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.

By Kevin Grogan

The spots run 90 seconds–30 seconds more than the ones Pfizer (nyse: PFE – news – people ) ran for just four months last year–and hew to the same narrative as the old one, using a race between a tortoise and a Belgian hare to dramatize the fact that quitting smoking that favors the slow and steady–and that Chantix can help.

Side effect information takes up 41 seconds of the advertisement, with about 20 seconds devoted to a warning that patients taking Chantix should stop taking it if they experience agitation, suicidal thoughts or suicidal behavior. Pfizer says the role of Chantix in those symptoms is “not known.”

“Some people think the drug has been withdrawn from the market,” says Veronique Cardon, team leader of U.S. marketing for Chantix. “More importantly, a lot of people haven’t heard of Chantix yet.”

The new campaign shows how pharmaceutical companies are trying to adapt the marketing of their products to a climate of hair-trigger concern over drug safety. But Pfizer faces other hurdles in launching Chantix, too. Its own communications to Wall Street before Chantix went on sale described the anti-smoking market as prone to dramatic sales spikes and stomach-heaving drops.

The drug’s success is particularly important as it tries to match the success of older medications like Lipitor, which loses patent protection in just three years. Pfizer shares have fallen 25% in 12 months.

Safety controversies only make that tougher. When ads are pulled because of new and serious side effects, some reappear in a longer form with more detail about the new risks, says Ruth Day, director of the Medical Cognition Laboratory at Duke University. This also happened with ads for Celebrex (also a Pfizer drug) after it was linked to an elevated risk of heart disease.