A farnesyl transferase inhibitor that blocks the post-translational lipid modification of oncogenic Ras isoforms H-Ras, N-Ras, and K-Ras (IC50s = 1.9, 2.8, and 5.2 nM, respectively) and Rheb (IC50 = 10-100 nM); demonstrates potent dose-dependent oral activity in an array of human tumor xenograft models including tumors originating from colon, lung, pancreas, prostate, and urinary bladder.