Three Phase III clinical trials of varenicline have been published. Two were randomized, placebo-controlled, double-blind studies, enrolling 1022 and 1023 patients, respectively.[12,13] Patients older than 18 years who smoked over 10 cigarettes daily were randomized to receive one of three treatments: varenicline 1 mg p.o. twice daily, extended-release bupropion 150 mg p.o. twice daily, or placebo. Patients who had previous exposure to bupropion and NRT were excluded. Patients received treatment for 12 weeks and then were followed for an additional 40 weeks. Patients received smoking-cessation literature and brief weekly counseling during the 12 weeks of treatment.[12,13] When the data of the two trials were pooled, varenicline use was associated with significant improvements in the four-week carbon-monoxide-confirmed continuous quit rate (44.2%) at weeks 9-12 compared with bupropion (29.7%) and placebo (17.7%) (p < 0.0001 for each comparison). Individual trial analysis found that 12-week abstinence rates were higher in patients who received varenicline versus bupropion (43.9% versus 29.8% and 44% versus 29.5%) (p < 0.001 for each comparison). Independently, continuous abstinence rates up to week 52 were significantly improved in only one of the two studies comparing varenicline with bupropion (23% versus 14.6%, p = 0.04), but varenicline maintained significant improvements over placebo in both studies (21.9% versus 8.4%, p < 0.001; 23% versus 10.3%, p < 0.004).
A third Phase III study had a 12-week open-label period where 1206 patients were treated with varenicline 1 mg p.o. twice daily. Those who remained abstinent at the end of the 12 weeks were enrolled in a second phase of blinded randomization to varenicline 1 mg p.o. twice daily or placebo for an additional 12 weeks. The continuous quit rates for weeks 13-24 of the trial were 70.5% and 49.6% for varenicline and placebo, respectively (p < 0.001). For weeks 13-52, the continuous quit rates were 43.6% and 36.9% for varenicline and placebo, respectively (p = 0.02).
Am J Health Syst Pharm. 2007;64(13):1381-1384. © 2007 American Society of Health-System Pharmacists
Cite this: Varenicline: The Newest Agent for Smoking Cessation - Medscape - Jul 01, 2007.