Anti-Smoking Drug Gets Support from Three Trials

July 7, 2006

PORTLAND, Ore - The novel anti-smoking drug Chantix (varenicline) is effective both to stop smoking and to keep off cigarettes, according to several investigations.

PORTLAND, Ore, July 7 ? The novel anti-smoking drug Chantix (varenicline) is effective both to stop smoking and to keep off cigarettes, according to according to several investigations.

Two separate studies ? one from the Oregon Health & Science University here and another from the University of Wisconsin in Madison ? concluded that Chantix is more effective than either placebo or Wellbutrin SR (bupropion) in helping patients stop smoking.

A third study, led by researchers from the University of Oslo in Norway, found that Chantix is more effective than placebo in preventing smokers who have quit from relapsing.

All three studies were financially supported by Pfizer, which makes Chantix, and were published in the July 5 issue of the Journal of the American Medical Association.

While the findings are promising, they are not a cure-all for smokers, according to an accompanying editorial by Robert Klesges, Ph.D., Karen Johnson, M.D., and Grant Somes, Ph.D., all of the University of Tennessee Health Science Center in Memphis. "Patients currently cannot and probably never will simply be able to "take a pill" that will make them stop smoking," they wrote.

The editorialists noted that Chantix is a novel medication for smoking cessation ? the first to be approved in nearly a decade ? and adds to the armamentarium available to clinicians and patients. But, they added, new drugs in this field tend to be greeted with immoderate enthusiasm that isn't justified by the evidence.

Chantix "definitely is not a panacea for smoking cessation," they said. "Many participants in these trials experienced adverse events, stopped taking their study medication before they should have, and discontinued participation in the studies."

"Importantly, the majority of participants in these three studies did not quit smoking even with (Chantix)," they said.

The first study, led by David Gonzales, Ph.D., of the Oregon Health & Science University, was a randomized double-blind, parallel-group, placebo- and active-treatment-controlled, phase III trial, conducted at 19 U.S. centers from June 19, 2003, to April 22, 2005.

The researchers recruited 1,025 smokers, who consumed 10 or more cigarettes a day, and randomized them to one of three arms ? placebo, Chantix titrated to 1 mg twice daily, and Wellbutrin titrated to SR 150 mg twice a day ? for 12 weeks, with 40 weeks of non-drug follow-up.

The study found:

  • For the last four weeks of the treatment period, the abstinence rate for Chantix was 44% compared with 17.7% for placebo and 29.5% for Wellbutrin. Both differences were statistically significant at P

Nearly 30% of participants reported nausea with Chantix, a rate significantly higher than with either Wellbutrin or placebo. Abnormal dreams were common and much more likely in the Chantix group.

In their editorial, Drs. Klesges, Johnson, and Somes noted that the study design did not include participants who had failed to quit smoking during the last week of the open-label phase, eliminating at a stroke the 35.9% of participants for whom the drug was apparently ineffective.

"The relapse prevention results reported are probably more optimistic than what would occur in a real-world situation," they said.

Also, because of the numerous exclusion and inclusion criteria for all the studies, their results may not be easily generalizable outside the clinic, they said.

Despite the limitations of the studies, they concluded, the research showed that investigators, clinicians and smokers "now have another product available that appears to help increase the probability of smoking cessation."