CYT997 is a novel anti-cancer vascular disrupting agent (VDA). In vitro, CYT997 is shown to potently inhibit the proliferation of vascular endothelial growth factor-stimulated human umbilical vein endothelial cells (IC(50) 3.7 ?? 1.8 nM) and cause significant morphological changes at 100 nM, including membrane blebbing.