KRN 633 is an ATP-competitive inhibitor of VEGFR kinase activity (IC50s = 170, 160, and 125 nM for VEGFR1, 2, and 3, respectively). At higher concentrations KRN 633 inhibits PDGFR-α and c-KIT with IC50 values of 0.97 and 4.3 μM, respectively, and is inactive towards a panel of 17 additional kinases. KRN 633 suppresses VEGF-dependent activation of MAPK and cell proliferation and demonstrates antitumor and antiangiogenic activity by inhibiting vessel formation and vascular permeability in human tumor xenograft models.
