- The Food and Drug Administration has agreed to drop a black box warning for Pfizer's quit-smoking drug Chantix (varenicline), the big biopharma announced on Friday.
- The agency's decision to remove its most restrictive caution comes after a post-marketing study of 8,144 patients found those taking Chantix were no more likely to have serious neuropsychiatric events than those on placebo.
- Chantix first gained approval in the U.S. in 2006, but got slapped with the warning in 2009 after some patients taking the drug reported mental side effects such as depression, hallucinations, aggression, and suicidal thoughts and actions.
Black box warnings are nothing to blink at, particularly because the FDA doesn't remove them very often.
But a meeting in September with the agency's Psychopharmacologic Drugs Advisory Committee and Drug Safety and Risk Management Advisory Committee helped Pfizer win a reprieve. Ten of the the joint panel's 19 members ultimately recommended removing the warning, leading to the FDA's decision to follow through with the removal.
Chantix relabeling will likely help Pfizer's bottom line. Though the drug is by no means Pfizer's biggest product, it did earn $631 million in worldwide sales during the first nine months of 2016, up nearly 30% from the same period last year.
The panel based its recommendation on testimonies from Pfizer about EAGLES — short for Evaluating Adverse Events in a Global Smoking Cessation Study — as well as critics of Chantix.
That study tested for adverse neuropsychiatric effects in smokers with and without histories of mental disorders who were treated with a placebo or a dermal patch containing either Chantix, bupropion or nicotine.
Results showed that across the various treatment groups, those receiving Chantix were more likely to demonstrate those effects. Composite data revealed the incidence rate for Pfizer's medication was 2.7% higher compared to placebo, whereas buproprion was 2.2% higher and nicotine was .4% higher. The rate of serious adverse effects was the same for both Chantix and the placebo.
For critics, the latter finding did not justify the removal of the black box warning.
"The EAGLES trial was powered to detect absolute differences in event rates between varenicline and placebo of 2.63% to 5.25% for non-psychiatric and psychiatric subjects, respectively," Sammy Almashat, a researcher for healthcare-centered consumer advocacy group Public Citizen, said in a testimony to the joint panel. "These represent exceedingly high estimates of the incidence of neuropsychiatric events."