Nalmefene implant to prevent opioid relapse
Official title: Nalmefene Implant for the Long-Term Treatment of Opioid Use Disorder
Funded at Reacx Pharmaceuticals, INC. · NIH-11262904 · Data updated 2026-11-12
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 type | NIH-funded research |
|---|---|
| Study type | NIH-funded research |
| Funding institution | Reacx Pharmaceuticals, INC. NIH-funded |
| Lab location | 1 site (South San Francisco, United States) |
| Project start | September 15, 2018 |
| Project end | January 31, 2028 |
| Funding year | 2026 |
| Award (this year) | $3,450,000 |
| NIH project number | 5UH3DA047707-04 |
| Project ID | NIH-11262904 on NIH RePORTER |
Who could benefit from this research
✓Could help
People with opioid use disorder who have completed detoxification and want long-term protection from relapse would be ideal candidates.
✕Less likely to help
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.
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.
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 gone: 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
-
Reacx Pharmaceuticals, INC.
South San Francisco, United States Active
Researchers
- Principal investigator: Patel, Rajesh a — Reacx Pharmaceuticals, INC.
- Study coordinator: Patel, Rajesh a
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About this research
- This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
- Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
- For full project details, budget, and progress reports, visit the official NIH RePORTER page.