Combination Varenicline/Bupropion Treatment Benefits Highly Dependent Smokers in an Adaptive Smoking Cessation Paradigm

Abstract

Introduction: This study replicated and extended results of a previous trial, which found that combination varenicline/bupropion treatment increased smoking abstinence in smokers who were male, highly dependent, and who did not respond to prequit nicotine patch treatment with a >50% reduction in expired-air carbon monoxide in the first week.

Methods: One hundred and twenty-two male nicotine patch nonresponders and 52 responders were identified. Smokers in each group were randomized to receive 12 weeks of varenicline plus bupropion treatment versus varenicline plus placebo. The primary outcome was continuous smoking abstinence at weeks 8-11 after the target quit date.

Results: For smokers with a high level of dependence, judged by having a baseline Fagerstrom Test for Nicotine Dependence (FTND) score ≥ 6 and cigarette consumption ≥ 20/d, combination varenicline/bupropion treatment increased the abstinence rate relative to varenicline alone: 71.0% versus 43.8% (odds ratio = 3.14; 95% confidence interval = 1.11-8.92, p [one tailed] = .016). In contrast, less dependent smokers did not show a benefit of combination treatment relative to varenicline (abstinence rates of 32.1% vs. 45.6%, respectively); there was a significant interaction of treatment and dependence level. Patch nonresponders tended to benefit the most from combination treatment, which was well tolerated overall.

Conclusions: Combination varenicline/bupropion treatment proved significantly more efficacious than varenicline alone among highly dependent male smokers. These results, together with prior studies, support an adaptive treatment paradigm that assigns smoking cessation treatment according to baseline smoker characteristics and initial response to nicotine patch treatment.

Implications: This study replicated, in a prospective manner, an important and surprising retrospective finding from a previous clinical trial, which showed that a specific subpopulation of smokers benefited substantially from receiving a combination treatment of varenicline plus bupropion, relative to varenicline plus placebo. Specifically, male smokers having high baseline nicotine dependence (FTND score ≥ 6 and cigarette consumption ≥ 20/d), showed a marked increase in smoking abstinence rate on combination pharmacotherapy. The present study likewise found an enhancement in end-of-treatment abstinence rate in this subgroup, from 43.8% to 71.0%. The adaptive treatment paradigm, which classifies smokers based on initial dependence level and response to prequit nicotine patch treatment, may be used to identify target populations of smokers whose success can be enhanced by intervening with combination pharmacotherapy before the quit-smoking date.

Trial registration: ClinicalTrials.gov identifier: NCT01806779.

Figure 1.

End-of-treatment (weeks 8–11 postquit date) abstinence rates by treatment condition, patch responder status, and dependence level (high = Fagerstrom Test for Nicotine Dependence [FTND] score ≥ 6 and baseline cigarettes/d ≥ 20).