Officials of Pfizer, the manufacturer of Chantix, and the Food and Drug Administration responded that they had been planning to conduct a joint analysis of clinical trials on whether Chantix posed heart risks, due next year.
“This would have raised a red flag for us if the flag hadn’t already been flying,’’ Dr. Celia Winchell, a team leader with the agency’s Center for Drug Evaluation and Research, said in an interview.
Pfizer, in a statement, said the analysis in the Canadian Medical Association Journal was based on too few heart or cardiovascular events to draw conclusions about the risks. The company said Chantix brought “immediate and substantial’’ health benefits to smokers who quit.
The senior author of the new report, Dr. Curt D. Furberg, a Wake Forest medical professor, said there were better ways to quit and called for removal of the drug from the market.
“It piles up,’’ he said. “I don’t see how the FDA can leave Chantix on the market.’’
The lead author, Dr. Sonal Singh, assistant professor of medicine at Johns Hopkins University, said the agency and Pfizer had failed to pursue signs of cardiovascular risk since Chantix was approved in 2006.
“The FDA should have already put it on their warning label,’’ Singh said. “The risk is substantial, the risk is present in smokers without heart disease, and Pfizer knew about this for five years.’’
Last month, the agency issued a safety notice about cardiovascular risk from Chantix use by people with a history of cardiovascular disease, based on a study of 700 people.
The new report is broader, analyzing 14 randomized clinical trials involving 8,200 patients, excluding those with cardiovascular disease so that it gives a better picture of which heart problems the drug could cause in otherwise healthy people trying to quit smoking.
