FDA Asks Pfizer About Chantix, Heart Risk And The Stop Smoking Drug

Pfizer's stop-smoking drugChantix (varenicline) can lead to a small increase in cardiovascular problems such as heart attacks for patients who already have cardiovascular disease, U.S. drug regulators said on Thursday. In fact, The Food and Drug Administration (FDA) is changing the label for Chantix after reviewing the results of a clinical trial. 

Annual sales are now about $800 million, making the pill a "moderate sized" product for the pharma giant. 

The FDA stated this week: 

"The known benefits of Chantix should be weighed against its potential risks when deciding to use the drug in smokers with cardiovascular disease."

An independent randomized trial of 700 smokers with cardiovascular disease who were treated with Chantix or a placebo showed that Chantix was effective in helping patients quit smoking for as long as one year, but patients who took the pill were also slightly more likely to have a heart attack or other adverse cardiovascular event versus patients on a placebo. 

Varenicline is in a class of medications called smoking cessation aids. It works by blocking the pleasant effects of nicotine (from smoking) on the brain. 

Investors had high hopes for the drug when Pfizer first launched its smoking-cessation aid in 2006, but reports of serious side effects have prevented strong sales growth. 

Varenicline received a "priority review" by the U.S. Food and Drug Administration (FDA) in February 2006, shortening the usual 10-month review period to 6 months because of its demonstrated effectiveness in clinical trials and perceived lack of safety issues. The agency's approval of the drug came on May 11, 2006. On August 1, 2006, varenicline was made available for sale in the United States and on September 29, 2006, was approved for sale in the European Union. 

Chantix has been associated with agitation, depression and suicidal thoughts, and, in clinical trials, linked with nightmares. That's no fun. Psychiatric symptoms have occurred in people without a history of mental illness and have worsened in people who already had mental illness. 

The drug already is required by the FDA to carry a black box warning, the agency's strongest safety warning, due to public reports of the said side effects above. 

There have been problems in the normally fairly lax country of Canada. On June 3, 2010, Health Canada also announced changes to the Canadian Product Monograph that include changes in mood or behavior, serious allergic reactions and skin reactions , neuropsychiatric side-effects in patients taking varenicline with or without a history of psychiatric disorder side-effects such as sleepiness, dizziness, loss of consciousness, seizures, or difficulty concentrating. 

Health Canada advised those taking varenicline not engage in potentially hazardous activities, such as driving a car or operating dangerous machinery until they know how they may be affected by varenicline. 

Finally, earlier this year in May, it was revealed that Pfizer had submitted 589 varenicline-related adverse effects reports to the FDA through "improper channels." These reports dated back through 2007 and included 150 completed suicides (more than twice the number previously reported).