This is a Phase 3 multi-center trial designed to evaluate the clinical efficacy and safety of VIVITROL® (Medisorb® naltrexone 380 mg) versus placebo when administered to adults upon discharge from inpatient treatment for opioid dependence.

The study was conducted in 2 parts, Part A and Part B. The clinical portion of both parts has completed. Results for Part B are not yet available.

Part A was a double-blind, randomized, placebo-controlled assessment of the efficacy and safety of 24 weeks of monthly treatment with VIVITROL compared to placebo in opioid-dependent adults.

Subjects who completed Part A could choose to continue to Part B, which was an open-label extension to assess longer-term safety, durability of effect, health economics, and quality of life (QOL) in the continuing study population for up to 1 year.

At the conclusion of both parts, each completing subject will have received a total of up to 19 injections of study drug over approximately 1.5 years.

Dosing was performed by the principal investigator or designated study staff member.

All subjects received standardized, manual-based psychosocial support at each scheduled visit. Opioid use was tracked through urine drug testing and subjects' self reports. Other evaluations for efficacy and safety, health economics, and quality of life were routinely conducted throughout the study.

Primary Inclusion Criteria:

• Written, informed consent
• 18 years of age or older
• Current diagnosis of opioid dependence, based on Diagnostic and Statistical Manual of Mental Health Disorders, 4th Ed. (DSM-IV-TR) criteria
• Voluntarily seeking treatment for opioid dependence
• Completing or recently completed up to 30 days of inpatient treatment for opioid detoxification, and off all opioids (including buprenorphine and methadone) for at least 7 days
• Noncustodial, stable residence and phone, plus 1 contact with verifiable address and phone
• Significant other (eg, spouse, relative) willing to supervise compliance with the study visit schedule and procedures
• Agree to use contraception for study duration if of childbearing potential

Primary Exclusion Criteria:

• Pregnancy or lactation
• Clinically significant medical condition or observed abnormalities (eg: physical exam, electrocardiogram (ECG), lab and/or urinalysis findings)
• Positive naloxone challenge test at randomization (Day 0)
• Evidence of hepatic failure including: ascites, bilirubin >10% above upper limit of normal (ULN) and/or esophageal variceal disease
• Past or present history of an acquired immunodeficiency syndrome (AIDS)-indicator disease in HIV-infected subjects
• Active hepatitis and/or aspartate aminotransferase (AST), alanine aminotransferase(ALT) >3xULN
• Current major depression with suicidal ideation, psychosis, bipolar disorder, or any psychiatric disorder that would compromise ability to complete the study
• Recent history (within 6 months prior to screening) of suicidal ideation or attempt
• Dependence within prior year based on DSM-IV-TR, to any drugs other than prescription opioids or heroin, caffeine, marijuana, or nicotine
• Active alcohol dependence within prior 6 months
• Current alcohol use disorder that would, in the Investigator's opinion, preclude successful completion of the study
• Positive urine drug test for cocaine, benzodiazepines, or amphetamines at screening
• Use of oral naltrexone for 7 consecutive days within 60 days prior to screening
• Known intolerance and/or hypersensitivity to naltrexone, carboxymethylcellulose, or polylactide-co-glycolide (PLG)

6 Months (Part A)

All participants who received at least 1 dose of randomized, double-blinded study drug (VIVITROL or placebo) are included in the safety population for Part A. Adverse events were tallied by number of participants affected as opposed to number of incidences reported for a given preferred term.