WASHINGTON -- The Food and Drug Administration announced Friday it will hold a public meeting in October to review the risks of psychiatric and behavioral side effects with Pfizer's anti-smoking drug Chantix.
The agency said in a federal notice it will convene its panel of psychiatric drug experts to discuss the pill's risks and how to best manage them.
Since 2009 Chantix has carried the government's strongest safety warning -- a "black box" label -- because of links to hostility, agitation, depression and suicidal thoughts. The warning was added after the FDA received dozens of reports of suicide and hundreds of reports of suicidal behavior among patients taking the smoking-cessation drug.
At that time, the FDA also required Pfizer to conduct additional studies to determine the extent of the side effects.
A spokeswoman for Pfizer said Friday that the company recently submitted new data to the FDA designed to establish the drug's safety compared with placebo and other anti-smoking therapies.
"Pfizer has proposed an update to the Chantix labeling based on these new data, which, we believe, would better reflect the product's safety profile as it pertains to neuropsychiatric symptoms," said Victoria Davis, in a statement.
The New York drugmaker's FDA submission includes data pooled from multiple Pfizer studies along with studies conducted by the U.S. Department of Defense and the Department of Veterans Affairs. The two federally-funded studies, released in 2011, did not show an increased rate of psychiatric hospitalizations among more than 26,000 Chantix patients when compared with patients using nicotine patches and other smoking cessation treatments. The studies only recorded psychiatric problems that resulted in hospitalization, meaning many issues likely went unreported, according to the authors.
Chantix works by binding to the same spots in the brain that are activated by nicotine when people smoke. The drug, known chemically as varenicline, blocks nicotine from binding to those spots and causes the release of a "feel-good" brain chemical called dopamine.
The FDA first began investigating potential side effects with Chantix in 2007, the year after the twice-a-day pill hit the market.
The drug's labeling tells patients to stop taking Chantix immediately if they experience agitation, depressed mood, suicidal thinking and other behavioral changes. Doctors are advised to weigh the drug's risks against its potential benefits in helping patients quit smoking.
Chantix had global sales of $648 million last year. That was down about 26 percent from the drug's peak sales of $883 million in 2007, its first full year on the market.
Shares of Pfizer Inc. rose 4 cents to close at $30.75 in trading.