CD48 ANTIBODIES AND CONJUGATES THEREOF
The invention provides murine, chimeric, and humanized antibodies that specifically bind to CD48 and conjugates thereof.
1 . A chimeric or humanized antibody that specifically binds to the human CD48 protein, wherein the antibody comprises heavy chain CDR sequences of SEQ ID NOs:3-5 and light chain CDR sequences of SEQ ID NOs:6-8, and wherein the antibody exhibits higher binding affinity to the human CD48 protein, as compared to a murine antibody that specifically binds to the human CD48 protein and comprises heavy chain CDR sequences of SEQ ID NOs:3-5 and light chain CDR sequences of SEQ ID NOs:6-8.
2 . The antibody of claim 1 , wherein the chimeric or humanized antibody exhibits at least 2-fold higher binding affinity for the human CD48 protein, as compared to the murine antibody.
3 . The antibody of claim 1 , wherein the antibody is a humanized antibody.
4 . The antibody of claim 1 , wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 1.
5 . The antibody of claim 1 , wherein the antibody comprises a light chain variable region of SEQ ID NO:2.
6 . The antibody of claim 4 , wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 1.
7 . The antibody of any one of claims 1 to 6 , wherein the antibody is conjugated to a cytotoxic drug attached to a linker.
8 . The antibody of claim 7 wherein the drug-linker has the formula:
or a pharmaceutically acceptable salt thereof wherein Z represents an organic moiety having a reactive site capable of reacting with a functional group on the antibody to form a covalent attachment thereto, n ranges from 8 to 36, R PR is hydrogen or a protecting group, R 21 is a capping unit for the polyethylene glycol moiety.
9 . A humanized antibody that specifically binds to the human CD48 protein, wherein the antibody comprises a heavy chain variable region of SEQ ID NO: 1 and a light chain variable region of SEQ ID NO:2.
10 . The antibody of any one of claim 9 , wherein the antibody is conjugated to a cytotoxic drug attached to a linker.
11 . The antibody of claim 10 wherein the drug-linker has the formula:
or a pharmaceutically acceptable salt thereof wherein Z represents an organic moiety having a reactive site capable of reacting with a functional group on the antibody to form a covalent attachment thereto, n ranges from 8 to 36, R PR is hydrogen or a protecting group, R 21 is a capping unit for the polyethylene glycol moiety.
12 . The antibody of claim 10 wherein the drug-linker has the formula:
or a pharmaceutically acceptable salt thereof wherein Z represents an organic moiety having a reactive site capable of reacting with a functional group on the antibody to form a covalent attachment thereto, n ranges from 8 to 36, R PR is hydrogen or a protecting group, R 21 is a capping unit for the polyethylene glycol moiety.
13 . The antibody of claim 10 wherein drug-linker has the formula
or a pharmaceutically acceptable salt thereof wherein, n ranges from 8 to 36, R PR is hydrogen or a protecting group, R 21 is a capping unit for the polyethylene glycol moiety.
14 . The antibody of claim 10 wherein drug-linker has the formula
or a pharmaceutically acceptable salt thereof wherein, n ranges from 8 to 36, R PR is hydrogen or a protecting group, R 21 is a capping unit for the polyethylene glycol moiety.
15 . The antibody of claim 1 or 9 wherein n ranges from 8 to 14.
16 . The antibody of claim 1 or 9 wherein n ranges from 10 to 12.
17 . The antibody of claim 1 or 9 wherein n is 12.
18 . The antibody of any one of claims 15 to 17 wherein R 21 is —CH 3 or —CH 2 CH 2 CO 2 H.
19 . An anti-CD48 antibody-drug conjugate compound having the formula
or a pharmaceutically acceptable salt thereof wherein Ab is an anti-CD48 antibody of claims 1 or 9 , Z represents an organic moiety linking the antibody and the remainder of the drug-linker via covalent bonds, n ranges from 8 to 36, R 21 is a capping unit for the polyethylene glycol moiety, and p is from 1 to 16.
20 . An anti-CD48 antibody-drug conjugate compound of claim 19 having the formula:
or a pharmaceutically acceptable salt thereof.
21 . An anti-CD48 antibody-drug conjugate compound of claim 19 having the formula:
or a pharmaceutically acceptable salt thereof wherein R PR is hydrogen or a protecting group.
22 . An anti-CD48 antibody-drug conjugate compound of claim 19 having the formula
or a pharmaceutically acceptable salt thereof.
23 . An anti-CD48 antibody-drug conjugate compound of claim 19 having the formula
or a pharmaceutically acceptable salt thereof.
