Monoclonal antibodies that specifically block biological activity of a tumor antigen

Abstract

This invention relates to novel monoclonal antibodies that specifically bind to the alpha-folate receptor. In some embodiments, the antibodies inhibit a biological activity of folate receptor-α (FR-α). The antibodies are useful in the treatment of certain cancers, particularly cancers that have increased cell surface expression of the alpha-folate receptor (“FR-α”), such as ovarian, breast, renal, colorectal, lung, endometrial, or brain cancer. The invention also relates to cells expressing the monoclonal antibodies, antibody derivatives, such as chimeric and humanized monoclonal antibodies, antibody fragments, and methods of detecting and treating cancer using the antibodies, derivatives, and fragments.

1 . A purified antibody that specifically binds to folate receptor-α (FR-α).  
     
     
         2 . The antibody of  claim 1  wherein said antibody blocks a biological activity of FR-α.  
     
     
         3 . The antibody of  claim 1  wherein said antibody induces antibody-dependent cellular cytotoxicity of an FR-α-bearing cell.  
     
     
         4 . The antibody of  claim 1  wherein the affinity of said antibody is at least about 1×10 −7  M.  
     
     
         5 . The antibody of  claim 1  comprising a heavy chain comprising an amino acid sequence of SEQ ID NO:5.  
     
     
         6 . The antibody of  claim 1  comprising a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         7 . The antibody of  claim 5  comprising a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         8 . The antibody of  claim 1  wherein said antibody is conjugated to a cytotoxic agent.  
     
     
         9 . A cell that expresses the antibody of  claim 1 .  
     
     
         10 . A cell that expresses an antibody that specifically binds to folate receptor-alpha (FR-α), wherein said cell is substantially free of FR-α binding competitors.  
     
     
         11 . A polynucleotide encoding a heavy chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said heavy chain comprises an amino acid sequence of SEQ ID NO:5.  
     
     
         12 . The polynucleotide of  claim 11  comprising a nucleic acid sequence of SEQ ID NO:7.  
     
     
         13 . A polynucleotide encoding a light chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said light chain comprises an amino acid sequence of SEQ ID NO:2.  
     
     
         14 . The polynucleotide of  claim 13  comprising a nucleic acid sequence of SEQ ID NO:8.  
     
     
         15 . The polynucleotide of  claim 11  further encoding a light chain of an antibody that specifically binds to FR-α wherein said light chain comprises an amino acid sequence of SEQ ID NO:2.  
     
     
         16 . The polynucleotide of  claim 15  comprising a nucleic acid sequence of SEQ ID NO:8.  
     
     
         17 . A vector comprising a polynucleotide encoding a heavy chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said heavy chain comprises an amino acid sequence of SEQ ID NO:5.  
     
     
         18 . A vector comprising a polynucleotide encoding a light chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said light chain comprises an amino acid sequence of SEQ ID NO:2.  
     
     
         19 . A vector comprising a polynucleotide encoding a heavy chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said heavy chain comprises an amino acid sequence of SEQ ID NO:5 and a polynucleotide encoding a light chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said light chain comprises an amino acid sequence of SEQ ID NO:2.  
     
     
         20 . A vector comprising the polynucleotide of  claim 15 .  
     
     
         21 . An expression cell comprising a polynucleotide encoding a heavy chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said heavy chain comprises an amino acid sequence of SEQ ID NO:5 and a polynucleotide encoding a light chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said light chain comprises an amino acid sequence of SEQ ID NO:2.  
     
     
         22 . An expression cell comprising a polynucleotide encoding a heavy chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said heavy chain comprises an amino acid sequence of SEQ ID NO:5 and a light chain of an antibody that specifically binds to folate receptor-α (FR-α) wherein said light chain comprises an amino acid sequence of SEQ ID NO:2.  
     
     
         23 . An expression cell comprising the vector of  claim 17 .  
     
     
         24 . An expression cell comprising the vector of  claim 18 .  
     
     
         25 . An expression cell comprising the vector of  claim 19 .  
     
     
         26 . An expression cell comprising the vector of  claim 20 .  
     
     
         27 . A pharmaceutical composition comprising an antibody that specifically binds to folate receptor-alpha (FR-α), wherein said composition is substantially free of FR-α binding competitors.  
     
