NEW YORK (CNNMoney.com) - The Food and Drug Administration today approved Chantix, the smoking-cessation drug from Pfizer.

Chantix, also known by its chemical name varenicline tartrate, is an anti-smoking drug that does not use nicotine. The drug works by blocking the pleasurable effects of smoking, and reduces the craving and withdrawal symptoms from quitting.

Pfizer's (down $0.12 to $24.92, Research) stock price edged up about 1 percent on the news. Pfizer spokeswoman Shreya Prudlo said the drug will be on pharmacy shelves in the second half of 2006.

Les Funtleyder, analyst for Miller Tabak, said the drug won't be a huge boon for Pfizer, but it will help to eliminate some of the "pipeline uncertainty" over Pfizer's ability to produce new drugs.

"This is going to be a positive, but until we get through the summer, the stock will probably tread water," said Funtleyder. He said the approval was expected, since the drug had received priority review status, a sped-up process that the Food and Drug Administration usually reserves for drugs with life-saving potential.

Funtleyder projects $900 million in peak annual sales for Chantix by 2010. Funtleyder said the drug acts in a unique way and does not have direct competitors, though GlaxoSmithKline's (up $0.03 to $57.20, Research) anti-smoking drug Zyban would provide some indirect competition.

Pfizer said that studies showed that Chantix, the fourth Pfizer drug to receive approval this year, had twice the quit rate of Zyban and quadruple the quit rate of placebo.

Pfizer chief executive officer Henry McKinnell said in a press release that Chantix "demonstrates groundbreaking science leading to the first prescription treatment aimed directly at smoking cessation in nearly a decade. This medical advance from Pfizer will now help many smokers end their addiction."

McKinnell said smoking was responsible for 20 percent of all U.S. fatalities and costs the health-care system $167 billion annually.

The drug is taken over a 12-week period of time. In a Pfizer-sponsored study released last year, the drug demonstrated a smoking quit rate of 44 percent while patients are on it, but the quit rate dropped to 22 percent after patients stop using the drug.

Chantix sales could help Pfizer on its comeback trail, as it tries to fill its impending, multibillion-dollar sales vacuum that will result from some of its older blockbusters losing patent protection. This year, Pfizer's patent is expiring on Zoloft, the antidepressant with $3.3 billion in 2005 sales, and in 2007 it loses blood pressure treatment Norvasc, with $4.7 billion in 2005 sales. Also, the arthritis painkiller Bextra from the same drug class as Merck's (up $0.01 to $34.68, Research) beleaguered Vioxx, was pulled off the market in 2005 because of health risks, wiping out $1.3 billion in annual sales.

In addition to Chantix, Pfizer recently received FDA approval for two other drugs that analysts have described as potential blockbusters: Exubera, the inhalable insulin for diabetics, and Sutent, an anti-tumor treatment for stomach and kidney cancer. Pfizer is awaiting FDA decision on Indiplon, a sleeping pill.

Pfizer is also undergoing a $4 billion cost-cutting to alleviate the pain of lost sales.

Based in New York City, Pfizer is the biggest drug company in the world, with $12.7 billion in first quarter, 2006 sales.

To read more about Chantix, which was previously known as Champix, click here.

To read about Pfizer's first-quarter earnings, click here.