Varenicline for smoking cessation: a placebo-controlled, randomized study

Varenicline tartrate, a novel, selective, nicotinic acetylcholine receptor partial agonist, has been developed specifically as a smoking cessation drug. This study evaluated the efficacy of a standard regimen of varenicline compared with placebo for smoking cessation in 333 subjects in China, Singapore and Thailand.

This 24-week, randomized, double-blind, placebo-controlled trial of varenicline, 1 mg bd, consisted of a 12-week treatment period followed by a 12-week non-treatment follow-up period. The primary study end-point was the 4-week continuous abstinence rate defined as the proportion of subjects who reported total abstinence from smoking and other nicotine products from weeks 9-12. A key secondary end-point was the continuous abstinence rate from weeks 9-24, defined as the proportion of subjects who achieved the primary end-point as well as total abstinence from all tobacco products from weeks 13-24.

Both end-points were achieved by a significantly higher proportion of subjects in the varenicline group than in the placebo group. The 4-week continuous abstinence end-point was achieved by 50.3% and 31.6% in the varenicline and placebo groups, respectively (P = 0.0003), while continuous abstinence from weeks 9-24 was achieved by 38.2% and 25.0% of subjects, respectively (P = 0.0080). The treatment effect was generalizable by treatment centre and country. Varenicline was safe and appeared to be well tolerated by most subjects.

Varenicline was significantly more efficacious for smoking cessation than placebo over a 12-week treatment period and a further 12-week non-treatment follow-up period in smokers from China, Singapore and Thailand. No significant side-effects were noted.