Efficacy of Varenicline for Cigarette Reduction Before Quitting in Japanese Smokers: A Subpopulation Analysis of the Reduce to Quit Trial

PurposeThis prospective analysis of the Japanese subpopulation of the varenicline reduce to quit study was conducted to evaluate whether results for Japanese participants were consistent with the full study population.MethodsPatients received varenicline or placebo for a 24-week treatment period (12-week smoking reduction phase then a 12-week smoking abstinence phase) followed by a 28-week nontreatment, follow-up phase. Participants were to reduce the daily number of cigarettes smoked by at least 50% by week 4 and by a further 50% by week 8, with the goal of achieving complete abstinence by week 12. The primary efficacy end point was the carbon monoxide-confirmed continuous abstinence during weeks 15 to 24.FindingsOverall, 210 Japanese patients were randomly assigned to 1 of the 2 study groups (varenicline, 107; placebo, 103). Continuous abstinence rates for weeks 15 to 24 were higher for participants in the varenicline group versus the placebo group (46.7% vs 12.6%; odds ratio = 14.68; 95% CI, 5.38-40.05), and the 7-day point prevalence of abstinence rates were higher for varenicline versus placebo at week 12 (odds ratio = 13.76; 95% CI, 5.28-35.86). The number of participants with a ≥50% reduction in the number of daily cigarettes smoked from baseline to week 4 and a ≥75% reduction by week 8 was greater in the varenicline group versus the placebo group (week 4: 59.8% vs 30.1%; week 8: 38.3% vs 12.6%). Serious adverse events were reported in 3.7% of varenicline participants and 1.0% of placebo participants.ImplicationsThe efficacy and tolerability results of this analysis are consistent with those of the full varenicline reduce to quit study. Varenicline treatment and cigarette reduction before quitting may provide an alternative approach to smoking cessation in Japanese smokers who are not ready to quit immediately. ClinicalTrials.gov identifier: NCT01370356.