FDA: Pfizer's Chantix carries "small, increased" cardiovascular risk

The FDA announced Thursday that Pfizer's smoking cessation drug Chantix (varenicline) may be linked "with a small, increased risk of certain cardiovascular adverse events in patients who have cardiovascular disease." The agency said that the information will be added to the product's label.

The regulator reviewed a clinical trial involving 700 patients with cardiovascular disease who received either Chantix or placebo. According to the FDA, Chantix "was effective in helping patients quit smoking and remain abstinent from smoking for as long as one year." However the agency noted that despite cardiovascular adverse events being infrequent overall, Chantix was associated with more frequent events than placebo.

In the study, seven patients receiving Chantix reported a heart attack, compared to three patients who took placebo, while eight patients who received Pfizer's drug had a need for coronary revascularisation, versus three for placebo. The drugmaker commented that the study, which was published in January last year, "was not designed to detect small differences in cardiovascular outcomes."

The FDA indicated that it is continuing to look at the safety of Chantix, and has asked Pfizer to undertake a large analysis of existing studies. The product, which had sales of $755 million last year, has previously been linked with an increased risk of serious mental health events, including changes in behaviour and suicidal thoughts.

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