the antibody or antigen-binding fragment thereof has one or more lysine residues that can be chemically modified to introduce one or more sulfhydryl groups. The ADC is then formed by conjugation of the sulphur atom of the sulfhydryl group as described above. Reagents that can be used to modify lysine include, but are not limited to, N-succinimidyl S-acetylthioacetate (SATA) and 2-iminothiolane hydrochloride (Traut' S reagent).

In another aspect, an antibody or antigen-binding fragment thereof can have one or more carbohydrate groups, which can be chemically modified to have one or more sulfhydryl groups. The ADC is then formed by conjugation of the sulphur atom of the sulfhydryl group as described above.

In yet another aspect, the antibody may have one or more carbohydrate groups that can be oxidized to provide an aldehyde (-CHO) group (see, e.g., Laguzza et al, j.med.chem.1989,32(3), 548-55). The ADCs were then formed by conjugation of the corresponding aldehydes as described above. Other Protocols for modifying proteins to attach or associate cytotoxins are described in Coligan et al, Current Protocols in Protein Science, vol.2, John Wiley & Sons (2002), incorporated herein by reference.

Methods for conjugating linker-drug moieties to cell-targeting proteins such as antibodies, immunoglobulins, or fragments thereof are found, for example, in U.S. Pat. nos. 5,208,020; U.S. Pat. nos. 6,441,163; WO 2005037992; in WO2005081711 and WO2006/034488, all of these patents are hereby expressly incorporated by reference in their entirety.

Alternatively, fusion proteins comprising an antibody and a cytotoxic agent may be prepared by, for example, recombinant techniques or peptide synthesis. The length of the DNA may comprise respective regions encoding the two portions of the conjugate that are adjacent to each other or separated by a region encoding a linker peptide that does not destroy the desired properties of the conjugate.

Method of treatment

The aforementioned anti-CD 117 antibodies or conjugates thereof may be used in the following methods for treatment.

As described herein, hematopoietic stem cell transplantation therapy can be administered to a subject in need of treatment for engraftment or reimplantation of one or more blood cell types. Hematopoietic stem cells typically exhibit pluripotency and, therefore, can differentiate into a variety of different blood lineages, including, but not limited to, granulocytes (e.g., promyelocytes, neutrophils, eosinophils, basophils), erythrocytes (e.g., reticulocytes, erythrocytes), thrombocytes (e.g., promegakaryocytes, platelet-producing megakaryocytes, platelets), monocytes (e.g., monocytes, macrophages), dendritic cells, microglia, osteoclasts, and lymphocytes (e.g., NK cells, B cells, and T cells). In addition, hematopoietic stem cells are capable of self-renewal and thus can produce daughter cells with equivalent potential to the parent cells, and also feature the ability to be reintroduced into the transplant recipient, at which time they home to the hematopoietic stem cell niche and reconstitute productive and sustained hematopoiesis.

Thus, hematopoietic stem cells can be administered to patients deficient or deficient in one or more cell types of the hematopoietic lineage in order to reconstitute the deficient or deficient population of cells in vivo, thereby treating pathologies associated with a deficiency or depletion of the endogenous blood cell population. Thus, the compositions and methods described herein can be used to treat non-malignant hemoglobin abnormalities (e.g., hemoglobin abnormalities selected from the group consisting of sickle cell anemia, thalassemia, fanconi's anemia, aplastic anemia, and wiskott-aldrich syndrome). Additionally or alternatively, the compositions and methods described herein may be used to treat an immunodeficiency, such as an congenital immunodeficiency. Additionally or alternatively, the compositions and methods described herein can be used to treat acquired immunodeficiency (e.g., acquired immunodeficiency selected from the group consisting of HIV and AIDS). The compositions and methods described herein can be used to treat metabolic disorders (e.g., a metabolic disorder selected from the group consisting of glycogen storage disease, mucopolysaccharidosis, gaucher's disease, herler disease, sphingolipid storage disease, and metachromatic leukodystrophy).

Additionally or alternatively, the compositions and methods described herein, and in particular the conjugates described herein, may be used to treat malignant tumors or proliferative disorders, such as hematological cancers, myeloproliferative diseases. In the case of cancer treatment, the compositions and methods described herein can be administered to a patient in order to deplete the population of endogenous hematopoietic stem cells prior to hematopoietic stem cell transplantation therapy, in which case the transplanted cells can home to the niche created by the endogenous cell depletion step and establish productive hematopoiesis. This in turn can reconstitute the population of cells depleted during cancer cell elimination, such as during systemic chemotherapy. Exemplary hematologic cancers that can be treated using the compositions and methods described herein include, but are not limited to, acute myelogenous leukemia, acute lymphatic leukemia, chronic myelogenous leukemia, chronic lymphatic leukemia, multiple myeloma, diffuse large B-cell lymphoma, and non-hodgkin's lymphoma, as well as other cancerous conditions, including neuroblastoma.

