A Food and Drug Administration expert panel has declined to endorse an opioid-based antidepressant drug, putting its chances for approval in jeopardy.
The FDA’s Psychopharmacologic Drugs Advisory Committee voted 21-to-2 that the risk-benefit profile of Alkermes’s ALKS 5461 was not sufficient to support the drug’s approval. The FDA is not bound to follow votes by advisory committees, also known as AdComs, when deciding whether or not to approve a drug, but usually does. That means it is likely Alkermes will receive a Complete Response Letter, indicating the agency has rejected the drug.
Briefing documents released earlier this week, prior to the AdCom meeting, had already cast doubt on PDAC’s sentiments toward the drug, raising concerns about safety and efficacy, as well as criticism of the use of an abbreviated scoring system for measuring efficacy. Shares of Dublin-based Alkermes, trading of which the company had suspended ahead of the PDAC meeting, were down 8 percent when markets opened Friday.
“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, particularly for the patients, their families and treatment providers who need and deserve access to novel therapies that work differently from currently available antidepressants,” Alkermes CEO Richard Pops said in a statement. “We remain steadfast in our commitment ot make a meaningful difference in the lives of people suffering with serious mental health conditions and will continue to work with the FDA as it completes its review of the ALKS 5461 regulatory submission.
ALKS 5461, the most advanced drug in Alkermes’s pipeline, combines an opioid, buprenorphine, with samodorphan, an opioid antagonist, and the FDA is expected to issue its verdict on the drug by Jan. 31. The company had submitted three Phase III trials and a Phase II trial to the FDA for review, but the agency rejected all but one of the Phase III trials, as the other late-stage studies were negative, and the regulators determined that the Phase II study was designed only for proof of concept, not for demonstrating efficacy. However, the FDA and the AdCom members also criticized the remaining Phase III trial’s use of an endpoint that incorporated a six-point scoring system known as MDRS-6, which excludes several important measures of depression systems used in the 10-point MDRS-10.
While the AdCom’s negative vote was anticipated, analysts from B. Riley FBR continue to give the company’s stock a buy rating and place it among their “Favorite Five” stocks for the second half of 2018. The analysts highlighted the company’s oral schizophrenia drug, ALKS 3831, for which confirmatory Phase III data are expected by the end of this year and which could have sales of $1 billion, in particular by offering strong efficacy while attenuating the issue of weight gain associated with marketed antipsychotics. Other drugs in the company’s pipeline include potential multiple sclerosis and immuno-oncology treatments.
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