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

Effectiveness of long-acting buprenorphine - A systematic review

ObjectiveTo analyse the evidence of the effectiveness of long-acting injection buprenorphine (LAI-B) in the management of opioid use disorder (OUD).MethodDatabases were searched for studies reporting on the effectiveness of LAI-B for the treatment of OUD. Risk of bias was assessed, and a narrative synthesis of data was presented. The study adhered to PRISMA guidelines and was registered with PROSPERO (CRD42023396033).ResultsEighteen studies were included in the final review: two double-blind randomised control trials, two open-label randomised control trials, two retrospective cohort studies, one non-controlled pilot study, and eleven observational studies. In comparative trials, LAI-B was superior to placebo and superior or non-inferior to treatment as usual. LAI-B was positively associated with improvements in abstinence rates and patient-centred outcomes. There was limited data on the long-term effects of continuous LAI-B prescription.ConclusionLAI-B is an effective treatment for OUD with advantages over existing forms of treatment. Patients reported high levels of medication satisfaction and there were no significant safety concerns. This review highlights the need for future research on long-term effectiveness outcomes, with participants of more varied demographics and psychiatric comorbidity, which is more reflective of the OUD population seen in community clinical settings.

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.

Case report: Local anesthesia with lidocaine infiltration for extended-release buprenorphine therapy

Background

Extended-release buprenorphine (BUP-XR) is a once-monthly subcutaneous injection for the treatment of opioid use disorder. Injection-site pain is a common adverse event reported with BUP-XR administration. Notwithstanding the advantages of BUP-XR, subjective pain and anxiety associated with injections can compromise patients' willingness to receive treatment. Lidocaine is an amide-type agent and sodium channel blocker commonly used for local and regional anesthesia in various fields of medicine.

Case presentation

We present two cases involving lidocaine infiltration to the induction phase of BUP-XR therapy in an outpatient setting. Prior to the intervention, 2 mL of 1% lidocaine was infiltrated subcutaneously at the sites of the planned needle insertion for a numbing effect. The following BUP-XR therapy was well tolerated by both participants and reported as a painless procedure.

Conclusions

Lidocaine infiltration may be a feasible way to successfully initiate and provide BUP-XR therapy to those who may be deterred by injection-related risks. Our cases describe how lidocaine can be useful in mitigating injection-site pain and encouraging greater uptake, and in turn, greater retention in opioid agonist therapy.

Provider costs of treating opioid dependence with extended-release buprenorphine in Australia

INTRODUCTION

The costs of providing medication-assisted treatment for opioid dependence can determine its scale of provision. To provide estimates of the costs of extended-release buprenorphine (BUP-XR), we performed a bottom-up costing analysis of provider operational treatment costs.

METHODS

Data were collected in a single-arm open label trial of BUP-XR injections conducted in specialist public drug treatment services and primary care private practices in three Australian states (the CoLAB study). The unit costs of resources used for each activity were combined with quantities used at each participating facility to arrive at the average annual cost per client.

RESULTS

One hundred participants across the six health facility sites received monthly subcutaneous BUP-XR injections administered by a health-care practitioner. The average cost of providing 1 year of treatment per participant was $6656 ($6026-$8326). Screening cost (initial assessment and medical history) was $282 while monthly follow-up appointments cost $531 per client. The main cost driver was the monthly treatment costs accounting for 79% of the average annual client cost, with medication costs comprising 95% of this cost.

DISCUSSION AND CONCLUSION

With medication costs making up the largest proportion of treatment costs, treatment using BUP-XR has the potential to free up other health system resources, for example, staff time. The costs reported in this study can be used in an economic evaluation to estimate the net benefit or cost-effectiveness of BUP-XR especially when compared to other opioid agonist treatments.

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.

Methadone and Buprenorphine in the Perioperative Setting: A Review of the Literature

PURPOSE OF REVIEW

The purpose of this review is to highlight the most recent literature and guidelines regarding perioperative methadone and buprenorphine use.

