Selective inhibitor of farnesyltransferase (FTase). Blocks farnesylation of H-Ras, N-Ras and K-Ras4B (IC50 values are 0.8, 1.2 and 2.0 nM respectively). Displays >50,000-fold selectivity for FTase over geranylgeranyltransferase (GGTase) I. Inhibits VEGF-induced Ras activation; suppresses angiogenesis in vivo and in vitro (IC50 = 75 nM). Orally active.