Transition of Patients with Opioid Use Disorder from Buprenorphine to Extended‐Release Naltrexone: A Randomized Clinical Trial Assessing Two Transition Regimens

BACKGROUND AND OBJECTIVE: When patients seek to discontinue buprenorphine (BUP) treatment, monthly injectable extended‐release naltrexone (XR‐NTX) may help them avoid relapse. The efficacy of low ascending doses of oral NTX vs placebo for patients transitioning from BUP to XR‐NTX is evaluated in this study. METHODS: In a phase 3, hybrid residential/outpatient study, clinically stable participants with opioid use disorder (N = 101), receiving BUP for more than or equal to 3 months and seeking antagonist treatment, were randomized (1:1) to 7 residential days of descending doses of BUP and low ascending doses of oral NTX (NTX/BUP, n = 50) or placebo (PBO‐N/BUP, n = 51). Both groups received standing ancillary medications and psychoeducational counseling. Following negative naloxone challenge, participants received XR‐NTX (day 8). The primary endpoint was the proportion of participants who received and tolerated XR‐NTX. RESULTS: There was no statistical difference between groups for participants receiving a first dose of XR‐NTX: 68.6% (NTX/BUP) vs 76.0% (PBO‐N/BUP; P = .407). The mean number of days with peak Clinical Opiate Withdrawal Scale (COWS) score less than or equal to 12 during the treatment period (days 1‐7) was similar for NTX/BUP and PBO‐N/BUP groups (5.8 vs 6.3; P = .511). Opioid withdrawal symptoms during XR‐NTX induction and post‐XR‐NTX observation period (days 8‐11) were mild and similar between groups (mean peak COWS score: NTX/BUP, 5.1 vs PBO‐N/BUP, 5.4; P = .464). Adverse events were mostly mild/moderate. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Low ascending doses of oral NTX did not increase induction rates onto XR‐NTX compared with placebo. The overall rate of successful induction across treatment groups supports a brief BUP taper with standing ancillary medications as a well‐tolerated approach for patients seeking transition from BUP to XR‐NTX. (Am J Addict 2020;00:00–00)