BMS-936564/MDX-1338: a fully human anti-CXCR4 antibody induces apoptosis in vitro and shows antitumor activity in vivo in hematologic malignancies

Purpose: CXCR4 has been identified as a prognostic marker for acute myeloid leukemia (AML) and other malignancies. We describe the development and characterization of a fully human antibody to CXCR4 and its application for therapy of AML, non-Hodgkin lymphoma (NHL), chronic lymphoid leukemia (CLL), and multiple myeloma.

Experimental design: Human transgenic mice were immunized with CXCR4-expressing cells, and Antibodies reactive with CXCR4 were analyzed for Apoptosis induction and ability to interfere with CXCL12-induced migration and calcium flux. In vivo efficacy was determined in multiple AML, NHL, and multiple myeloma xenograft tumors in severe combined immunodeficient mice.

Results: BMS-936564/MDX-1338 is a fully human IgG(4) monoclonal antibody that specifically recognizes human CXCR4. In vitro studies show that MDX-1338 binds to CXCR4-expressing cells with low nanomolar affinity, blocks CXCL12 binding to CXCR4-expressing cells, and inhibits CXCL12-induced migration and calcium flux with low nanomolar EC(50) values. When given as monotherapy, MDX-1338 exhibits antitumor activity in established tumors including AML, NHL, and multiple myeloma xenograft models. In addition, we show that MDX-1338 induced Apoptosis on a panel of cell lines and propose that antibody-induced Apoptosis is one of the mechanisms of tumor growth inhibition.

Conclusions: BMS-936564/MDX-1338 is a potent CXCR4 Antagonist which is efficacious as monotherapy in tumor-bearing mice and is currently in phase I for the treatment of relapsed/refractory AML, NHL, CLL, and multiple myeloma.