Extended-Release Naltrexone + Buprenorphine for Cocaine Use Disorder

(CURB-2 Trial)

No longer recruiting at 11 trial locations

Overseen By Peter Hendricks, PhD

Age: 18+

Sex: Any

Trial Phase: Phase 2

Sponsor: University of Texas Southwestern Medical Center

Disqualifiers: Others

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 21

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests whether a combination of two medications, extended-release naltrexone and extended-release buprenorphine (used to treat opioid use disorder), can help treat cocaine use disorder. Researchers aim to determine if these medications reduce cocaine cravings compared to a placebo (a treatment with no active drug). Individuals who use cocaine and wish to cut back or quit might be suitable candidates. Participants will receive injections over eight weeks and must adhere closely to study guidelines. As a Phase 2 trial, this research focuses on assessing the treatment's effectiveness in an initial, smaller group of people.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial team to understand any specific requirements.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that extended-release buprenorphine (XR-BUP) is generally safe and well-tolerated. In studies, participants maintained high levels of buprenorphine in their blood without major issues. However, some did not continue treatment for long, indicating that while the drug is safe for many, it might not suit everyone.

Extended-release naltrexone (XR-NTX) is another part of the treatment. The FDA has already approved it for other uses, confirming its safety. This version is administered as an injection and lasts longer in the body. Participants using XR-NTX in studies did not report any major safety concerns.

Both treatments have been used together in other studies to help reduce cocaine use without significant side effects. This combination appears safe for most people, but individual reactions can vary, as with any medical treatment. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about these treatments because they combine extended-release formulations of naltrexone and buprenorphine, which are both already known for their use in treating substance use disorders. Unlike most treatments for cocaine use disorder that rely on behavioral therapy and medications targeting dopamine pathways, this combination targets the brain's opioid system. The extended-release delivery method is particularly noteworthy as it provides a steady release of medication, reducing the need for daily dosing and potentially improving adherence. This approach could offer a new, more convenient option for those struggling with cocaine use disorder.

What evidence suggests that this trial's treatments could be effective for cocaine use disorder?

Research has shown that both extended-release naltrexone (XR-NTX) and extended-release buprenorphine (XR-BUP) can help reduce cocaine use. In this trial, participants in one arm will receive a combination of XR-NTX and XR-BUP. A previous study found that these medications effectively lowered cocaine use. Extended-release buprenorphine also helps people stay in treatment longer and reduces drug use. Another study found that extended-release naltrexone decreased alcohol use, suggesting its potential for treating substance use disorders. These findings suggest that using both treatments together could effectively address cocaine use disorder. ^{3 5 6 7 8}

Who Is on the Research Team?

Madhukar Trivedi, MD

Principal Investigator

UT Southwestern Medical Center

Are You a Good Fit for This Trial?

Adults aged 18-65 with moderate to severe Cocaine Use Disorder, who want to reduce or stop cocaine use. They must have used cocaine frequently in the past month and not be using opioids. Women should agree to birth control measures. People with certain psychiatric conditions, heart issues, liver problems, blood disorders, or those at risk for serotonin syndrome are excluded.

Inclusion Criteria

Be interested in reducing or stopping cocaine use

Be willing to comply with all study procedures and medication instructions

Exclusion Criteria

Have any condition for which, in the opinion of the site investigator or designee, study participation would not be in their best interest or that could prevent, limit, or confound the protocol-specified assessments.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

3 weeks

Varies by participant

Medication Induction

Participants are randomized and begin the 1-week medication induction phase

1 week

1 visit (in-person)

Medication

Participants receive XR-NTX and XR-BUP or placebo injections and attend clinic twice weekly for assessments

8 weeks

16 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

4 visits (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Extended Release Buprenorphine
• Extended-Release Naltrexone
• Placebo Injectable

Trial Overview

The trial is testing if a combination of extended-release naltrexone (XR-NTX) and extended-release buprenorphine (XR-BUP) is more effective than placebo injections in treating Cocaine Use Disorder over an 8-week period. Participants will be randomly assigned to receive either the medication combo or placebo.

How Is the Trial Designed?

Group I: Drug intervention (XR-NTX+XR-BUP) Experimental Treatment 2 Interventions

The study intervention is three doses of 380mg XR-NTX (Weeks 0, 3 and 6) and two doses of 300mg XR-BUP (Weeks 0, 4). Drug: XR-NTX XR-NTX: 3 intramuscular injections administered Week 0, 3, 6. Other Names: Extended Release Injectable Naltrexone Arm: Experimental Drug: XR-BUP XR-BUP: 2 subcutaneous injections administered Week 0, 4. Other Names: Extended Release Injectable Buprenorphine Arm: Experimental

Group II: Placebo Placebo Group 2 Interventions

Matched placebo injections (PBO-Inj) for the treatment of cocaine use disorder (CUD). Drug: Placebo (PLB) Injectable Placebo: 3 intramuscular injections administered Week 0, 3, 6. Other Names: Injectable matching (to XR-NTX) placebo Arm: Placebo Comparator - matched Placebo (PLB) Drug: Placebo (PLB) Injectable Placebo: 2 subcutaneous injections administered Week 0, 4. Other Names: Injectable matching (to XR-BUP) placebo Arm: Placebo Comparator - matched Placebo (PLB)

Extended Release Buprenorphine is already approved in United States, European Union for the following indications:

Approved in United States as Brixadi for:

• Moderate to severe opioid use disorder

Approved in European Union as Buvidal for:

• Opioid dependence

Approved in United States as Sublocade for:

• Moderate to severe opioid use disorder

Who Is Running the Clinical Trial?

