Antibodies with immune effector activity and that internalize in folate receptor alpha-positive cells

Abstract

This invention relates to the use of monoclonal and polyclonal antibodies that specifically bind to and have the ability in the alternative to become internalized by cells expressing folate receptor alpha (FRA) and to induce an immune effector activity such as antibody-dependent cellular cytotoxicity. The antibodies are useful in specific delivery of pharmacologic agents to FRA-expressing cells as well as in eliciting an immune-effector activity particularly on tumor cells and precursors. The invention is also related to nucleotides encoding the antibodies of the invention, cells expressing the antibodies; methods of detecting cancer cells; and methods of treating cancer using the antibodies.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This claims benefit of U.S. Provisional Application 60 / 674,185, filed Apr. 22, 2005, which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION [0002] This invention relates to the use of monoclonal and polyclonal antibodies that specifically bind to and alternatively become internalized by cells expressing or bearing folate receptor alpha (FRA) (“FRA-positive cells”) and induce an immune effector activity such as antibody dependent cellular cytotoxicity. The antibodies are useful in specific delivery of pharmacologic agents to FRA-positive cells as well as in eliciting an immune-effector activity particularly on tumor and dysplastic cells. The invention is also related to cells expressing the monoclonal antibodies, polyclonal antibodies, antibody derivatives, such as chimeric and humanized monoclonal antibodies, antibody fragments, methods of detecting FRA-positive cells, and methods of treating cancer using the an...

AI Technical Summary

Benefits of technology

[0009] Provided herein are FRA-specific antibodies that alternatively elicit a robust immune-effector function yet are able to internalize in FRA-positive cells, referred to here as in-out anti-FRA antibodies. As used herein, “in-out antibodies” (“in-out Abs”) refer to antibodies that can alternatively elicit an immune effector activity and internalize within an antigen-presenting cell by binding to target antigen. Without wishing to be bound by any particular theory, it is believed that in-out Abs bind to the cell surface of an antigen-bearing cell and internalize after a period of time unless engaged by immune-effector cells or biochemicals that are recruited to the antigen-antibody-bearing cell. Antibodies that are able to elicit an immune effector effect such ADCC or CDC and internalize have been previously described (Wolff et al. Monoclonal antibody homodimers: enhanced antitumor activity in nude mice. Cancer Res. Jun. 1, 1993;53:2560-5), however, it is not obvious that in-out antibodies can be developed against any antigen or epitope (Kusano et al. Immunocytochemical study on internalization of anti-carbohydrate monoclonal antibodies. Anticancer Res. November-December 1993;13(6A):2207-12). In-out antibodies that can target FRA have not been described previously. FRA-specific antibodies have been previously described but such antibodies are not known to internalize upon binding to the antigen (Cogliati et al. Preparation and biological characterization of conjugates consisting of ricin and a tumor-specific non-internalizing MAb. Anticancer Res. 11:417-21, 1991). Antibodies that can target cell surface antigens do not always elicit an immune effector function upon binding to the cell surface antigen (Niwa et al. Defucosylated chimeric anti-CC chemokine receptor 4 IgG1 with enhanced antibody-dependent cellular cytotoxicity shows potent therapeutic activity to T-cell leukemia and lymphoma. Cancer Res. 64:2127-33, 2004; Kikuchi et al. Apoptosis inducing bivalent single-chain antibody fragments against CD47 showed antitumor potency for multiple myeloma. Leuk Res. 29:445-50, 2005; Scott et al. Immunological effects of chimeric anti-GD3 monoclonal antibody KM871 in patients with metastatic melanoma. Cancer Immun. February 22;5:3, 2005). Provided herein are antibodies that bind to the cell surface antigen FRA and, in the alternative, elicit an immune effector activity (such as ADCC or CDC) and internalize within antigen-positive cells. These antibodies and derivatives thereof are useful for cancer therapy.

Problems solved by technology

Although chemotherapy is the recommended treatment and has enjoyed some success, the 5-year survival term is still less than 40%.

A difficult problem in treating ovarian cancer as well as other cancers with cytotoxic drugs is that often the cytotoxin causes toxicity to normal tissues as well as cancerous tissues.

Finding antibodies that can specifically bind to and effectively kill antigen-bearing tumor cells has proven difficult for many cancers.

This has been due in part to the inability to obtain robust killing due to lack of immune-effector function or to lack of efficient internalization of antibodies carrying immunotoxins.

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