CSF-1R, PD-1 blockade combo shows efficacy
SOUTH SAN FRANCISCO, Calif.—Biotechnology company Five Prime Therapeutics Inc. presented new preclinical data last month at the 2017 AACR Annual Meeting in a poster titled “Antibody-Based Inhibition of CSF-1R as a Component of Combination Immunotherapy in Preclinical Models.” The colony stimulating factor 1 receptor (CSF-1R) signaling pathway encourages tumor progression due to the recruitment, differentiation and survival of immunosuppressive, M2 polarized, tumor-associated macrophages (TAMs). Five Prime has found that CSF-1R inhibition affects the tumor microenvironment, namely in the reduction of TAMs and an increase in tumor PD-L1 expression. The company’s cabiralizumab (FPA008) is an IgG4 antibody against CSF-1R that modulates the immune response to tumorigenesis by blocking the ability of CSF-1R and IL-34 to bind to and activate the CSF-1R receptor. When added to PD-1/PD-L1 blockade, this antibody can boost antitumor efficacy.