The US Food and Drug Administration has granted Pfizer Inc. a six-month priority review for the new drug application (NDA) for Pfizer's smoking cessation medicine, varenicline tartrate, which the company intends to market under the brand name Champix.

"If current smoking patterns continue, the annual number of people dying of smoking-related diseases globally will double from five to ten million deaths by 2020. Pfizer's research and development effort for Champix represents the best of what medical innovation can bring to patients and families struggling to overcome tobacco addiction," said Hank McKinnell, chairman and chief executive officer of Pfizer.

When smokers inhale a lit cigarette, nicotine within seconds reaches the brain and binds to a nicotinic receptor which activates the reward pathway in brain circuitry. This creates a powerful sense of satisfaction. The initial effects recede quickly and a cycle of craving and withdrawal ensues.

Applying new understanding about the brain, biology and chemistry to smoking cessation, Pfizer researchers at the company's Groton laboratories in 1993 took a wholly new therapeutic approach to this medical condition. They specifically designed and developed a pill for smoking cessation, varenicline that targets the nicotinic receptor in a unique way. Varenicline is designed to activate the nicotinic receptor to reduce both the severity of the smoker's craving and the withdrawal symptoms from nicotine, claims a Pfizer release.

In all trials, varenicline was well tolerated, with overall discontinuation rates similar to placebo. The most common side effects included nausea, headache, trouble sleeping and abnormal dreams.

"Smoking, the leading cause of preventable death worldwide, is a critical public health imperative that takes an extraordinary toll on health care systems. In the United States alone, the cost of treating smoking-related diseases is an estimated $150 billion a year," said Karen Katen, Pfizer vice chairman and president, Pfizer Human Health.

"The priority review designation for Champix underscores the significant patient need for new therapies that will reduce the health burden of smoking," added Katen.

In November 2005, Pfizer submitted an FDA new drug application and European marketing authorisation application for varenicline for smoking cessation.

The FDA assigns priority review status to medicines that may provide a significant therapeutic advance over existing therapies. Once the FDA formally determines the application is sufficiently complete for review, the filing will move forward under priority review.

According to the World Health Organization, every eight seconds a person dies of a smoking-related disease. At present, less than seven percent of smokers who try to quit on their own achieve more than one year of abstinence and most relapse within a few days of attempting to quit.