Buprenorphine exposure levels to optimize treatment outcomes in opioid use disorder

Monthly buprenorphine depot injection (SUBLOCADE®) for opioid use disorder during pregnancy

BACKGROUND AND OBJECTIVES

Untreated opioid use disorder (OUD) in pregnancy is associated with adverse obstetrical outcomes, maternal morbidity, and maternal mortality. This article will inform clinicians about the use of monthly extended-release buprenorphine (BUP-XR, SUBLOCADE®) to treat OUD during pregnancy and postpartum.

METHODS

We examined the use of monthly BUP-XR during pregnancy in patients with OUD, summarizing case studies (N = 4) from clinical practice, reviewing >5 years of pregnancy and postpartum surveillance data (quantitative [N = 322] and qualitative) and relevant literature in PubMed (N = 4).

RESULTS

The clinical practice case studies highlight the experience from four pregnant patients with OUD who received monthly BUP-XR. All four neonates were delivered full-term with normal birthweight, no fetal anomalies, and no medication required for neonatal opioid withdrawal syndrome. Additionally, over 300 pregnancies have been reported through postmarketing surveillance, of which 68 have known outcomes consistent with information described in the product label. Findings from literature, postmarketing surveillance, and clinical practice case studies were consistent with the established safety profile of buprenorphine.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

This study addresses a lack of knowledge of treatment of pregnant individuals with OUD and draws on relevant experience from prescribers treating patients with monthly BUP-XR during pregnancy and postpartum. These data support consideration of implementing BUP-XR as part of evidence-based practice that prioritizes OUD treatment access, patient stability, and patient choice during the perinatal period. Three sources of data illustrate that the use of monthly BUP-XR during pregnancy has demonstrated no increased risk and is consistent with the established buprenorphine safety profile.

Social Listening for Patient Experiences With Stopping Extended-Release Buprenorphine: Content Analysis of Reddit Messages

BACKGROUND

Discontinuation of buprenorphine as a medication for opioid use disorder (MOUD) necessitates careful tapering to reduce opioid withdrawal and relapse. With a half-life of 43-60 days, buprenorphine extended-release formulation (BUP-XR) may provide gradual taper, facilitating successful treatment discontinuation.

OBJECTIVE

This study sought to understand experiences with stopping BUP-XR as described on social media.

METHODS

Reddit records (March 2018 to August 2022) were evaluated for the presence of referents to BUP-XR using parallel criteria based on predefined keywords and subreddit context. The keyword-based search identified records mentioning "Sublocade" (or similar search strings) regardless of subreddit. The subreddit context-based criteria identified records that were created within the r/Sublocade subreddit. Records that included reference to BUP-XR were further evaluated for mentions of treatment cessation using predefined keywords. A 50% randomized sample was then selected for qualitative analysis by a single experienced subject matter expert. Records were manually coded to validate references to BUP-XR and MOUD cessation and were evaluated for additional predefined constructs related to opioid craving and withdrawal, BUP-XR and other MOUD treatment details, and other nonmedical opioid use. Emergent constructs related to cessation-related knowledge, attitudes, behaviors, and experiences were also identified as part of the data coding and annotation process.

RESULTS

Of 6082 total, 3041 records were coded and analyzed; most (n=2692, 97.4%) referenced BUP-XR, of which, 43.8% (n=1179) referenced cessation of BUP-XR as MOUD. Many individuals shared information about prior use of MOUD, primarily transmucosal buprenorphine (185 records/63 authors), including the use of BUP-XR to taper off buprenorphine. Individuals provided details of their BUP-XR treatment experiences before and following cessation. Only 102 (8.7%) records mentioned opioid withdrawal; 1 record mentioned craving. Withdrawal experiences with BUP-XR were generally described as less intense than other drugs, although at least mild withdrawal was seen as an inevitable part of cessation. Thematic analysis revealed discussions of polypharmacy with transmucosal buprenorphine and the importance of personalized treatment and patient agency.

