Potent and selective inhibitor of human vascular endothelial growth factor receptor 2 (VEGFR-2/KDR) activity. Selectively inhibits VEGFR-2 (IC50 = 2 nM) over VEGFR-1 and a range of other receptor tyrosine kinases such as PDGFRβ, FGFR1, EGFR and erbB2 (IC50 > 50 μM). Inhibits VEGF-A-induced endothelial cell proliferation in vitro (IC50 = 8 nM).