G4723A

G4723A is a humanized IgG1 monoclonal antibody that specifically targets the alpha subunit of the interleukin-3 receptor (IL-3Rα), also known as CD123. Developed by ImmunoGen, G4723A was derived from the murine antibody CD123-6 and engineered with a cysteine residue at position 442 (EU numbering) to facilitate site-specific drug attachment. Unlike other CD123-targeting antibodies that bind the N-terminal domain, G4723A binds to the D2-D3 region of the extracellular domain, effectively inhibiting IL-3-mediated signaling and cell proliferation. While it possesses inherent inhibitory activity, G4723A serves primarily as the targeting component of the antibody-drug conjugate (ADC) IMGN632 (pivekimab sunirine), where it is linked to a potent DNA-alkylating indolinobenzodiazepine pseudodimer (IGN) payload for the treatment of hematologic malignancies such as acute myeloid leukemia (AML).

Other names

humanized anti-CD123 antibody