BIM-46050 is a potent and specific inhibitor of human farnesyltransferase. BIM-46050 is free acidic form of BIM-46068. The IC50 values for in vitro inhibition of human brain FTase indicate that BIM-46050 and the ester form BIM-46068 are potent inhibitors of farnesyltransferase. Their potencies are in the nanomolar range and compare favorably with the compounds B581, FTI-277 and L745,631. B581 is an analog of the tetrapeptide Cys-Val-Phe-Met obtained by replacement of the amino-terminal amide bonds inhibiting processing of farnesylated proteins specifically. FTI-277 is a methyl ester of FTI-276, reported as a preferential inhibitor of FTase over GGTase I (100-fold). L745,631 is a 2-substituted piperazine reported to be a highly selective inhibitor of FTase over GGTase (2,000-fold). The selectivity of BIM-46050 and BIM-46068 for FTase over GGTase is very similar for both compounds (3,000-fold).