NEW YORK (Reuters) -- Treatment with a new drug called Chantix may be more effective than Zyban in helping smokers kick the habit, and it may also promote longer-lasting abstinence, suggest results of three studies in the Journal of the American Medical Association this week.
However, according to a related editorial, the drug is no panacea for people wishing to quit smoking. "There are some important gastrointestinal side effects and, in the current studies, most people given the drug actually did not quit smoking," co-author Dr. Robert C. Klesges, from the University of Tennessee in Memphis, told Reuters.
Chantix, the first prescription anti-smoking drug in over a decade, belongs to a different drug class from other agents currently used for smoking cessation. It stimulates sufficient dopamine release to curb cravings while blocking the reinforcing effects of smoked nicotine.
The drug, which is marketed by Pfizer Inc., received FDA approval in May.
In two of the Pfizer-sponsored studies, Dr. Karen R. Reeves, from Pfizer Global Research and Development in Groton, Connecticut, and colleagues compared the effects of Chantix (varenicline) against those of Zyban (bupropion) and placebo. In the third study, Chantix was tested against placebo in maintaining abstinence from smoking.
In the first study, which involved 1,025 people who smoked at least 10 cigarettes per day, 12 weeks of Chantix was associated with an immediate abstinence rate of 44 percent, significantly higher than the 29.5 percent and 17.7 percent rates achieved with Zyban and placebo, respectively.
However, at 1 year, the abstinence rate for Chantix was not significantly different from that of Zyban: 21.9 percent vs. 16.1 percent. Still, these rates were significantly higher than that seen with placebo -- 8.4 percent.
Nausea was a common finding with Chantix, noted in 28.1 percent of patients. Zyban, by comparison, was tied to a high rate of insomnia -- 21.9 percent.
The second study was similar to the first except this time, the abstinence rate at 1 year was significantly higher with Chantix compared with Zyban: 23 percent vs. 14.6 percent. Once again, Chantix was often linked to nausea with a rate of nearly 30 percent.
The third study involved 1,210 smokers who remained abstinent for at least 7 days after completing a 12-week course of Chantix. The subjects were randomized to continue the drug for an additional 12 weeks or switch to placebo.
Subjects who remained on Chantix had a continuous abstinence rate from weeks 13 to 52 of 43.6 percent, significantly higher than the 36.9 percent rate seen in the placebo group.
While the results are encouraging, Klesges noted, smokers should not get caught up in the media hype likely to surround this new drug and think that it represents any easy cure for their problem. "There is no such thing as a magic bullet for any condition, let alone one that involves complex human behavior."
Still, "this drug may be as good as we're going to get in terms of a medical therapy for smoking cessation," Klesges noted. "There clearly is an addictive component to smoking and the best results are achieved when a medical therapy is combined with a behavioral intervention."