EXPO is a pragmatic, multi-centre, open label, four-arm, parallel group, superiority RCT, with a qualitative (mixed-methods) evaluation. The objective of the study is to determine the effectiveness and cost-effectiveness of XR-BUP versus SOC SL-BUP or MET. The primary study endpoint is six months of study treatment. EXPO also contains a single-site evaluation of the effectiveness of XR-BUP with adjunctive PSI versus SOC with adjunctive PSI. Participants allocated to XR-BUP can request to receive longer-term treatment for the duration of the study.~The study population is adults (≥18 years) enrolled in standard-of-care medication treatment for OUD. The study setting is specialist community addiction treatment programmes operated by the National Health Service in England and Scotland. There will be five participant treatment sites in South-East England (South London); North-East England (Newcastle); West Midlands, England (Solihull and Wolverhampton); North-West England (Manchester), and Tayside, Scotland (Dundee).~Groups~In all sites, participants will be randomly allocated to one of two groups:~Group 1. Injectable medication for OUD for 24 weeks (XR-BUP; the experimental condition) Group 2. Oral medication for OUD for 24 weeks (SL-BUP or MET; the control condition).~At the EXPO co-ordinating centre in South London, there will also be random allocation of participants to two additional groups, as follows:~Group 3. Injectable medication for OUD with adjunctive PSI for 24 weeks (XR-BUP with PSI; the experimental condition)~Group 4. Oral medication for OUD with adjunctive PSI for 24 weeks (SL-BUP or MET with PSI; the control condition).~Study aims~Across 24-weeks of study treatment, the primary aim of the EXPO study is to determine:~The effectiveness and cost-effectiveness of XR-BUP versus SL-BUP or MET; and~The effectiveness of XR-BUP with PSI versus SL-BUP or MET with PSI.~Across 24-weeks of study treatment, secondary study aims will determine the:~Safety of XR-BUP;~Retention of XR-BUP; SL-BUP; MET; XR-BUP with PSI; and SL-BUP or MET with PSI;~Effectiveness of XR-BUP and SL-BUP and MET to reduce opioid craving;~Effectiveness of XR-BUP; SL-BUP; MET; XR-BUP with PSI; SL-BUP with PSI; and MET with PSI to reduce use of heroin, cocaine, and benzodiazepines;~Effectiveness of XR-BUP and SL-BUP and MET to improve social functioning and recovery.~Cost-effectiveness of XR-BUP versus SL-BUP and MET, based on the incremental cost per quality-adjusted life year (QALY) gained.~Study aims will be evaluated by following a pre-registered statistical and health economic analysis plan.
The primary objective is a clinical superiority effectiveness contrast to standard of care. Reported following SPIRIT and CONSORT standards, the study will determine whether extended-release injectable depot Buprenorphine (XR-Bup) maintenance therapy for OUD over six months is clinically superior to standard-of-care, oral medication (sublingual Buprenorphine [SL-Bup] or oral methadone [Met]; together: Bup/Met)