Alkermes rebuffed by FDA on antidepressant

Alkermes is facing a significant delay for its ALKS 5461 candidate for major depressive disorder after the FDA turned down its marketing application. The negative outcome for the review isn’t surprising given that an FDA advisory committee voted by 21-2 in November that the drug’s benefit-risk profile is not adequate to support its approval for treatment-resistant MDD. However, the outcome is something of a worst-case scenario for Alkermes as it seems the US regulator wants a new clinical trial of the drug, and that could hold up approval by a couple of years.
Alkermes announced the FDA’s decision after trading halted on Friday, but its stock fell almost 5% after-hours. In its statement, the Dublin drugmaker said the FDA had requested “additional clinical data to provide substantial evidence of the effectiveness of ALKS 5461” in the adjunctive treatment of MDD. The agency refused to accept Alkermes’ first filing attempt last year but agreed to the submission later after it received additional clarifications about the data. ALKS 5461 is a combination of buprenorphine, a mixed mu opioid receptor agonist/kappa opioid receptor antagonist, and an opioid antagonist called samidorphan.