SIRPα and combinations

CTX-5861 is a fully human SIRPα antibody which binds and blocks all polymorphic alleles of SIRPα. By inhibiting SIRPα engagement with CD47, it prevents the “do not eat me” signal in macrophages, leading to enhanced antibody-mediated phagocytosis (ADCP) of tumor cells. In syngeneic tumor models, CTX-5861 significantly increases the efficacy of tumor-targeting antibodies, checkpoint blockers, and our CD137 agonist CTX-471, without inducing the hematological toxicities (hemagglutination, anemia) observed with CD47-directed therapies.