Mechanism of action
From the NCI Drug Dictionary: A humanized monoclonal antibody targeting the human cell surface antigen CD47, with potential immunostimulating and antineoplastic activities. Upon administration, anti-CD47 monoclonal antibody Hu5F9-G4 selectively binds to CD47 expressed on tumor cells and blocks the interaction of CD47 with its ligand signal regulatory protein alpha (SIRPa), a protein expressed on phagocytic cells. This prevents CD47/SIRPa-mediated signaling, allows the activation of macrophages, through the induction of pro-phagocytic signaling mediated by calreticulin, which is specifically expressed on the surface of tumor cells, and results in specific tumor cell phagocytosis. In addition, blocking CD47 signaling activates an anti-tumor T-lymphocyte immune response and T-cell mediated cell killing.
- Advani R, Flinn I, Popplewell L, Forero A, Bartlett NL, Ghosh N, Kline J, Roschewski M, LaCasce A, Collins GP, Tran T, Lynn J, Chen JY, Volkmer JP, Agoram B, Huang J, Majeti R, Weissman IL, Takimoto CH, Chao MP, Smith SM. CD47 Blockade by Hu5F9-G4 and Rituximab in Non-Hodgkin's Lymphoma. N Engl J Med. 2018 Nov 1;379(18):1711-1721. link to original article PubMed