Clinical Case Conference: Unobserved “Home” Induction Onto Buprenorphine

Extended-Release 7-Day Injectable Buprenorphine for Patients With Minimal to Mild Opioid Withdrawal

Importance

Buprenorphine is an effective yet underused treatment for opioid use disorder (OUD).

Objective

To evaluate the feasibility (acceptability, tolerability, and safety) of 7-day injectable extended-release buprenorphine in patients with minimal to mild opioid withdrawal.

Design, Setting, and Participants

This nonrandomized trial comprising 4 emergency departments in the Northeast, mid-Atlantic, and Pacific geographic areas of the US included adults aged 18 years or older with moderate to severe OUD and Clinical Opiate Withdrawal Scale (COWS) scores less than 8 (minimal to mild), in which scores range from 0 to 7, with higher scores indicating increasing withdrawal. Exclusion criteria included methadone-positive urine, pregnancy, overdose, or required admission. Outcomes were assessed at baseline, daily for 7 days by telephone surveys, and in person at 7 days. Patient recruitment occurred between July 13, 2020, and May 25, 2023.

Intervention

Injection of a 24-mg dose of a weekly extended-release formulation of buprenorphine (CAM2038) and referral for ongoing OUD care.

Main Outcomes and Measures

Primary feasibility outcomes included the number of patients who (1) experienced a 5-point or greater increase in the COWS score or (2) transitioned to moderate or greater withdrawal (COWS score ≥13) within 4 hours of extended-release buprenorphine or (3) experienced precipitated withdrawal within 1 hour of extended-release buprenorphine. Secondary outcomes included injection pain, satisfaction, craving, use of nonprescribed opioids, adverse events, and engagement in OUD treatment.

Results

A total of 100 adult patients were enrolled (mean [SD] age, 36.5 [8.7] years; 72% male). Among the patients, 10 (10.0% [95% CI, 4.9%-17.6%]) experienced a 5-point or greater increase in COWS and 7 (7.0% [95% CI, 2.9%-13.9%]) transitioned to moderate or greater withdrawal within 4 hours, and 2 (2.0% [95% CI, 0.2%-7.0%]) experienced precipitated withdrawal within 1 hour of extended-release buprenorphine. A total of 7 patients (7.0% [95% CI, 2.9%-13.9%]) experienced precipitated withdrawal within 4 hours of extended-release buprenorphine, which included 2 of 63 (3.2%) with a COWS score of 4 to 7 and 5 of 37 (13.5%) with a COWS score of 0 to 3. Site pain scores (based on a total pain score of 10, in which 0 indicated no pain and 10 was the worst possible pain) after injection were low immediately (median, 2.0; range, 0-10.0) and after 4 hours (median, 0; range, 0-10.0). On any given day among those who responded, between 29 (33%) and 31 (43%) patients reported no cravings and between 59 (78%) and 75 (85%) reported no use of opioids; 57 patients (60%) reported no days of opioid use. Improving privacy (62%) and not requiring daily medication (67%) were deemed extremely important. Seventy-three patients (73%) were engaged in OUD treatment on day 7. Five serious adverse events occurred that required hospitalization, of which 2 were associated with medication.

Conclusions and Relevance

This nonrandomized trial of the feasibility of a 7-day buprenorphine injectable in patients with minimal to mild opioid withdrawal (COWS scores, 0-7) found the formulation to be acceptable, well tolerated, and safe in those with COWS scores of 4 to 7. This new medication formulation could substantially increase the number of patients with OUD receiving buprenorphine.

Trial Registration

ClinicalTrials.gov Identifier: NCT04225598.

The design and conduct of a randomized clinical trial comparing emergency department initiation of sublingual versus a 7-day extended-release injection formulation of buprenorphine for opioid use disorder: Project ED Innovation

ED-INNOVATION (Emergency Department-INitiated bupreNOrphine VAlidaTION) is a Hybrid Type-1 Implementation-Effectiveness multisite emergency department (ED) study funded through The Helping to End Addiction Long-term^SM Initiative, or NIH HEAL Initiative^SM efforts to increase access to medications for opioid use disorder (OUD). We use components of Implementation Facilitation to enhance adoption of ED-initiated buprenorphine (BUP) at approximately 30 sites. Subsequently we compare the effectiveness of two BUP formulations, sublingual (SL-BUP) and 7-day extended-release injectable (CAM2038, XR-BUP) in a randomized clinical trial (RCT) of approximately 2000 patients with OUD on the primary outcome of engagement in formal addiction treatment at 7 days. Secondary outcomes assessed at 7 and 30 days include self-reported opioid use, craving and satisfaction, health service utilization, overdose events, and engagement in formal addiction treatment (30 days) and receipt of medications for OUD (at 7 and 30 days). A sample size of 1000 per group provides 90% power at the 2-sided significance level to detect a difference in the primary outcome of 8% and accommodates a 15% dropout rate. We will compare the cost effectiveness of the two treatments on the primary outcome using the incremental cost-effectiveness ratio. We will also conduct an ancillary study in approximately 75 patients experiencing minimal to no opioid withdrawal who will undergo XR-BUP initiation. If the ancillary study demonstrates safety, we will expand the eligibility criteria for the RCT to include individuals with minimal to no opioid withdrawal. The results of these studies will inform implementation of ED-initiated BUP in diverse EDs which has the potential to improve treatment access.