drug_type
RELEVANT_DRUG
intervention_type
Biologic (antibody fusion protein)
drug_description
Antibody fusion protein combining an anti-CD20 monoclonal antibody with the CD47-binding domain of SIRPα; blocks the CD47–SIRPα checkpoint to promote macrophage phagocytosis and engages Fcγ receptors to enhance ADCC against CD20+ B cells.
nci_thesaurus_concept_id
C179653
nci_thesaurus_definition
A bispecific antibody directed against both the B-cell-specific membrane protein and tumor-associated antigen (TAA) CD20, and the human cell surface antigen CD47, with potential immunostimulating, phagocytosis-inducing and antineoplastic activities. Upon administration of amulirafusp alfa, the anti-CD20 moiety selectively targets and binds to CD20 on CD20-positive B-cells, thereby improving the binding of the anti-CD47 moiety to the CD20-positive malignant B-cells. The CD47 binding by amulirafusp alfa blocks the interaction of CD47 with signal regulatory protein alpha (SIRPalpha), an inhibitory protein expressed on macrophages and dendritic cells (DCs), which prevents CD47/SIRPalpha-mediated signaling and abrogates the CD47/SIRPalpha-mediated inhibition of phagocytosis. This induces pro-phagocytic signaling mediated by the binding of calreticulin (CRT), which is specifically expressed on the surface of tumor cells, to low-density lipoprotein (LDL) receptor-related protein (LRP), expressed on macrophages, which results in macrophage activation and the specific phagocytosis of the CD20/CD47-expressing tumor cells. Additionally, blocking CD47 signaling activates an anti-tumor T-lymphocyte immune response and T-cell-mediated killing of CD20/CD47-expressing tumor cells. In addition, amulirafusp alfa induces an anti-tumor activity through the induction of antibody dependent cellular cytotoxicity (ADCC). CD47, also called integrin-associated protein (IAP), is widely expressed on normal, healthy cells, such as red blood cells and platelets, and overexpressed on the surface of a variety of cancer cells. Expression of CD47, and its interaction with SIRPalpha, leads to the inhibition of macrophage activation and protects cancer cells from phagocytosis, which allows cancer cells to proliferate. CD20 is a membrane antigen that is overexpressed in B-cell malignancies. By co-targeting CD47 and CD20, amulirafusp alfa has the potential to overcome the limitations of existing CD47-targeted therapies by possibly avoiding the side effects caused by binding to CD47 on healthy hematopoietic stem cells (HSCs) which causes unwanted macrophage-mediated phagocytosis.
drug_category
INHIBITORY FUSION PROTEIN
drug_class
Inhibitor
drug_delivery_route
Intravenous
drug_mechanism_of_action
Bispecific antibody fusion that targets CD20 on B cells while presenting a SIRPα domain to bind CD47, locally blocking the CD47–SIRPα innate immune checkpoint. This removes the “don’t‑eat‑me” signal to promote macrophage-mediated phagocytosis (ADCP) and, via its IgG1 Fc, engages Fcγ receptors to enhance NK cell/macrophage ADCC against CD20+ B cells, with secondary activation of adaptive anti-tumor immunity.
drug_name
IMM0306
nct_id_drug_ref
NCT05771883