The farnesyl protein transferase inhibitor lonafarnib (SCH66336) is an inhibitor of multidrug resistance proteins 1 and 2.

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Wang EJ, Johnson WW

The farnesyl protein transferase inhibitor lonafarnib (SCH66336) is an inhibitor of multidrug resistance proteins 1 and 2.

Chemotherapy. 2003 Dec;49(6):303-8. doi: 10.1159/000074531.

PubMed ID

14671431 [ View in PubMed

]

Abstract

Clinical studies indicate that the farnesyl protein transferase inhibitor SCH66336 (lonafarnib), an anticancer agent developed to antagonize oncogenic Ras, is generally well tolerated. Lonafarnib has also demonstrated therapeutic synergy with coadministered taxanes, vincristine, cisplatin, cyclophosphamide, 5-fluorouracil (5-FU) and Gleevec. Lonafarnib has recently been shown, in addition, to be a potent inhibitor of the transmembrane efflux transporter P-glycoprotein (P-gp), which confers cellular resistance to the substrates vincristine, taxol and paclitaxel. Treatment with lonafarnib would therefore be predicted to be synergistic with these coadministered cancer therapeutics that are substrates of P-gp. However, cisplatin, 5-FU and cyclophosphamide are not P-gp substrates, yet cisplatin, 5-FU and possibly cyclophosphamide are purported substrates for multidrug resistance proteins (MRPs) 1 and 2 (known to cause chemotherapy resistance). Lonafarnib is shown here to inhibit the function of MRP1 and MRP2 with a potency similar to that of cyclosporin A and may therefore cause the observed synergy with cisplatin and other agents by inhibiting these MRPs. Coadministration of lonafarnib could thus reduce chemotherapy dosage and hence produce lower exposure to normal cells and less undesired toxicity.

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Lonafarnib	Canalicular multispecific organic anion transporter 1	Protein	Humans	No	Inhibitor	Details
Lonafarnib	P-glycoprotein 1	Protein	Humans	No	Substrate Inhibitor	Details