A potent and selective FTase inhibitor (IC50 = 21 nM); greater than 30-fold selective for FTase over GGTase (IC50 = 790 nM); prevents farnesylation of Ras; inhibits proliferation of cells transformed by Ras farnesylation; reduces GTP-Ras, decreases angiographic vasospasm, and improves clinical scores in a dog model of subarachnoid hemorrhage ,