CONCLUSIONS

There was nuanced discussion of treatment cessation using BUP-XR on Reddit, with individuals describing detailed courses of treatment and treatment experiences. Few records mentioned opioid withdrawal, and when discussed, withdrawal experiences during cessation of BUP-XR were generally described as less intense than withdrawal experiences with other drugs. These results suggest that social media, such as Reddit, can be leveraged to explore perspectives on treatment and recovery among individuals with opioid use disorder. Overall, this study provides insights into real-world patient experiences with cessation of BUP-XR and is consistent with prior case series; however, more research is needed to understand the course of opioid use disorder following cessation of BUP-XR as well as other MOUD.

Initiation and Dosing of Extended-Release Buprenorphine: A Narrative Review of Emerging Approaches for Patients Who Use Fentanyl

Individuals with Opioid Use Disorder (OUD) who use fentanyl are at high risk of mortality due to opioid-related overdose. While buprenorphine extended-release (BUP-XR) may reduce this risk, there is a need to optimize clinical practice with BUP-XR to overcome barriers to treatment initiation and retention in patients who use fentanyl. Through a narrative review of evidence from peer-reviewed publications and conference abstracts, this article provides an overview of current novel initiation and dosing strategies for BUP-XR in patient populations with confirmed or presumed use of fentanyl. Evidence in this area is rapidly emerging with multiple studies describing BUP-XR initiation prior to 7-day stabilization on transmucosal buprenorphine (TM-BUP). Results from a randomized controlled study indicate that initiating BUP-XR following a single TM-BUP dose is noninferior to standard initiation in terms of treatment retention at injection 2, with similar rates of precipitated withdrawal and adverse events, and this protocol is now included in the approved prescribing information in the USA. While additional "macro/high-dose" or "micro/low-dose" and "direct dose" induction approaches have also been reported, evidence for these is limited to small uncontrolled studies or case reports. Consistent with evidence from studies of TM-BUP, which suggests individuals who use fentanyl may require higher maintenance doses in order to be retained in treatment, administrative and observational data suggests that use of the 300-mg maintenance dose, shortened intervals between doses, and supplemental TM-BUP may be feasible approaches to increase buprenorphine exposure in patients with ongoing symptoms and improve retention. Evidence in this area is rapidly evolving, and many of these strategies are increasingly being adopted clinically and incorporated into clinical guidelines. Further research should incorporate increased sample sizes, broader and more consistent outcome measurement, and increased duration of follow-up to facilitate more robust evaluation of efficacy and safety as well as increase comparability between studies.

Making long-acting treatment work: Tracing connections with extended-release buprenorphine depot through time

INTRODUCTION

How people connect with opioid agonist treatment is an ongoing concern. Extended-release buprenorphine depot (BUP-XR) has been designed with 'retention' in mind. It is important to consider what makes a difference to clients in helping them to stay connected to treatment over time.

METHODS

We report findings from the third wave of in-depth interviews with participants (n = 26) in the Community Long-Acting Buprenorphine (CoLAB) study, tracing accounts of connection, disconnection and reconnection with BUP-XR since initiation into treatment.

RESULTS

Changing situations in treatment delivery and in people's lives created conditions of possibility for connection and disconnection to treatment. Clients used BUP-XR in different ways. Personalisation of dosing regimens and stretching out of time between doses was common, creating a sense of stability for some. For others, this flexibility potentiated fragility in treatment connection. Disconnection from BUP-XR was common, but frequently this was not the ultimate outcome. Treatment connections were shaped by fluctuating life circumstances, with re-connections imagined, attempted and sometimes realised.

DISCUSSION AND CONCLUSIONS

Clients' accounts reveal the complexities of how 'long-acting' treatments are made to work over time. Connecting with treatment in the long-term is a process, contingent on social relations, fluctuating life conditions and systems of care. Rather than treating connection and disconnection as opposites, we suggest seeing these as entangled and fluid elements of an ongoing process. What is needed is an adaptive and emergent conceptualisation of what 'retention' in treatment can mean, reflective of how people connect with their treatment and make it work, in practice.

