Anti-CD45 antibodies and conjugates thereof
Disclosed are anti-CD45 antibodies and antibody drug conjugates (ADCs) useful in therapeutic methods, including targeting CD45 expressing hematopoietic stem cells (HSCs) or immune cells prior to transplantation.
1. An isolated anti-CD45 antibody, or antigen binding portion thereof, comprising:
(i) a heavy chain comprising a variable region comprising a CDR1 having the amino acid sequence as set forth in SEQ ID NO: 2, a CDR2 having the amino acid sequence as set forth in SEQ ID NO: 3, a CDR3 having the amino acid sequence as set forth in SEQ ID NO: 4, and comprising a light chain comprising a variable region comprising a CDR1 having the amino acid sequence as set forth in SEQ ID NO: 6, a CDR2 having the amino acid sequence as set forth in SEQ ID NO: 7, a CDR3 having the amino acid sequence as set forth in SEQ ID NO: 8;
(ii) a heavy chain comprising a variable region comprising a CDR1 having the amino acid sequence as set forth in SEQ ID NO: 10, a CDR2 having the amino acid sequence as set forth in SEQ ID NO: 11, a CDR3 having the amino acid sequence as set forth in SEQ ID NO: 12, and comprising a light chain comprising a variable region comprising a CDR1 having the amino acid sequence as set forth in SEQ ID NO: 14, a CDR2 having the amino acid sequence as set forth in SEQ ID NO: 15, a CDR3 having the amino acid sequence as set forth in SEQ ID NO: 16; or
(iii) a heavy chain comprising a variable region comprising a CDR1 having the amino acid sequence as set forth in SEQ ID NO: 18, a CDR2 having the amino acid sequence as set forth in SEQ ID NO: 19, a CDR3 having the amino acid sequence as set forth in SEQ ID NO: 20, and comprising a light chain comprising a variable region comprising a CDR1 having the amino acid sequence as set forth in SEQ ID NO: 22, a CDR2 having the amino acid sequence as set forth in SEQ ID NO: 23, a CDR3 having the amino acid sequence as set forth in SEQ ID NO: 24.
2. The anti-CD45 antibody, or antigen binding portion thereof, of claim 1 , wherein:
(i) the heavy chain variable region comprises the amino acid sequence as set forth in SEQ ID NO: 1;
(ii) the heavy chain variable region comprises the amino acid sequence as set forth in SEQ ID NO: 9; or
(iii) the heavy chain variable region comprises the amino acid sequence as set forth in SEQ ID NO: 17.
3. The anti-CD45 antibody, or antigen binding portion thereof, of claim 1 , wherein:
(i) the light chain variable region comprises the amino acid sequence as set forth in SEQ ID NO: 5;
(ii) the light chain variable region comprises the amino acid sequence as set forth in SEQ ID NO: 13; or
(iii) the light chain variable region comprises the amino acid sequence as set forth in SEQ ID NO: 21.
4. The anti-CD45 antibody, or antigen binding portion thereof, of claim 1 , which is (i) a de-immunized antibody, or antigen binding fragment thereof, or (ii) a humanized antibody, or antigen binding fragment thereof, or (iii) a chimeric antibody, or antigen binding fragment thereof.
5. An isolated de-immunized monoclonal anti-CD45 antibody, or antigen binding portion thereof, that specifically binds human CD45 and cyno CD45, wherein the anti-CD45 antibody, or antigen binding portion thereof, of claim 1 is the parent antibody of the de-immunized anti-CD45 antibody, or antigen binding portion thereof.
6. The anti-CD45 antibody of claim 1 , which is an intact monoclonal IgG antibody.
7. The anti-CD45 antibody, or antigen binding portion thereof, of claim 1 , wherein the antibody, or antigen binding portion thereof, is an IgG.
8. A pharmaceutical composition comprising the antibody of claim 1 , and a pharmaceutically acceptable carrier.
9. A method of depleting a population of hematopoietic stem cells (HSC) in a human patient, the method comprising administering to the patient an effective amount of the antibody of claim 1 .