University of Texas Southwestern Medical Center

Lead Sponsor

Trials

1,102

Recruited

1,077,000+

National Institute on Drug Abuse (NIDA)

Collaborator

Trials

2,658

Recruited

3,409,000+

Published Research Related to This Trial

In a study of 533 participants over 18 months after stopping extended-release buprenorphine injection (BUP-XR), 47% reported sustained opioid abstinence, with higher rates of abstinence linked to longer treatment durations.

More than 60% of participants showed stable or improved outcomes in health-related quality of life and mental health scores, indicating that BUP-XR has a long-term positive impact on recovery from opioid use disorder.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Continued Posttrial Benefits of Buprenorphine Extended Release: RECOVER Study Findings. Boyett, B., Nadipelli, VR., Solem, CT., et al.[2023]

In a 24-week study involving 570 patients with opioid use disorder, those who were homeless had a significantly lower relapse rate when treated with extended-release naltrexone (51.6%) compared to buprenorphine-naloxone (70.4%).

Conversely, non-homeless patients had a higher relapse rate with extended-release naltrexone (70.9%) compared to buprenorphine-naloxone (53.1%), indicating that demographic factors like homelessness can influence the effectiveness of these treatments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Sublingual Buprenorphine-Naloxone Compared With Injection Naltrexone for Opioid Use Disorder: Potential Utility of Patient Characteristics in Guiding Choice of Treatment. Nunes, EV., Scodes, JM., Pavlicova, M., et al.[2021]

In a study of 283 participants, extended-release naltrexone (XR-NTX) had lower initiation rates compared to buprenorphine-naloxone (BUP-NX) due to the requirement of completing opioid detoxification first, with 72% starting XR-NTX versus 94% for BUP-NX.

By optimizing the initiation process for XR-NTX, the cost difference between XR-NTX and BUP-NX treatment over 24-36 weeks was reduced from statistically significant to non-significant, suggesting that both treatments could be economically comparable in the long run.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cost-effectiveness implications of increasing the efficiency of the extended-release naltrexone induction process for the treatment of opioid use disorder: a secondary analysis. Murphy, SM., Jeng, PJ., McCollister, KE., et al.[2022]

In a study involving 302 participants with cocaine dependence and a history of opioid dependence, buprenorphine + naloxone (BUP) combined with extended-release injectable naltrexone (XR-NTX) showed a significant reduction in cocaine use for those receiving 16 mg/day of BUP compared to placebo, indicating its potential effectiveness in this population.

However, no significant differences were observed in the primary outcome for the 4 mg/day BUP group compared to placebo, suggesting that higher doses may be necessary for efficacy, while adherence, retention, and adverse events were similar across all groups.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Buprenorphine + naloxone plus naltrexone for the treatment of cocaine dependence: the Cocaine Use Reduction with Buprenorphine (CURB) study. Ling, W., Hillhouse, MP., Saxon, AJ., et al.[2018]

The CURB study is a multi-site, double-blind, placebo-controlled trial involving 300 participants to evaluate the safety and efficacy of sublingual buprenorphine (BUP) combined with extended-release injectable naltrexone (XR-NTX) for treating cocaine dependence in individuals with a history of opioid use disorders.

The study aims to determine if BUP can effectively reduce cocaine use while XR-NTX prevents the development of physical dependence on BUP, with participants receiving cognitive behavioral therapy alongside their medication regimen.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cocaine use reduction with buprenorphine (CURB): rationale, design, and methodology. Mooney, LJ., Nielsen, S., Saxon, A., et al.[2021]

In a study involving 570 adults with opioid use disorder, buprenorphine-naloxone was found to be more cost-effective than extended-release naltrexone, being preferred in 97% of cases at 24 weeks and 85% at 36 weeks based on quality-adjusted life-years (QALYs).

The analysis suggests that buprenorphine-naloxone is the better first-line treatment option, especially for patients needing detoxification before starting extended-release naltrexone, although the study had limitations such as a relatively short follow-up period.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cost-Effectiveness of Buprenorphine-Naloxone Versus Extended-Release Naltrexone to Prevent Opioid Relapse. Murphy, SM., McCollister, KE., Leff, JA., et al.[2020]

The new sublingual buprenorphine/naloxone tablet (Zubsolv®) has higher bioavailability and better taste, which may improve patient adherence and reduce the risk of misuse compared to the reference product (Suboxone®).

In large phase III trials lasting up to 28 days, Zubsolv® demonstrated high treatment retention rates and effectively reduced opioid cravings and withdrawal symptoms, making it a viable option for treating opioid dependence in adults and adolescents over 15 years old.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Buprenorphine/Naloxone (Zubsolv®): A Review in Opioid Dependence. Heo, YA., Scott, LJ.[2021]

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