This was a Phase 3 multicenter randomized, open-label, safety study assessing the safety of repeat doses of Medisorb® naltrexone 380 mg (VIVITROL®) administered for up to 1 year to adults with alcohol and/or opioid dependence as defined by Diagnostic and Statistical Manual of Mental Health Disorders (DSM-IV) criteria. Eligible subjects were randomized in a 6:1 ratio to receive 1 of the following regimens: a single intramuscular (IM) injection of VIVITROL administered once every 4 weeks or oral naltrexone 50 mg administered daily.

Safety evaluations included physical examinations, electrocardiograms (ECGs), laboratory measures (including plasma concentrations of naltrexone and 6β-naltrexol), assessments of injection sites, and adverse events (AEs).

All subjects received psychosocial support at each study visit for the duration of the study, with interim telephone contact 2 weeks after each monthly visit.

Primary Inclusion Criteria:

• Current diagnosis of DSM-IV alcohol dependence and/or diagnosis of DSM-IV opiate dependence within 3 months prior to screening
• 18 years or older
• Desire to seek treatment for alcohol and/or opiate abuse/dependence
• Agree to use contraception for the study duration if of childbearing potential
• Written informed consent and willingness to perform study procedures
• Stable address and phone and at least 1 source of contact information (eg, family member, significant other)

Primary Exclusion Criteria:

• Presence of opiates in the urine (as determined by urine drug test) on Day 0 prior to naltrexone treatment
• Clinically significant medical/psychological condition or abnormality at screening (ie, physical examination, electrocardiogram [ECG], hematology or blood chemistry evaluation, or urinalysis findings)
• Clinically significant active hepatitis or hepatic failure evidenced by 1 of the following: aspartate transaminase (AST) or alanine transaminase (ALT) higher than 3 times the upper limit of normal (3xULN), hyperbilirubinemia (bilirubin >10% above ULN), creatine phosphokinase (CPK) higher than 10xULN, prolonged prothrombin time(international normalized ratio ≥1.7), ascites, or esophageal variceal disease
• Manifestation of suicidal ideation, psychotic symptoms (including significant violent behavior), or psychiatric disorders that would compromise ability to complete the study
• Participation in a formal methadone program currently or within prior 3 years
• More than 2 prior medically supervised detoxification treatments in prior 3 years
• Pregnancy or lactation
• Current prescribed opiate therapy, or receipt of opiates within 7 days prior to study drug dosing, or ongoing medical condition likely to require prescribed opiate therapy during study period
• Failed naloxone challenge on Day 0 (the challenge could be repeated up to 2 times, with at least 24 hours between attempts)
• Participation in a clinical trial within 30 days of screening
• Previous enrollment in a VIVITROL clinical trial
• Receipt of any drug product administered as a gluteal injection within 180 days prior to Day 0 or anticipated need for gluteal injections during study period
• Intolerance and/or hypersensitivity to naltrexone, naloxone, or polylactide-co-polymers such as polylactide-co-glycolide (PLG)

1 year