Adding bupropion to varenicline doesn't improve smoking quit rates

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - Smokers who want to quit may have more early success with varenicline plus bupropion SR (sustained-release) vs varenicline alone, but by the end of a year the treatments work equally well, new research shows.

"For heavier smokers, though, who smoke one pack or more of cigarettes per day, and for more dependent smokers, the combination of varenicline and bupropion SR increases smoking quit rates more than does varenicline alone," wrote principal investigator Dr. Jon O. Ebbert of the Mayo Clinic College of Medicine in Rochester, Minnesota, in an email to Reuters Health.

Results of the randomized trial, conducted in three centers in the US, were published online January 8 in a special issue of JAMA devoted to smoking-cessation. The issue coincides with the 50th anniversary this week of the 1964 Surgeon General's report on the health hazards of tobacco.

People eligible for Dr. Ebbert's study were at least 18 (mean, 42), had smoked at least 10 cigarettes per day for at least six months, were in good health and motivated to quit.

The researchers randomly assigned the 506 participants to twelve weeks of either varenicline plus bupropion SR (n=249) or varenicline plus placebo (n=257).

Overall, 315 (62%) people completed the study, 158 on combination therapy and 157 on monotherapy.

All participants took the Fagerström Test for Nicotine Dependence to assess their smoking dependence. They also took the Beck Depression Inventory, 2nd edition, at baseline and at weeks 2, 4, 8, 14, 26, and 52, and the Columbia Suicide Severity Rating Scale to gauge their depressive symptoms and suicidality, respectively.

The participants were treated for 12 weeks and followed up through week 52. They had two clinic visits before being treated, six visits while being treated, and three afterward. They also had follow-up telephone calls during treatment, at the target quit date and after the treatment stopped.

At 12 weeks, 53.0% of the combination therapy group had quit long-term (no smoking from two weeks after the target quit date) and 56.2% had not smoked in the past 7 days, compared with 43.2% and 48.6% of the patients on varenicline monotherapy (odds ratio, 1.49; p=0.03 and OR, 1.36; p=0.09, respectively).

At 26 weeks, 36.6% of the combination therapy group had quit and 38.2% had not smoked in the past 7 days, compared with 27.6% and 31.9% on varenicline monotherapy (OR, 1.52; p=0.03 and OR, 1.32; p=0.14, respectively).

At 52 weeks, 30.9% of the combination therapy group had quit and 36.6% % had not smoked in the past 7 days, compared with 24.5% and 29.2% on varenicline monotherapy (OR, 1.39; p=0.11 and OR, 1.40; p=0.08, respectively).

Both groups gained similar amounts of weight at 52 weeks from baseline: 4.9 kg for the combination therapy group, and 6.1 kg for the monotherapy group (p=0.23).

The combination therapy group reported more anxiety (7.2% vs 3.1%; p=0.04) and depressive symptoms (3.6% vs 0.8%; p=0.03) than the monotherapy group.

Dr. Judith Prochaska of the Stanford Prevention Research Center of Stanford University in Stanford, California told Reuters Health in an email that "this is the first rigorous, blinded, randomized controlled trial to evaluate the efficacy and tolerability of this medication combination."

Dr. Prochaska, who was not involved in the study, added that "while the mechanism of action by which bupropion improved upon varenicline's effects is not clear, varenicline and bupropion are two medications with consistent evidence of efficacy from multiple randomized trials."

The varenicline in the study was provided by Pfizer.

SOURCE: http://bit.ly/1gEMA4i

JAMA 2014.

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