Potent ATP-competitive PDGFR and VEGFR inhibitor (Ki = 5 and 6 nM, respectively); inhibits phosphorylation of c-Kit and suppresses the growth of mast cell lines expressing mutant Kit, inducing cell cycle arrest and apoptosis. Also inhibits FGFR1 (Ki = 0.5 μM). Effective in vivo. Purity 98%. MW (observed): 396.46