Additional diseases that may be treated with the compositions and methods described herein include, but are not limited to, adenosine deaminase deficiency and severe combined immunodeficiency disease, hyper-immunoglobulin M syndrome, east-respiratory disease, hereditary lymphohistiocytosis, osteopetrosis, osteogenesis imperfecta, storage disease, thalassemia major, systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, and juvenile rheumatoid arthritis.

The antibodies or antigen-binding fragments and conjugates thereof described herein can be used to induce solid organ transplant tolerance. For example, the compositions and methods described herein can be used to deplete or eliminate a population of cells from a target tissue (e.g., to deplete hematopoietic stem cells from a bone marrow stem cell niche). Upon such depletion of cells from the target tissue, a population of stem or progenitor cells from an organ donor (e.g., hematopoietic stem cells from an organ donor) can be administered to a transplant recipient, and upon implantation of such stem or progenitor cells, transient or stable mixed chimerism (chimerism) can be achieved, allowing long-term transplant organ tolerance without the need for additional immunosuppressive agents. For example, the compositions and methods described herein can be used to induce graft tolerance (e.g., kidney, lung, liver, and heart grafts, among others) in a recipient of a solid organ graft. The compositions and methods described herein are well suited for use with inducing tolerance to solid organ transplants, for example, because a low percentage of temporary or stable donor implants are sufficient to induce long-term tolerance of the transplanted organ.

In addition, the compositions and methods described herein can be used to directly treat cancer, such as cancer characterized by cells that are CD117 +. For example, the compositions and methods described herein may be used to treat leukemia, particularly in patients exhibiting CD117+ leukemia cells. The compositions and methods described herein can be used to directly treat a variety of cancers by depleting CD117+ cancerous cells, such as leukemia cells. Exemplary cancers that may be treated in this manner include hematological cancers such as acute myelogenous leukemia, acute lymphatic leukemia, chronic myelogenous leukemia, chronic lymphatic leukemia, multiple myeloma, diffuse large B-cell lymphoma, and non-hodgkin's lymphoma.

In addition, the compositions and methods described herein can be used to treat autoimmune disorders. For example, the antibody or antigen-binding fragment thereof can be administered to a subject, such as a human patient suffering from an autoimmune disorder, in order to kill CD117+ immune cells. The CD117+ immune cells may be autoreactive lymphocytes, such as T cells that express a T cell receptor that specifically binds to and generates an immune response against an autoantigen. The compositions and methods described herein may be used to treat autoimmune pathologies, such as those described below, by depleting autoreactive CD117+ cells. Additionally or alternatively, the compositions and methods described herein can be used to treat autoimmune diseases by depleting a population of endogenous hematopoietic stem cells prior to hematopoietic stem cell transplantation therapy, in which case the transplanted cells can home to the niche created by the endogenous cell depletion step and establish productive hematopoiesis. This in turn can reconstitute the population of cells that are depleted during the autoimmune cell depletion.

Autoimmune diseases that can be treated using the compositions and methods described herein include, but are not limited to, psoriasis, psoriatic arthritis, Type 1diabetes mellitis (Type 1diabetes), Rheumatoid Arthritis (RA), human Systemic Lupus Erythematosus (SLE), Multiple Sclerosis (MS), Inflammatory Bowel Disease (IBD), lymphocytic colitis, Acute Disseminated Encephalomyelitis (ADEM), addison's disease, alopecia universalis, ankylosing spondylitis, antiphospholipid antibody syndrome (APS), aplastic anemia, autoimmune hemolytic anemia, autoimmune hepatitis, Autoimmune Inner Ear Disease (AIED), autoimmune lymphoproliferative syndrome (ALPS), autoimmune oophoritis, barllosis, behcet's disease, bullous pemphigoid, cardiomyopathy, chagas ' disease, Chronic Fatigue Immune Dysfunction Syndrome (CFIDS), Chronic inflammatory demyelinating polyneuropathy, crohn's disease, cicatricial pemphigoid, celiac disease-dermatitis herpetiformis, cold agglutinin disease, CREST syndrome, malignant atrophic papulopathy, discoid lupus erythematosus, autonomic dysfunction, endometriosis, primary mixed cryoglobulinemia, fibromyalgia-fibromyositis, goodpasture's syndrome, graves disease, guillain-barre syndrome (GBS), hashimoto's thyroiditis, hidradenitis suppurativa, idiopathic and/or acute thrombocytopenic purpura, idiopathic pulmonary fibrosis, IgA neuropathy, interstitial cystitis, juvenile arthritis, kawasaki disease, lichen planus, lyme disease, meniere disease, Mixed Connective Tissue Disease (MCTD), myasthenia gravis, myotonia nervosa, strabismus contracture syndrome (OMS), Optic neuritis, alder's thyroiditis, pemphigus vulgaris, pernicious anemia, polychondritis, polymyositis and dermatomyositis, primary biliary cirrhosis, polyarteritis nodosa, polyglandular syndrome, polymyalgia rheumatica, primary agammaglobulinemia, raynaud's phenomenon, reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, sjogren's syndrome, stiff person syndrome, takayasu's arteritis, temporal arteritis (also known as "giant cell arteritis"), ulcerative colitis, collagenous colitis, uveitis, vasculitis, vitiligo, vulvodynia ("vulvar vestibulitis"), and wegener's granulomatosis.

