Earlier this week, an FDA advisory committee voted 21 to two against backing approval of Alkermes’ ALKS 5461 for the treatment of major depressive disorder (MDD). Ahead of the committee meeting, FDA reviewers had questioned the safety of the drug and raised a number of other concerns, particularly that in two prior late-stage studies, ALKS 5461 failed to significantly improve symptoms in certain patients with MDD. However, results from a separate study indicated that the drug met its primary endpoint versus placebo. 

Furthermore, FDA staff also questioned the lack of data on the effects of ALKS 5461 on unborn infants when the treatment was administered to pregnant women. “We don’t know what the mechanism of action is…and the likelihood of dependence and withdrawal,” commented panel member Jane Acri, adding “I think it’s a very vulnerable population at risk for drug dependence in the first place.”

“We were disappointed and surprised by the FDA’s characterization of the safety and efficacy data for ALKS 5461 and the resulting outcome of the Advisory Committee vote,” commented Richard Pops, CEO of Alkermes. He added, “We […] will continue to work with the FDA as it completes its review of the ALKS 5461 regulatory submission.”

Panel member, Terri Warholak, said, “I’m not convinced there is a big enough treatment effect to make a clinical difference.” 

ALKS 5461 is a combination of two opioid drugs: buprenorphine, a common treatment for opioid addiction, and a relatively new compound called samidorphan.

Shares in Alkermes fell as much as nine percent in response to the vote. The agency is expected to make a decision on whether to approve the once-daily, oral drug by January 31 of next year.  

(Sources: MarketWatch; Alkermes plc; Boston Business Journal)