The chemokine receptor CXCR4 is a seven-transmembrane G-protein coupled receptor that mediates chemotaxis and cell migration upon stimulation via its ligand, stromal-derived factor 1 (SDF-1), also called CXCL12. CXCR4 is normally expressed on bone marrow stem and progenitor cells, various circulating lymphocytes, endothelial precursor cells, tissue macrophages and fibroblasts but the aberrant overexpression of CXCR4 is linked to various hematological malignancies, solid tumors and metastatic neoplasms. Moreover, CXCR4 overexpression is correlated with poor prognosis in many types of cancer, including breast, ovarian, colon, pancreatic, AML and glioblastomas. CXCR4 inhibition using siRNA, small-molecule and peptide inhibitors has demonstrated that it can inhibit tumor growth by blocking tumor cell survival/proliferation, metastasis, angiogenesis and tumor immune infiltrates. Here we describe a novel, fully human, antagonistic antibody to CXCR4, MEDI3185, which blocks SDF-1 binding to CXCR4. MEDI3185 has picomolar binding affinity to human CXCR4 and exhibits no significant binding to other chemokine receptors such as CCR4 or CXCR3. In vitro studies demonstrated that MEDI3185 inhibited tumor cell migration, blocked SDF-1 induced tumor cell signaling and induced apoptosis of tumor cells. In preclinical human tumor xenograft models in mouse, MEDI3185 showed single-agent tumor growth inhibition in multiple myeloma and B-cell Burkitt's lymphoma models and had combination activity in ovarian models. In addition, MEDI3185 extended survival as combination therapy in mouse models of CLL and also blocked lung tumor burden in a disseminated ovarian model. Combined, these data suggest that MEDI3185 is a potent CXCR4 antibody for the treatment of both hematological and solid tumors because it has pleiotropic effects on tumor biology that may enhance the efficacy of the current standard of care.

Citation Format: Adeela Kamal, Youzhen Wang, Philipp Steiner, Anne-Marie Mazzola, Leslie Wetzel, Melissa Passino, Brenda McDermott, Keven Huang, Vahe Bedian, Norman Greenberg. MEDI3185, a potent anti-CXCR4 antibody, inhibits tumor cell migration, signaling and tumor growth in preclinical models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5462. doi:10.1158/1538-7445.AM2013-5462