Fit to Quit

October 1, 2008

Julie Nicholis / Corbis

Smokers seeking to kick the habit may soon be able to save time, money, and boxes of unused patches. For the first time, researchers have identified patterns of genes that appear to influence how well individuals respond to specific smoking cessation treatments.

Scientists at Duke Medical Center, the National Institute of Drug Abuse, Brown University, and the University of Pennsylvania scanned the entire human genome in a comprehensive search for genes that could determine treatment outcome. They identified several genetic variations that seem to indicate the likelihood of success or failure of nicotine replacement therapy (NRT) and bupropion (Zyban).

Both NRT and Zyban have proven effective at helping people abstain from smoking, but use different pharmacological mechanisms to achieve that abstinence.

The results of the study, which was supported by the National Institutes of Health, Philip Morris USA Inc., and GlaxoSmithKline, appear in the Archives of General Psychiatry.

The latest results supported the findings of an earlier study, in which the researchers performed a genome-wide scan of more than 520,000 genetic markers taken from blood samples of smokers entered in a quit-smoking trial. They compared the genes of those who had successfully quit to those who had failed, and found clusters of positive results in gene variants present more frequently in the successful quitters.

The researchers stress that the presence of these genetic variants alone may not be enough to predict the success or failure of a particular treatment, and that more research is necessary to determine the exact effect of each variant. But at the same time, they say genetic differences may help to explain why some people have an easier time quitting smoking than others.

"This takes us a big step forward in being able to tailor treatment to individual smokers to provide the therapies that are most likely to benefit them," says Jed Rose, director of Duke's Center for Nicotine and Smoking Cessation Research and one of the study's authors. "In a few years, a simple blood test may provide physicians with enough information to recommend one treatment over another."