New Data: Pfizer Inc.'s Varenicline Is An Effective And Safe Treatment For Smoking Cessation; More Effective Than GlaxoSmithKline's Zyban

DALLAS, Nov. 15 /PRNewswire-FirstCall/ -- Pfizer Inc's smoking cessation medicine varenicline tartrate was shown to be more effective than the only marketed oral prescription anti-smoking medicine, according to data presented here today at the annual meeting of the American Heart Association. Upon approval, Pfizer intends to market varenicline under the brand name Champix(R).

Discovered and developed by Pfizer, varenicline is a selective nicotinic acetylcholine receptor partial agonist, the first in a new class of potential smoking cessation therapies.

In two double-blind placebo-controlled studies involving about 2,000 smokers, patients received either varenicline (1 mg twice daily), bupropion, marketed as Zyban (150 mg twice daily), or placebo for 12 weeks. Patients were followed for an additional 40 weeks without treatment.

In both studies, 44 percent of varenicline-treated patients quit by the end of the 12-week treatment period, significantly more than the 30 percent of Zyban patients who quit. Among patients who received placebo, 18 percent had quit by the end of the 12-week treatment period. The odds of quitting smoking for patients taking varenicline were approximately two times higher than those on bupropion, and four times higher than those on placebo.

After one year, patients who received varenicline were significantly more likely to remain smoke-free compared to patients who received bupropion or placebo.

"These results are very encouraging," said Dr. Serena Tonstad, head physician, Department of Preventive Cardiology, Ulleval University Hospital, Norway. "Smoking doubles a person's risk of cardiovascular disease and triples the risk of death from heart attack. Patients who are serious about quitting should seek medical support and treatment to help them ultimately succeed."

A third study randomized smokers who successfully quit smoking after 12 weeks of varenicline to 12 weeks of either placebo or an additional 12 weeks of varenicline. These patients were followed for 28 weeks after the treatment period.

There were significant benefits observed among patients who received additional treatment after successfully quitting on varenicline. Seventy-one percent of patients who received the additional course of varenicline remained abstinent after six months, compared to 50 percent who received placebo as the second course.

Smoking is the leading preventable cause of illness and premature death in the United States. Each year, smoking is responsible for 140,000 deaths from cardiovascular disease by increasing the risk of heart attack, stroke and sudden death. Annual health-related costs in the United States are estimated to be $167 billion.

Smoking is a chronic relapsing condition that involves a physical and psychological addiction to nicotine. When a smoker inhales a cigarette, nicotine reaches the brain in less than 10 seconds. The nicotine binds to receptors, leading to the release of dopamine in the pleasure centers of the brain. As nicotine levels drop, satisfaction recedes quickly, resulting in craving and withdrawal symptoms such as irritability and anxiety. This, in turn, leads to continued smoking behavior.

"Varenicline was specifically designed to work at the same receptor site as nicotine to relieve craving and withdrawal symptoms while at the same time blocking the reinforcing effects of nicotine," said Dr. Salomon Azoulay, varenicline development lead at Pfizer.

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.

This month Pfizer submitted a New Drug Application to the FDA for varenicline as well as European registration for smoking cessation.

DISCLOSURE NOTICE: The information contained in this release is as of November 15, 2005. Pfizer assumes no obligation to update any forward-looking statements contained in this release as the result of new information or future events or developments.

This release contains forward-looking information about a product candidate which is under regulatory review in the United States and Europe that involves substantial risks and uncertainties. Such risks and uncertainties include, among other things, whether and when such regulatory authorities will approve the product candidate, their decisions regarding labeling and other matters that could affect its commercial potential as well as competitive developments.

A further list and description of risks and uncertainties can be found in Pfizer's Annual Report on Form 10-K for the fiscal year ended December 31, 2004 and in its reports on Form 10-Q and Form 8-K.

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