RECENT FINDINGS

Surgical patients taking methadone and buprenorphine are being encountered more frequently in the perioperative period, and providers are becoming more familiar with their pharmacologic properties, benefits as well as precautions. Recommendations pertaining to buprenorphine therapy in the perioperative settings have changed in recent years, owing to more clinical and basic science research. In addition to their use in chronic pain and opioid use disorders, they can also be initiated for acute postoperative pain indications, in select patients and situations. Methadone and buprenorphine are being more commonly prescribed for pain management and opioid use disorder, and their continuation during the perioperative period is generally recommended, to reduce the risk of opioid withdrawal, relapse, or inadequately controlled pain. Additionally, both may be initiated safely and effectively for acute pain management during and after the operating room period.

Perceptions of extended-release buprenorphine among people who received medication for opioid use disorder in jail: a qualitative study

BACKGROUND

Incarceration provides an opportunity for health interventions, including opioid use disorder (OUD) treatment and prevention of opioid-related overdoses post-release. All FDA-approved forms of medication for OUD (MOUD) treatment were mandated in several Massachusetts jails in 2019, with some jails offering extended-release buprenorphine (XR-Bup). Little is known about patient perspectives on and experiences with XR-Bup in carceral settings.

METHODS

We conducted semi-structured interviews in 2022 with community-dwelling people who received MOUD during a recent incarceration in a Massachusetts jail. We asked participants about their experiences with and perspectives on XR-Bup while in jail. Qualitative data were double-coded deductively and reviewed inductively to identify emergent themes, which were structured using the Theoretical Framework of Acceptability (TFA).

RESULTS

Participants (n = 38) had a mean age of 41.5 years, were 86% male, 84% White, 24% Hispanic, and 95% continued to receive MOUD at the time of their interview, including 11% receiving XR-Bup. Participants who viewed XR-Bup favorably appreciated avoiding the taste of sublingual buprenorphine; avoiding procedural difficulties and indignities associated with daily dosing in carceral settings (e.g., mouth checks, stigmatizing treatment from correctional staff); avoiding daily reminders of their addiction; experiencing less withdrawal; having extra time for other activities, such as work; and reduction of diversion of MOUD within the jail setting. Participants who viewed XR-Bup less favorably preferred to maintain their daily dosing routine; liked daily time out of their housing unit; wanted to know what was "going into my body everyday"; and feared needles and adverse events. Participants also reported that jail clinicians used XR-Bup for patients who were previously caught diverting sublingual buprenorphine, suggesting limited patient participation in decision-making around XR-Bup initiation in some jails.

CONCLUSION

People who received MOUD in Massachusetts jails had both favorable and unfavorable views and experiences with XR-Bup. Understanding these preferences can inform protocols in jails that are considering implementation of XR-Bup treatment.

Reduced emergency department use among insured individuals receiving extended-release buprenorphine in a health system setting

Introduction

Extended-release buprenorphine (XR-Bup) is associated with reduced opioid use and opioid negative urine drug screens. Little is known about its use in outpatient addiction care provided within health systems.

Methods

Individuals prescribed XR-Bup were identified from electronic health records; chart abstraction was conducted. Primary outcome was all-cause emergency department (ED) use. Secondary outcomes included ED use or inpatient stays for mental health or substance use, ED use for any other cause, discontinuation reasons, and drug substitution. Statistical comparisons used nonparametric tests from related samples (McNemar's test and Wilcoxon matched pair tests) to test outcomes six months prior and 6 months following XR-Bup initiation.

Results

152 individuals had an XR-Bup order, 126 received >1 injection. Among those consistently insured 6 months prior to and following XR-Bup initiation (n=99), the mean number of injections following initiation was 3.95; one-third received 6 doses in the 6 months. The proportion of individuals using ED services for all causes declined (41% prior vs. 28% following XR-Bup initiation, p<.05); similar results were found for secondary ED use outcomes. The proportion of individuals requiring inpatient treatment for mental health or substance use also declined (46% vs. 16%, p<.01). Common reasons for discontinuing XR-Bup included losing insurance (21%) or cost (11%). The most common non-prescribed substances used during treatment were opioids (n=31) and THC (n=20).

Conclusions

In this non-randomized retrospective observational study, use of XR-Bup was associated with reduced ED use 6 months following initiation. XR-Bup may help health systems reduce use of costly ED services.

Long-acting injectable buprenorphine in the real world: case report on dual disorders

OBJECTIVES

Long-acting injectable buprenorphine (LAIB) has demonstrated a good profile for opioid use disorder (OUD) management. However, there is scarce information on LAIB in OUD patients with comorbid mental disorders (dual disorder patients).

