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drug_type
RELEVANT_DRUG
intervention_type
Biological (bispecific monoclonal antibody)
drug_description
An intravenous, every-2-weeks bispecific monoclonal antibody immunotherapy that binds CLDN18.2 on tumor cells and blocks the CD47–SIRPα checkpoint to enhance macrophage-mediated phagocytosis and antigen presentation, aiming to focus CD47 blockade on CLDN18.2-positive tumors to reduce off-tumor hematologic toxicity.
nci_thesaurus_concept_id
C204802
nci_thesaurus_definition
A bispecific antibody directed against both the tumor-associated antigen (TAA) Claudin18.2 (CLDN18.2; A2 isoform of claudin-18) and the human cell surface antigen CD47, with potential immunostimulating, phagocytosis-inducing and antineoplastic activities. Upon administration of anti-CLDN18.2/CD47 bispecific antibody AK132, the anti-CLDN18.2 moiety selectively targets and binds to CLDN18.2 on CLDN18.2-expressing tumor cells, thereby improving the binding of the anti-CD47 moiety to the CLDN18.2-expressing tumor cells. The CD47 binding by AK132 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 CLDN18.2-expressing tumor cells. Additionally, blocking CD47 signaling activates an anti-tumor T-lymphocyte immune response and T-cell-mediated killing of CLDN18.2-expressing tumor cells. CD47, also called integrin-associated protein (IAP), is widely expressed on normal, healthy cells, such as red blood cells (RBCs) 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. CLDN18.2, a tight junction protein and stomach-specific isoform of Claudin-18, is expressed on a variety of tumor cells. Its expression in healthy tissues is strictly confined to short-lived differentiated epithelial cells of the gastric mucosa. Co-targeting CD47 and CLDN18.2 may limit the binding of AK132 to CD47 on healthy hematopoietic stem cells (HSCs) and may minimize any associated adverse effects.
drug_mesh_term
Antibodies, Bispecific
drug_category
INHIBITORY ANTIBODY
drug_class
Inhibitor
drug_delivery_route
Intravenous
drug_mechanism_of_action
Bispecific monoclonal antibody that binds CLDN18.2 on tumor cells while blocking the CD47–SIRPα checkpoint, concentrating CD47 inhibition on CLDN18.2-positive tumors to enhance macrophage-mediated phagocytosis and antigen presentation (with potential Fc effector functions), thereby promoting anti-tumor immunity and reducing off-tumor hematologic toxicity.
drug_name
AK132
nct_id_drug_ref
NCT06166472