18-Month efficacy and safety analysis of monthly subcutaneous buprenorphine injection for opioid use disorder: Integrated analysis of phase 3 studies.

BACKGROUND

Few studies investigate the natural history of patients on long-term treatment for opioid use disorder (OUD). We evaluated the long-term efficacy, safety, and tolerability experience of monthly extended-release buprenorphine (BUP-XR) in participants seeking treatment for OUD, via integrated analysis of phase 3 studies.

METHODS

Study 1 was a 24-week randomized, double-blind, placebo-controlled trial of participants receiving monthly injections of BUP-XR (300 mg × 2, 100 mg × 4 [n = 203] or 300 mg × 6 [n = 201]) or placebo (n = 100). Study 2 was a 48-week, open-label trial enrolling 257 participants who completed study 1 and 412 de novo participants, to receive 6 and 12 BUP-XR injections, respectively. Study 3 was a 24-week, open-label extension enrolling 208 participants who completed study 2 for 6 additional injections. We assessed opioid abstinence as the proportion of urine opioid negative participants by visit and the percentage of each participant's negative opioid assessments during the first 6 months.

RESULTS

In total, 916 participants were treated with BUP-XR or placebo. By the end of 18 months, 92.7 % of the de novo cohort and 81.8 % of the study 1 cohort were urine negative for opioids. Among early nonresponders (percentage of abstinence ≤20 %), 73.1 % were urine negative after 18 months. The longer treatment period was well tolerated, with no new safety concerns, and a low incidence of opioid withdrawal signs and symptoms, and hepatic disorder.

CONCLUSIONS

Extending BUP-XR treatment beyond 6 months sustained improvement in opioid abstinence and was well tolerated, supporting clinical benefit up to 18 months.

TRIAL REGISTRATION: NCT02357901 (study 1); NCT02510014 (study 2); NCT02896296 (study 3).