Pfizer yesterday saw the thumbs up for its new smoking cessation pill, Chantix (varenicline).

It becomes only the second nicotine-free drug ever to win marketing clearance from the US Food and Drug Administration and has a dual approach to helping smokers quit – by blocking the pleasure receptors in the brain associated with cigarette smoking and nicotine, as well as cutting the level of withdrawal symptoms that are often blamed for a return to the addiction.

Chantix was given priority review by the US drug regulator late 2005 and, in head to head clinical trials, has been shown to nearly double the likelihood of a smoker finally stubbing out than GlaxoSmithKline’s Zyban (bupropion), an antidepressant also sold as Wellbutrin. Zyban has had the market to itself since its launch in 2000 but has suffered from concerns over its safety and has become a relatively unimportant product for the UK giant in terms of sales.

The need for an effective drug to help smokers kick their habit is greater than ever. In the USA, it is responsible for one in five deaths and costs the US healthcare system some $167 billion every year. And, according to the Centers for Disease Control and Prevention, an estimated 44.5 million adults in the USA smoke cigarettes and more than 8.6 million of them have at least one serious illness caused by smoking.

Analysts have forecast peak sales for Chantix of $500 million to $1 billion, which will please investors in Pfizer, who have seen the share price plunge over the last couple of years. But the company is looking up, with four new products approved already this year: the inhaled insulin drug Exubera, Eraxis (anidulafungin) for candidaemia and the oncology agent Sutent, which was cleared for advanced kidney cancer and gastrointestinal stromal tumours.

Pfizer also filed for European approval of varenicline in November 2005 and looks set to have a clear run at the market for a while at least, after US and European regulators put the clamp on Sanofi-Aventis’ pill Acomplia (rimonabant) for smoking cessation – although they gave it a nod for treating obesity.