RBC-Specific CD47 Pruning Confers Protection and Underlies the Transient Anemia in Patients Treated with Anti-CD47 Antibody 5F9

CD47 is an anti-phagocytic (i.e. “don't eat me”) signal and macrophage checkpoint that cancer cells utilize to evade innate immunity and establish disease. 5F9 is a humanized IgG4 monoclonal antibody (mAb) that binds to human CD47 and blocks its interaction with SIRPα, its cognate inhibitory receptor.5F9 is undergoing investigation in several clinical trials and preliminary analyses have revealed encouraging therapeutic potential.