Chantix now available for quitting smoking

  Article date: 2006/08/04: Chantix Now Available for Quitting Smoking - Studies Offer Details of New

The recently approved smoking cessation drug Chantix (varenicline) became available in US pharmacies at this week, according to its manufacturer Pfizer.

The announcement comes just a few weeks after the publication of 3 studies which offer new details about how Chantix stacks up against the competition. The reports in the Journal of the American Medical Association show that Chantix outperforms placebos in the short term and long term, and also bests the antidepressant Zyban (bupropion) under some circumstances.

Chantix, which was approved by the US Food and Drug Administration in May 2006, works differently than nicotine replacement products or Zyban. Chantix acts on the nicotine receptors in the brain, helping people overcome nicotine cravings and withdrawal symptoms, and lessening the pleasure they get from smoking. At the time Chantix was approved, the studies used to evaluate its effectiveness had not been published in a peer reviewed journal. Now those details are available to help smokers and their doctors decide if this drug is worth trying.

The studies all involved healthy adults (aged 18-75) who smoked 10 or more cigarettes a day and who wanted to quit. In 2 of the studies, participants were randomly assigned to take either Chantix, Zyban, or a placebo for 12 weeks. All of them also got brief counseling sessions to help them quit. Quit rates were compared during the last 4 weeks of treatment, 6 months later, and a year later.

Chantix was better than placebo and Zyban at helping people quit in the short term. In both comparison trials, about 44% of people on Chantix were still off cigarettes during the last 4 weeks of treatment, compared to about 30% of those on Zyban and about 18% of those on placebo. After 6 months, nearly 30% of the Chantix users remained smoke-free, compared to about 21% of Zyban users and just 11%-13% of placebo patients.

Chantix also outperformed placebo for keeping people smoke-free one year after treatment. But the long-term differences between Chantix and Zyban were not as clear. In one study, 23% of people on Chantix were still smoke-free after a year compared to about 15% of Zyban users. That difference was statistically significant, meaning it was unlikely to be due to chance. In the second study, though, the gap was slightly smaller (22% vs. 16%) and no longer statistically significant -- so it’s not clear that Chantix was superior.
More Treatment Yields Better Results

The third study investigated whether taking Chantix for a longer period of time would improve quit rates even more. This time, all study participants started out with 12 weeks of Chantix. Those who quit successfully were then randomly assigned to receive either another 12 weeks of Chantix or 12 weeks of a placebo. The participants did not know which group they’d been assigned to.

The added months of treatment did improve quit rates. After 6 months, about 71% of those who got more Chantix were still off cigarettes, compared to 50% of the people on placebo. After a year, the figures were 44% and 37%.

All the studies showed primarily mild side effects from any of the drugs. Some people on Chantix complained of nausea and unusual dreams, while those on Zyban had more insomnia. People in all three groups also gained weight -- around 6 pounds -- when they quit smoking.

However, the people who took part in the studies were all fairly healthy. The researchers excluded anyone with heart disease, diabetes, kidney or liver problems, uncontrolled high blood pressure, a history of cancer, significant allergies, as well as people with depression, panic disorder, psychosis, bipolar disorder, eating disorders, and alcohol or drug abuse. It’s not known whether Chantix will have different effects in people who have any of these conditions.

Nevertheless, many experts are glad to have another weapon available to fight smoking and nicotine addiction.

"Chantix offers clinicians and smokers a unique therapeutic approach to quitting and an important new tool in the effort to reduce tobacco-related cancers and other diseases," said Tom Glynn, PhD, American Cancer Society director of international tobacco programs.

Chantix is available only by prescription. Smokers who get the drug will also be able to enroll in a free quitting support program designed by Pfizer called GETQUIT. The program will teach smokers about managing cravings and help them identify and handle their individual smoking triggers, Pfizer said.

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