METHODS

We present a case report on OUD patients with a comorbid mental disorder who have received LAIB for at least 3 months.

RESULTS

Two women and one man with OUD and another comorbid mental disorder were prescribed with LAIB ranging from three to twelve months. Good adherence and opioid abstinence were observed during the follow-up. Psychopathological issues related to comorbid mental disorders were stabilized. A deep discussion on LAIB in this profile of patients is conducted.

CONCLUSIONS

LAIB in OUD patients with comorbid mental disorders may be a safe and well tolerated option, similar to OUD patients without comorbid mental disorders. LAIB's impact on psychopathological issues requires further high-quality research to understand the real impact of LAIB on OUD and comorbid mental disorders.

96-week retention in treatment with extended-release subcutaneous buprenorphine depot injections among people with opioid dependence: Extended follow-up after a single-arm trial

BACKGROUND

The most recent formulation of buprenorphine treatment is extended-release depot injections (BUP-XR) that are administered subcutaneously by health care professionals. This study aimed to observe treatment outcomes of BUP-XR delivered in standard practice during a 96-week follow-up period in a community setting.

METHODS

This study is an extension of the CoLAB study, a prospective single-arm, multicentre, open label trial (N=100, 7 sites in Australia) among people with opioid dependence who received monthly injections of BUP-XR to evaluate the retention in treatment. Participants were followed for 96 weeks, comprising 48 weeks of the CoLAB study followed by a 48-week extension.

RESULTS

Of 100 participants at baseline, 47 were retained on BUP-XR at 96 weeks. The median time retained on monthly depot was 90 weeks. Heroin use (adjusted OR=0.19, P=0.012) in the month prior to baseline was associated with lower odds of retention on BUP-XR. Older age at first opioid use (adjusted OR= 1.08, P=0.009) and longer duration in OAT at baseline (adjusted OR= 1.12, P=0.001) were associated with increased retention. Prevalence of past four-weeks opioid use was estimated at 4% at 96 weeks of treatment (prevalence 0.04, 95%CI: 0.00-0.11) compared to 15% at baseline. Quality of life and medication treatment satisfaction improved over time for those retained in treatment.

CONCLUSION

This is one of the few studies to describe long term (96 week) retention in treatment with BUP-XR in a community setting. It displayed retention rates with 47% of participants completing 96 weeks of treatment with BUP-XR. Patient reported outcomes suggest improvements in client wellbeing.

FUNDING

Indivior.

In-situ forming biodegradable implants for sustained Fluocinolone acetonide release to the posterior eye: In-vitro and in-vivo investigations in rabbits

Delivering medication to the posterior segment of the eye presents a significant challenge. Intravitreal injection has emerged as the preferred method for drug delivery to this area. However, current injectable non-biodegradable implants for fluocinolone acetonide (FA) require surgical removal after prolonged drug release, potentially affecting patient compliance. This study aimed to develop an in-situ forming biodegradable implant (ISFBI) optimal formulation containing PLGA504H and PLGA756S (50:50 w/w%) with the additive NMP solvent. The goal was to achieve slow and controlled release of FA over a two-month period with lower burst release, following a single intravitreal injection. Through morphology, rheology, stability and in-vitro release evaluations, the optimal formulation demonstrated low viscosity (0.12-1.25 Pa. s) and sustained release of FA at a rate of 0.36 µg/day from the third day up to two months. Furthermore, histopathology and in-vivo studies were conducted after intravitreal injection of the optimal formulation in rabbits' eye. Pharmacokinetic analysis demonstrated mean residence time (MRT) of 20.02 ± 0.6 days, half-life (t1/2) of 18.80 ± 0.4 days, and clearance (Cl) of 0.29 ± 0.03 ml/h for FA in the vitreous humor, indicating sustained and slow absorption of FA by the targeted retinal tissue from vitrea over the two-month period and eliminating through the anterior section of the eye, as revealed by its presence in the aqueous humor. Additionally, FA exhibited no detection in the blood and no evidence of systemic side effects or damage on the retinal layer and other organs. Based on these findings, it can be concluded that in-situ forming injectable biodegradable PLGA implants can show promise as a long-acting and controlled-release system for intraocular drug delivery.

