The 13th World Conference on Tobacco OR Health

Objective: This study evaluated the benefit of an additional 12 weeks of treatment with varenicline in subjects who had successfully stopped smoking at the end of 12-week, open-label varenicline treatment. Varenicline is a novel α4β2 nicotinic receptor partial agonist that has been proposed to reduce craving and withdrawal symptoms while blocking the reinforcing effects of nicotine.

Methods: Subjects received open-label varenicline 1 mg bid for 12 weeks. Those who were abstinent during the last week of the treatment period were randomized to receive either varenicline 1 mg bid or placebo for an additional 12 weeks, followed by a 28-week nontreatment period. The primary end point was carbon monoxide (CO)-confirmed continuous abstinence rate (CAR) for weeks 13-24. A secondary end point was the CAR for weeks 13-52.

Results: Approximately 63% of open-label varenicline treated subjects entered the double-blind phase. The CO-confirmed CAR for weeks 13-24 was significantly higher for varenicline than for placebo (70.6% vs 49.8%), (OR 2.47, p<0.0001). Abstinence rates were higher for varenicline than for placebo (44.0% vs 37.1%) for weeks 13-52 (OR 1.35, p=0.0126). During the double-blind phase, the occurrence of treatment-related adverse events with varenicline was <3% and similar to placebo. Discontinuations due to nausea were infrequent and similar to placebo (1.4%, open-label phase; 0.2%, double-blind phase). For subjects who stopped smoking at the end of 12 weeks, an additional 12 weeks was more effective than placebo in maintaining abstinence to the end of treatment and to 1 year from the start of treatment.