     
         28 . The pharmaceutical composition of  claim 27  wherein said antibody comprises a heavy chain comprising an amino acid sequence of SEQ ID NO:5.  
     
     
         29 . The pharmaceutical composition of  claim 27  wherein said antibody comprises a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         30 . The pharmaceutical composition of  claim 27  wherein said antibody comprises a heavy chain comprising an amino acid sequence of SEQ ID NO:5 and a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         31 . The pharmaceutical composition of  claim 27  wherein said antibody blocks a biological activity of FR-α.  
     
     
         32 . The pharmaceutical composition of  claim 27  wherein the binding affinity of said antibody to FR-α is at least about 1×10 −7  M.  
     
     
         33 . The pharmaceutical composition of  claim 27  further comprising a cytotoxic agent.  
     
     
         34 . The pharmaceutical composition of  claim 33  wherein said antibody is conjugated to said cytotoxic agent.  
     
     
         35 . The pharmaceutical composition of  claim 27  further comprising an antifolate compound.  
     
     
         36 . A method of producing an antibody that specifically binds folate receptor-α comprising culturing the cell of  claim 23 .  
     
     
         37 . A method of producing an antibody that specifically binds folate receptor-α comprising culturing the cell of  claim 24 .  
     
     
         38 . A method of producing an antibody that specifically binds folate receptor-α comprising culturing the cell of  claim 25 .  
     
     
         39 . A method of producing an antibody that specifically binds folate receptor-α comprising culturing the cell of  claim 26 .  
     
     
         40 . A method of producing an antibody that specifically binds folate receptor-α comprising culturing the cell of  claim 9 .  
     
     
         41 . A method of producing an antibody that specifically binds folate receptor-α comprising the step of culturing the cell of  claim 10 .  
     
     
         42 . A method of generating an antibody-producing cell, said method comprising: inhibiting mismatch repair in a cell comprising a nucleic acid sequence encoding an amino acid sequence of SEQ ID NO:5 and a nucleic acid sequence encoding an amino acid sequence of SEQ ID NO:2 and selecting a cell that produces antibodies that specifically bind folate receptor-alpha (FR-α), wherein substantially all of the antibodies produced by said cell comprise a heavy chain comprising an amino acid sequence of SEQ ID NO:5 and a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         43 . The method of  claim 42  wherein said step of inhibiting mismatch repair comprises introducing a dominant negative inhibitor of a mismatch repair gene into said cell.  
     
     
         44 . The method of  claim 42  wherein said cell produces antibodies comprising at least about 90% by weight of said antibody comprising a heavy chain comprising an amino acid sequence of SEQ ID NO:5 and a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         45 . The method of  claim 42  further comprising restoring genetic stability to said cell.  
     
     
         46 . A cell produced according to the method of  claim 42 .  
     
     
         47 . A method of producing an antibody that specifically binds folate receptor-α comprising the step of culturing the cell of  claim 46 .  
     
     
         48 . A method of generating a cell that expresses an antibody that specifically binds folate receptor-alpha (FR-α) and is substantially free of FR-α binding competitors comprising inhibiting mismatch repair in a cell comprising a nucleic acid sequence encoding an amino acid sequence of SEQ ID NO:5 and a nucleic acid sequence encoding an amino acid sequence of SEQ ID NO:2 and selecting a cell that expresses antibodies that specifically bind folate receptor alpha (FR-α) with a binding affinity of at least about 1×10 −7  M.  
     
     
         49 . The method of  claim 48  wherein said step of inhibiting mismatch repair comprises introducing a dominant negative inhibitor of a mismatch repair gene into said cell.  
     
     
         50 . The method of  claim 48  further comprising restoring genetic stability to said cell.  
     
     
         51 . A cell produced according to the method of  claim 48 .  
     
     
         52 . A method of producing an antibody that specifically binds folate receptor-α comprising the step of culturing the cell of  claim 51 .  
     
     
         53 . A method of inhibiting the growth of dysplastic cells associated with increased expression of FR-α comprising administering to a patient with such dysplastic cells the pharmaceutical composition of  claim 27 .  
     
     
         54 . The method of  claim 53  wherein said dysplastic cells are ovarian, breast, renal, colorectal, lung, endometrial, or brain carcinoma cells.  
     
     
         55 . The method of  claim 53  wherein said dysplastic cells are ovarian carcinoma cells.  
     
