Evaluation of Long-term Buprenorphine Plasma Exposure

The study objective is to characterise the long-term plasma exposure to buprenorphine after stopping SUBLOCADE treatment. There are no interventions planned. This multicentre investigation will enroll participants from Study RB-US-13-0003 (NCT02510014) or both Studies RB-US-13-0003 and INDV-6000-301 (NCT02896296) and who received at least 2 subcutaneous (SC) injections of SUBLOCADE. There are two parts to the study: Part A consists of a single visit during which urine samples are collected to measure free buprenorphine and free norbuprenorphine concentrations; qualitative urine drug samples (UDS) for opioids, including buprenorphine; quantitative UDS for buprenorphine, norbuprenorphine and naloxone; and determination of creatinine concentration. Blood samples are collected for the determination of buprenorphine and norbuprenorphine plasma concentrations. Results on the quantitative UDS performed in Part A determine enrollment in Part B: participants who provide a quantifiable (i.e., positive) result for buprenorphine and/or norbuprenorphine and a non-quantifiable (i.e., negative) result for naloxone meet continuation criteria to move on to Part B if Part B is still open to enrolment. Part B consists of two visits 30 days apart in which the same tests are run as were done in Part A.