Pain Management in Patients With Opioid Use Disorder on Extended-release Buprenorphine: A Case Report

ABSTRACT

Persons with opioid use disorder (OUD) are receiving extended-release buprenorphine (ER-buprenorphine) for treatment of OUD. There are no clinical guidelines for management of patients with OUD on ER-buprenorphine experiencing acute or chronic pain. This case report describes 3 patient-involved, multidisciplinary approaches for pain management in various clinical scenarios, including a scheduled knee replacement, emergent surgery for an ischemic limb, and management of chronic pain from metastatic malignancy. These cases illustrate that adequate analgesia for patients who have received ER-buprenorphine is possible, and approaches can be individualized, with shared decision making between providers and patients addressing all barriers to optimize treatment outcomes. Options for acute pain management that can be considered include supplemental sublingual buprenorphine, nonopioid adjuncts, and short courses of full opioid agonists. Potential barriers that impact OUD and acute/chronic pain are provider bias, limited access to palliative care clinicians with addiction medicine training, and payor restrictions to adding sublingual buprenorphine for patients that are on ER-buprenorphine. Additional training for clinicians and other members of the health care team is recommended to improve patient-involved care of persons with OUD experiencing pain.

Characteristics, treatment patterns and retention with extended-release subcutaneous buprenorphine for opioid use disorder: A population-based cohort study in Ontario, Canada

BACKGROUND

Uptake and retention for opioid agonist treatment (OAT) remains low. Novel extended-release formulations may improve OAT accessibility by reducing the frequency of healthcare visits. Our aim was to examine uptake, characteristics, treatment patterns and retention of individuals initiating extended-release subcutaneous buprenorphine (BUP-ER), a monthly injectable OAT.

METHODS

We conducted a population-based cohort study among adults aged 18+ initiated on BUP-ER between February 3, 2020 and March 31, 2022 in Ontario, Canada. Using administrative health data, we defined continuous BUP-ER use based on repeat injections within a 56-day period and used Kaplan-Meier curves to estimate time on treatment. Among new BUP-ER recipients, we described individual and prescriber characteristics, healthcare utilization and treatment patterns.

RESULTS

2366 individuals initiated BUP-ER. The median time to BUP-ER discontinuation was 183 days (interquartile range: 66-428 days) and 52.0% of individuals were co-prescribed buprenorphine/naloxone at least once throughout the period of BUP-ER receipt. Among individuals who initiated on a dose of 300mg BUP-ER and had three or more injections, 18.8% continued to receive only 300mg doses (N=276 of 1470). Furthermore, 28.6% of those whose dose was reduced to 100mg (N=341 of 1194) had a subsequent dose increase to 300mg.

CONCLUSIONS

On average, people initiating BUP-ER discontinue within the first 6 months of treatment. While BUP-ER is likely providing an important OAT option, the high occurrence of discontinuation, supplementation with buprenorphine/naloxone, and frequent dose increases suggest inadequacy of current dosing recommendations among a proportion of individuals.

Postpartum Extended-Release Buprenorphine Tissue Necrosis

BACKGROUND

Extended-release buprenorphine (XRB) may improve medication for opioid use disorder continuation among postpartum individuals. However, obstetric clinicians have relatively little experience with XRB. We describe two cases of XRB-related tissue necrosis in postpartum individuals to highlight recommended injection technique and management strategies for this rare complication.

CASES

One patient developed tissue necrosis after her initial injection. Her wound was expectantly managed. Another patient on long-term XRB developed tissue necrosis within 1 day of injection. General surgery excised the depot. Both instances were attributed to injection of XRB intradermally rather than subcutaneously. Both patients continued monthly XRB without recurrence, suggesting that this complication is not an allergy.

CONCLUSION

Clinicians should be able to prevent, recognize, and manage tissue necrosis, a rare complication of XRB injection.

Buprenorphine for Chronic Pain Management: a Narrative Review

PURPOSE OF REVIEW

The aim of this review is to educate healthcare professionals regarding buprenorphine for the use of opioid use disorder (OUD) as well as for chronic pain management. This review provides physicians and practitioners with updated information regarding the distinct characteristics and intricacies of prescribing buprenorphine.