MOUD 2.0: a clinical algorithm and implementation evaluation protocol for sublingual and injectable buprenorphine treatment of opioid use disorder

Background

Primary care is the initial contact point for most patients with opioid use disorder (OUD) but lacks tools for guiding treatment. Only a small fraction of patients access evidence-based care. Long-acting injectable buprenorphine has potential to improve medication adherence and program retention in low-barrier primary care treatment settings. We present the first clinical decision support algorithm incorporating long-acting buprenorphine (LAIB) in primary care. We include a protocol for a future evaluation of the algorithm's implementation process, "Medication for Opioid Use Disorder (MOUD) 2.0," at a housing and integrated care clinic at a Federally Qualified Health Center.

Methods

Literature review and expert consensus informed creation of the algorithm, which underwent iterative development with feedback from clinicians, staff, and patients. Patients are categorized by adherence to therapy and retention in the program, with recommendations for each category. Adherence is determined by urine screen supplemented by self-report. To ensure all patients in this high morbidity and mortality risk population are treated, we will treat patients as their own controls in the evaluation, with potential for multisite comparisons. We will present descriptive statistics for adherence proportion before and after MOUD 2.0 implementation, testing for differences using McNemar's test. We will then present pre- and post-implementation unadjusted six-month survival curves for retention.

Discussion

LAIB is incorporated as an alternative or adjunctive treatment for patients refractory to sublingual buprenorphine and as an initial treatment for selected patients. We developed an algorithm with 4-, 8-, and 12-week decision points to guide treatment for patients with varying levels of response to sublingual buprenorphine and LAIB. This clinical decision tool incorporates LAIB among treatment options for OUD in primary care settings. The protocol will evaluate the algorithm's implementation, presenting a replicable method for assessing adherence and retention among high-risk patients in similar settings.

A Single-Dose Study to Evaluate the Relative Bioavailability, Safety, and Tolerability of Monthly Extended-Release Buprenorphine at Alternative Injection Locations in Adult Participants with Opioid Use Disorder

BACKGROUND AND OBJECTIVES

Buprenorphine extended-release monthly formulation (BUP-XR, SUBLOCADE®) is approved for treatment of moderate-to-severe opioid use disorder (OUD) following subcutaneous injection in the abdomen. This open-label pharmacokinetic study assessed three alternative injection locations (upper arm, thigh, buttocks) to offer additional flexibility considering the chronic nature of the disease and patient preferences.

METHODS

Following stabilization on 12/3 mg/day of sublingual buprenorphine/naloxone for ≥ 7 days, participants with moderate-to-severe OUD were randomized to receive a single 300-mg BUP-XR injection in the upper arm, thigh, buttocks, or abdomen (reference). Serial blood samples were taken to measure buprenorphine plasma concentrations over 28 days and assess buprenorphine relative bioavailability. Safety evaluations included treatment-emergent adverse events and assessments of injection site pain, tenderness, erythema, induration, and swelling.

RESULTS

A total of 88 participants received a single subcutaneous injection of 300-mg BUP-XR in the upper arm (N = 21), thigh (N = 23), buttocks (N = 22), or abdomen (N = 22); 81/88 (92%) completed the study. Buprenorphine plasma exposure (area under the plasma concentration-time curve over 28 days) was comparable across injection site groups with mean buprenorphine plasma concentrations sustained at approximately 2 ng/mL (therapeutic target concentration) or above. Buprenorphine maximum plasma concentration (Cmax) was approximately 39% and 52% higher after injection in the upper arm and thigh, respectively, versus the abdomen, while comparable between buttocks and abdomen. Higher Cmax values were not associated with an increased incidence of adverse events. Safety and injection site tolerability were comparable across injection groups.

