Despite research demonstrating the efficacy of buprenorphine (BPN), effectiveness in real-world settings has been limited by shorter retention than for methadone, and the need for daily or near-daily dosing (frequently supervised in Australia). Newly developed sustained-release BPN formulations could provide rapid onset and sustained release of BPN.

Current formulations include six-monthly implants, and once-weekly or once-monthly injections, removing the need for frequent clinic or pharmacy attendance. Improved medication adherence may result in improved patient outcomes and fewer unintended consequences such as diversion, but more data are needed in real-world settings. These innovations have the potential to dramatically change the treatment settings and options for people who are opioid dependent.

The study aims to evaluate the patient outcomes following the implementation of a monthly BPN depot injection for the treatment of opioid dependence in community-based treatment settings with a focus on opioid and other illicit drug use, adherence and retention, and participants' experiences of the implementation.

Opioid agonist treatment (OAT) 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.

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 8-32mg 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 sub-studies will examine implementation barriers and facilitators at the client and provider level.

The study population is individuals diagnosed with opioid dependence who are currently receiving sublingual buprenorphine treatment at participating drug and alcohol services, express interest in receiving depot buprenorphine injections and are deemed suitable for treatment with RBP-6000 by the Investigator.

Inclusion criteria

To be eligible for the study, participants must meet all of the following inclusion criteria:

1. Voluntarily signed the informed consent form
2. Aged 18 to 65 years
3. Opioid-dependent (ICD-10) currently receiving treatment
4. Has been receiving 8-32mg sublingual buprenorphine +/- naloxone tablets/film for at least 7 days
5. Negative pregnancy test at screening and baseline in females of childbearing potential (please refer to Section 5.7 for long acting reversible contraceptive methods with efficacy considered to reasonably eliminate pregnancy potential)

Exclusion criteria

Participants who meet any of the exclusion criteria are not to be enrolled in this study:

1. Currently lactating or pregnant, or of childbearing potential and not willing to avoid becoming pregnant during the study
2. History or presence of allergic or adverse response (including rash or anaphylaxis) to buprenorphine or the ATRIGEL® Delivery System
3. Significant, medical or psychiatric conditions (other than opioid dependence), or other circumstances which, in the opinion of the Investigator, would compromise compliance with the protocol and/or patient safety. Specific conditions of interest include severe hepatic disease (Child-Pugh Class B), severe renal or respiratory disease, or severe cognitive impairment or psychiatric condition that impairs the ability to provide informed consent (e.g. psychosis, delirium, hypomania, severe depression or suicidal ideation)
4. Subjects who are currently participating in any other clinical study involving investigational medication(s)
5. Inability or unwillingness to provide informed consent or abide by the requirements of the study