     
         56 . The method of  claim 53  wherein said patient is a human patient.  
     
     
         57 . The method of  claim 53  wherein said pharmaceutical composition comprises at least one cytotoxic agent.  
     
     
         58 . The method of  claim 57  wherein said cytotoxic agent is conjugated to the antibody of said pharmaceutical composition.  
     
     
         59 . The method of  claim 53  further comprising administering to said patient an antifolate compound.  
     
     
         60 . A method of detecting a dysplastic cell which presents folate receptor-alpha (FR-α) on its surface comprising contacting said cell with an antibody that specifically binds FR-α and determining binding of said antibody to said cell.  
     
     
         61 . The method of  claim 60  wherein said antibody blocks a biological activity of said FR-α.  
     
     
         62 . The method of  claim 60  wherein said antibody comprises a heavy chain comprising an amino acid sequence of SEQ ID NO:5.  
     
     
         63 . The method of  claim 60  wherein said antibody comprises a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         64 . The method of  claim 60  wherein said antibody comprises a heavy chain comprising an amino acid sequence of SEQ ID NO:5 and a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         65 . The method of  claim 60  wherein said step of contacting said cell with said antibody occurs in the absence of an FR-α binding competitor.  
     
     
         66 . The method of  claim 60  wherein said cancer cell is an ovarian, breast, renal, colorectal, lung, endometrial, or brain carcinoma cell.  
     
     
         67 . The method of  claim 60  wherein said cancer cell is an ovarian carcinoma cell.  
     
     
         68 . The method of  claim 60  wherein said antibody is labeled with a detectable label.  
     
     
         69 . The method of  claim 60  comprising detecting said cancer cell in vitro.  
     
     
         70 . The method of  claim 60  comprising detecting said cancer cell in vivo.  
     
     
         71 . A method of inhibiting the growth of dysplastic cells associated with increased expression of folate receptor-α (FR-α) comprising administering to a patient having said dysplastic cells a composition comprising an antibody that specifically binds to a FR-α.  
     
     
         72 . The method of  claim 71  wherein said antibody blocks a biological activity of FR-α on FR-α-bearing cells.  
     
     
         73 . The method of  claim 71  wherein said composition is substantially free of FR-α binding competitors.  
     
     
         74 . The method of  claim 71  wherein said antibody comprises a heavy chain comprising an amino acid sequence of SEQ ID NO:5.  
     
     
         75 . The method of  claim 71  wherein said antibody comprises a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         76 . The method of  claim 71  wherein said antibody comprises a heavy chain comprising an amino acid sequence of SEQ ID NO:5 and a light chain comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         77 . The method of  claim 71  wherein said dysplastic cells are ovarian, breast, renal, colorectal, lung, endometrial, or brain carcinoma cells.  
     
     
         78 . The method of  claim 71  wherein said dysplastic cells are ovarian carcinoma cells.  
     
     
         79 . The method of  claim 71  wherein said patient is a human patient.  
     
     
         80 . The method of  claim 71  wherein said antibody is conjugated to a cytotoxic agent.  
     
     
         81 . The method of  claim 71  wherein said patient is further administered at least one antifolate compound.  
     
     
         82 . A method of treating a patient having cancer comprising administering to said patient the pharmaceutical composition of  claim 27 .  
     
     
         83 . The method of  claim 81  wherein said cancer is an epithelial cancer.  
     
     
         84 . The method of  claim 81  wherein said cancer is ovarian, breast, renal, colorectal, lung, endometrial, or brain cancer.  
     
     
         85 . The method of  claim 81  wherein said cancer is ovarian cancer.  
     
     
         86 . The method of  claim 81  wherein said patient is a human patient.  
     
     
         87 . The method of  claim 81  wherein said pharmaceutical composition comprises at least one cytotoxic agent.  
     
     
         88 . The method of  claim 87  wherein said cytotoxic agent is conjugated to the antibody of said pharmaceutical composition.  
     
     
         89 . The method of  claim 81  further comprising administering to said patient an antifolate compound.  
     
     
         90 . The method of  claim 81  wherein said pharmaceutical composition comprises said antifolate compound.  
     
     
         91 . A kit comprising an antibody that specifically binds to folate receptor-alpha (FR-α) and blocks a biological activity of FR-α.