CONCLUSIONS

These pharmacokinetic and safety findings support BUP-XR injection into the upper arm, thigh, and buttocks.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT05704543.

Personalized medicine and opioid use disorder

Opioid use disorder (OUD) is a major public health problem affecting millions of people worldwide. Although OUD is a chronic and relapsing disorder, a variety of pharmacological and non-pharmacological interventions are available. Medication-assisted treatment of OUD generally relies on competition for opioid receptors against the addictive substance. The mechanisms of this competition are to block or inactivate the opioid receptor or activate the receptor with a substance that is intermittent or long acting. Methadone and buprenorphine are two United States Food and Drug Administration-approved medications that have long-term positive effects on the health of opioid-dependent individuals. Although clinical studies of drugs generally demonstrate efficacy in thousands of people and toxicity is excluded, it cannot be predicted whether the given drug will cause side effects in one of the patients at the treatment dose. Individual differences can be explained by many biological and environmental factors. Variations in genes encoding drug metabolism or cellular drug targets significantly explain the variability in drug response between individuals. Therefore, for the effects of candidate genes to be accepted and included in individual treatment protocols, it is important to repeat studies on individuals of different ethnic backgrounds and prove a similar effect.

Assessing predictors of adequate individual buprenorphine maintenance dosage for the treatment of opioid use disorder: Listening to the patient

OBJECTIVE

Dose optimization plays a key role in determining clinical outcomes in patients on opioid agonist treatment (OAT). The objective of this study was to identify the variables independently associated with buprenorphine/naloxone (B/N) dose adequacy in patients with opiate use disorder (OUD).

METHOD

Cross-sectional study of a convenience sample of patients with OUD treated with B/N (n = 315) in four regions in Spain. The Opiate Dosage Adequacy Scale (ODAS) was used to determine B/N dose adequacy. The ODAS evaluate the six components of the "dose adequacy" construct, as follows: continued use of heroin; narcotic blockade or crossed tolerance; objective opioid withdrawal symptoms (OWS); subjective OWS; craving for heroin; and overmedication. A binomial logistic regression analysis was performed to identify the variables associated with the condition "ODAS Adequate B/N dose". Participants completed a battery of instruments to assess sociodemographic, substance use, clinical, and treatment variables.

RESULTS

The B/N dose was considered adequate in 231 of the 315 participants (73.3 %). Two variables, satisfaction with B/N as a medication (OR=5.764, 95 % CI=2.211-15.030) and patient-perceived participation in B/N dose decisions (OR=1.790, 95 % CI=1221-2623), were independently, significantly, and positively associated with the "ODAS Adequate B/N dose" condition. While the severity of heroin dependence was significantly associated with buprenorphine dose adequacy in the bivariate analyses, significance was lost in the full regression model.

CONCLUSION

Satisfaction with B/N as a medication and patient-perceived involvement in the dose decision are associated with clinician-assessed dose adequacy. In the context of good clinical practice, it is important to take into account both of these variables to individualize the prescribed dose through a shared decision-making process.

OPRM1 rs2075572 has potential to affect plasma buprenorphine level in opioid users, but not OPRM1 rs562859

OPRM1 gene encoding mu-opioid receptor (MOR) is the primary candidate gene for buprenorphine (BUP) pharmacogenetics. OPRM1 undergoes alternative splicing leading to multiple MOR subtypes. Thus, in the current study 2 SNPs (rs1799972 and rs562859) were selected due to evidence for their contribution to alternative splicing of OPRM1. The effects of 2 SNPs of OPRM1 gene on plasma buprenorphine and norbuprenorphine levels in a sample of 233 OUD patients receiving BUP/naloxone were examined. Polymorphisms were analyzed by PCR and RFLP. BUP and norbuprenorphine concentrations in plasma were measured by LC-MS/MS. OPRM1 rs2075572 GC + CC (0.12 ng/ml) had significantly higher plasma BUP level compared to GG (0.084 ng/ml) (p = 0.043). Although there was not a statistically significant difference between OPRM1 rs562859 genotypes (p = 0.46), patients with OPRM1 rs562859 CT + TT had higher plasma BUP and BUP-related values as compared to those with CC. In conclusion, the effect of OPRM1 rs2075572 on BUP levels in opioid users' plasma was shown in a Caucasian population for the first time. On the other hand, OPRM1 rs562859 seems not to influence the BUP pharmacology.

