Cd48 antibodies and conjugates thereof

Abstract

The invention provides murine, chimeric, and humanized antibodies that specifically bind to CD48 and conjugates thereof.

What is claimed is: 
     
         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.