– CP-609754 (LNK-754) is a potent and reversible farnesyltransferase inhibitor with potential anticancer activity. It inhibits farnesylation of recombinant human H-Ras (IC50=0.57 ng/mL) and K-Ras (IC50=46 ng/mL)[1]. In 3T3 H-ras (61L)-transfected cell lines, CP-609754 exhibits a slow on/off rate, inhibiting mutant H-Ras farnesylation with an IC50 of 1.72 ng/mL[1]. The compound is competitive for the prenyl acceptor (H-Ras protein) and noncompetitive for the prenyl donor farnesyl PPI, selectively inhibiting farnesylation of both H- and K-Ras proteins in 3T3 transfectants[1]. In vivo, CP-609754 shows antitumor activity against 3T3 H-ras (61L) tumors, with tumor regression achieved at 100 mg/kg twice daily and an ED50 for tumor growth inhibition at 28 mg/kg[1]. Continuous i.p. infusion of CP-609754 inhibits tumor growth by over 50% and reduces tumor farnesyltransferase activity by over 30% when plasma concentration is maintained above 118 ng/mL[1]. [1]. Stacy L Moulder, et al. A phase I open label study of the farnesyltransferase inhibitor CP-609,754 in patients with advanced malignant tumors. Clin Cancer Res. 2004 Nov 1;10(21):7127-35.