Relationship between opioid cross-tolerance during buprenorphine stabilization and return to opioid use during buprenorphine dose tapering

RATIONALE

Opioid injection drug use (IDU) has been linked to a more severe pattern of use (e.g. tolerance, overdose risk) and shorter retention in treatment, which may undermine abstinence attempts.

OBJECTIVES

This secondary data analysis of four human laboratory studies investigated whether current opioid IDU modulates subjective abuse liability responses to high-dose hydromorphone during intermediate-dose buprenorphine stabilization (designed to suppress withdrawal but allow surmountable agonist effects), and whether hydromorphone response magnitude predicts latency of return to opioid use during buprenorphine dose-tapering.

METHODS

Regular heroin users not currently seeking treatment (n = 54; 29 current injectors, 25 non-injectors) were stabilized on 8-mg/day sublingual buprenorphine and assessed for subjective responses (e.g. 'liking', craving) to hydromorphone 24-mg intramuscular challenge (administered 16-hr post-buprenorphine) under randomized, double-blinded, controlled conditions. A subgroup (n = 35) subsequently completed a standardized 3-week outpatient buprenorphine dose-taper, paired with opioid-abstinent contingent reinforcement, and were assessed for return to opioid use based on thrice-weekly urinalysis and self-report.

RESULTS

During buprenorphine stabilization, IDU reported lower 'liking' of buprenorphine and post-hydromorphone peak 'liking', 'good effect' and 'high' compared to non-IDU. Less hydromorphone peak increase-from-baseline in 'liking' (which correlated with less hydromorphone-induced craving suppression) predicted significantly faster return to opioid use during buprenorphine dose-tapering.

CONCLUSIONS

In these buprenorphine-stabilized regular heroin users, IDU is associated with attenuated 'liking' response (more cross-tolerance) to buprenorphine and to high-dose hydromorphone challenge and, in turn, this cross-tolerance (but not IDU) predicts faster return to opioid use. Further research should examine mechanisms that link cross-tolerance to treatment response.

Pharmacokinetic-pharmacodynamic analysis of drug liking blockade by buprenorphine subcutaneous depot (CAM2038) in participants with opioid use disorder

Buprenorphine is used to treat opioid use disorder (OUD). Weekly and monthly subcutaneous long-acting buprenorphine injections (CAM2038) provide more stable buprenorphine plasma levels and reduce the treatment burden, misuse, and diversion associated with sublingual transmucosal buprenorphine formulations. To characterize the pharmacokinetic/pharmacodynamic (PK/PD) relationship, a maximum inhibition (Imax) model was developed relating CAM2038 buprenorphine plasma concentration to drug liking maximum effect (Emax) visual analog scale (VAS; bipolar) score after intramuscular hydromorphone administration. Data included time-matched observations of buprenorphine plasma concentration and drug liking Emax VAS score after hydromorphone 18 mg administration in 47 non-treatment-seeking adults with moderate to severe OUD in a phase 2 study. Analysis used non-‍linear mixed-effects modeling (NONMEM®). The final Imax model adequately described the PK/PD relationship between buprenorphine plasma concentration and drug liking Emax VAS score. Simulations showed drug liking was effectively blocked at low buprenorphine plasma concentrations (0.4 ng/mL) where the upper 95% confidence interval of the drug liking Emax VAS score was below the pre-defined 11-point complete blockade threshold. The buprenorphine plasma concentration required to achieve 90% of the maximal effect (IC90) of drug liking was 0.675 ng/mL. Interindividual variability in responses to buprenorphine was observed; some participants experienced fluctuating responses, and a few did not achieve drug liking blockade even with higher buprenorphine plasma concentrations. This affirms the need to individualize treatment and titrate doses for optimal treatment outcomes. PK/PD models were also developed for desire to use VAS and Clinical Opiate Withdrawal Scale (COWS) scores, with results aligned to those for drug liking.

