A Study of Ulonivirine (MK-8507) and Methadone in Healthy Volunteers (MK-8507-019)

NCT07595263 | Not Yet Recruiting Phase 1 FDA Drug

• 2 other identifiers: 8507-019MK-8507-019
• Study Type: interventional
• Target: 14
• Locations: 0 countries
• Sites: N/A

Brief Summary

This study is designed to determine the effect of ulonivirine (MK-8507) on methadone in the body. Participants will take methadone alone and then methadone with ulonivirine to see if ulonivirine changes how the body processes methadone.

Conditions

Healthy

Outcome Measures

Primary Outcomes (2)

• Dose-Normalized Area Under the Plasma Concentration Time Curve From 0-24 Hours Postdose (AUC0-24) of R-Methadone

  The AUC0-24 of R-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).

  Up to 24 hours post-dose

• Dose-Normalized AUC0-24 of S-Methadone

  The AUC0-24 of S-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).

  Up to 24 hours post-dose

Secondary Outcomes (12)

• Dose-Normalized Maximum Plasma Concentration (Cmax) of R-Methadone

  Up to 24 hours post-dose

• Dose-Normalized Plasma Concentration 24 Hours Postdose (C24) of R-Methadone

  24 hours post-dose

• Time to Maximum Plasma Concentration (Tmax) of R-Methadone

  Up to 24 hours post-dose

• Dose-Normalized Cmax of S-Methadone

  Up to 24 hours post-dose

• Dose-Normalized C24 of S-Methadone

  24 hours post-dose

Study Arms (1)

Methadone + Ulonivirine

EXPERIMENTAL

Participants receive a stable dose of methadone orally from Day -14 through Day 16. Methadone is co-administered with one dose of oral ulonivirine on Day 2.

Drug: Ulonivirine; Drug: Methadone

Interventions

Ulonivirine DRUG

Oral Tablet

Also known as: MK-8507

Methadone + Ulonivirine

Methadone DRUG

Oral (per local guidelines)

Methadone + Ulonivirine

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Is in good health
• Has a body mass index (BMI) between \>18 and ≤40 kg/m\^2
• Is reliably participating in a methadone maintenance program for at least 2 months prior to Day 1 and is on a documented stable dose of methadone for at least 14 days prior to Day 1

You may not qualify if:

• Has a history of cancer (malignancy)
• Has a history of significant multiple and/or severe allergies, or has had an anaphylactic reaction or significant intolerability to prescription or nonprescription drugs or food
• Has tested positive human immunodeficiency virus (HIV) or for a sexually transmitted infection at screening
• Is under the age of legal consent

Sponsors & Collaborators

• Merck Sharp & Dohme LLC: lead

Related Links

• Merck Clinical Trials Information

MeSH Terms

Interventions

ulonivirine; Methadone

Intervention Hierarchy (Ancestors)

Ketones; Organic Chemicals

Study Officials

• Medical Director

  Merck Sharp & Dohme LLC

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 12, 2026
• First Posted: May 19, 2026
• Study Start (Estimated): June 15, 2026
• Primary Completion (Estimated): January 15, 2027
• Study Completion (Estimated): January 15, 2027
• Last Updated: May 19, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share