Treatment of opioid dependence with buprenorphine/naloxone sublingual tablets: A phase 3 randomized, double-blind, placebo-controlled trial

Introduction The purpose of the study is to evaluate the efficacy and safety of buprenorphine/naloxone sublingual tablets for the treatment of opioid dependence in Chinese adults. Methods This multicenter, double-blind, placebo-controlled study included four periods: induction (3-5 days), stabilization (7-21 days), randomization/treatment (6 weeks), and postmedication follow-up (1 week). A total of 442 participants with opioid dependence were enrolled; 260 were randomized to buprenorphine/naloxone or placebo. The primary outcome was retention in treatment, defined as the time from randomization to treatment completion or treatment failure. Secondary outcomes included maximum consecutive days of abstinence from opioids, self-reported craving and opioid withdrawal symptoms, and urine drug screen results. Safety assessments included adverse event reporting, electrocardiograms, clinical laboratory tests, vital signs, and prior/concomitant medications. Results The median treatment retention time (95% confidence internal) with buprenorphine/naloxone was 32 days (26-38) versus 6 days (5-8) for placebo, with a Cox hazard ratio of 0.28 (95% confidence interval, 0.21-0.38; P < 0.0001). The median maximum consecutive days of abstinence (95% confidence interval) was: buprenorphine/naloxone, 21 days (26-38); placebo, 5 days (5-8) with a Cox hazard ratio of 0.38 (95% confidence interval, 0.25-0.60; P < 0.0001). Withdrawal and craving symptoms were significantly milder with buprenorphine/naloxone versus placebo (P < 0.001). Urine drug screen results indicated significantly lower opioid usage in the buprenorphine/naloxone group compared with placebo (P < 0.001). The most commonly reported adverse events in the buprenorphine/naloxone group during treatment were aspartate aminotransferase increased and nasopharyngitis. Discussion Efficacy and safety results from this clinical trial support a positive benefit-risk ratio for buprenorphine/naloxone sublingual tablet use in the treatment of an opioid-dependent Chinese population.