Drug-drug Interaction Study of Bemnifosbuvir/Ruzasvir (BEM/RZR) and Buprenorphine/Naloxone or Methadone

April 8, 2026 updated by: Atea Pharmaceuticals, Inc.

A Phase 1, Open-Label, Two-Part, Single-Sequence Study to Evaluate the Effect of Multiple Oral Doses of BEM/RZR FDC on the Pharmacokinetics of Buprenorphine/Naloxone or Methadone in Participants on Stable Maintenance Therapy for Opiate Withdrawal

Drug-drug interaction study between Bemnifosbuvir/Ruzasvir (BEM/RZR) and Buprenorphine/Naloxone or Methadone

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

32

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Florida
      • Hollywood, Florida, United States, 33019
    • Kansas
      • Overland Park, Kansas, United States, 66212
    • New Jersey
      • Marlton, New Jersey, United States, 08053

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Must agree to use acceptable contraceptive methods through at least 90 days after the last dose of study drug.
  • Minimum body weight of 50 kg and body mass index (BMI) of 18-32 kg/ m2.
  • Willing to comply with the study requirements and to provide written informed consent.

Exclusion Criteria:

  • Infected with hepatitis B virus, hepatitis C virus, HIV.
  • Abuse of alcohol or drugs.
  • Use of other investigational drugs within 28 days prior to Day -5.
  • Concomitant use of prescription medications, or systemic over-the-counter medications (apart from methadone or buprenorphine/naloxone as assigned maintenance therapy).
  • Other clinically significant medical conditions or laboratory abnormalities.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: (n=16) buprenorphine/naloxone + BEM/RZR
Drug: Buprenorphine/Naloxone + BEM/RZR

Day -5 to Day -1:buprenorphine/naloxone as individualized QD doses up to 24mg/6mg.

Day 1 to Day 5:Individualized QD doses of buprenorphine/naloxone. Day 6 to Day 12:Individualized QD doses of buprenorphine/naloxone + BEM 550mg/RZR 180mg QD.

Day 13 Individualized QD doses of buprenorphine/naloxone.

Other Names:
  • BEM (AT-527)/RZR (AT-038)
Experimental: (n=16) methadone + BEM/RZR
Drug: Methadone +BEM/RZR
Day -5 to Day -1:methadone individualized QD doses: 30-150mg. Day 1 to Day 5:Individualized QD does of methadone. Day 6 to Day 12:Individualized QD doses of methadone + BEM 550mg/RZR 180mg QD. Day 13 Individualized QD doses of methadone.
Other Names:
  • BEM (AT-527)/RZR (AT-038)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Effect of BEM/RZR on PK of buprenorphine,norbuprenorphine and naloxone
Time Frame: Day -5 to Day 13
Cmax
Day -5 to Day 13
Effect of BEM/RZR on PK of buprenorphine,norbuprenorphine and naloxone
Time Frame: Day -5 to Day 13
AUC
Day -5 to Day 13
Effect of BEM/RZR on PK of methadone
Time Frame: Day -5 to Day 13
Cmax
Day -5 to Day 13
Effect of BEM/RZR on PK of methadone
Time Frame: Day -5 to Day 13
AUC
Day -5 to Day 13

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Atea Pharmaceuticals, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 7, 2025

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

June 1, 2026

Study Registration Dates

First Submitted

December 18, 2025

First Submitted That Met QC Criteria

December 18, 2025

First Posted (Actual)

January 2, 2026

Study Record Updates

Last Update Posted (Actual)

April 13, 2026

Last Update Submitted That Met QC Criteria

April 8, 2026

Last Verified

December 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AT-01B-013

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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