10. The method of claim 9 , further comprising administering to the patient a transplant comprising hematopoietic stem cells.
11. A method comprising administering to a human patient a transplant comprising hematopoietic stem cells, wherein the patient has been previously administered the antibody of claim 1 in an amount sufficient to deplete a population of hematopoietic stem cells or a population of immune cells in the patient.
12. The method of claim 11 , wherein the hematopoietic stem cell is a CD45+ cell.
13. The method of claim 9 , wherein the patient has a blood disease, a metabolic disorder, cancer, or an autoimmune disease, or severe combined immunodeficiency disease (SCID).
14. A method of treating leukemia in a human patient, said method comprising administering the antibody of claim 1 to the human patient having leukemia.
15. An antibody drug conjugate (ADC) comprising the antibody of claim 1 conjugated to a cytotoxin via a linker.
16. The ADC of claim 15 , wherein the cytotoxin is an RNA polymerase inhibitor.
17. The ADC of claim 16 , wherein the RNA polymerase inhibitor is an amatoxin.
18. The ADC of claim 17 , wherein the amatoxin is represented by formula (IV)
wherein R 1 is H, OH, OR A , or OR C ;
R 2 is H, OH, OR B , or OR C ;
R A and R B , together with the oxygen atoms to which they are bound, combine to form an optionally substituted 5-membered heterocycloalkyl group;
R 3 is H, R C , or R D ;
R 4 , R 5 , R 6 , and R 7 are each independently H, OH, OR C , OR D , R C , or R D ;
R 8 is OH, NH 2 , OR C , OR D , NHR C , or NR C R D ;
R 9 is H, OH, OR C , or OR D ;
X is —S—, —S(O)—, or —SO 2 —;
R C is -L-Z;
R D is optionally substituted C 1 -C 6 alkyl, optionally substituted C 1 -C 6 heteroalkyl, optionally substituted C 2 -C 6 alkenyl, optionally substituted C 2 -C 6 heteroalkenyl, optionally substituted C 2 -C 6 alkynyl, optionally substituted C 2 -C 6 heteroalkynyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;
L is optionally substituted C 1 -C 6 alkylene, optionally substituted C 1 -C 6 heteroalkylene, optionally substituted C 2 -C 6 alkenylene, optionally substituted C 2 -C 6 heteroalkenylene, optionally substituted C 2 -C 6 alkynylene, optionally substituted C 2 -C 6 heteroalkynylene, optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted arylene, optionally substituted heteroarylene, a peptide, a dipeptide, —(C═O)—, or a combination thereof; and
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 comprises exactly one R C substituent.
19. The ADC of claim 15 , wherein the ADC has a formula of
wherein Ab represents the point of attachment of the anti-CD45 antibody.
20. The ADC of claim 15 , wherein the cytotoxin is selected from the group consisting of a pseudomonas exotoxin A, deBouganin, diphtheria toxin, saporin, maytansine, a maytansinoid, an auristatin, an anthracycline, a calicheamicin, irinotecan, SN-38, a duocarmycin, a pyrrolobenzodiazepine, a pyrrolobenzodiazepine dimer, an indolinobenzodiazepine, and an indolinobenzodiazepine dimer.
21. The ADC of claim 15 , wherein the antibody is conjugated to the cytotoxin by way of a cysteine residue in the Fc domain of the antibody.
22. The ADC of claim 21 , wherein the cysteine residue is introduced by way of an amino acid substitution in the Fc domain of the antibody.
23. A pharmaceutical composition comprising the ADC of claim 15 , and a pharmaceutically acceptable carrier.
24. A method of depleting a population of hematopoietic stem cells (HSC) in a human patient, the method comprising administering to the patient an effective amount of the ADC of claim 15 .
25. A method comprising administering to a human patient a transplant comprising hematopoietic stem cells, wherein the patient has been previously administered the ADC of claim 15 in an amount sufficient to deplete a population of hematopoietic stem cells or a population of immune cells in the patient.
26. A method of treating leukemia in a human patient, said method comprising administering the ADC of claim 15 the human patient having leukemia.