HuGAL-FR21 is a humanized monoclonal IgG1 antibody targeting FGFR2IIIb. It effectively blocks the binding of FGF2, FGF7, and FGF10 to FGFR2IIIb and inhibits FGF-induced phosphorylation of FGFR2IIIb. Additionally, HuGAL-FR21 reduces FGFR2 expression in SNU-16 cells and demonstrates significant antitumor activity in gastric cancer xenograft models in nude mice. This compound is valuable for research in cancers such as gastric cancer.

HuGAL-FR21 (0.001-1 μg/mL) specifically binds to FGFR2IIIb (EC50 approximately 20 pM) and its mutant S252W in SNU-16 cells. It effectively blocks the binding of FGFR2IIIb to FGF2, FGF7, and FGF10 at concentrations of 0.01-100 μg/mL with an IC50 of about 1.5-3 μg/mL. Additionally, at 10 μg/mL for 30 minutes, HuGAL-FR21 effectively inhibits FGF7-induced phosphorylation and significantly suppresses FGF2-induced phosphorylation in SNU-16 cells. When used at 10 μg/mL for 2-24 hours, it downregulates FGFR2 protein levels in SNU-16 cells.

Administered HuGAL-FR21 (0.5-5 mg/kg, intraperitoneal injection, twice a week for 25-30 days) effectively inhibits tumor growth without significant toxicity in nude mice with SNU-16/OCUM-2M xenografts.