Abstract

Introduction: Since the 1990s, opioid maintenance treatments (OMTs), i.e. mostly methadone and buprenorphine, have represented the therapeutic cornerstone of opioid dependence. In France, the public health strategy on opioid dependence, identified here as the 'French model', has consisted of offering a facilitated access to buprenorphine, to reach a large treatment coverage and reduce opioid-related mortality. Areas covered: Recently, a new formulation of subcutaneous buprenorphine depot (Buvidal®) has been approved in Europe for treatment of opioid dependence. The place of Buvidal® among the pre-existing arsenal of OMTs is discussed in the light of the pharmacological specificities of this new formulation, and with the particular standpoint of the French model on opioid dependence. Expert opinion: Buvidal® could constitute a promising treatment option mainly in case of: 1) OMT initiation, including in non-specialized addiction medicine care; 2) Discharge from prison or hospital; Diversion/misuse of 3) buprenorphine or 4) methadone; 5) Clinically stabilized patients wishing to avoid daily oral taking of the medication. As such, this new formulation should be highly accessible, which will require specific pathways through care as the product is intended to be administered by a healthcare professional.

Importance: Fentanyl has exacerbated the opioid use disorder (OUD) and opioid overdose epidemic. Data on the effectiveness of medications for OUD among patients using fentanyl are limited.

Objective: To assess the effectiveness of sublingual or extended-release injection formulations of buprenorphine for the treatment of OUD among patients with and without fentanyl use.

Design, setting, and participants: Post hoc analysis of a 24-week, randomized, double-blind clinical trial conducted at 35 outpatient sites in the US from December 2015 to November 2016 of sublingual buprenorphine-naloxone vs extended-release subcutaneous injection buprenorphine (CAM2038) for patients with OUD subgrouped by presence vs absence of fentanyl or norfentanyl in urine at baseline. Study visits with urine testing occurred weekly for 12 weeks, then 6 times between weeks 13 and 24. Data were analyzed on an intention-to-treat basis from March 2022 to August 2023.

Intervention: Weekly and monthly subcutaneous buprenorphine vs daily sublingual buprenorphine-naloxone.

Main outcomes and measures: Retention in treatment, percentage of urine samples negative for any opioids (missing values imputed as positive), percentage of urine samples negative for fentanyl or norfentanyl (missing values not imputed), and scores on opiate withdrawal scales and visual analog craving scales.

Results: Of 428 participants, 123 (subcutaneous buprenorphine, n = 64; sublingual buprenorphine-naloxone, n = 59; mean [SD] age, 39.1 [10.8] years; 75 men [61.0%]) had evidence of baseline fentanyl use and 305 (subcutaneous buprenorphine, n = 149; buprenorphine-naloxone, n = 156; mean [SD] age, 38.1 [11.1] years; 188 men [61.6%]) did not have evidence of baseline fentanyl use. Study completion was similar between the fentanyl-positive (60.2% [74 of 123]) and fentanyl-negative (56.7% [173 of 305]) subgroups. The mean percentage of urine samples negative for any opioid were 28.5% among those receiving subcutaneous buprenorphine and 18.8% among those receiving buprenorphine-naloxone in the fentanyl-positive subgroup (difference, 9.6%; 95% CI, -3.0% to 22.3%) and 36.7% among those receiving subcutaneous buprenorphine and 30.6% among those receiving buprenorphine-naloxone in the fentanyl-negative subgroup (difference, 6.1%; 95% CI, -1.9% to 14.1%), with significant main associations of baseline fentanyl status and treatment group. In the fentanyl-positive subgroup, the mean percentage of urine samples negative for fentanyl during the study was 74.6% among those receiving subcutaneous buprenorphine vs 61.9% among those receiving sublingual buprenorphine-naloxone (difference, 12.7%; 95% CI, 9.6%-15.9%). Opioid withdrawal and craving scores decreased rapidly after treatment initiation across all groups.

Conclusions and relevance: In this post hoc analysis of a randomized clinical trial of sublingual vs extended-release injection buprenorphine for OUD, buprenorphine appeared to be effective among patients with baseline fentanyl use. Patients with fentanyl use had fewer opioid-negative urine samples during the trial compared with the fentanyl-negative subgroup. These findings suggest that the subcutaneous buprenorphine formulation may be more effective at reducing fentanyl use.

Trial registration: ClinicalTrials.gov Identifier: NCT02651584.