Buprenorphine Induction Low-Dose to Depot (BUILD2depot): development of safe rapid transfer to depot medication and Go/NoGo testing potential of remote community-based monitoring.

Research question This study addresses the question of whether methadone-to-buprenorphine depot injection transfer can be facilitated by low dose induction and digital monitoring. Background Buprenorphine is safer than methadone, reducing the risk of drug-related death. Buprenorphine depot medications reduce health service burden by reducing directly supervised consumption.

Conventional means of transferring from methadone to buprenorphine involve withdrawal symptoms during reduction of methadone and potentially precipitated withdrawal during induction of buprenorphine. Low dose induction has the potential to reduce these risks, but involves intensive contact and monitoring.

Digital tools - a smartphone-based app which patients can use to monitor their withdrawal symptoms and access advice and help, and a chest wall sensor to monitor respiratory depression, have the potential to expedite delivery of transfer in out-patient settings.

Aims and objectives The primary aim of this study is to establish the feasibility and acceptability of using low dose buprenorphine induction from higher-dose methadone (methadone doses still at substantially more than 30mg daily) to depot buprenorphine on an out-patient basis.

The ultimate purpose of the project is to develop a protocol which is not only safe and effective but also applicable and acceptable to a predominantly home-based community monitoring context. Methods This is a single site open label feasibility study. The protocol and app interface will be co-produced with the PPIE group ahead of recruitment.

Stage 1: Patients with opioid dependence prescribed methadone >30mg per day will be recruited from community drug services (n = 25).

They will receive training in the use of the app and the application of the Pneumowave device and be given a smartphone.

During Week 1 of induction, participants will receive small doses of sublingual buprenorphine and on two occasions will have simulated remote monitoring post ingestion.

At the end of Week 1, they will switch to depot buprenorphine and post-injection simulated remote monitoring will be done following each injection. Further doses of buprenorphine depot will be given during Week 2 according to the usual depot initiation protocol. During Week 2, methadone will be reduced and stopped.

Following Stage 1 data analysis, the decision to proceed to Stage 2 will be made based on success of simulated remote monitoring, participant retention, and the safety and tolerability of the protocol.

During Stage 2, the protocol will be repeated with fewer, shorter study visits and more reliance on remote monitoring, with a further group of participants (n = 10).

Timelines for delivery Stage 1: Months 1-6: PPIE group establishment, protocol development, app development Months 7-24: CRF-based trial of new protocol; qualitative interviews, PPI consultation, Go/No Go decision Stage 2: Months 25-33: testing of protocol with home-based digital monitoring. Months 34-26: Concluding data analysis; report preparation; PPIE feedback; dissemination.

Impact and dissemination This study could increase the implementation of transfer onto buprenorphine depot from methadone and other full agonists with digital tools, with applicability in rural or office-based settings.

Findings will be disseminated via academic presentations and papers, communication with commissioners and industry, and continued engagement of the PPIE networks.