RECENT FINDINGS

Buprenorphine is approved by the US Food and Drug Administration (FDA) for acute pain, chronic pain, opioid use disorder (OUD), and opioid dependence. When compared to most other opioids, buprenorphine offers superior patient tolerability, an excellent half-life, and minimal respiratory depression. Buprenorphine does have notable side effects as well as pharmacokinetic properties that require special attention, especially if patients require future surgical interventions. Many physicians are not trained to initiate or manage patients on buprenorphine. However, buprenorphine offers a potentially safer alternative for medication management for patients who require chronic opioid therapy for pain or have OUD. This review provides updated information on buprenorphine for both chronic pain and OUD.

18-Month efficacy and safety analysis of monthly subcutaneous buprenorphine injection for opioid use disorder: Integrated analysis of phase 3 studies

BACKGROUND

Few studies investigate the natural history of patients on long-term treatment for opioid use disorder (OUD). We evaluated the long-term efficacy, safety, and tolerability experience of monthly extended-release buprenorphine (BUP-XR) in participants seeking treatment for OUD, via integrated analysis of phase 3 studies.

METHODS

Study 1 was a 24-week randomized, double-blind, placebo-controlled trial of participants receiving monthly injections of BUP-XR (300 mg × 2, 100 mg × 4 [n = 203] or 300 mg × 6 [n = 201]) or placebo (n = 100). Study 2 was a 48-week, open-label trial enrolling 257 participants who completed study 1 and 412 de novo participants, to receive 6 and 12 BUP-XR injections, respectively. Study 3 was a 24-week, open-label extension enrolling 208 participants who completed study 2 for 6 additional injections. We assessed opioid abstinence as the proportion of urine opioid negative participants by visit and the percentage of each participant's negative opioid assessments during the first 6 months.

RESULTS

In total, 916 participants were treated with BUP-XR or placebo. By the end of 18 months, 92.7 % of the de novo cohort and 81.8 % of the study 1 cohort were urine negative for opioids. Among early nonresponders (percentage of abstinence ≤20 %), 73.1 % were urine negative after 18 months. The longer treatment period was well tolerated, with no new safety concerns, and a low incidence of opioid withdrawal signs and symptoms, and hepatic disorder.

CONCLUSIONS

Extending BUP-XR treatment beyond 6 months sustained improvement in opioid abstinence and was well tolerated, supporting clinical benefit up to 18 months.

TRIAL REGISTRATION

NCT02357901 (study 1); NCT02510014 (study 2); NCT02896296 (study 3).

Integrating long-acting injectable treatment to improve medication adherence among persons living with HIV and opioid use disorder: study protocol

BACKGROUND

Oral antiretroviral therapy (ART) has been effective at reducing mortality rates of people with HIV. However, despite its effectiveness, people who use drugs face barriers to maintaining ART adherence. Receipt of opioid agonist treatment, in the context of HIV care, is associated with medication adherence and decreased HIV viral loads. Recent pharmacological advancements have led to the development of novel long-acting, injectable, medications for both HIV (cabotegravir co-administered with rilpivirine) and OUD (extended-release buprenorphine). These therapies have the potential to dramatically improve adherence by eliminating the need for daily pill-taking. Despite the extensive evidence base supporting long-acting injectable medications for both HIV and OUD, and clinical guidelines supporting integrated care provision, currently little is known about how these medications may be optimally delivered to this population. This paper presents the study design for the development of a clinical protocol to guide the delivery of combined treatment for HIV and OUD using long-acting injectable medications.

METHODS

The study aims are to: (1) develop a clinical protocol to guide the delivery of combined LAI for HIV and OUD by conducting in-depth interviews with prospective patients, clinical content experts, and other key stakeholders; and (2) conduct This single group, open pilot trial protocol to assess feasibility, acceptability, and safety among patients diagnosed with HIV and OUD. Throughout all phases of the study, information on patient-, provider-, and organizational-level variables will be collected to inform future implementation.

DISCUSSION

Findings from this study will inform the development of a future study to conduct a fully-powered Hybrid Type 1 Effectiveness-Implementation design.

