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Reprinted from the NCI Cancer Bulletin, vol. 3/no. 28, July 11, 2006 (see the current issue).

Several articles published in the July 5, 2006, issue of the Journal of the American Medical Association discuss the safety, efficacy, and side effects of a smoking cessation drug, varenicline (Chantix®), which was approved by the FDA in May of this year. The related studies were supported by the drug's manufacturer, Pfizer, and conducted by the Varenicline Phase 3 Study Group.

Dr. David Gonzales and colleagues tested the efficacy of 1 mg of varenicline given twice a day for 12 weeks against 150 mg of the sustained-release antidepressant bupropion - also a smoking cessation aid - as well as a placebo (see the journal abstract). Of the 1,025 smokers who participated, 44 percent who received varenicline were able to quit smoking between weeks 9 and 12, while 29.5 percent quit with buproprion and 17.7 percent quit with placebo.

After 52 weeks, abstinence dropped to 21.9 percent for varenicline, 16.1 percent for bupropion, and 8.4 percent for placebo. The test group reported nausea and insomnia, but generally had fewer side effects than those who took bupropion.

These results were mirrored by Dr. Douglas E. Jorenby and colleagues, who tested a similar protocol in 1,027 smokers (see the journal abstract).

A third study, by Dr. Serena Tonstad and colleagues, showed that an additional 12 weeks of treatment with varenicline significantly improved continuous abstinence up to 52 weeks after the study began: 43.6 percent remained smoke free between weeks 13 and 52, compared with 36.9 percent who received a placebo throughout the same period (see the journal abstract).

In an editorial, Drs. Robert C. Klesges, Karen C. Johnson, and Grant Somes of the University of Tennessee Health Science Center and St. Jude Children's Research Hospital acknowledged that varenicline is effective for smoking cessation, but warned that high dropout rates in the nonvarenicline study groups may have skewed results in favor of the drug.

Noting that the majority of participants in the three related studies were unable to quit smoking, even with pharmacologic aids, they wrote, "Patients currently cannot and probably never will simply be able to 'take a pill' that will make them stop smoking. Smokers must want to stop smoking and must be willing to work hard to achieve [that goal]."

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