Purpose: This is a phase I study of the retinoid X receptor agonist bexarotene (Targretin(®)) in combination with the chemotherapeutic drugs cisplatin and vinorelbine and lipid-lowering therapy. This study looked for pharmacokinetic (PK) interactions between the agents in parallel with a phase III study of the combination.
Methods: Patients (n = 26) with advanced-stage non-small-cell lung cancer received intravenous cisplatin 100 mg/m(2) on day 1 and at 4-week intervals plus intravenous vinorelbine 25 mg/m(2) weekly. Continuous oral bexarotene therapy (400 mg/m(2)/day) was initiated at day 4. Lipid-lowering therapy was initiated in all patients due to hypertriglyceridemia associated with bexarotene use. PK profiles of the chemotherapeutic agents were obtained on day 1 (without bexarotene) and during cycles 2-4 (with bexarotene). Vinorelbine (n = 18) and free cisplatin (n = 17) PK parameters in evaluable patients were determined using non-compartmental methods.
Results: Mean vinorelbine and free cisplatin clearance and dose-corrected AUC values with bexarotene were within 20% of respective values without concomitant bexarotene. Bexarotene levels did not vary with or without co-administration of the chemotherapeutic agents. There was no evidence of increased toxicity when bexarotene was co-administered with the chemotherapeutic agents.
Conclusions: Bexarotene does not substantially affect vinorelbine or cisplatin PK, and the combination is well tolerated. The results are consistent with the mechanisms of elimination of vinorelbine (high metabolic clearance) and cisplatin (non-enzymatic and renal elimination).