Evaluating the feasibility of prolonged-release buprenorphine formulations as an alternative to daily opioid agonist therapy regardless of prior treatment adherence: a pilot study

BACKGROUND: Effective opioid agonist therapy (OAT) depends on good patient adherence. However, the daily, supervised administration of standard OAT represents a significant burden to patients and often drives poor adherence. Prolonged-release buprenorphine (PRB) formulations may mitigate some of this burden, enabling clinic visits to be substantially reduced. For treatment guidelines to be effective, the likely benefit of a transition to PRB therapy in different patient populations must be established. METHODS: The aim was to determine the feasibility of assessing PRB as an alternative to daily OAT in two groups: those currently adhering well to daily OAT (group 1, N = 5) and those not currently showing adherence or a positive response to daily OAT (group 2, N = 10). This open-label, prospective, non-controlled pilot study was conducted at the Kaleidoscope Drug Project in South Wales, UK. Participants were assessed for history, drug use, psychosocial assessment scores, and clinical severity at baseline and after 6 months of treatment. Primary outcomes were the feasibility of assessing PRB as an alternative to daily OAT and the acceptability of PRB therapy in each group. Secondary outcomes were treatment response, on-top drug use, psychosocial measures, and assessment of clinical severity. RESULTS: Participants from both groups demonstrated high levels of participation with assessment protocols at both baseline and 6-month follow-up, indicating study feasibility. PRB treatment was acceptable to the majority of participants, with all of group 1 and 70% of group 2 adhering to PRB therapy for the duration of the study and opting to persist with PRB therapy over other OAT options after study completion. All participants who remained on treatment demonstrated marked improvements in psychosocial and clinical severity assessment scores, with some returning to employment or education. On-top drug use remained absent in group 1 and was reduced in group 2. CONCLUSIONS: Evaluation of transition of participants from daily OAT to PRB therapy was shown to be feasible, acceptable, and effective across both groups. A larger randomised controlled trial is warranted, particularly to assess PRB therapy in participants with a history of poor treatment engagement, as the need for therapy is greater in this group and their management is associated with higher costs of care.