Combination Therapy With Anti-CD74 and Anti-CD20 Antibodies Provides Enhanced Toxicity to B-Cell Diseases

Abstract

Disclosed are compositions and methods comprising combinations of anti-CD74 and anti-CD20 antibodies or antigen-binding fragments thereof. The antibody combination may also be used with a therapeutic agent that is attached to antibody or fragment thereof or separately administered. The therapeutic agent may be an immunomodulator, a cytokine, a toxin or other known therapeutic agent. Preferably, the anti-CD74 and anti-CD20 antibody or fragment are part of a DNL complex. More preferably, combination therapy with the anti-CD74 and anti-CD20 antibody or fragment is more effective than either antibody alone, or the combination of unconjugated antibodies. Administration of combination induces apoptosis of target cells in diseases in which CD74 is overexpressed, such as solid tumors, B-cell lymphomas or leukemias, autoimmune disease, immune dysfunction disease or diabetes. Preferably, the target cells are B cells.

What is claimed is: 
     
         1 . A method of killing human B cells comprising:
 a) obtaining a bispecific antibody that comprises (i) an anti-CD74 antibody or antigen-binding fragment thereof that binds to human CD74 and (ii) an anti-CD20 antibody or antigen-binding fragment thereof that binds to human CD20; and   b) exposing human B cells to the bispecific antibody.   
     
     
         2 . The method of  claim 1 , wherein the anti-CD20 antibody is rituximab or hA20. 
     
     
         3 . The method of  claim 1 , wherein the anti-CD74 antibody is hLL1. 
     
     
         4 . The method of  claim 1 , wherein the anti-CD20 and anti-CD74 antibodies are chimeric, humanized or human. 
     
     
         5 . The method of  claim 1 , wherein the anti-CD20 and anti-CD74 antibodies are a G1m3 allotype. 
     
     
         6 . The method of  claim 1 , wherein the anti-CD74 antibody competes with, blocks binding to, or binds to the same epitope of CD74 as an LL1 antibody comprising the light chain CDR sequences CDR1 (RSSQSLVHRNGNTYLH; SEQ ID NO:1), CDR2 (TVSNRFS; SEQ ID NO:2), and CDR3 (SQSSHVPPT; SEQ ID NO:3) and the heavy chain variable region CDR sequences CDR1 (NYGVN; SEQ ID NO:4), CDR2 (WINPNTGEPTFDDDFKG; SEQ ID NO:5), and CDR3 (SRGKNEAWFAY; SEQ ID NO:6). 
     
     
         7 . The method of  claim 1 , wherein the anti-CD20 antibody competes with, blocks binding to, or binds to the same epitope of CD20 as an A20 antibody comprising the light chain CDR sequences CDR1 (RASSSVSYIH; SEQ ID NO:7), CDR2 (ATSNLAS; SEQ ID NO:8), and CDR3 (QQWTSNPPT; SEQ ID NO:9) and the heavy chain variable region CDR sequences CDR1 (SYNMH; SEQ ID NO:10), CDR2 (AIYPGNGDTSYNQKFKG; SEQ ID NO:11), and CDR3 (STYYGGDWYFDV; SEQ ID NO:12). 
     
     
         8 . The method of  claim 1 , further comprising exposing the human B cells to a therapeutic agent selected from the group consisting of an immunomodulator, a cytotoxic agent, a drug, a toxin, an anti-angiogenic agent, a proapoptotic agent, a cytokine inhibitor, a chemokine inhibitor, a tyrosine kinase inhibitor, a sphingosine inhibitor, a hormone, a hormone antagonist, an enzyme inhibitor, an oligonucleotide and a radionuclide. 
     
     
         9 . The method of  claim 8 , wherein the therapeutic agent is selected from the group consisting of aplidin, azaribine, anastrozole, azacytidine, bleomycin, bortezomib, bryostatin-1, busulfan, calicheamycin, camptothecin, 10-hydroxycamptothecin, carmustine, celecoxib, chlorambucil, cisplatinum, irinotecan (CPT-11), SN-38, carboplatin, cladribine, cyclophosphamide, cytarabine, dacarbazine, docetaxel, dactinomycin, daunomycin glucuronide, daunorubicin, dexamethasone, diethylstilbestrol, doxorubicin, doxorubicin glucuronide, epirubicin glucuronide, ethinyl estradiol, estramustine, etoposide, etoposide glucuronide, etoposide phosphate, floxuridine, 3′,5′-O-dioleoyl-floxuridine, fludarabine, flutamide, fluorouracil, fluoxymesterone, gemcitabine, hydroxyprogesterone caproate, hydroxyurea, idarubicin, ifosfamide, L-asparaginase, leucovorin, lomustine, mechlorethamine, medroprogesterone acetate, megestrol acetate, melphalan, mercaptopurine, 6-mercaptopurine, methotrexate, mitoxantrone, mithramycin, mitomycin, mitotane, paclitaxel, phenyl butyrate, prednisone, procarbazine, pentostatin, PSI-341, semustine streptozocin, tamoxifen, taxanes, testosterone propionate, thalidomide, thioguanine, thiotepa, teniposide, topotecan, uracil mustard, vinblastine, vinorelbine, vincristine, ricin, abrin, ribonuclease, ranpirnase, rapLRl, DNase I, Staphylococcal enterotoxin-A, pokeweed antiviral protein, gelonin, diphtheria toxin,  Pseudomonas  exotoxin, and  Pseudomonas  endotoxin. 
     
     
         10 . The method of  claim 8 , wherein the therapeutic agent is fludarabine. 
     
     
         11 . The method of  claim 8 , wherein the immunomodulator is selected from the group consisting of a cytokine, a stem cell growth factor, a lymphotoxin, a hematopoietic factor, a colony stimulating factor (CSF), an interferon (IFN), erythropoietin, thrombopoietin, IL-1, IL-2, IL-3, IL-6, IL-10, IL-12, IL-18, IL-21, interferon-α, interferon-β, interferon-γ, G-CSF and GM-CSF. 
     
     
         12 . The method of  claim 8 , wherein the anti-angiogenic agent is selected from the group consisting of angiostatin, endostatin, baculostatin, canstatin, maspin, an anti-VEGF binding molecule, an anti-placental growth factor binding molecule and an anti-vascular growth factor binding molecule.