ALK33BUP-201: Safety and Tolerability Study of ALKS 33-BUP (ALKS 5461) Administration in Subjects With MDD

Inclusion Criteria: * Male and female subjects between 18 and 65 years of age, inclusive. * Meet Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) criteria for MDD. * Current episode lasting ≥8 weeks prior to screening with an inadequate/partial response to an adequate trial (defined as at least 8 weeks) of a stable dose of an SSRI or SNRI. Inadequate/partial response is defined as: 1. A Hamilton Depression Rating Scale total score (HAM-D17) ≥14, and 2. Less than 50% reduction in depressive symptom severity on the Massachusetts General Hospital Antidepressant Treatment Response Questionnaire (ATRQ), and 3. Clinical Global Impression - Severity (CGI-S) score of ≥3. Exclusion Criteria: * Axis I diagnosis of delirium, dementia, amnestic or other cognitive disorder, schizophrenia or other psychotic disorder, bipolar I or II disorder, eating disorder, obsessive-compulsive disorder, panic disorder, or posttraumatic stress disorder. * A clinically significant current Axis II diagnosis of borderline, antisocial, paranoid, schizoid, schizotypal, or histrionic personality disorder. * Experiencing hallucinations, delusions, or any psychotic symptomatology in the current episode. * The use of inducers or inhibitors of cytochrome P450 (CYP) 3A4 (prescription medications, over-the-counter \[OTC\] medications, or dietary supplements) within 30 days before dosing. * Have received electroconvulsive therapy during the current MDD episode. * Pose current suicide risk as confirmed by the Columbia Suicide Severity Rating Scale (C SSRS). * History of intolerance or hypersensitivity to buprenorphine. * History of allergy or hypersensitivity to opioid antagonists (eg, naltrexone, naloxone) or quinine.