24 . An anti-CD48 antibody-drug conjugate compound of claim 19 having the formula
or a pharmaceutically acceptable salt thereof wherein R PR is hydrogen or a protecting group.
25 . The anti-CD48 antibody-drug conjugate compound of any one of claims 19 to 24 wherein n ranges from 8 to 14.
26 . The anti-CD48 antibody-drug conjugate compound of any one of claims 19 to 24 wherein n ranges from 10 to 12.
27 . The anti-CD48 antibody-drug conjugate compound of any one of claims 19 to 24 wherein n is 12.
28 . The anti-CD48 antibody-drug conjugate compound of any one of claims 19 to 27 wherein R21 is —CH3 or —CH2CH2CO2H.
29 . The antibody-drug conjugate compound of any one of claims 19 to 28 wherein p is 8.
30 . The antibody-drug conjugate compound of any one of claims 19 to 29 wherein attachment to Ab is via the cysteine residues of the interchain disulfide bonds of the antibody.
31 . An antibody-drug conjugate composition comprising a population of anti-CD48 antibody-drug conjugate molecules of any one of claims 19 to 30 wherein the average drug load of the composition is 8 and the predominant drug load in the composition is 8.
32 . The composition of claim 31 that is a pharmaceutical composition.
33 . A method of treating a patient with a CD48 expressing cancer, the method comprising the step of administering a composition of claim 31 to the patient.
34 . The method of claim 33 , wherein the CD48 expressing cancer is multiple myeloma.
35 . The method of claim 33 , wherein the CD48 expressing cancer is selected from the group consisting of B cell malignancies and acute myelogenous leukemia.
36 . An isolated nucleic acid comprising a sequence encoding a heavy chain variable region comprising CDRs having the amino acid sequences of SEQ ID NOs: 3-5 and a light chain variable region comprising CDRs having the amino acid sequences of SEQ ID NOs: 6-8 of an antibody that specifically binds to the human CD48 protein.
37 . An isolated vector comprising the nucleic acid of claim 36 .
38 . An isolated host cell comprising the vector of claim 37 .
39 . The host cell of claim 38 , wherein the host cell is a mammalian host cell.
40 . The host cell of claim 39 , wherein the host cell is selected from the group consisting of CHO, COS, HeLA, HEK293, L, Sp2/0, and NS0.
41 . A method of making an anti-CD48 antibody, wherein the method comprises:
culturing the host cell of claim 38 under conditions suitable for expression of the nucleic acid encoding the antibody; and
isolating the antibody.
42 . A method of making an anti-CD48 antibody drug conjugate, wherein the method comprises:
culturing the host cell of claim 38 under conditions suitable for expression of the nucleic acid encoding the antibody;
isolating the antibody; and
conjugating a cytotoxic drug attached to a linker to the antibody.
43 . The method of claim 42 , wherein the drug-linker has the formula:
or a pharmaceutically acceptable salt thereof wherein Z represents an organic moiety having a reactive site capable of reacting with a functional group on the antibody to form a covalent attachment thereto, n ranges from 8 to 36, R PR is hydrogen or a protecting group, R 21 is a capping unit for the polyethylene glycol moiety.
44 . An isolated nucleic acid comprising a sequence encoding a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 1 and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 2.
45 . An isolated vector comprising the nucleic acid of claim 44 .
46 . An isolated host cell comprising the vector of claim 45 .
47 . The host cell of claim 46 , wherein the host cell is a mammalian host cell.
48 . The host cell of claim 47 , wherein the host cell is selected from the group consisting of CHO, COS, HeLA, HEK293, L, Sp2/0, and NS0.
49 . A method of making an anti-CD48 antibody, wherein the method comprises:
culturing the host cell of claim 46 under conditions suitable for expression of the nucleic acid encoding the antibody; and
isolating the antibody.
50 . A method of making an anti-CD48 antibody drug conjugate, wherein the method comprises:
culturing the host cell of claim 46 under conditions suitable for expression of the nucleic acid encoding the antibody;
isolating the antibody; and
conjugating a cytotoxic drug attached to a linker to the antibody.
51 . The method of claim 50 , wherein the drug-linker has the formula:
or a pharmaceutically acceptable salt thereof wherein Z represents an organic moiety having a reactive site capable of reacting with a functional group on the antibody to form a covalent attachment thereto, n ranges from 8 to 36, R PR is hydrogen or a protecting group, R 21 is a capping unit for the polyethylene glycol moiety.