INCB126503 is a highly potent, selective, orally bioavailable FGFR2/3 inhibitor with IC50 of 2.1/1.2 nM respectively.
INCB126503 shows potent activity when tested against both of the FGFR3 gatekeeper mutants FGFR3-V555L (IC50 = 0.92 nM) and FGFR3-V555 M (IC50 = 0.85 nM).
INCB126503 displays single-digit nanomolar potency against FGFR3 in BAF3 cells (IC50 = 6.8 nM) while featuring excellent selectivity over FGFR1 (58-fold), also is highly selective over FGFR4 (IC50 = 64 nM).
INCB126503 inhibits both pFGFR3 and pERK signaling in RT112/84 tumor cells following a single oral dose of 100 mg/kg in RT112/84 tumors, demonstrates significant antitumor efficacy without inducing hyperphosphatemia.
