This is a randomized, double-blind, double-dummy, active-controlled multi-center study to evaluate the efficacy of transition to four 80 mg Probuphine implants in adult outpatients with opioid dependence, who are clinically stabilized on 8 mg or less of SL BPN. The study will include 3 Phases; Screening, Maintenance and Follow-up.~Medical and eligibility screening should occur within 2 weeks of the first Maintenance Phase visit. The Screening Visit will include standard medical screening procedures, complete medical/psychosocial history, urine toxicology and detailed substance use and treatment history.~All subjects who have provided written informed consent and have met the other study entry criteria will be eligible for randomization. Following confirmation of eligibility, subjects will be randomized to one of two treatment groups in a 1:1 ratio:~Treatment Group A: Daily SL BPN tablets (≤8 mg/daily) + four placebo implants~Treatment Group B: Four 80 mg Probuphine implants + daily SL placebo tablets~Implants will be surgically inserted on Day 1 (Baseline and Initiation of Study Drugs Visit). On Post-Implant Visit, additional follow-up safety and implant assessment procedures will be conducted. Subjects will return for monthly study visits on Weeks 4, 8, 12, 16, 20, and 24 (End of Treatment Visit). In addition to the monthly scheduled visits, subjects will provide 4 random urine toxicology samples throughout the 24-week treatment period.~A total of 10 urine toxicology samples will be collected; 6 at scheduled visits (1 per month) and 4 at random urine toxicology visits throughout the 24-week treatment period. At the scheduled visits, other assessments of efficacy and safety will be collected. Implants will be removed at the End of Treatment Visit on Week 24.~Following Week 24, subjects will be re-transitioned back to usual care (pre-trial), as needed. During Week 25, telephone contact will be made with all subjects. and Week 26 will include an on-site visit to the clinic for final follow-up assessments (Follow-up Visit).
The primary objective of the study is to demonstrate maintenance of treatment efficacy when transferring adult outpatients with opioid dependence, who are clinically stabilized on 8 mg or less of sublingual (SL) buprenorphine (BPN), to 4 Probuphine implants compared to SL BPN.~The secondary objective of the study is to confirm safety of 4 Probuphine implants in adult outpatients with opioid dependence who are clinically stabilized on 8 mg or less of SL BPN.