Management of Critically Ill Patients Receiving Medications for Opioid Use Disorder

TOPIC IMPORTANCE

Critical care clinicians are likely to see an increasing number of patients admitted to the ICU who are receiving US Food and Drug Administration-approved medications for opioid use disorder (MOUDs) given the well-documented benefits of these agents. Oral methadone, multiple formulations of buprenorphine, and extended-release naltrexone are the three types of MOUD most likely to be encountered by ICU clinicians; however, these drugs vary with respect to formulations, pharmacokinetics, and adverse effects.

REVIEW FINDINGS

No published clinical practice guidelines or consensus statements are available to guide decision-making in patients admitted to the ICU setting who are receiving MOUDs before admission. Additionally, no randomized trials and limited observational studies have evaluated issues related to MOUD use in the ICU. Therefore, ICU clinicians caring for patients admitted who are taking MOUDs must base their decision-making on data extrapolation from pharmacokinetic, pharmacologic, and clinical studies performed in non-ICU settings.

SUMMARY

Despite the challenges in administering MOUDs in critically ill patients, extrapolation of data from other hospital settings suggests that the benefits of continuing MOUD therapy outweigh the risks in patients able to continue therapy. This article provides guidance for critical care clinicians caring for patients admitted to the ICU already receiving methadone, buprenorphine, or extended-release naltrexone. The guidance includes algorithms to aid clinicians in the clinical decision-making process, recognizing the inherent limitations of the existing evidence on which the algorithms are based and the need to account for patient-specific considerations.

Examining the benefit of a higher maintenance dose of extended-release buprenorphine in opioid-injecting participants treated for opioid use disorder

BACKGROUND

BUP-XR (SUBLOCADE®) is the first buprenorphine extended-release subcutaneous injection approved in the USA for monthly treatment of moderate-to-severe opioid use disorder (OUD). Among patients with OUD, those who inject or use high doses of opioids likely require higher doses of buprenorphine to maximize treatment efficacy. The objective of this analysis was to compare the efficacy and safety of 100-mg versus 300-mg maintenance doses of BUP-XR in OUD patients who inject opioids.

METHODS

This was a secondary analysis of a randomized, double-blind, placebo-controlled study in which adults with moderate or severe OUD received monthly injections of BUP-XR (2 × 300-mg doses, then 4 × 100-mg or 300-mg maintenance doses) or placebo for 24 weeks. Abstinence was defined as opioid-negative urine drug screens combined with negative self-reports collected weekly. Each participant's percentage abstinence was calculated after the first, second, and third maintenance doses in opioid-injecting and non-injecting participants. The proportion of participants achieving opioid abstinence in each group was also calculated weekly. Treatment retention rate following the first maintenance dose was estimated for opioid-injecting participants with Kaplan-Meier method. Risk-adjusted comparisons were made via inverse propensity weighting using propensity scores. Buprenorphine plasma concentration-time profiles were compared between injecting and non-injecting participants. The percentages of participants reporting treatment-emergent adverse events were compared between maintenance dose groups within injecting and non-injecting participants separately.

RESULTS

BUP-XR 100-mg and 300-mg maintenance doses were equally effective in non-injecting participants. However, in opioid-injecting participants, the 300-mg maintenance dose delivered clinically meaningful improvements over the 100-mg maintenance dose for treatment retention and opioid abstinence. Exposure-response analyses confirmed that injecting participants would require higher buprenorphine plasma concentrations compared to non-injecting opioid participants to achieve similar efficacy in terms of opioid abstinence. Importantly, both 100- and 300-mg maintenance doses had comparable safety profiles, including hepatic safety events.

