BISPECIFIC ANTIBODY FOR CANCER IMMUNOTHERAPY
Disclosed are compositions and methods for targeted treatment of TAG-72-expressing cancers. In particular, bispecific antibodies are disclosed that are able to engage T-cells to destroy TAG-72-expressing malignant cells. Disclosed are bispecific antibodies that are able to engage T-cells to destroy TAG-72-expressing malignant cells. The antibodies can be engineered from fusion polypeptides comprising 1) variable domains of antibodies that specifically bind an immune cell antigen and 2) variable domains of antibodies that specifically bind TAG-72.
1 . A fusion polypeptide comprising the following formula:
V L I-V H I--V L T---V H T,
V H I-V L I--V L T---V H T,
V L I-V H I--V H T---V L T, or
V H I-V L I--V L T---V H T,
wherein “V H T” is a heavy chain variable domain specific for TAG-72;
wherein “V L T” is a light chain variable domain specific for TAG-72;
wherein “V L I” is a light chain variable domain specific for an immune cell antigen;
wherein “V H I” is a heavy chain variable domain specific for the immune cell antigen;
wherein “-” consists of a peptide linker or a peptide bond;
wherein “--” consists of a peptide linker or a peptide bond; and
wherein “---” consists of a peptide linker comprising the amino acid sequence SEQ ID NO:5.
2 . The fusion polypeptide of claim 1 , wherein the immune cell antigen is selected from the group consisting of human CD3 antigen, the human CD16 antigen, the human NKG2D antigen, the human CD2 antigen, the human CD28 antigen and the human CD25 antigen.
3 . An isolated nucleic acid encoding the fusion polypeptide claim 1 .
4 . A bispecific antibody, comprising the fusion polypeptide of claim 1 , wherein the V L I and the V H I have dimerized to form an antigen binding site for the immune cell antigen, and wherein the V H T and the V L T have dimerized to form an antigen binding site for TAG-72;
5 . The bispecific antibody of claim 4 , wherein the immune cell antigen is selected from the group consisting of human CD3 antigen, the human CD16 antigen, the human NKG2D antigen, the human CD2 antigen, the human CD28 antigen and the human CD25 antigen.
6 . A bispecific antibody comprising a single polypeptide chain comprising a bispecific antibody comprising a first antigen-binding region and a second antigen-binding region;
wherein the first antigen-binding region is capable of recruiting the activity of a human immune effector cell by specifically binding to an immune cell antigen located on the human immune effector cell; and
wherein the second antigen-binding region comprises a dimerized variable heavy (V H ) domain and a variable light (V L ) domain that is capable of specifically binding to TAG-72 on a target cell,
wherein the V H domain of the second antigen-binding region comprises complementarity determining regions (CDRs) selected from the group consisting of a CDR1 having amino acid sequence SEQ ID NO:12, a CDR2 having amino acid sequence SEQ ID NO:13, and a CDR3 having amino acid sequence SEQ ID NO:14, and
wherein the V L domain of the second antigen-binding region comprises CDRs selected from the group consisting of a CDR1 having amino acid sequence SEQ ID NO:15, a CDR2 having amino acid sequence SEQ ID NO:16, and a CDR3 having amino acid sequence SEQ ID NO:17.
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11 . (canceled)
12 . The bispecific antibody of claim 6 , wherein the human effector cell is a member of the human lymphoid lineage.
13 . The bispecific antibody of claim 6 , wherein the effector cell is capable of exerting a cytotoxic or an apoptotic effect on a target cell.
14 . The bispecific antibody of claim 13 , wherein the immune cell antigen is selected from the group consisting of human CD3 antigen, the human CD16 antigen, the human NKG2D antigen, the human CD2 antigen, the human CD28 antigen and the human CD25 antigen.
15 . The bispecific antibody of claim 6 , wherein the human effector cell is a member of the human myeloid lineage.
16 . The bispecific antibody of claim 15 , wherein the human effector cell is capable of exerting a cytotoxic or an apoptotic effect on a target cell.
17 . The bispecific antibody of claim 16 , wherein the immune cell antigen is chosen from one or more of the human CD64 antigen or the human CD89 antigen.
18 . The bispecific antibody of claim 6 , wherein the second antigen-binding region comprises a V H domain having CDR1, CDR2 and CDR3 sequences of SEQ ID NOs: 12, 13 and 14, respectively
19 . The bispecific antibody of claim 18 , wherein the second antigen-binding region comprises a V H domain having the amino acid sequence of SEQ ID NO: 2.
20 . The bispecific antibody of claim 6 , wherein the second antigen-binding region comprises a V L domain having CDR1, CDR2 and CDR3 sequences of SEQ ID NOs: 15, 16 and 17, respectively
21 . The bispecific antibody of claim 20 , wherein the second antigen-binding region comprises a V L domain having the amino acid sequence of SEQ ID NO:4.
22 . The bispecific antibody of claim 6 , wherein the antibody has an amino acid sequence as set out in SEQ ID NO: 11.
23 . A pharmaceutical composition comprising the bispecific antigen binding molecule of claim 6 in a pharmaceutically acceptable carrier.
24 . A method for treating cancer in a subject, comprising administering to the subject a therapeutically effective amount of the pharmaceutical composition of claim 23 .
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