Varenicline increased quit rates among smokers contemplating cessation

Varenicline increased smoking cessation rates compared to placebo in smokers who were contemplating quitting but were not ready to do so immediately, a manufacturer-sponsored study found.

The double-blind trial randomized 1,510 cigarette smokers recruited through advertising to 61 centers in 10 countries in 2011 to 2013. All of them were not willing or able to quit immediately but were willing to reduce their smoking and make a quit attempt within 3 months. They were randomized to 24 weeks of varenicline titrated to 1 mg twice daily or placebo, and all received support and counseling. The results were published in the Feb. 17 Journal of the American Medical Association.

According to carbon monoxide-confirmed self-reports, the varenicline group had significantly higher abstinence rates than the placebo group during weeks 15 to 24 (32.1% vs. 6.9%; relative risk [RR], 4.6; 95% CI, 3.5 to 6.1). That trend continued during weeks 21 to 24 (37.8% on varenicline vs. 12.5% on placebo; RR, 3.0; 95% CI, 2.4 to 3.7) and through the end of the study at week 52 (27.0% vs. 9.9%; RR, 2.7; 95% CI, 2.1 to 3.5). Serious adverse events occurred in 3.7% of varenicline patients and 2.2% of the placebo group (P=0.07).

Varenicline treatment significantly increased cessation rates among smokers who were contemplating quitting soon but were not ready to stop within the next month, the study authors concluded. Abstinence rates among the study's patients were similar to those in prior trials of smokers motivated to quit after 1 week of treatment. This could result from the drug's abilities to reduce cigarette cravings or to block the reinforcing action of nicotine, the authors speculated.

The active group did have higher rates of constipation and weight gain, but these are established side effects of smoking cessation and so may not have been a direct effect of the drug. The study was limited by its exclusion of patients with severe diseases, and given the support and counseling provided in the trial, real-world cessation rates are likely to be lower, the study authors noted. The study also didn't compare varenicline to other smoking cessation treatments.

Still, the trial's approach could be a useful therapeutic option for clinicians treating patients who want to quit sometime between 1 and 6 months in the future, who make up about a third of smokers in the U.S., the study authors said.