CONCLUSIONS

These analyses show clear benefits of the 300-mg maintenance dose in injecting participants, while no additional benefit was observed in non-injecting participants relative to the 100-mg maintenance dose. This is an important finding as opioid-injecting participants represent a high-risk and difficult-to-treat population. Optimal buprenorphine dosing in this population might facilitate harm reduction by improving abstinence and treatment retention.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02357901.

Superiority and cost-effectiveness of monthly extended-release buprenorphine versus daily standard of care medication: a pragmatic, parallel-group, open-label, multicentre, randomised, controlled, phase 3 trial

Background

Daily methadone maintenance or buprenorphine treatment is the standard-of-care (SoC) medication for opioid use disorder (OUD). Subcutaneously injected, extended-release buprenorphine (BUP-XR) may be more effective-but there has been no superiority evaluation.

Methods

This pragmatic, parallel-group, open-label, multi-centre, effectiveness superiority randomised, controlled, phase 3 trial was conducted at five National Health Service community-based treatment clinics in England and Scotland. Participants (adults aged ≥ 18 years; all meeting DSM-5 diagnostic criteria for moderate or severe OUD at admission to their current maintenance treatment episode) were randomly assigned (1:1) to receive continued daily SoC (liquid methadone (usual dose range: 60-120 mg) or sublingual/transmucosal buprenorphine (usual dose range: 8-24 mg) for 24 weeks; or monthly BUP-XR (Sublocade;® two injections of 300 mg, then four maintenance injections of 100 mg or 300 mg, with maintenance dose selected by response and preference) for 24 weeks. In the intent-to-treat population (senior statistician blinded to blinded to treatment group allocation), and with a seven-day grace period after randomisation, the primary endpoint was the count of days abstinent from non-medical opioids between days 8-168 (i.e., weeks 2-24; range: 0-161 days). Safety was reported for the intention-to- treat population. Adopting a broad societal perspective inclusive of criminal justice, NHS and personal social service costs, a trial-based cost-utility analysis estimated the Incremental Cost-effectiveness Ratio (ICER) per quality-adjusted life year (QALY) of BUP-XR versus SoC at the National Institute for Health and Care Excellence threshold. The study was registered EudraCT (2018-004460-63) and ClinicalTrials.gov (NCT05164549), and is completed.

Findings

Between Aug 9, 2019 and Nov 2, 2021, 314 participants were randomly allocated to receive SoC (n = 156) or BUP-XR (n = 158). Participants were abstinent from opioids for an adjusted mean of 104.37 days (standard error [SE] 9.89; range: 0-161 days) in the SoC group and an adjusted mean of 123.43 days (SE 4.76; range: 24-161 days) in the BUP-XR group (adjusted incident rate ratio [IRR] 1.18, 95% confidence interval [CI] 1.05-1.33; p-value 0.004). The incidence of any adverse event was higher in the BUP-XR group than the SoC group (128 [81.0%] of 158 participants versus 67 [42.9%] of 156 participants, respectively-most commonly rapidly-resolving (mild-moderate range) pain from drug administration in the BUP-XR group (121 [26.9%] of 450 adverse events). There were 11 serious adverse events (7.0%) in the 158 participants in the BUP-XR group, and 18 serious adverse events (11.5%) in the 156 participants in the SoC group-none judged to be related to study treatment. The BUP-XR treatment group had a mean incremental cost of £1033 (95% central range [CR] -1189 to 3225) and was associated with a mean incremental QALY of 0.02 (95% CR 0.00-0.05), and an ICER of £47,540 (0.37 probability of being cost-effective at the £30,000/QALY gained willingness-to-pay threshold). However, BUP-XR dominated the SoC among participants who were rated more severe at study baseline, and among participants in maintenance treatment for more that 28 days at study enrolment.

Interpretation

Evaluated against the daily oral SoC, monthly BUP-XR is clinically superior, delivering greater abstinence from opioids, and with a comparable safety profile. BUP-XR was not cost-effective in a base case cost-utility analysis using the societal perspective, but it was more effective and less costly (dominant) among participants with more severe OUD, or those whose current treatment episode was longer than 28 days. Further trials are needed to evaluate if BUP-XR is associated with better clinical and health economic outcomes over the longer term.

Funding

Indivior.

Evidence on Buprenorphine Dose Limits: A Review

OBJECTIVES

As overdose deaths from fentanyl continue to increase, optimizing use of medications for opioid use disorder has become increasingly important. Buprenorphine is a highly effective medication for reducing the risk of overdose death, but only if a patient remains in treatment. Shared decision making between prescribers and patients is important to establish a dose that meets each patient's treatment needs. However, patients frequently face a dose limit of 16 or 24 mg/d based on dosing guidelines on the Food and Drug Administration's package label.

METHODS

This review discusses patient-centered goals and clinical criteria for determining dose adequacy, reviews the history of buprenorphine dose regulation in the United States, examines pharmacological and clinical research results with buprenorphine doses up to 32 mg/d, and evaluates whether diversion concerns justify maintaining a low buprenorphine dose limit.

RESULTS

Pharmacological and clinical research results consistently demonstrate buprenorphine's dose-dependent benefits up to at least 32 mg/d, including reductions in withdrawal symptoms, craving, opioid reward, and illicit use while improving retention in care. Diverted buprenorphine is most often used to treat withdrawal symptoms and reduce illicit opioid use when legal access to it is limited.

CONCLUSIONS

In light of established research and profound harms from fentanyl, the Food and Drug Administration's current recommendations on target dose and dose limit are outdated and causing harm. An update to the buprenorphine package label with recommended dosing up to 32 mg/d and elimination of the 16 mg/d target dose would improve treatment effectiveness and save lives.

Rapid induction onto extended-release injectable buprenorphine following opioid overdose: A case series

Background

Buprenorphine treatment has been associated with reduced non-prescribed opioid use and opioid related overdose (OD). We evaluated initial outcomes of rapid induction onto extended-release injectable buprenorphine (BUP-XR) within 7 days of emergency department presentation for unintentional OD.

Methods

Between February 2019-February 2021, N = 19 patients with opioid use disorder received buprenorphine/naloxone (4/1 mg), followed by BUP-XR (300 mg) at induction and continued BUP-XR outpatient for 6 months. Primary outcomes included adverse events, repeat OD, and death.

Results

For patients who received at least one dose of BUP-XR, there were no treatment related serious adverse events or symptoms of precipitated withdrawal. In addition, there were no repeat visits for ODs or deaths within 6 months of the initial OD.

Discussion

These preliminary findings support the need for larger controlled clinical trials to examine the safety and efficacy of rapid induction of BUP-XR in patients with opioid use disorder at high risk of opioid OD. Rapid induction onto long-lasting injectable buprenorphine may be a promising and protective treatment approach in the future.

History of the discovery, development, and FDA-approval of buprenorphine medications for the treatment of opioid use disorder

Buprenorphine-based medications were first approved by the United States Food and Drug Administration in 2002 for the treatment of opioid dependence, or opioid use disorder (OUD) as the condition is presently known. This regulatory milestone was the outcome of 36 years of research and development, which also led to the development and approval of several other new buprenorphine-based medications. In this short review, we first describe the discovery and early development stages of buprenorphine. Second, we review key steps that led to the development of buprenorphine as a drug product. Third, we explain the regulatory approval of several buprenorphine-based medications for the treatment of OUD. We also discuss these developments in the context of the evolution of regulations and policies that have progressively improved OUD treatment availability and efficacy, although challenges remain in removing system-level, provider-level, and local-level barriers to quality treatment, to integrating OUD treatment into routine care and other settings, to reducing disparities in access to treatment, and to optimizing person-centered outcomes.