ALKS 5461 is a proprietary, investigational, once-daily oral medicine with a novel mechanism of action for the adjunctive treatment of major depressive disorder (MDD) in patients with an inadequate response to standard antidepressant therapies.
ALKS 5461 is a fixed-dose combination of samidorphan. a partial mu-opioid receptor agonist and kappa-opioid receptor antagonist, and samidorphan, a mu-opioid receptor antagonist.
The firm has secured a refusal to file letter from the FDA regarding its NDA for ALKS 5461.
After completion of preliminary review, the FDA concluded that evidence of overall effectiveness for the proposed indication is insufficient to complete a substantive review of the regulatory package.
FDA has also requested the company to carry out a bioavailability study to gather additional bridging data between ALKS 5461 and the reference listed drug buprenorphine.
Alkermes said that it disagrees with the FDA's conclusions and plans to appeal its decision.
The firm is planning to seek immediate guidance, including requesting a type A meeting with the FDA, to determine necessary steps and collect additional information required to resubmit the NDA.
Alkermes is assessing the impact of the rejection on its previously-issued financial guidance for 2018, and the details will be provided details in the first quarter financial results disclosures.
Alkermes CEO Richard Pops said: "We are extremely disappointed with this decision and the implications for patients in the U.S. suffering from major depressive disorder, a serious disease where there is a clear and urgent need for new treatment options for patients and their families.
"We strongly believe that the clinical development program, including data from more than 1,500 patients with MDD, provides substantial evidence of ALKS 5461's consistent antidepressant activity and a favorable benefit-risk profile."
Alkermes is engaged in the development of novel medicines for the treatment of central nervous system (CNS) diseases.