Press Release

U.S. Long-Acting Naltrexone Implant Research Advances in 2026 as Two Investigational Programs Remain in Active Clinical Development

Published first-in-human data and two recruiting U.S. Phase 1 studies show continued development of implantable naltrexone, while long-acting naltrexone implants remain investigational in the United States.

NASSAU, The Bahamas, September 26, 2026 — U.S. clinical development of investigational long-acting naltrexone implants is active in 2026, with published first-in-human Phase 1 data for the iSTEP-N program and two separate recruiting early-phase U.S. studies evaluating implantable naltrexone technologies.

DeBinge reviewed current public records from ClinicalTrials.gov, NIH RePORTER, PubMed and the U.S. Food and Drug Administration to distinguish what is currently established from what remains investigational.

Published first-in-human iSTEP-N data

A first-in-human Phase 1 study of iSTEP-N was published in the Journal of Addiction Medicine on January 26, 2026. The study enrolled 16 healthy adults and primarily evaluated safety and pharmacokinetics. Participants received one 4.8 g implant, two implants totaling 9.6 g, or placebo implants and were followed for 12 weeks.

The published study reported that the 9.6 g cohort maintained mean plasma naltrexone concentrations above the study’s stated 2.0 ng/mL opioid-blockade threshold throughout the 12-week observation period. Approximately 22% of implant drug content was released over 12 weeks. Three of six participants in the 9.6 g group developed seromas that were reported to have resolved without intervention, and no serious adverse events were reported.

Because the study involved healthy volunteers and did not measure relapse, abstinence or overdose outcomes, it should not be interpreted as proof of long-term clinical effectiveness in people with opioid use disorder.

iSTEP-N Phase 1b study

ClinicalTrials.gov record NCT07064564 describes a recruiting Phase 1 study of two investigational iSTEP-N implant doses compared with monthly 380 mg extended-release injectable naltrexone in healthy adult volunteers. The study is sponsored by Akyso Therapeutics, LLC and is designed primarily to evaluate pharmacokinetics and safety over extended follow-up.

NIH RePORTER identifies Akyso Therapeutics as the awardee organization for a NIDA-supported long-acting bioabsorbable naltrexone implant development program. NIH records identify Steven M. Cohen, MD as Contact Principal Investigator/Project Leader and Jeffrey Benner as an additional Principal Investigator. Clinical study records identify Todd Bertoch, MD with CenExel JBR in Utah as a principal investigator associated with study conduct.

A separate U.S. program: BICX104

ClinicalTrials.gov record NCT07269873 describes a separate recruiting Phase 1 study of BICX104, an investigational subcutaneous naltrexone implantable pellet developed by BioCorRx Pharmaceuticals. The study evaluates BICX104 alone and in combination with bupropion and includes an extended-release injectable naltrexone comparator.

The study is focused primarily on pharmacokinetics and safety in healthy adult volunteers. NIH RePORTER identifies BioCorRx Pharmaceuticals as the awardee organization for the NIDA-funded development program and identifies Katherine Beebe DeVarney, PhD as Contact Principal Investigator/Project Leader.

What the current evidence does — and does not — show

Current U.S. regulatory position

The FDA currently lists extended-release injectable naltrexone, Vivitrol, among FDA-approved naltrexone options for opioid use disorder. Long-acting naltrexone implants are not currently listed by the FDA as an approved medication formulation for opioid use disorder in the United States.

An investigational product being studied under an Investigational New Drug pathway should not be described as FDA-approved for marketing.

Why DeBinge is publishing the update

DeBinge is publishing the review to help journalists, researchers, healthcare professionals and patients distinguish current U.S. implant research from older studies, commercial descriptions and claims that extend beyond the available evidence.

“Long-acting naltrexone research is an area where the details matter,” DeBinge said in its editorial statement. “The current U.S. studies are scientifically important, but early-phase pharmacokinetic and safety research should not be presented as completed evidence of long-term relapse-prevention effectiveness.”

Primary sources

PubMed — First-in-human iSTEP-N Phase 1 study

ClinicalTrials.gov — NCT07064564

ClinicalTrials.gov — NCT07269873

NIH RePORTER — iSTEP-N development program

NIH RePORTER — BICX104 development program

FDA — Information about Medications for Opioid Use Disorder

About DeBinge

DeBinge provides addiction-treatment information and treatment-related resources concerning recovery, relapse prevention and long-acting naltrexone. DeBinge is located in Nassau, The Bahamas. DeBinge does not operate a treatment facility in the United States.

For background research, visit the DeBinge Research Updates, Research and Newsroom.

Media enquiries

Journalists, researchers, podcast producers, universities and healthcare publications can contact DeBinge through the DeBinge contact page.