A Study of ALKS 5461 for Treatment Refractory Major Depressive Disorder (MDD)

Inclusion Criteria:

• Have a Major Depressive Disorder (MDD) primary diagnosis
• Have a body mass index (BMI) of 18.0 to </= 40.0 kg/m^2
• Be willing and able to follow the study procedures and visits as outlined in theprotocol (including agreeing not to enroll in any other clinical trials)
• Have inadequate responses to antidepressant therapy (ADT) in the current MajorDepressive Episode (MDE)
• Additional criteria may apply

Exclusion Criteria:

• Has any finding that would compromise the safety of the subject or affect theirability to adhere to the protocol visit schedule or fulfill visit requirements
• Has any other significant medical condition (eg, neurological, psychiatric, ormetabolic) or clinical symptom that could unduly risk the subject or affect theinterpretation of study data
• Has any current primary diagnosis other than MDD, where primary diagnosis is definedas the primary source of current distress and functional impairment
• Has experienced hallucinations, delusions, or any psychotic symptoms in the currentMDE
• Has been hospitalized for MDD within 3 months before screening
• Has used opioid agonists (eg, codeine, oxycodone, tramadol, morphine) or opioidantagonists (eg, naloxone, naltrexone) within 14 days prior to screening
• Has received electroconvulsive therapy treatment within the last 2 years or within thecurrent MDE or failed a course of electroconvulsive treatment at any time
• Has a significant risk for suicide
• Has a positive breath alcohol test at screening
• Has a positive test for drugs of abuse at screening or visit 2
• Is pregnant, planning to become pregnant, or is breastfeeding during the study
• Additional criteria may apply