Alofanib (RPT835) is a novel selective allosteric inhibitor of FGFR2 and has a dramatic inhibitory effect with IC50 <10 nM on FGF2-induced phoshphorylation of FRS2a in KATO III cells. It has no direct effect on FGF2-dependent FGFR1 and FGFR3 phosphorylation levels in either cell lines and no effects on FGF2-FGFR2 binding.