Long-Acting Buprenorphine Formulations as a New Strategy for the Treatment of Opioid Use Disorder

Long-acting buprenorphine formulations have been recently marketed for the Opioid Agonist Treatment (OAT) of opioid use disorder (OUD) associated with medical, social, and psychological support. Their duration of action ranges from one week up to 6 months. The non-medical use of opioids is increasing with a parallel rise in lethal overdoses. Methadone and buprenorphine are the standard treatment for opioid dependence. Methadone Maintenance Treatment (MMT) is widely recognized as one of the most effective ways of reducing the risks of overdose, crime, and transmission of HIV (Human Immunodeficiency Virus) in people who use opioids; however, its effectiveness has been hindered by low rates of uptake and retention in treatment. Furthermore, both methadone and buprenorphine are widely diverted and misused. Thus, a crucial aspect of treating OUD is facilitating patients' access to treatment while minimizing substance-related harm and improving quality of life. The newly developed long-acting buprenorphine formulations represent a significant change in the paradigm of OUD treatment, allowing an approach individualized to patients' needs. Strengths of this individualized approach are improved adherence (lack of peaks and troughs in blood concentrations) and a reduced stigma since the patient doesn't need to attend their clinic daily or nearly daily, thus facilitating social and occupational integrations as the quality of life. However, less frequent attendance at the clinic should not affect the patient-physician relationship. Therefore, teleconsulting or digital therapeutic services should be developed in parallel. In addition, diversion and intravenous misuse of buprenorphine are unlikely due to the characteristics of these formulations. These features make this approach of interest for treating OUD in particular settings, such as subjects staying or when released from prison or those receiving long-term residential treatment for OUD in the therapeutic communities. The long-lasting formulations of buprenorphine can positively impact the OUD treatment and suggest future medical and logistic developments to maximize their personalized management and impact.

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.

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.

Negative allosteric modulation of CB1 cannabinoid receptor signaling suppresses opioid-mediated reward

Blockade of cannabinoid type 1 (CB₁)-receptor signaling decreases the rewarding properties of many drugs of abuse and has been proposed as an anti-addiction strategy. However, psychiatric side-effects limit the clinical potential of orthosteric CB₁ antagonists. Negative allosteric modulators (NAMs) represent a novel and indirect approach to attenuate CB₁ signaling by decreasing affinity and/or efficacy of CB₁ ligands. We hypothesized that a CB₁-NAM would block opioid reward while avoiding the unwanted effects of orthosteric CB₁ antagonists. GAT358, a CB₁-NAM, failed to elicit cardinal signs of direct CB₁ activation or inactivation when administered by itself. GAT358 decreased catalepsy and hypothermia but not antinociception produced by the orthosteric CB₁ agonist CP55,940, suggesting that a CB₁-NAM blocked cardinal signs of CB₁ activation. Next, GAT358 was evaluated using in vivo assays of opioid-induced dopamine release and reward in male rodents. In the nucleus accumbens shell, a key component of the mesocorticolimbic reward pathway, morphine increased electrically-evoked dopamine efflux and this effect was blocked by a dose of GAT358 that lacked intrinsic effects on evoked dopamine efflux. Moreover, GAT358 blocked morphine-induced reward in a conditioned place preference (CPP) assay without producing reward or aversion alone. GAT358-induced blockade of morphine CPP was also occluded by GAT229, a CB₁ positive allosteric modulator (CB₁-PAM), and absent in CB₁-knockout mice. Finally, GAT358 also reduced oral oxycodone (but not water) consumption in a two-bottle choice paradigm. Our results support the therapeutic potential of CB₁-NAMs as novel drug candidates aimed at preventing opioid reward and treating opioid abuse while avoiding unwanted side-effects.

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.

Endogenous opiates and behavior: 2020

This paper is the forty-third consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2020 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).

Skin Necrosis Following Inadvertent Dermal Injection of Extended-release Buprenorphine

INTRODUCTION

Extended-release subcutaneous buprenorphine injection is a relatively new formulation and clinicians are still gaining experience with its use. There is sparse literature available on adverse events. We describe a case of skin necrosis associated with the injection site of extended-release buprenorphine.

CASE REPORT

A 35-year-old reported immediate swelling and eventual skin breakdown near his buprenorphine injection site. He was found to have ulceration down to the subcutis with no evidence of infection. The patient followed up with dermatology and underwent debridement of the site. The injection site healed with scar formation.

DISCUSSION

Although mild to moderate adverse events related to the injection site have been reported in Phase 3 studies of extended-release buprenorphine injection, this is a rare case of skin necrosis requiring surgical intervention and excision of the depot.

CONCLUSIONS

This case highlights the potential complication of skin necrosis after inadvertent dermal of extended-release buprenorphine and reviews proper administration techniques.