Routes of administration and administration

The antibodies or antigen-binding fragments thereof described herein can be administered to a patient (e.g., a human patient suffering from cancer, an autoimmune disease, or in need of hematopoietic stem cell transplantation therapy) in a variety of dosage forms. For example, an antibody or antigen-binding fragment thereof described herein can be administered to a patient suffering from cancer, an autoimmune disease, or in need of hematopoietic stem cell transplantation therapy in the form of an aqueous solution, such as an aqueous solution containing one or more pharmaceutically acceptable excipients. Pharmaceutically acceptable excipients for use with the compositions and methods described herein include viscosity modifiers. The aqueous solution may be sterilized using techniques known in the art.

Pharmaceutical formulations comprising an anti-CD 117 antibody and an ADC as described herein are prepared by mixing such an antibody or ADC with one or more optional pharmaceutically acceptable carriers (Remington's Pharmaceutical Sciences 16 th edition, Osol, a. eds. (1980)), either as a lyophilized formulation or as an aqueous solution. Pharmaceutically acceptable carriers are generally non-toxic to recipients at the dosages and concentrations employed, and include, but are not limited to: buffers such as phosphates, citrates and other organic acids; antioxidants, including ascorbic acid and methionine; preservatives (such as octadecyl dimethyl benzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride; benzethonium chloride; phenol, butanol or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose, or sorbitol; salt-forming counterions such as sodium; metal complexes (e.g., Zn-protein complexes); and/or a non-ionic surfactant such as polyethylene glycol (PEG).

The antibodies and antigen-binding fragments described herein can be administered by a variety of routes, such as oral, transdermal, subcutaneous, intranasal, intravenous, intramuscular, intraocular, or parenteral. In any particular case, the most suitable route of administration will depend on the particular antibody or antigen-binding fragment being administered, the patient, the method of pharmaceutical formulation, the method of administration (e.g., time of administration and route of administration), the age, body weight, sex, severity of the disease being treated, the diet of the patient, and the rate of excretion by the patient.

An effective dose of an anti-CD 117 conjugate, antibody, or antigen-binding fragment thereof described herein can range, for example, from about 0.001mg/kg body weight to about 100mg/kg body weight per single (e.g., bolus) administration, multiple administrations, or continuous administration, or can range to achieve an optimal serum concentration of the antibody or antigen-binding fragment thereof (e.g., a serum concentration of 0.0001 μ g/mL to 5000 μ g/mL). The dose may be administered to a subject (e.g., a human) suffering from cancer, an autoimmune disease, or undergoing a regulatory therapy to prepare for receiving a hematopoietic stem cell transplant one or more times per day, week, or month (e.g., 2-10 times). In the case of a regulatory procedure prior to hematopoietic stem cell transplantation, the antibody or antigen-binding fragment thereof can be administered to the patient at a time that optimally promotes engraftment of the exogenous hematopoietic stem cell, e.g., 1 hour to 1 week (e.g., 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, or 7 days) or more prior to administration of the exogenous hematopoietic stem cell transplant.

Using the methods disclosed herein, a physician of skill in the art can administer to a human patient in need of hematopoietic stem cell transplantation therapy an anti-CD 117 ADC, antibody, or antigen-binding fragment thereof capable of binding to an antigen expressed by hematopoietic stem cells, such as an antibody or antigen-binding fragment thereof that binds CD117 (e.g., an antibody or antigen-binding fragment thereof that binds GNNK + CD 117). In this manner, prior to administration of the exogenous hematopoietic stem cell implant, the population of endogenous hematopoietic stem cells can be depleted so as to facilitate implantation of the hematopoietic stem cell implant.

