Pfizer's prescription smoking cessation agent varenicline will have a user fee deadline in the first half of September 2006, assuming a standard 10-month review.

Pfizer filed an NDA for varenicline "this month," the company said Nov. 15. The proposed trade name for the selective nicotinic acetylcholine receptor partial agonist is Champix .

By partially activating nicotinic receptors, varenicline may reduce cravings, withdrawal symptoms and satisfaction experienced by smokers, Pfizer said.

The varenicline NDA includes two studies comparing varenicline to GlaxoSmithKline's smoking cessation therapy Zyban (bupropion) and placebo.

"In both studies, 44% of varenicline-treated patients quit by the end of the 12-week treatment period, significantly more than the 30% of Zyban patients who quit," Pfizer said in a press release issued in conjunction with the presentation of varenicline data at the American Heart Association annual meeting in Dallas Nov. 15.

In comparison, 18% of placebo patients had quit at the end of 12 weeks.

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

In a third study, varenicline patients who successfully quit smoking were randomized to a further 12 weeks of varenicline treatment or placebo and followed for an additional 28 weeks.

"Seventy-one percent of patients who received the additional course of varenicline remained abstinent after six months, compared to 50% who received placebo as the second course," Pfizer said.

Pfizer reports the most common varenicline side effects include nausea, headache, and trouble sleeping.

The company also markets the Rx nicotine replacement therapies Nicotrol inhaler and Nicotrol NS nasal spray.

-Elizabeth Walker

Pfizer's Varenicline NDA For Smoking Cessation Includes Comparison To GSK’s Zyban

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