Outcomes of a single-arm implementation trial of extended-release subcutaneous buprenorphine depot injections in people with opioid dependence

BACKGROUND

Opioid agonist treatment (OAT) is an effective intervention for opioid dependence. Extended-release buprenorphine injections (BUP-XR) may have additional potential benefits over sublingual buprenorphine. This single-arm trial evaluated outcomes among people receiving 48 weeks of BUP-XR in diverse community healthcare settings in Australia, permitting examination of outcomes when BUP-XR is delivered in standard practice.

METHODS

Participants were recruited from a network of specialist public drug treatment services, primary care and some private practices in three states. Following a minimum 7 days on 8-32 mg of sublingual buprenorphine (±naloxone), participants received monthly subcutaneous BUP-XR injections administered by a healthcare practitioner and completed monthly research interviews. The primary endpoint was retention in treatment at 48 weeks.

FINDINGS

Participants (n = 100) were 28% women, mean age 44 years with a long history of OAT (median 5.8 years); heroin was the most common opioid of concern (58%). Treatment retention at 24 and 48 weeks was 86% and 75%, respectively. Participants with past-month injecting drug use (OR 0.23; 95%CI: 0.09-0.61) or heroin use (OR 0.23; 95%CI: 0.08-0.65) at baseline had lower odds of being retained in treatment to 48 weeks. Reductions in multiple forms of extra-medical drug use were observed. Improvements in quality of life, participation in employment, and treatment satisfaction measures were also observed.

INTERPRETATION

This real-world implementation study of BUP-XR demonstrated high retention and treatment satisfaction. This study provides important additional data on the uptake and experience of clients, with relevance for policy makers, health service planners, administrators, and practitioners.

FUNDING

Indivior.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03809143.

Recent advances in the treatment of opioid use disorders-focus on long-acting buprenorphine formulations

Oral methadone or sublingual buprenorphine are first-line medications for pharmacotherapy of opioid use disorders (OUDs). Three long-acting buprenorphine depot or implant formulations are currently available for the treatment of OUDs: (1) CAM 2038 (Buvidal) for subcutaneous weekly and monthly application; (2) RBP-6000 (Sublocade™) as a monthly depot formulation; and (3) A six-month buprenorphine implant [Probuphine™]. The pharmacology, clinical efficacy and prospects of these medications are discussed.

Evaluation of Drug-Drug Interaction Liability for Buprenorphine Extended-Release Monthly Injection Administered by Subcutaneous Route

Buprenorphine extended‐release (BUP‐XR) formulation is a once‐monthly subcutaneous injection for the treatment of opioid use disorder (OUD). Buprenorphine undergoes extensive cytochrome P450 (CYP) 3A4 metabolism, leading to potential drug‐drug interactions (DDIs) as reported for sublingual buprenorphine. Sublingual buprenorphine is subject to first‐pass extraction, as a significant proportion of the dose is swallowed. Because subcutaneous administration avoids first‐pass extraction, the DDI with CYP3A4 inhibitors is expected to be less than the 2‐fold increase reported for the sublingual route. The objective of this analysis was to predict the magnitude of DDI following coadministration of BUP‐XR with a strong CYP3A4 inhibitor or inducer using physiologically based pharmacokinetic (PBPK) modeling. Models were developed and verified by comparing predicted and observed data for buprenorphine following intravenous and sublingual dosing. Comparison of predicted and observed pharmacokinetic (PK) profiles and PK parameters demonstrated acceptable predictive performance of the models (within 1.5‐fold). Buprenorphine plasma concentrations following administration of a single dose of BUP‐XR (300 mg) were simulated using a series of intravenous infusions. Daily coadministration of strong CYP3A4 inhibitors with BUP‐XR predicted mild increases in buprenorphine exposures (AUC, 33%‐44%; C_max, 17‐28%). Daily coadministration of a strong CYP3A4 inducer was also associated with mild decreases in buprenorphine AUC (28%) and C_max (22%). In addition, the model predicted minimal increases in buprenorphine AUC (8%‐11%) under clinical conditions of 2 weeks’ treatment with CYP3A4 inhibitors administered after initiation of BUP‐XR. In conclusion, the PBPK predictions indicate that coadministration of BUP‐XR with strong CYP3A4 inhibitors or inducers would not result in clinically meaningful interactions.

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.