Potent inhibitor of VEGFR-1, -2 and -3 (IC50 values are 0.2, 0.1 to 0.3, and 1.2 nM for VEGFR-2, VEGFR-3 and VEGFR-1 respectively). Inhibits angiogenesis and vascular permeability. Displays little activity at 'off-target' protein kinases and exhibits no significant activity in a broad protein kinase screen. Orally available.