Placebo-controlled trial of bexarotene, a retinoid x receptor agonist, as maintenance therapy for patients treated with chemotherapy for advanced non-small-cell lung cancer.

This study was designed as a multicenter, randomized, double-blind, placebo-controlled trial. Patients were randomized by center to placebo (16 patients, 31%), oral bexarotene 300 mg/m2/day (21 patients, 40%), or oral bexarotene 600 mg/m2/day (15 patients, 29%) following demonstration of stable or responsive disease after first-line chemotherapy. The study was prematurely terminated because of slow accrual after 54 patients enrolled. Median time to progression (TTP) from the beginning of study drug treatment was 56 days for placebo, 82 days for moderate-dose bexarotene (300 mg/m2/day), and 128 days for high-dose bexarotene (600 mg/m2/day) (P = 0.56, log-rank test). For prior chemotherapy responders only, median TTP from the beginning of study drug treatment was 56 days for placebo, 146 days for moderate-dose bexarotene, and 177 days for high-dose bexarotene. Of note, there were more chemotherapy responders randomized to the placebo group (63%) than the bexarotene treatment arms (48% and 47%), further supporting a bexarotene-related improvement in TTP. Bexarotene-related toxicity was manageable and consisted primarily of elevated serum triglycerides and asthenia, skin toxicity (dryness, peeling, flaking), thyroid dysfunction, and headache. Because this study was closed prematurely, it does not have the statistical power to detect differences among the treatment groups. This study shows that patients can tolerate bexarotene at initial doses up to 600 mg/m2/day after platinum-based chemotherapy and that bexarotene may have the potential to delay disease progression in patients with advanced non-small-cell lung cancer with previously stable or responsive disease following platinum-based chemotherapy.