Varenicline Effective for Highly Nicotine-Dependent Smokers With COPD

Kristina Rebelo

November 06, 2009

November 6, 2009 (San Diego, California) — Smokers with chronic obstructive pulmonary disease (COPD) have a harder time with smoking cessation than other populations of smokers, and they have been shown to be more dependent on nicotine. Varenicline (Chantix, Pfizer), a nicotinic receptor partial agonist, is an effective aid for this difficult-to-treat population of patients, according to the results of a study presented here at CHEST 2009: American College of Chest Physicians Annual Meeting.

Dr. Donald P. Tashkin

"The most effective strategy for preventing progression of COPD is smoking cessation," Donald P. Tashkin, MD, emeritus professor of medicine, David Geffen School of Medicine, University of California at Los Angeles, told Medscape Pulmonary Medicine in an interview at his poster presentation. "Despite that, up to 50% of symptomatic COPD patients continue to smoke."

Dr. Tashkin and colleagues conducted a multicenter, double-blind, placebo-controlled trial of 499 patients at 27 centers with mild to moderate COPD who had smoked for an average of 41 years. Participants smoked half a pack or more per day in the year before enrollment. Eligibility requirements were a postbronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity ratio of less than 70% and FEV1 percent of predicted normal value of 50% or more. As indicated by the Fagerstrom Test for Nicotine Dependence score, all subjects had a high level of nicotine addiction.

Participants were randomized to varenicline 1 mg twice a day or placebo for 12 weeks. They also received printed information to assist with the task of giving up nicotine and were provided a modicum of counseling at baseline and again by telephone and at clinic visits.

Varenicline Reduced Pleasure Associated With Nicotine

Dr. Tashkin pointed out that the drug doesn't work like nicotine-replacement therapies, such as nicotine patches or gum: "Varenicline is a high-affinity nicotinic acetylcholine receptor partial agonist and we believe it stimulates dopamine release, thereby reducing cravings, and acts as an antagonist. It competes with nicotine for binding and reduces pleasure effects of the nicotine."

He noted that this study did not look at sex or age in the primary results, but did say that older patients quit smoking more successfully than their younger counterparts. "In age subsets, younger patients didn't do as well."

Patients were evaluated for 40 weeks after the 12-week treatment program. The primary end point, according to the study, was a continuous abstinence rate for the last 4 weeks of the 12-week treatment.

A cessation efficacy odds ratio of 3.1 (95% confidence interval, 2.5 - 3.8) was recorded 6 months after cessation, compared with placebo.

During the last 4 weeks of treatment, 42.3% of the varenicline group was able to stop smoking and stay off nicotine-replacement therapy, compared with 8.8% of those in the placebo group (P < .0001). After 1 year, 18.6% of the varenicline group remained off nicotine, compared with 5.6% of the placebo group.

Adverse events occurred in 2.8% of the varenicline group and 4.4% of the placebo group. These included nausea, abnormal dreams and sleep issues, upper respiratory tract infections, insomnia, and headache.

Black Box Warning on Varenicline

The US Food and Drug Administration (FDA) issued a Black Box Warning on varenicline on July 1, 2009, because of reports of serious adverse events, including depression, suicidal ideation, and suicidal actions. In 2008, the FDA issued an Alert warning of a possible association between varenicline and neuropsychiatric symptoms, but it wasn't clear if this was due to the drug or the nicotine withdrawal symptoms.

Mr. Matthew Bars

Dr. Tashkin said that none of the participants in the varenicline group in this study reported suicidal ideation, but there was 1 such report in the placebo group.

"It's very important to evaluate the different smoking cessation therapies and to develop new ones," said Dr. Tashkin.

Commenting on the study, Matthew Bars, MS, CTTS, a board-certified tobacco treatment specialist from the Columbia Presbyterian Healthcare System in New York City, said that "there are so many smokers who have airway disorders and/or full-blown COPD, so this is highly significant. It's also significant because anybody who has been diagnosed with COPD and still smokes tends to be more addicted. This study demonstrates that varenicline works in a more addicted population," he told Medscape Pulmonary Medicine at the conference. Mr. Bars was part of a team that developed a tobacco treatment program for the New York Fire Department.

This study was funded by Pfizer, Inc., the maker of Chantix. Dr. Tashkin is a consultant for Pfizer. Mr. Bars has disclosed no relevant financial relationships.

CHEST 2009: American College of Chest Physicians Annual Meeting. Presented November 4, 2009.

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