Conditions: Opiate Dependence
Keywords: Opiate Dependence
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 27
Healthy volunteers: yes

Brief summary:
This was a Phase 2, multicenter, randomized, double-blind pilot study in opioid-using adults to assess the presence, duration, and degree of opiate blockade as well as the safety and tolerability of Medisorb® naltrexone (VIVITROL®). Subjects were randomized in a 1:1:1 ratio to receive a single gluteal intramuscular (IM) injection of Medisorb naltrexone 75, 150, or 300 mg.

Detailed description:
Potential subjects were screened within 21 days prior to dosing of study drug (Medisorb naltrexone or placebo) on Day 0. Screening evaluations included a baseline hydromorphone challenge session in which increasing doses of hydromorphone (0 mg \[placebo\], 3 mg, 4.5 mg, and 6 mg) were administered at hourly intervals to produce a cumulative dose-response curve. Throughout the 4-hour challenge period, subject-rated measures (Visual Analog Scale \[VAS\] questions) and physiological measures (ie, pupil size) were recorded.

As a safety measure, at least 7 days after the baseline hydromorphone challenge, a naloxone challenge was performed followed by a 1-day oral naltrexone tolerability assessment. On Day 0, eligible subjects were administered a single dose of study drug. To assess the level of opiate blockade and surmountability attributable to Medisorb naltrexone, experimental hydromorphone challenge sessions were conducted postdose at Days 7, 14, 21, 28, 42, and 56, with a single placebo hydromorphone challenge administered at a randomly selected visit. Pupil size was measured 15 minutes prior to the first hydromorphone dose and at 15, 30, 45, and minutes after each ascending hydromorphone/placebo for hydromorphone dose. Blood samples for measurement of naltrexone and 6B-naltrexol were obtained at screening and before hydromorphone/placebo administration on Days 7, 14, 21, 28, 42, and 56.

Subjects were monitored for safety through Day 56.

Arms:
arm 1: None arm 2: None arm 3: None

Interventions: intervention 1: Medisorb naltrexone 75 mg intervention 2: Medisorb naltrexone 150 mg intervention 3: Medisorb naltrexone 300 mg intervention 4: Hydromorphone (10 mg/mL) intervention 5: Naloxone Challenge and Oral Naltrexone Tolerability Testing
Intervention descriptions: intervention 1: Single administration via intramuscular (IM) injection. intervention 2: Single administration via IM injection. intervention 3: Single administration via IM injection. intervention 4: Increasing doses of 0, 3, 4.5, and 6 mg were administered at baseline (pre-study drug administration). After study drug administration, additional hydromorphone challenge sessions consisting of administering 0, 3, 4.5, and 6 mg were administered at 1-hr intervals at each of the postdose evaluation visits. In addition, at a randomly selected evaluation visit, subjects received four 0 mg (placebo) doses at 1-hour intervals. intervention 5: Administered according to the instructions provided by the respective manufacturer. Testing occurred at least 7 days after the baseline hydromorphone challenge and prior to study drug administration.

Protocol document: