Sustained-Release Buprenorphine (RBP-6000) Blocks the Effects of Opioid Challenge With Hydromorphone in Subjects With Opioid Use Disorder

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.

Long-Acting Injectable Buprenorphine for Opioid Use Disorder: A Qualitative Analysis of Patients' Interpersonal Relationships during the First Year of Treatment

Introduction: Long-acting injectable buprenorphine (LAIB) is a new treatment for opioid use disorder. Drawing upon new materialism and the concept of social capital, this article provides a focused analysis of how LAIB affects, and is affected by, patients' relationships with other people. Methods: Data derive from a longitudinal qualitative study. Twenty-six people (18 males; 8 females) initiating LAIB were recruited from England and Wales (2020/2021) and interviewed up to six times each over a year (125 interviews in total). Interviews were audio-recorded, transcribed, and coded. Coded relationship data were summarized in Excel and analyzed via Iterative Categorization. Results: Core significant others who did not use substances offered participants important support with LAIB. Children and grandchildren provided motivation for LAIB, whilst other family relationships could be supportive and unsupportive. Participants wanted to avoid friends, peers and associates who might offer them substances, but valued sharing experiences with others in similar circumstances. Whilst some participants were unconcerned when treatment staff did not contact them, others were angry and upset. Those who did not continue LAIB or were lost from the study were more isolated at recruitment. Meanwhile, participants who remained on LAIB described increased sociability over time. Conclusions: Findings are consistent with ideas relating to new materialism (LAIB is part of an interacting network of material and non-material factors) and social capital (those with supportive relationships benefited more from LAIB). Interpersonal relationships need to be considered as part of routine care and should be reviewed with patients throughout the treatment journey.

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.

Estradiol and Mu opioid-mediated reward: The role of estrogen receptors in opioid use

Opioid use and opioid use disorder are characterized by sex and gender differences, and some of these differences may be mediated by differences in the hormonal milieu within and across individuals. This review focuses on the role of ovarian hormones, and particularly estradiol, on the endogenous mu opioid receptor system. There is an abundance of data indicating that estradiol influences the activity of endogenous mu opioid peptides, the activation of mu opioid receptors, and the internalization and desensitization of mu opioid receptors. These effects have functional consequences on behaviors mediated by endogenous mu opioid receptor activity and on sensitivity to mu opioid agonists and antagonists. Recent behavioral data suggest these consequences extend to mu opioid reward, and preclinical studies report that estradiol decreases self-administration of mu opioid receptor agonists across a range of experimental conditions. Data collected in human laboratory studies suggest that estradiol may have functionally similar effects in clinical populations, and thus estrogen receptors may be a potential target in the development of novel therapeutics. This review summarizes data from cellular assays to clinical trials to explore how estradiol influences mu opioid receptor activity, as well as potential ways in which estrogen receptors may be targeted to address the problems of opioid use.

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.

ASAM Clinical Considerations: Buprenorphine Treatment of Opioid Use Disorder for Individuals Using High-potency Synthetic Opioids

ABSTRACT

Treatment of opioid use disorder (OUD) with buprenorphine has evolved considerably in the last decade as the scale of the OUD epidemic has increased along with the emergence of high-potency synthetic opioids (HPSOs) and stimulants in the drug supply. These changes have outpaced the development of prospective research, so a clinical consideration document based on expert consensus is needed to address pressing clinical questions. This clinical considerations document is based on a narrative literature review and expert consensus and will specifically address considerations for changes to the clinical practice of treatment of OUD with buprenorphine for individuals using HPSO. An expert panel developed 6 key questions addressing buprenorphine initiation, stabilization, and long-term treatment for individuals with OUD exposed to HPSO in various treatment settings. Broadly, the clinical considerations suggest that individualized strategies for buprenorphine initiation may be needed. The experience of opioid withdrawal negatively impacts the success of buprenorphine treatment, and attention to its management before and during buprenorphine initiation should be proactively addressed. Buprenorphine dose and dosing frequency should be individualized based on patients' treatment needs, the possibility of novel components in the drug supply should be considered during OUD treatment, and all forms of opioid agonist treatment should be offered and considered for patients. Together, these clinical considerations attempt to be responsive to the challenges and opportunities experienced by frontline clinicians using buprenorphine for the treatment of OUD in patients using HPSOs and highlight areas where prospective research is urgently needed.

Safer opioid supply: qualitative program evaluation

BACKGROUND

As the overdose crisis in Canada continues to escalate in severity, novel interventions and programs are required. Safer Supply programs offer pharmaceutical-grade medication to people who use drugs to replace and decrease harms related to the toxic illicit drug supply. Given the paucity of research surrounding these programs, we sought to better understand the experience of being part of a Safer Supply program from the perspective of current participants.

METHODS

We completed semi-structured interviews and surveys with Safer Supply participants in Ottawa, Canada. Interviews were audio-recorded, transcribed, and analyzed thematically. Descriptive statistics were used to report survey data.

RESULTS

Participants most commonly discussed Safer Supply benefits. This included programs offering a sense of community, connection, hope for the future, and increased autonomy. Participants also described program concerns, such as restrictive protocols, inadequate drugs, and diversion.

CONCLUSIONS

Our research demonstrated that participants found Safer Supply to be effective and impactful for their substance use goals. While participants did discuss concerns about the program, overall, we found that this is an important harm reduction-based program for people who use drugs in the midst of the overdose crisis.

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.

Continued Posttrial Benefits of Buprenorphine Extended Release: RECOVER Study Findings

BACKGROUND

This analysis describes participants' opioid use disorder (OUD) outcomes for 18 months after discontinuing extended-release buprenorphine injection (BUP-XR, SUBLOCADE).

METHODS

The RECOVER (Remission From Chronic Opioid Use: Studying Environmental and Socioeconomic Factors on Recovery) study recruited participants from BUP-XR clinical trials (NCT02357901, NCT025100142, and NCT02896296) to assess whether there were sustained benefits after leaving the trial. Abstinence from opioids and from all illicit substances (excluding medical cannabis), health-related quality of life, depression, and employment were measured after BUP-XR discontinuation and change in outcomes assessed at 6, 12, and 18 months. Results were analyzed within the full cohort and by duration of BUP-XR treatment (0-2 months, 3-5 months, 6-11 months, 12 months, or 13-18 months) with and without inverse probability weights adjusting for differences in baseline characteristics.

RESULTS

Of 533 participants, 529 were assessed over the 18-month study period. Further posttrial pharmacotherapy was reported by 33% of participants. At RECOVER baseline, longer BUP-XR was associated with higher abstinence (0-2 months BUP-XR [n = 116]: 38.8%; 3-5 months BUP-XR [n = 61]: 41.0%; 6-11 months BUP-XR [n = 86]: 68.6%; 12 months BUP-XR [n = 135]: 71.9%; 18 months BUP-XR [n = 131]: 88.2%) and greater 12-Item Short Form Health Survey mental component scores. Over 60% of participants had stable or improved outcomes at 6, 12, and 18 months assessments. Overall 47% of participants self-reported sustained opioid abstinence for the full 18-month follow-up, with greater sustained abstinence associated with longer BUP-XR treatment duration. A sensitivity analysis, removing patients receiving medications for OUD, yielded similar results.

CONCLUSIONS

Participants from BUP-XR clinical trials who continued into RECOVER maintained or improved on numerous outcomes over 18 months, demonstrating the long-term positive impact of OUD pharmacotherapy.

Open-label, rapid initiation pilot study for extended-release buprenorphine subcutaneous injection

Background: For patients with opioid use disorder, buprenorphine extended-release injection (BUP-XR) achieves sustained therapeutic plasma concentrations, controls craving and withdrawal symptoms, and improves patient outcomes. Given retention challenges during transmucosal buprenorphine (BUP-TM) induction, assessing methods to quickly achieve sustained buprenorphine concentrations is important.Objectives: This open-label, single-group, single-center pilot study (NCT03993392) evaluated safety and tolerability of initiating BUP-XR following a single BUP-TM 4 mg dose.Methods: Eligible participants abstained from short and long-acting opioids for 6 and 24  hours, respectively. If the Clinical Opiate Withdrawal Scale (COWS) was ≥8, BUP-TM 4 mg was administered. Participants not exhibiting hypersensitivity, precipitated opioid withdrawal (POW), or sedation symptoms within 1 hour received BUP-XR 300 mg (assessed as inpatients for 48 hours and outpatients to Day 29). Endpoints were COWS score increase ≥6, independent adjudication of POW, and opioid use.Results: Twenty-six participants (14 male) received BUP-TM, 24 received BUP-XR, and 20 completed the study. After injection, COWS scores decreased from pre-BUP-TM baseline of 14.6 ± 4.1 to 6.9 ± 4.1 at 6 hours and 4.2 ± 3.2 at 24 hours. Most participants (62.5%) experienced maximum COWS scores pre-BUP-XR; 2 experienced a COWS score increase ≥6, occurring at 1 and 2 hours post-BUP-XR. By adjudication, 2/24 participants experienced POW. Irritability, anxiety, nausea, and pain were the most frequent adverse events (AEs) with no serious AEs.Conclusions: Results support increased flexibility for initiating BUP-XR. Initiating BUP-XR 300 mg following a single BUP-TM 4 mg dose was well tolerated. Although some participants initially experienced withdrawal symptoms after injection, significant symptomatic improvement was observed in all participants within 24 hours.

Buprenorphine exposure levels to optimize treatment outcomes in opioid use disorder

The severity of the ongoing opioid crisis, recently exacerbated by the COVID-19 pandemic, emphasizes the importance for individuals suffering from opioid use disorder (OUD) to have access to and receive efficacious, evidence-based treatments. Optimal treatment of OUD should aim at blocking the effects of illicit opioids while controlling opioid craving and withdrawal to facilitate abstinence from opioid use and promote recovery. The present work analyses the relationship between buprenorphine plasma exposure and clinical efficacy in participants with moderate to severe OUD using data from two clinical studies (39 and 504 participants). Leveraging data from placebo-controlled measures assessing opioid blockade, craving, withdrawal and abstinence, we found that buprenorphine plasma concentrations sustained at 2-3 ng/ml (corresponding to ≥70% brain mu-opioid receptor occupancy) optimized treatment outcomes in the majority of participants, while some individuals (e.g., injecting opioid users) needed higher concentrations. Our work also included non-linear mixed effects modeling and survival analysis, which identified a number of demographic, genetic and social factors modulating treatment response and retention. Altogether, these findings provide key information on buprenorphine plasma levels that optimize clinical outcomes and increase the likelihood of individual treatment success. NLM identifiers: NCT02044094, NCT02357901.

Opioid Use Disorder: Treatment Outcomes in U.S. Veterans

BACKGROUND

Substance use disorders are a leading cause of morbidity and mortality in the United States, with opioid use disorder representing a growing public health concern and economic burden. Veterans within the Veterans Health Administration are impacted by opioid use disorder.

SIGNIFICANCE

A common medication-assisted treatment is sublingual Suboxone (buprenorphine/naloxone) used in combination with behavior modification therapy. Missed Suboxone doses may lead to withdrawal and potential drug diversion. Sublocade (buprenorphine extended-release) is an alternative once-monthly subcutaneous injection administered by a healthcare provider. The purpose of this quality improvement project was to examine the effects of Sublocade on cravings in veterans with opioid use disorder.

METHODS

Veterans were considered for Sublocade monthly injections if they were enrolled in the Suboxone program, not taking Suboxone as prescribed, and disenrolled from the Suboxone program more than 2 times. Cravings were measured before and after Sublocade program enrollment.

RESULTS

Fifteen veterans were enrolled in the Sublocade program over a 12-month timeframe. Most were male (93%) with a median (range) age of 42 (33-62) years. The following were the primary opioids used before enrollment in the substance use disorder program: hydrocodone (47%), oxycodone (20%), and heroin (20%). Sublocade significantly reduced cravings (p = .001). In this small group, cravings were fully eliminated.

DISCUSSION

Recent studies have shown Sublocade effectively blocks the effects of other opioids and minimizes the risk of medication diversion that occurs with Suboxone. For these reasons, Sublocade is an alternative medication-assisted treatment for veterans with opioid use disorder.

Buprenorphine and its formulations: a comprehensive review

Buprenorphine, a novel long-acting analgesic, was developed with the intention of two purposes: analgesia and opioid use disorder. Regarding its pharmacodynamics, it is a partial agonist at mu receptors, an inverse agonist at kappa receptors, and an antagonist at delta receptors. For the purpose of analgesia, three formulations of buprenorphine were developed: IV/IM injectable formulation (Buprenex®), transdermal patch formulation (Butrans®), and buccal film formulation (Belbuca®). Related to opioid dependence, the formulations developed were subcutaneous extended release (Sublocade®), subdermal implant (Probuphine®), and sublingual tablets (Subutex®). Lastly, in order to avoid misuse of buprenorphine for opioid dependence, two combination formulations paired with naloxone were developed: film formulation (Suboxone®) and tablet formulation (Zubsolv®). In this review, we present details of each formulation along with their similarities and differences between each other and clinical considerations.

Extended-release pharmacotherapy for opioid use disorder (EXPO): protocol for an open-label randomised controlled trial of the effectiveness and cost-effectiveness of injectable buprenorphine versus sublingual tablet buprenorphine and oral liquid methadone

BACKGROUND

Sublingual tablet buprenorphine (BUP-SL) and oral liquid methadone (MET) are the daily, standard-of-care (SOC) opioid agonist treatment medications for opioid use disorder (OUD). A sizable proportion of the OUD treatment population is not exposed to sufficient treatment to attain the desired clinical benefit. Two promising therapeutic technologies address this deficit: long-acting injectable buprenorphine and personalised psychosocial interventions (PSI). This study will determine (A) the effectiveness and cost-effectiveness - monthly injectable, extended-release (BUP-XR) in a head-to-head comparison with BUP-SL and MET, and (B) the effectiveness of BUP-XR with adjunctive PSI versus BUP-SL and MET with PSI. Safety, retention, craving, substance use, quality-adjusted life years, social functioning, and subjective recovery from OUD will be also evaluated.

METHODS

This is a pragmatic, multi-centre, open-label, parallel-group, superiority RCT, with a qualitative (mixed-methods) evaluation. The study population is adults. The setting is five National Health Service community treatment centres in England and Scotland. At each centre, participants will be randomly allocated (1:1) to BUP-XR or SOC. At the London study co-ordinating centre, there will also be allocation of participants to BUP-XR with PSI or SOC with PSI. With 24 weeks of study treatment, the primary outcome is days of abstinence from non-medical opioids during study weeks 2-24 combined with up to 12 urine drug screen tests for opioids. For 90% power (alpha, 5%; 15% inflation for attrition), 304 participants are needed for the BUP-XR versus SOC comparison. With the same planning parameters, 300 participants are needed for the BUP-XR and PSI versus SOC and PSI comparison. Statistical and health economic analysis plans will be published before data-lock on the Open Science Framework. Findings will be reported in accordance with the Consolidated Standards of Reporting Trials and Consolidated Health Economic Evaluation Reporting Standards.

DISCUSSION

This pragmatic randomised controlled trial is the first evaluation of injectable BUP-XR versus the SOC medications BUP-SL and MET, with personalised PSI. If there is evidence for the superiority of BUP-XR over SOC medication, study findings will have substantial implications for OUD clinical practice and treatment policy in the UK and elsewhere.

TRIAL REGISTRATION

EU Clinical Trials register 2018-004460-63.

The introduction of a novel formulation of buprenorphine into organized health systems

Background

Effective medications for opioid use disorder (MOUD) are underutilized. This exploratory study used real-world data to analyze US distribution patterns of buprenorphine extended-release (BUP-XR) within organized health systems (OHS), including the Veterans Health Administration (VHA), Indian Health Service (IHS), criminal justice system (CJS), and integrated delivery networks (IDNs).

Methods

National BUP-XR distribution data within each OHS were available from WNS Global Services and were evaluated from July 2019 through July 2020. BUP-XR distribution data by OHS subtype (VHA, IHS, CJS, IDN) and state were aggregated and reported.

Results

The total distribution of BUP-XR increased from 6,721 units in the second half of 2019 (H2'19) to 12,925 in the first half of 2020 (H1'20). OHS distribution increased from H2'19 to H1'20 in every subtype but was primarily driven by IDN distribution growth. IDNs accounted for 73% of total units in H2'19 and continued to grow in H1'20. In H1'20, IDNs accounted for 78%, VHA for 12%, CJS for 6%, and IHS for 4%. IDN distribution for BUP-XR increased from 4,911 to 10,100 units, showing the highest growth rate of 106% within all OHS subtypes. The states with the highest total BUP-XR distribution over the 12-month period were Massachusetts (4,534), Pennsylvania (3,773), and California (1,866).

Conclusions

Overall distribution of BUP-XR, as a treatment option for OUD, is increasing; however, access to MOUD varies greatly across OHS subtypes and geography. Identifying and overcoming barriers to appropriate MOUD use is critical in addressing the opioid crisis.

A comparison of registered and published primary outcomes in clinical trials of opioid use disorder: ACTTION review and recommendations

BACKGROUND AND AIMS

Prospective trial registration can increase research integrity. This Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) review was designed to compare the primary outcomes (PO) reported in registries with associated publications for opioid use disorder (OUD) clinical trials.

DESIGN

The World Health Organization's International Clinical Trials Registry Platform (ICTRP) was searched for completed trials (2010 through 2019). Associated publications were identified and paired with trial registry data based on the publication date.

MEASUREMENTS

Reviewers independently rated the occurrence of discrepancies between the POs in the registry compared to the publication. An analysis of prospective versus retrospective registration was also completed.

FINDINGS

One-hundred and forty trials were identified in the search, and 43 registry-publication pairs evaluated. Only 34 of the 43 pairs could be examined for discrepancies because nine did not report a PO in registry and publication. Of the 34 pairs, only four met rigorous criteria for prospective trial registration and had an exact match of POs. In contrast, the majority of the 34 trials, or 80%, had inconsistent POs (e.g., registered secondary outcomes published as primary; the timing of PO not specified) and/or were retrospectively registered.

CONCLUSIONS

Many clinical trials focused on OUD have not met the standards of trial registration, such as consistent reporting of POs and prospective registration. Failure to properly register trial characteristics undermines the validity of research findings and can delay the development of life-saving treatments. Recommendations for improving prospective trial reporting practices are provided.

Perioperative Opioids, the Opioid Crisis, and the Anesthesiologist

This review summarizes current evidence related to perioperative opioid prescription fulfillment and use and discusses the role of personalized anesthesia care in mitigating opioid-related harms without compromising analgesia.

Open-label trial of a single-day induction onto buprenorphine extended-release injection for users of heroin and fentanyl

BACKGROUND AND OBJECTIVES

Fentanyl and other highly potent synthetic opioids are the leading cause of opioid overdose deaths in the United States.

METHODS

This study was an open-label, uncontrolled 12-week outpatient clinical trial to test the feasibility of a single-day induction onto extended-release buprenorphine (BXR) injection treatment for five adults (N = 5) with opioid use disorder using heroin-containing fentanyl. Participants were planned to receive three monthly BXR injections (300, 300, and 100 mg).

RESULTS

After receiving 24 mg sublingual buprenorphine (SL-BUP), all five participants received the BXR 300 mg injection on the first day of induction. All five participants were retained for the full 3-month study period postinduction and received all three scheduled BXR injections.

DISCUSSION AND CONCLUSION

This study provides preliminary evidence supporting the feasibility of inducting users of heroin-containing fentanyl onto BXR 300 mg in a single day.

SCIENTIFIC SIGNIFICANCE

The ability to administer a long-acting injection of BXR that assures therapeutic serum levels for a month on the first day of treatment contact is a promising development for the treatment of OUD.

Reprint of: Biotechnologies and the future of opioid addiction treatments

The future of treatment-including addiction treatment-is biotechnological. Depot injections, agonist/antagonist implants, deep brain stimulation, and hapten conjugate vaccines are hailed by researchers and pharmaceutical manufacturers as medicine's best hope to minimize illicit use, to decrease risk of overdose and painful withdrawal, and to prevent diversion of medicines to illicit markets. Marketing and use of new technologies reveal old tensions framing concepts of addiction and its treatment: between medical condition and disorder of the will, between criminal justice and health, and between patient choice and system control. Using the examples of depot naltrexone and implantable and injectable buprenorphine in the U.S., this essay considers the arc of long-acting opioid treatment and implications for the future. These include the rise of Vivitrol courts and "carceral prescription"-where criminal justice systems mandate medicine to lock up brain receptors much as they might lock up people themselves-as well as use of buprenorphine formulations positioned as increasing both patient benefit and provider control. We also consider lessons from debates on long-acting contraceptive technologies such as Norplant and Depo-Provera. While multiple new long-acting formulations are under development, success will be determined less by characteristics of particular formulations and more by whether or not the new technologies are accompanied by a new ethics of addiction treatment that emphasizes therapeutic alliance, concordance over compliance, and a genuine commitment to allowing patients the ability to narrate and be believed in their descriptions of their treatment experiences.

Biodistribution and efficacy of the anticancer drug, oxaliplatin palmitate acetate, in mice

Oxaliplatin palmitate acetate (OPA), a platinum (IV) oxaliplatin derivative, was previously designed with the aim to improve the platinum-based anti-cancer therapy. In this work, we further explore the potential of OPA in extensive in vitro and in vivo studies. OPA in pancreatic (BxPC3-luc), lung (NCI-H1993) and liver (Hep3B) cancer cell lines showed a higher toxicity in comparison to oxaliplatin. The in vitro release kinetic experiments of OPA from the nanoparticles (NPs) under sink conditions exhibited a very rapid profile. Furthermore, OPA cannot be considered a prodrug of oxaliplatin, based on the OPA intact molecule pharmacokinetic profile study in rats. The formation of oxaliplatin from the biodegradation of OPA ranges only from 5% to 7% and both drugs were rapidly eliminated from the plasma. Pharmacokinetics of OPA PLGA nanoparticles in mice showed that nanoparticles failed to prolong the release of OPA in the plasma and did not add any therapeutic benefit over OPA solution, as suggested by the rapid in vitro release of OPA from nanoparticles. In pancreatic xenograft BxPC3-luc cancer model, both OPA in solution and OPA nanoparticles inhibited the tumor growth, equally and significantly, as compared to oxaliplatin. In liver xenograft Hep3B cancer model, OPA solution and cisplatin demonstrated good and similar antitumor efficacy. In lung xenograft NCI-H1993 cancer model, OPA solution, with a significant antitumor efficacy, was superior to cisplatin, which did not differ from the vehicle. In conclusion, OPA may offer a promising advance in platinum-based chemotherapy against various forms of cancers in an adequate dose and schedule.

A drug-vs-food "choice" self-administration procedure in rats to investigate pharmacological and environmental mechanisms of substance use disorders

BACKGROUND

Preclinical drug self-administration procedures are commonly used to investigate expression, mechanisms, and treatment of substance use disorders.

NEW METHOD

The aims were to back-translate an intravenous drug-vs-food choice procedure primarily utilized in monkeys to male and female rats and to develop a surgical method for sustained intravenous catheter patency suitable for long-term drug-choice studies.

RESULTS

The surgical protocol resulted in a median intravenous jugular catheter patency in male and female rats of 126 days (range: 25-365 days). Drug-vs-food choice was established with opioids (fentanyl and heroin), psychostimulants (cocaine, methamphetamine, and amphetamine), and an opioid/psychostimulant mixture (fentanyl + methamphetamine). The average time from catheter implantation to stable choice behavior across all drugs was 27 sessions (range: 16-44 sessions). Choice behavior stabilized more quickly for cocaine and fentanyl than for other drugs. Manipulations of both environmental variables (e.g., response requirement or food reinforcer magnitude) and pharmacological variables (e.g., extended access drug self-administration or continuous buprenorphine treatment via osmotic pump) significantly shifted opioid-vs-food choice consistent with previous monkey studies.

COMPARISON WITH EXISTING METHODS

Duration of intravenous catheter patency in rats was suitable for long-term, within-subject drug choice studies. Effects of environmental and pharmacological manipulations in rats confirmed and extended previous results from monkeys.

CONCLUSIONS

The concordance of behavioral results between rats and monkeys using the present drug-vs-food choice procedure supports its utility to improve our basic understanding of the expression and mechanisms of substance use disorders towards to development of more effective therapeutics.

Buprenorphine implants: a model for expedited development and approval of new drugs

Regulations for new drug approvals require stringent safety testing and efficacy trial programs. The approval process for generic drugs, however, is significantly streamlined. Bioavailability data can substitute for new rounds of efficacy trials, thereby both decreasing time to approval and reducing the costs required for new studies. This regulatory choice has not been available when generic drugs are offered in a controlled release format such as a subcutaneous depot, transdermal patch or implant. The purpose of this review is to suggest that the approval of generic drugs in inert controlled release envelopes should be eligible for similar regulatory relief. Proof for this concept is provided by the example of the numerous controlled release buprenorphine products. Buprenorphine is a generic opioid used since the 1980s in tablet form to treat pain and to treat opioid addiction. Long-acting, inert delivery vehicles for the drug have become available for the same indications. Safety and bioavailability profiles of the long-acting products are the same or improved over the parent product. A review of the long-acting drugs provides compelling evidence to recommend that generic drug-controlled release products may be eligible for alternative regulatory programs.

A synthetic opioid vaccine attenuates fentanyl-vs-food choice in male and female rhesus monkeys

AIM

Opioid-targeted vaccines are under consideration as candidate Opioid Use Disorder medications. We recently reported that a fentanyl-targeted vaccine produced a robust and long-lasting attenuation of fentanyl-vs-food choice in rats. In the current study, we evaluated an optimized fentanyl-targeted vaccine in rhesus monkeys to determine whether vaccine effectiveness to attenuate fentanyl choice translated to a species with greater phylogenetic similarity to humans.

METHODS

Adult male (2) and female (3) rhesus monkeys were trained to respond under a concurrent schedule of food (1 g pellets) and intravenous fentanyl (0, 0.032-1 μg/kg/injection) reinforcement during daily 2 h sessions. Fentanyl choice dose-effect functions were determined daily and 7-day buprenorphine treatments (0.0032-0.032 mg/kg/h IV; n = 4-5) were determined for comparison to vaccine effects. Subsequently, a fentanyl-CRM₁₉₇ conjugate vaccine was administered at week 0, 3, 8, 15 over a 29-week experimental period during which fentanyl choice dose-effect functions continued to be determined daily.

RESULTS

Buprenorphine significantly decreased fentanyl choice and reciprocally increased food choice. Vaccination eliminated fentanyl choice and increased food choice in four-of-the-five monkeys. A transient and less robust vaccine effect was observed in the fifth monkey. Fentanyl-specific antibody concentrations peaked after the third vaccination to approximately 50 μg/mL while anti-fentanyl antibody affinity increased to a sustained low nanomolar level.

CONCLUSION

These results translate fentanyl vaccine effectiveness from rats to rhesus monkeys to decrease fentanyl-vs-food choice, albeit with greater individual differences observed in monkeys. These results support the potential and further clinical evaluation of this fentanyl-targeted vaccine as a candidate Opioid Use Disorder medication.

Biotechnologies and the future of opioid addiction treatments

The future of treatment-including addiction treatment-is biotechnological. Depot injections, agonist/antagonist implants, deep brain stimulation, and hapten conjugate vaccines are hailed by researchers and pharmaceutical manufacturers as medicine's best hope to minimize illicit use, to decrease risk of overdose and painful withdrawal, and to prevent diversion of medicines to illicit markets. Marketing and use of new technologies reveal old tensions framing concepts of addiction and its treatment: between medical condition and disorder of the will, between criminal justice and health, and between patient choice and system control. Using the examples of depot naltrexone and implantable and injectable buprenorphine in the U.S., this essay considers the arc of long-acting opioid treatment and implications for the future. These include the rise of Vivitrol courts and "carceral prescription"-where criminal justice systems mandate medicine to lock up brain receptors much as they might lock up people themselves-as well as use of buprenorphine formulations positioned as increasing both patient benefit and provider control. We also consider lessons from debates on long-acting contraceptive technologies such as Norplant and Depo-Provera. While multiple new long-acting formulations are under development, success will be determined less by characteristics of particular formulations and more by whether or not the new technologies are accompanied by a new ethics of addiction treatment that emphasizes therapeutic alliance, concordance over compliance, and a genuine commitment to allowing patients the ability to narrate and be believed in their descriptions of their treatment experiences.

Population Pharmacokinetics of a Monthly Buprenorphine Depot Injection for the Treatment of Opioid Use Disorder: A Combined Analysis of Phase II and Phase III Trials

Background

BUP-XR (a.k.a. RBP-6000 or SUBLOCADE™) is an extended-release subcutaneous buprenorphine formulation for the treatment of opioid use disorder. BUP-XR was designed to provide sustained buprenorphine exposure throughout the monthly dosing interval, at concentrations sufficient to control all aspects of the disease (withdrawal, craving, and blockade of opioid subjective effects).

Objectives

To characterize the population pharmacokinetics of BUP-XR based on phase II and phase III data and to evaluate whether target therapeutic concentrations were reached with the dosing regimens evaluated in the phase III program.

Methods

The population pharmacokinetic analysis included 570 subjects with opioid use disorder who received up to 12 monthly BUP-XR injections following induction with sublingual buprenorphine.

Results

In phase III studies, target therapeutic concentrations of buprenorphine were achieved from the first injection and maintained over the entire treatment duration. Buprenorphine plasma concentration–time profiles were well described by a two-compartment model, with first-order absorption for sublingual buprenorphine and a dual absorption submodel for BUP-XR. A covariate analysis evaluated the effects of subjects’ demographic characteristics, laboratory data, and genetic status regarding buprenorphine-metabolizing enzymes. Only two covariates, body mass index and body weight, were retained in the final model. Overall, their effects were not of sufficient magnitude to justify a dose adjustment. Finally, pharmacokinetic simulations showed that buprenorphine plasma concentrations decreased slowly after discontinuation of treatment and that a 2-week occasional delay in dosing would not impact efficacy, which translated into labeling claims.

Discussion

In conclusion, the present analysis led to the development of a robust population pharmacokinetic model and confirms the ability of BUP-XR to deliver and maintain therapeutic plasma concentrations over the entire treatment duration.

Electronic supplementary material

The online version of this article (10.1007/s40262-020-00957-0) contains supplementary material, which is available to authorized users.

Non-Opioid Treatments for Opioid Use Disorder: Rationales and Data to Date

Opioid use disorder (OUD) represents a major public health problem that affects millions of people in the USA and worldwide. The relapsing and recurring aspect of OUD, driven by lasting neurobiological adaptations at different reward centres in the brain, represents a major obstacle towards successful long-term remission from opioid use. Currently, three drugs that modulate the function of the opioidergic receptors, methadone, buprenorphine and naltrexone have been approved by the US Food and Drug Administration (FDA) to treat OUD. In this review, we discuss the limitations and challenges associated with the current maintenance and medication-assisted withdrawal strategies commonly used to treat OUD. We further explore the involvement of glutamatergic, endocannabinoid and orexin signaling systems in the development, maintenance and expression of addiction-like behaviours in animal models of opioid addiction, and as potential and novel targets to expand therapeutic options to treat OUD. Despite a growing preclinical literature highlighting the role of these potential targets in animal models of opioid addiction, clinical and translational studies for novel treatments of OUD remain limited and inconclusive. Further preclinical and clinical investigations are needed to expand the arsenal of primary treatment options and adjuncts to maximise efficacy and prevent relapse.

Open-label, multicentre, single-arm trial of monthly injections of depot buprenorphine in people with opioid dependence: protocol for the CoLAB study

INTRODUCTION

Opioid agonist treatment is effective for opioid dependence and newer extended-release buprenorphine (BUP-XR) injections represent a significant development. The Community Long-Acting Buprenorphine (CoLAB) study aims to evaluate client outcomes among people with opioid dependence receiving 48 weeks of BUP-XR treatment, and examines the implementation of BUP-XR in diverse community healthcare settings in Australia.

METHODS AND ANALYSIS

The CoLAB study is a prospective single-arm, multicentre, open-label trial of monthly BUP-XR injections in people with opioid dependence. Participants are being recruited from a network of general practitioner and specialist drug treatment services located in the states of New South Wales, Victoria and South Australia in Australia. Following a minimum 7 days on 8-32 mg of sublingual buprenorphine (±naloxone), participants will receive monthly subcutaneous BUP-XR injections administered by a healthcare practitioner at intervals of 28 days (-2/+14 days). The primary endpoint is participant retention in treatment at 48 weeks after treatment initiation. Secondary endpoints will evaluate dosing schedule variations, craving, withdrawal, substance use, health and well-being, and client-reported treatment experience. Qualitative and costing substudies will examine implementation barriers and facilitators at the client and provider level.

ETHICS AND DISSEMINATION

The study has received ethics approval from the St Vincent's Hospital Sydney Human Research Ethics Committee (Ref. HREC/18/SVH/221). The findings will be disseminated via publication in peer-reviewed journals, presentations at national and international scientific conferences, and in relevant community organisation publications and forums.

TRIAL REGISTRATION NUMBER

NCT03809143 PROTOCOL IDENTIFIER: CoLAB1801, V.4.0 dated 01 August 2019.

[Prolonged-release buprenorphine formulations: Perspectives for clinical practice]

Buprenorphine and methadone are the two main opioids agonist treatments approved for opioid use disorder. Buprenorphine is a partial agonist of the mu-opioid receptors, which has been merely available through sublingual form until now. In practice, the use of buprenorphine is smoother than that of methadone, and it induces reduced risks of overdose. However, sublingual buprenorphine also exposes to risks (e.g., withdrawal, misuse) and constraints (e.g., daily intake). Three new galenic formulations of prolonged-release buprenorphine (PRB) are being commercialized and should allow some improvements in patients' comfort and safety. This narrative review aims to describe the main technical features and efficacy and safety data of these PRBs, as well as patients' and professionals' expectancies and concerns, using data of the scientific literature and the regulatory texts. PRBs consist of one subcutaneous implant and two subcutaneous injection depots. Sixmo®/Probuphine® is a six-month-long implant which needs to be surgically placed and removed and is approved for subjects previously treated with a maximum daily dose of 8mg of sublingual buprenorphine, and can be used only for two successive periods of six months before the subject needs to be switched back to sublingual form. Sublocade® is a one-month-long depot formulation that is indicated in switch from sublingual buprenorphine, and which proposes only two dose schemes, i.e., 100 and 300mg monthly. Buvidal®/Brixadi® is a one-week- or one-month-long depot formulation with multiple dosages, which can be used in initiation or in switched from sublingual formulations. While opioid users report some concerns with a risk of coercive use of long-acting forms of buprenorphine, both users and professionals deem that these new specialties could be particularly appreciated in stabilized patients bothered with the daily intake of the treatments, or specific situations at risk of treatment dropout (e.g., following hospital discharge or prison release).

Prolonged-release buprenorphine formulations: Perspectives for clinical practice

Buprenorphine and methadone are the two main opioid agonist treatments approved for opioid use disorder. Buprenorphine is a partial agonist of the mu opioid receptors, which has been merely available through sublingual form until now. In practice, the use of buprenorphine is smoother than that of methadone, and it induces reduced risks of overdose. However, sublingual buprenorphine also exposes to risks (e.g., withdrawal, misuse) and constraints (e.g., daily intake). Three new galenic formulations of prolonged-release buprenorphine (PRB) are being commercialized and should allow some improvements in patients' comfort and safety. This narrative review aims to describe the main technical features and efficacy and safety data of these PRBs, as well as patients' and professionals' expectancies and concerns, using data of the scientific literature and the regulatory texts. PRBs consist of one subcutaneous implant and two subcutaneous injection depots. Sixmo®/Probuphine® is a six-month-long implant which needs to be surgically placed and removed and is approved for subjects previously treated with a maximum daily dose of 8mg of sublingual buprenorphine, and can be used only for two successive periods of six months before the subject needs to be switched back to sublingual form. Sublocade® is a one-month-long depot formulation that is indicated in switch from sublingual buprenorphine, and which proposes only two dose schemes, i.e., 100 and 300mg monthly. Buvidal®/Brixadi® is a one-week- or one-month-long depot formulation with multiple dosages, which can be used in initiation or in switched from sublingual formulations. While opioid users report some concerns with a risk of coercive use of long-acting forms of buprenorphine, both users and professionals deem that these new specialties could be particularly appreciated in stabilized patients bothered with the daily intake of the treatments, or specific situations at risk of treatment dropout (e.g., following hospital discharge or prison release).

Buprenorphine Pharmacology Review: Update on Transmucosal and Long-acting Formulations

: Buprenorphine is an effective treatment for opioid use disorder. As a high-affinity, partial agonist for the mu-opioid receptor, buprenorphine suppresses opioid withdrawal and craving, reduces illicit opioid use, and blocks exogenous opioid effects including respiratory depression. Other pharmacologic benefits of buprenorphine are its superior safety profile compared with full opioid agonists and its long half-life that allows daily or less-than-daily dosing. New and innovative buprenorphine formulations, with pharmacokinetic profiles that differ from the original tablet formulation, continue to be developed. These include higher bioavailability transmucosal tablets and films and also 6-month implantable and monthly injectable products. This growing array of available formulations allows more choices for patients and increased opportunity for clinicians to individualize treatment; thus, it is important for buprenorphine prescribers to understand these differences.

Perceptions and preferences for long-acting injectable and implantable medications in comparison to short-acting medications for opioid use disorders

Aim

Treatment for opioid use disorders has recently evolved to include long-acting injectable and implantable formulations of medications for opioid use disorder (MOUD). Incorporating patient preferences into treatment for substance use disorders is associated with increased motivation and treatment satisfaction. This study sought to assess treatment preferences for long-acting injectable and implantable MOUD as compared to short-acting formulations among individuals with OUD.

Methods

We conducted qualitative, semi-structured telephone interviews with forty adults recruited from across the United States through Craigslist advertisements and flyers posted in treatment programs. Eligible participants scored a two or greater on the heroin or opioid pain reliever sections of the Tobacco, Alcohol, Prescription Medications, and Other Substances (TAPS) Tool, indicative of a past-year OUD. Interviews were transcribed, coded, and thematically analyzed.

Results

Twenty-four participants (60%) currently or previously had been prescribed MOUD. Sixteen participants (40%) expressed general opposition to MOUD, citing concerns that MOUD is purely financial gain for pharmaceutical companies and/or a "band aid" solution replacing one drug with another, rather than a path to abstinence. Some participants expressed personal preference for long-acting injectable (n = 16/40: 40%) and implantable formulations (n = 12/40: 30%) over short-acting formulations. About half of the participants were not willing to use injectables (n = 19/40: 48%) or implantables (n = 22/40: 55%), preferring short-acting formulations. Mixed evaluations of long- and short-acting MOUD focused on considerations of medication-related beliefs (privacy, concern over an embedded foreign body), the medication-related burden (convenience, provision of structure and support, medication administration, potential side effects), and medication-taking practices (potential for non-prescribed use, control over dosage, and duration of treatment).

Conclusions

Though many participants personally prefer short-acting to long-acting MOUD, some were open to including long-acting formulations in the range of options for those with OUD. Participants felt long-acting formulations may reduce medication-related burden and the risk of diversion. Conversely, participants expressed concern about invasive administration and loss of control over their treatment. Results suggest support for expanded access to a variety of formulations of MOUD. The use of shared decision making may also help patients select the formulation best aligned with their experiences, values, and treatment goals.

Case Series: Rapid Induction Onto Long Acting Buprenorphine Injection for High Potency Synthetic Opioid Users

BACKGROUND AND OBJECTIVES

Highly potent synthetic opioids (HPSO) are increasingly responsible for opioid overdose deaths in the United States.

METHODS

In an open-label, uncontrolled trial to test the feasibility of extended-release buprenorphine (BXR) injection treatment of heroin-using individuals with opioid use disorder testing positive for HPSO, participants were enrolled and began an induction with sublingual BXR (n = 5). During the induction, ancillary medications (clonidine, clonazepam, zolpidem, and prochlorperazine) were provided for breakthrough opioid withdrawal symptoms.

RESULTS

Two participants received the BXR injection on the second day of the induction and three participants on the third day.

DISCUSSION AND CONCLUSION

All five participants were retained at least 1-month postinduction.

SCIENTIFIC SIGNIFICANCE

It may be feasible to provide BXR treatment to HPSO-positive heroin users rapidly to achieve clinical stabilization. (Am J Addict 2020;00:00-00).

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Opioid use disorder

Opioid use disorder (OUD) is a chronic relapsing disorder that, whilst initially driven by activation of brain reward neurocircuits, increasingly engages anti-reward neurocircuits that drive adverse emotional states and relapse. However, successful recovery is possible with appropriate treatment, although with a persisting propensity to relapse. The individual and public health burdens of OUD are immense; 26.8 million people were estimated to be living with OUD globally in 2016, with >100,000 opioid overdose deaths annually, including >47,000 in the USA in 2017. Well-conducted trials have demonstrated that long-term opioid agonist therapy with methadone and buprenorphine have great efficacy for OUD treatment and can save lives. New forms of the opioid receptor antagonist naltrexone are also being studied. Some frequently used approaches have less scientifically robust evidence but are nevertheless considered important, including community preventive strategies, harm reduction interventions to reduce adverse sequelae from ongoing use and mutual aid groups. Other commonly used approaches, such as detoxification alone, lack scientific evidence. Delivery of effective prevention and treatment responses is often complicated by coexisting comorbidities and inadequate support, as well as by conflicting public and political opinions. Science has a crucial role to play in informing public attitudes and developing fuller evidence to understand OUD and its associated harms, as well as in obtaining the evidence today that will improve the prevention and treatment interventions of tomorrow.

Treating Opioid Use Disorder With a Monthly Subcutaneous Buprenorphine Depot Injection: 12-Month Safety, Tolerability, and Efficacy Analysis

BACKGROUND

BUP-XR (RBP-6000 or SUBLOCADE) is the first Food and Drug Administration-approved subcutaneously administered monthly extended-release buprenorphine medication for the treatment of moderate or severe opioid use disorder. The primary objective of this phase III study was to assess the long-term safety, tolerability, and efficacy of BUP-XR.

METHODS

This open-label multicenter study in adults with moderate or severe opioid use disorder enrolled 257 participants from a previously conducted placebo-controlled, double-blind phase III study (rollover group) and 412 de novo participants not previously treated with BUP-XR. Participants received an initial injection of BUP-XR 300 mg and subsequent monthly 300 mg or 100 mg flexible doses. By study end, participants received up to 12 injections.

RESULTS

Overall, 66.8% of participants reported more than 1 treatment-emergent adverse event (TEAE). Injection-site TEAEs (13.2% of participants) were mostly mild or moderate in severity. There were no clinically meaningful changes in safety assessments. An integrated analysis of the double-blind and open-label study participants showed that the incidence of TEAEs, including injection-site TEAEs, was lower in the second 6 months of treatment versus the first 6 months. After 12 months of treatment, 61.5% of the rollover participants and 75.8% of the de novo participants were abstinent. Retention rates after 12 months were 50.6% for the participants who initiated BUP-XR in the double-blind study and 50.5% for de novo participants.

CONCLUSIONS

This study demonstrates that the clinical benefits and acceptable safety profile of BUP-XR demonstrated in the 6-month double-blind study are sustained over a 12-month open-label study, with lower incidence of TEAEs in the second 6 months of treatment.

Depot Buprenorphine Injection In The Management Of Opioid Use Disorder: From Development To Implementation

Buprenorphine has pharmacologic advantages over methadone, especially buprenorphine's better safety profile. The true significance of buprenorphine's introduction lies in returning the care of those suffering from opioid use disorder (OUD) to the hands of the physician. The clinical success of buprenorphine has been meager, in part because most physicians have not been exposed to treating these patients. For physicians inclined to treat OUD, the barriers to buprenorphine's implementation have been onerous and largely counter to the norms of medical practice. Some notable concerns pertain to buprenorphine's clinical pharmacology like street diversion, unintended use and accidental poisoning. Recently, injectable buprenorphine preparations have been introduced to mitigate these latter shortcomings. Yet, the injectable preparations' clinical and commercial success has fallen far short of expectation. Here, we review the clinical pharmacology of these products and their expected clinical advantages for the manufacturers, clinicians, policy makers and patients, and offer our perspective, as clinicians and researchers, on how things can improve. Questions remain whether clinicians are willing to overcome barriers to treat OUD using these medications.

Innovations in efforts to expand treatment for opioid use disorder

Fewer than 20% of Americans with opioid use disorder receive empirically-supported treatment. There is a critical need for innovative approaches to support expansion of evidence-based opioid treatment, particularly in rural geographic areas so impacted by the current opioid public health crisis. Doing so will require more diverse pathways into treatment, novel pharmacological tools, improved integration and efficiency among treatment modalities, and harm reduction when treatment is not available. In this invited commentary, we review exciting recent efforts to accomplish these aims as well as offer additional considerations for future clinical and research efforts to increase the availability of treatment for opioid use disorder.

Opioid users' willingness to receive prolonged-release buprenorphine depot injections for opioid use disorder

AIMS

Prolonged-release implantable and depot injection formulations of buprenorphine are very recent developments in the treatment of opioid use disorder. Such formulations remove the need for daily dosing and provide patients with sustained concentrations of buprenorphine over a period of weeks or months. We explored opioid users' personal willingness to receive prolonged-release buprenorphine depot injections and factors influencing their interest.

METHODS

The study took place in London during 2018, before depot buprenorphine was licensed for use in Europe. Thirty-six face-to-face, semi-structured qualitative interviews were conducted with people who were: i) using heroin daily and not receiving any treatment for opioid use (n = 12); or ii) prescribed daily oral buprenorphine (n = 12); or iii) prescribed daily oral methadone (n = 12). Participants were asked about their willingness to receive depot buprenorphine and were encouraged to discuss factors that might alter their opinions. Interview data were analysed following the stages of Iterative Categorization.

FINDINGS

Participants expressed a high level of willingness to receive depot buprenorphine. Their views were influenced both positively and negatively by six key features of depot buprenorphine: i) reduced contact with pharmacies and drug treatment services; ii) impact on illicit drug use and recovery; iii) the perceived effectiveness of depot buprenorphine; iv) the duration and dosage of depot buprenorphine injections; v) clinical administration of the depot buprenorphine injection; and vi) potential for side effects associated with the depot buprenorphine injection.

CONCLUSIONS

Willingness to receive a given medication is complex, individual and changeable. Opioid users seem likely to welcome greater choice and flexibility in respect of opioid agonist medications and appear more likely to accept and adhere to depot buprenorphine if it enables them to reduce their illicit drug use and facilitates their recovery. Research is now needed to assess whether patients' reported willingness to receive depot buprenorphine translates into actual uptake and adherence.

Buprenorphine Treatment for Opioid Use Disorder: An Overview

Opioid use disorder affects over 26 million individuals worldwide. There are currently three World Health Organization-recommended and US Food and Drug Administration-approved medication treatments for opioid use disorder: the full opioid agonist methadone, the opioid partial agonist buprenorphine, and the opioid receptor antagonist naltrexone. We provide a review of the use of buprenorphine for the treatment of opioid use disorder and discuss the barriers, challenges, risks, and efficacy of buprenorphine treatment vs. other treatments. Although evidence from numerous studies has shown buprenorphine to be effective for the treatment of opioid use disorder, a majority of patients with opioid use disorder do not receive buprenorphine, or any other medical treatment. We review the different formulations of buprenorphine, including newer long-acting injectable formulations that may decrease the risk of diversion and improve adherence.

Novel Formulations of Buprenorphine for Treatment of Opioid Use Disorder

Opioid use disorder (OUD) is epidemic in the United States. In addition to medical, economic, and social impairments, risk of overdose fatality is high. In 2017, there were 14,958 deaths from natural or semisynthetic opioids, 15,958 from heroin, and 29,406 from synthetic opioids, such as fentanyl. Psychosocial interventions do not add substantial efficacy to medical OUD treatments, and thus making evidence-based OUD treatments more accessible is urgent. However, considerable diversion of oral and transmucosal opioid maintenance medications has been documented. Delivery systems that reduce risks of nonadherence through diversion or altered self-administration may increase buprenorphine's effectiveness for clinical stabilization via increased treatment exposure. The article presents findings from multisite efficacy studies of two subcutaneous depot buprenorphine formulations and a long-acting implant. Novel delivery systems show promise in providing improved outcomes through intermediate- and long-acting exposure to medication while reducing the risk of medication nonadherence, diversion, and accidental exposure.

Efficacy and safety of a monthly buprenorphine depot injection for opioid use disorder: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

RBP-6000, referred to as BUP-XR (extended-release buprenorphine), is a subcutaneously injected, monthly buprenorphine treatment for opioid use disorder. BUP-XR provides sustained buprenorphine plasma concentrations to block drug-liking of abused opioids over the entire monthly dosing period, while controlling withdrawal and craving symptoms. Administration of BUP-XR in a health-care setting also mitigates abuse, misuse, diversion, and unintentional exposure. We aimed to investigate the efficacy of different BUP-XR dosing regimens in participants with opioid use disorder.

METHODS

This randomised, double-blind, placebo-controlled, phase 3 trial was done at 36 treatment centres in the USA. Treatment-seeking adults aged 18-65 years who had moderate or severe opioid use disorder (as defined by the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders) entered an open-label run-in phase of up to 2 weeks' treatment with buprenorphine-naloxone sublingual film. Eligible participants were then randomly assigned (4:4:1:1) with an interactive voice/web-response system to receive BUP-XR 300 mg/300 mg (six injections of 300 mg), BUP-XR 300 mg/100 mg (two injections of 300 mg plus four injections of 100 mg), or volume-matched placebo every 28 days, and received weekly individual drug counselling. No supplemental buprenorphine was allowed. The primary efficacy endpoint was participants' percentage abstinence from opioid use, defined as the percentage of each participant's negative urine samples and self-reports of illicit opioid use from week 5 to week 24, analysed in the full analysis set. Safety was assessed in all participants who received at least one dose of BUP-XR or placebo. This study is registered with ClinicalTrials.gov, number NCT02357901.

FINDINGS

From Jan 28, 2015, to Nov 12, 2015, 1187 potential participants were screened, 665 entered run-in, and 504 received BUP-XR 300 mg/300 mg (n=201), BUP-XR 300 mg/100 mg (n=203), or placebo (n=100). Mean participants' percentage abstinence was 41·3% (SD 39·7) for BUP-XR 300 mg/300 mg and 42·7% (38·5) for 300 mg/100 mg, compared with 5·0% (17·0) for placebo (p<0·0001 for both BUP-XR regimens). No compensatory non-opioid drug use was observed during BUP-XR treatment. The most common adverse events were headache (17 [8%] participants in the BUP-XR 300 mg/300 mg group vs 19 [9%] participants in the BUP-XR 300 mg/100 mg group vs six [6%] participants in the placebo group), constipation (16 [8%] vs 19 [9%] vs 0), nausea (16 [8%] vs 18 [9%] vs five [5%]), and injection-site pruritis (19 [9%] vs 13 [6%] vs four [4%]). The BUP-XR safety profile was consistent with other buprenorphine products for treatment of opioid use disorder, except for injection-site reactions, which were reported in more than 5% of all participants who received BUP-XR, but were mostly mild and not treatment-limiting.

INTERPRETATION

Participants' percentage abstinence was significantly higher in both BUP-XR groups than in the placebo group. Treatment with BUP-XR was also well tolerated. The availability of this monthly formulation, delivered by health-care providers, represents an advance in treatment for opioid use disorder that enhances the benefits of buprenorphine by delivering sustained, optimal exposure, while reducing risks of current buprenorphine products.

FUNDING

Indivior.

Anti-stress neuropharmacological mechanisms and targets for addiction treatment: A translational framework

Stress-related substance use is a major challenge for treating substance use disorders. This selective review focuses on emerging pharmacotherapies with potential for reducing stress-potentiated seeking and consumption of nicotine, alcohol, marijuana, cocaine, and opioids (i.e., key phenotypes for the most commonly abused substances). I evaluate neuropharmacological mechanisms in experimental models of drug-maintenance and relapse, which translate more readily to individuals presenting for treatment (who have initiated and progressed). An affective/motivational systems model (three dimensions: valence, arousal, control) is mapped onto a systems biology of addiction approach for addressing this problem. Based on quality of evidence to date, promising first-tier neurochemical receptor targets include: noradrenergic (α1 and β antagonist, α2 agonist), kappa-opioid antagonist, nociceptin antagonist, orexin-1 antagonist, and endocannabinoid modulation (e.g., cannabidiol, FAAH inhibition); second-tier candidates may include corticotropin releasing factor-1 antagonists, serotonergic agents (e.g., 5-HT reuptake inhibitors, 5-HT3 antagonists), glutamatergic agents (e.g., mGluR2/3 agonist/positive allosteric modulator, mGluR5 antagonist/negative allosteric modulator), GABA-promoters (e.g., pregabalin, tiagabine), vasopressin 1b antagonist, NK-1 antagonist, and PPAR-γ agonist (e.g., pioglitazone). To address affective/motivational mechanisms of stress-related substance use, it may be advisable to combine agents with actions at complementary targets for greater efficacy but systematic studies are lacking except for interactions with the noradrenergic system. I note clinically-relevant factors that could mediate/moderate the efficacy of anti-stress therapeutics and identify research gaps that should be pursued. Finally, progress in developing anti-stress medications will depend on use of reliable CNS biomarkers to validate exposure-response relationships.

Advances in the delivery of buprenorphine for opioid dependence

Opioid use disorders (OUDs) have long been a global problem, but the prevalence rates have increased over 20 years to epidemic proportions in the US, with concomitant increases in morbidity and all-cause mortality, but especially opioid overdose. These increases are in part attributable to a several-fold expansion in the prescription of opioid pain medications over the same time period. Opioid detoxification and psychosocial treatments alone have each not yielded sufficient efficacy for OUD, but μ-opioid receptor agonist, partial agonist, and antagonist medications have demonstrated the greatest overall benefit in OUD treatment. Buprenorphine, a μ-opioid receptor partial agonist, has been used successfully on an international basis for several decades in sublingual tablet and film preparations for the treatment of OUD, but the nature of formulation, which is typically self-administered, renders it susceptible to nonadherence, diversion, and accidental exposure. This article reviews the clinical trial data for novel buprenorphine delivery systems in the form of subcutaneous depot injections, transdermal patches, and subdermal implants for the treatment of OUD and discusses both the clinical efficacy of longer-acting formulations through increasing consistent medication exposure and their potential utility in reducing diversion. These new delivery systems also offer new dosing opportunities for buprenorphine and strategies for dosing intervals in the treatment of OUD.

Drug Formulation Advances in Extended-Release Medications for Pain Control

Prescription opioid abusers frequently tamper with opioid tablets in order to either accelerate the delivery of the euphoria-inducing agent or to alter the route of delivery, such that it may be delivered intranasally or intravenously. As one strategy to combat the opioid epidemic in the USA, drug manufacturers have begun to explore formulations which resist such tampering by abusers. Techniques to prevent tampering consist of physical barriers to crushing, chewing, and drug extraction, or aversive or antagonistic agents, incorporated within the formulation itself. Recent years have seen the development of numerous extended-release opioid agents, which are described in this review. This article provides a comprehensive summary of the pharmacology, benefits, risks, and processes behind the development of currently available extended-release opioid drugs, as well as a glimpse into promising future formulations.