ontorpacept

Ontorpacept is a fully human recombinant fusion protein that acts as a CD47-blocking checkpoint inhibitor. It consists of the signal regulatory protein alpha (SIRPα) linked to an IgG1 Fc fragment. Ontorpacept binds to CD47 on tumor cells, blocking the "don't eat me" signal and thereby enhancing macrophage-mediated phagocytosis of malignant cells. This mechanism promotes immune-mediated clearance of cancer cells and is being investigated as a novel therapeutic strategy in oncology. Ontorpacept has shown activity in preclinical models and early-phase clinical trials for various hematologic malignancies and solid tumors, including acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), multiple myeloma, B-cell acute lymphoblastic leukemia (B-ALL), T-cell acute lymphoblastic leukemia (T-ALL), cutaneous T-cell lymphoma, leiomyosarcoma, small cell lung cancer, and other solid tumors[1][3][4][5][7]. The drug was initially developed by University Health Network/The Hospital for Sick Children and further developed by Trillium Therapeutics; Pfizer is now the main developer following acquisition[3][4][7]. Ontorpacept has orphan drug designation for cutaneous T-cell lymphoma but is not yet approved in any country.

Other names

CD47 antigen/SIRPalpha protein modulator1-118-signal regulatory protein alpha (human) fusion protein with immunoglobulin g1 (human fc fragment), dimer