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fizer has presented data which claims that significantly more smokers with mild-to-moderate chronic obstructive pulmonary disease who are treated with Chantix/Champix quit the habit compared with those on placebo.

The study, presented at American College of Chest Physicians annual meeting in San Diego, involved 499 adults suffering from mild-to-moderate COPD, who had smoked an average of 10 cigarettes or more per day in the year before enrollment. The participants, who had smoked for an average of 41 years, had a high level of nicotine dependence.

The primary efficacy endpoint was to compare 12 weeks of treatment with Chantix (varenicline) 1mg twice-daily to placebo and to evaluate abstinence from smoking for the 40 weeks after the treatment period. The data showed that during weeks 9-12, 42.3% of those on Chantix remained abstinent compared with 8.8% on placebo and at the end of 52 weeks, 18.6% on varenicline were still not smoking, versus 5.6% on placebo.

Pfizer noted that Chantix was generally well-tolerated in the study, with treatment-emergent serious adverse events of 2.8% versus 4.4% in placebo. Briggs Morrison, senior vice president, at the company’s Primary Care Medicines Development Group, said that the trial “is just one of several planned and ongoing studies of varenicline that we hope will enhance the medical community’s understanding of this important medicine”.

Launched in May 2006, Chantix has had a tricky time of late. Earlier this year, the US Food and Drug Administration said that the treatment should include a boxed warning, highlighting the risk of changes in behaviour, “depressed mood hostility, and suicidal thoughts”.

Sales have been disappointing and third-quarter turnover of Chantix fell 15% to $155 million, down 22% in the USA.