m15-IgG4

m15-IgG4 is a humanized monoclonal antibody that targets the C-X-C chemokine receptor type 4 (CXCR4). It is an IgG4 isotype variant of PF-06747143, a clinical-stage IgG1 CXCR4 antibody developed for hematologic malignancies. While m15-IgG4 retains similar binding affinity for CXCR4 and inhibits CXCL12-driven signaling pathways, it lacks the Fc-effector functions—such as antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC)—that are present in the IgG1 version. In preclinical studies, m15-IgG4 demonstrated significantly reduced anti-tumor efficacy in lymphoma models and induced more prolonged leukocyte mobilization from the bone marrow compared to PF-06747143. It was utilized by Pfizer as a research tool to characterize the role of Fc-mediated cytotoxicity in the therapeutic and safety profile of their CXCR4-targeting program.

Other names

IgG4 version of PF-06747143IgG-4 version of PF-06747143IgG 4 version of PF-06747143