As described above, the antibody may be covalently conjugated to a toxin described herein or known in the art, such as a cytotoxic molecule. For example, an anti-CD 117 antibody or antigen-binding fragment thereof (such as an anti-GNNK + CD117 antibody or antigen-binding fragment thereof) can be covalently conjugated to a cytotoxin, such as pseudomonas exotoxin A, deBouganin, diphtheria toxin, amanitins such as gamma-amanitin, alpha-amanitin, saporin, maytansine alkaloids, auristatins, anthracyclines, calicheamicin, irinotecan, SN-38, duocarmycins, pyrrolobenzodiazepines, pyrrolobenzodiazepine dimers, indolopendazepins dimers, or variants thereof. The conjugation can be performed using covalent bond formation techniques described herein or known in the art. The antibody, antigen-binding fragment thereof, or drug-antibody conjugate can then be administered to the patient by, for example, intravenous administration prior to transplanting exogenous hematopoietic stem cells (such as autologous, syngeneic, or allogeneic hematopoietic stem cells) to the patient.

An anti-CD 117 (e.g., anti-GNNK + CD117) antibody, antigen-binding fragment thereof, or drug-antibody conjugate can be administered prior to hematopoietic stem cell transplantation therapy in an amount sufficient to reduce the number of endogenous hematopoietic stem cells by, e.g., 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or more. The reduction in hematopoietic stem cell count can be monitored using conventional techniques known in the art, such as by FACS analysis of cells expressing characteristic hematopoietic stem cell surface antigens in blood samples drawn from patients at different intervals during regulatory therapy. For example, a physician skilled in the art can draw blood samples from a patient at different time points during regulatory therapy and determine the extent of endogenous hematopoietic stem cell depletion by performing FACS analysis to elucidate the relative concentration of hematopoietic stem cells in the sample using antibodies that bind to hematopoietic stem cell marker antigens. According to some embodiments, when the concentration of hematopoietic stem cells reaches a minimum in response to regulatory therapy with an anti-CD 117 (e.g., anti-GNNK + CD117) antibody, antigen-binding fragment thereof, or drug-antibody conjugate, the physician may end the regulatory therapy and may begin preparing the patient for hematopoietic stem cell transplantation therapy.

An anti-CD 117 (e.g., anti-CNNK + CD117) antibody, antigen-binding fragment thereof, or drug-antibody conjugate can be administered to a patient in an aqueous solution containing one or more pharmaceutically acceptable excipients such as a viscosity modifier. The aqueous solution may be sterilized using techniques described herein or known in the art. The antibody, antigen-binding fragment thereof, or drug-antibody conjugate can be administered to the patient at a dose of, for example, from 0.001mg/kg to 100mg/kg prior to administration of the hematopoietic stem cell graft to the patient. The antibody, antigen-binding fragment thereof, or drug-antibody conjugate can be administered to the patient at a time that optimally promotes engraftment of the exogenous hematopoietic stem cells, for example, 1 hour to 1 week (e.g., 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, or 7 days) or more prior to administration of the exogenous hematopoietic stem cell graft.

After the regulatory therapy is over, the patient may then receive an infusion (e.g., intravenous infusion) of exogenous hematopoietic stem cells, such as from the same physician performing the regulatory therapy or by a different physician. The physician may administer to the patient, for example, a dose of from 1x10³To 1x10⁹Infusion of autologous, syngeneic or allogeneic hematopoietic stem cells per kg of hematopoietic stem cells. The physician may, for example, determine hematopoietic stem cells or cells by taking a blood sample from the patient after administration of the graftThe increase in the concentration of blood lineage cells (such as megakaryocytes, thrombocytes, platelets, erythrocytes, mast cells, myeloblasts, basophils, neutrophils, eosinophils, microglia, granulocytes, monocytes, osteoclasts, antigen presenting cells, macrophages, dendritic cells, natural killer cells, T lymphocytes, and B lymphocytes) monitors the engraftment of hematopoietic stem cell grafts. The assay can be performed, for example, 1 hour to 6 months or more (e.g., 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, 12 weeks, 13 weeks, 14 weeks, 15 weeks, 16 weeks, 17 weeks, 18 weeks, 19 weeks, 20 weeks, 21 weeks, 22 weeks, 23 weeks, 24 weeks, or more) after hematopoietic stem cell transplantation therapy. The discovery that the concentration of hematopoietic stem cells or cells of the hematopoietic lineage has increased after the transplantation therapy (e.g., by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 500% or more) relative to the concentration of the corresponding cell type prior to the transplantation therapy provides an indication that treatment with an anti-CD 117 (e.g., anti-GNNK + CD117) antibody, antigen-binding fragment thereof, or drug-antibody conjugate has successfully facilitated engraftment of the transplanted hematopoietic stem cell implant.

Examples

The following examples are put forth so as to provide those of ordinary skill in the art with a description of how the compositions and methods described herein can be used, made, and evaluated, and are intended to be purely exemplary of the invention and are not intended to limit the scope of what the inventors regard as their invention.