UPDATED: No more black box for Pfizer's Chantix? After split panel backing, it's up to the FDA


Pfizer’s ($PFE) stop-smoking drug Chantix may be one step closer to escaping the FDA’s black box. An agency advisory panel narrowly voted in favor of removing the FDA’s most serious warning, which focuses on neuropsychiatric side effects such as suicidal thoughts and depression.

Of 19 panel members, 10 voted Wednesday to remove the black-box box warning. Four backed changes to the wording, while 5 others recommended keeping it.

The split vote doesn’t give the FDA a clear recommendation to lift the warning, and the FDA doesn’t always follow its advisory committees’ advice in any case. And the agency’s own reviewers picked apart the Chantix safety study that Pfizer had submitted to support its request.

Pfizer said it was pleased with the vote. The committee's overall recommendation is "an important step" toward a more accurate label for Chantix, which would help patients and doctors make "informed decisions" about the drug, CMO Dr. Freda Lewis-Hall said in a statement.

“The totality of available scientific evidence, including the outcomes of EAGLES, supports the safety and efficacy of Chantix, and we look forward to the FDA’s decision on the Chantix labeling,” Lewis-Hall said. 

It’s anybody’s guess what the FDA will decide. Sometimes, the agency responds to a murky vote by taking the middle ground--which would be changing the label language rather than removing the black box completely.

Still, the majority backing is much better than Pfizer achieved with its previous fight against the black box. An advisory panel voted in 2014 to retain the agency’s most severe label warning, and FDA officials followed that recommendation last year. Eleven of the 18 votes supported the black box, while 6 said the warning should actually be strengthened. Only one voted to remove it.

At the time, the committee members said the FDA should wait for postmarketing safety data before considering Pfizer’s request. It’s that safety data--from the EAGLES study--that Pfizer used to make its case for the advisory panel this time.

In that 8,000-patient study, paid for by Pfizer and GlaxoSmithKline ($GSK), investigators tracked neuropsychiatric side effects for Chantix, GSK’s smoking-cessation pill Zyban (bupropion), nicotine patch therapy, and placebo. They concluded that neither Chantix nor Zyban raised the risk of those side effects.

Chantix has been fighting against safety worries for more than 7 years. Soon after the drug’s 2006 launch, reports about erratic behavior and suicidal thinking began to surface, and the FDA added the black-box warning in 2009.

The fact that several cases captured media attention didn’t help. Musician Carter Albrecht, for example, went on a violent tear after starting Chantix therapy. Albrecht, who played keyboards for Edie Brickell and New Bohemians, threatened a neighbor, who shot him to death. That case went on Good Morning America. And after that, 5,000 adverse event reports poured in, prompting the FDA investigation that yielded the black box.

Until the side-effects concerns surfaced, Chantix had been hailed as Pfizer’s fastest launch ever, with monthly sales that quickly climbed past $80 million. Early blockbuster estimates dropped, however, and the drug brought in $671 million last year, in the same ballpark as sales in 2013 and 2014.

Pfizer obviously hasn’t given up on growing Chantix sales, and losing the black box can only help. Ads for the brand recently ran during the Republican National Convention, for instance, and the drug came in 9th for TV ad spend in 2015, with $68.5 million. Chantix’s overall spend in 2014 was $103 million.

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Editor's note: This story was updated with comments from Pfizer.