Alkermes today announced that the U.S. Food and Drug Administration (FDA) has accepted for review the New Drug Application (NDA) for ALKS 5461, a novel, once-daily, oral investigational medicine for the adjunctive treatment of major depressive disorder (MDD) in patients with an inadequate response to standard antidepressant therapies. FDA's target action date for the ALKS 5461 NDA is Jan. 31, 2019.

This surprising news comes just two weeks after the FDA issued a Refusal to File letter regarding ALKS 5461. At the time, the FDA indicated that the application was not complete enough to allow for a review. More specifically, the application did not contain enough data to demonstrate overall effectiveness and would require more studies.

After receiving the Refusal to File letter, Alkermes issued a statement that they disagreed and intended to file an appeal. The appeal was apparently successful. Alkermes will host a conference call at 8:30 a.m. ET (1:30 p.m. BST) on Monday, April 16, 2018, to discuss this update.

ALKS 5461 is a proprietary, investigational, once-daily oral medicine that acts as an opioid system modulator and represents 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 buprenorphine, a partial mu-opioid receptor agonist and kappa-opioid receptor antagonist, and samidorphan, a mu-opioid receptor antagonist.

As of this writing, Alkermes is up over 13% in pre-market trading.