Nalmefene implant to prevent opioid relapse

Nalmefene Implant for the Long-Term Treatment of Opioid Use Disorder

NIH-funded research Reacx Pharmaceuticals, INC. · NIH-11262904

This project is developing a small under-the-skin nalmefene implant to help people recovering from opioid use disorder block opioid effects and lower relapse risk for six months or longer.

Quick facts

Grant typeNIH-funded research
Study typeNIH-funded research
Funding institutionReacx Pharmaceuticals, INC. NIH-funded
Lab location1 site (South San Francisco, United States)
Project IDNIH-11262904 on NIH RePORTER

What this research studies

If you're recovering from opioid use disorder, this project is building a tiny implant that a doctor places under the skin in one office visit. The implant slowly releases nalmefene, an opioid blocker, to keep opioid receptors occupied and blunt or block the effects of illicit opioids. Because it provides steady drug levels for months, it aims to remove the need for daily pills or frequent clinic visits and improve treatment adherence. The work includes testing the implant's safety, measuring drug levels in the blood over time, and tracking whether it reduces relapse and overdose compared with usual care.

Who could benefit from this research

Good fit: People with opioid use disorder who have completed detoxification and want long-term protection from relapse would be ideal candidates.

Not a fit: People currently on opioid agonist maintenance (such as methadone or buprenorphine), those who need opioids for ongoing pain, pregnant people, or anyone allergic to nalmefene or unwilling to have an implant are unlikely to benefit.

Why it matters

Potential benefit: If successful, this could provide six months or more of continuous opioid-blocking protection from a single insertion, lowering relapse and overdose risk without daily pills.

How similar studies have performed: Monthly injectable opioid antagonists (like extended-release naltrexone) have reduced relapse for some patients, but six-month antagonist implants are a newer approach with limited prior human data.

Where this research is happening

South San Francisco, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.