A Phase 2, Randomized, Double-Blind, Placebo-controlled Study to Evaluate the Safety and Efficacy of ALKS 7290 as an Adjunctive Therapy to Antidepressants in Adult Participants With Major Depressive Disorder

Inclusion Criteria: * Meets the DSM-5 criteria for MDD, as confirmed by both MINI and an adequate clinical psychiatric evaluation. * Is otherwise healthy as determined by medical evaluation, including medical history, physical examination, laboratory tests, and cardiac monitoring. * Participants must be stable on permitted medication prior to screening. * An inadequate response to an adequate dosage of antidepressant therapy in the current depressive episode. * Symptoms of depression that are considered moderate to severe, based on assessments completed with the study team during both screeni…