A potent, selective, nonpeptidomimetic inhibitor of farnesyl protein transferase (FPT), an enzyme involved in protein processing (farnesylation) for signal transduction. Displays significant antitumor effects in vivo. Tipifarnib competitively inhibits the farnesylation of lamin B (IC50 = 0.86 nM) and K-RasB (IC50 = 7.9 nM) peptide substrates and inhibits the cell growth of ~75% of a panel of 53 human tumor cell lines tested. MW: 489.4. Purity ≥98% by HPLC