A randomized, placebo-controlled trial of varenicline, a selective alpha4beta2 nicotinic acetylcholine receptor partial agonist, as a new therapy for smoking cessation in Asian smokers.

Background: Rates of smoking in East Asian men range from >35% to >60%, and are increasing in women and the young.

Objective: This study evaluated the efficacy and tolerability of 1 mg BID varenicline, a novel alpha4beta2 nicotinic acetylcholine receptor partial agonist, for smoking cessation in smokers in Taiwan and Korea.

Methods: A randomized, double-blind, placebo-controlled, 12-week treatment, 12-week follow-up trial was conducted at 5 sites each in Korea and Taiwan. Eligible subjects, smoking >or=10 cigarettes/d, received brief smoking-cessation counseling and were randomly assigned in a 1:1 ratio to varenicline 1 mg BID (titrated during the first week) or placebo. Smoking status was established by self-report and confirmed at clinic visits by end-expiratory carbon monoxide
Results: Overall, 126 subjects (84.9% male) received varenicline, and 124 (92.7% male) received placebo, Subjects were aged 21 to 73 years (mean age, 39.7 and 40.9 years for varenicline and placebo groups, respectively), and the mean (range) body weights were 69.0 (44.8-110.0) kg and 71.4 (45.5-102.0) kg, respectively. Subjects had smoked for 3 to 52 years (mean, 20.2 and 22.1 years in the varenicline and placebo groups, respectively). Subjects had smoked a mean of 23 cigarettes/d over the past month, with 51.6% (varenicline) and 46.0% (placebo) having made 1 or more prior serious quit attempts. Smoking-cessation rates at the end of treatment were 59.5% with varenicline versus 32.3% with placebo (P < 0.001). CARs through 12 weeks post-treatment (weeks 9-24) were 46.8% with varenicline and 21.8% with placebo (P < 0.001). The 7-day PP was 67.5% with varenicline versus 36.3% with placebo at week 12, and 57.1% versus 29.0% with placebo at week 24 (both, P < 0.001). Treatment-emergent, all-causality adverse events with an incidence >or= 5% for varenicline were nausea (43.7% for varenicline vs 11.3% placebo), insomnia (15.1% vs 13.7%), increased appetite (7.9% vs 6.5%), constipation (7.1% vs 2.4%), anxiety (5.6% vs 2.4%), and abnormal dreams (5.6% vs 0.8%). Adverse events resulted in <10% treatment discontinuations overall.

Conclusion: Varenicline was an efficacious and well-tolerated pharmacotherapy for smoking cessation in this group of Asian smokers over a 12-week treatment period, and its effects persisted for a further 12-week follow-up period.