A Study of Ulonivirine (MK-8507) and Methadone in Healthy Volunteers (MK-8507-019)
Healthy
What this study involves
The registry does not currently label this study as recruiting. Ask about its status before planning a screening visit.
- Study type
- Interventional
- Phase
- Phase 1
- Age range
- 18 years - 65 years
- Sex eligible
- All sexes
- Healthy volunteers
- Accepted
- Participants
- 14 Actual
These are starting points, not an eligibility decision. The research team must review the full requirements.
About the research
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.
Who may be able to participate?
The list below is the sponsor’s full registry wording. It can include conditions, prior treatment, test results and other requirements. A match in search does not mean you qualify.
Inclusion Criteria
The main Inclusion Criteria include but are not limited to:
- 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
Exclusion Criteria
The main Exclusion Criteria include but are not limited to:
- 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
Treatment, groups and participation
The registry may describe treatments and study duration without a complete visit calendar. Ask the study team for the exact schedule, procedures, risks, costs and alternatives. Keep your usual care plan unless your treating clinician tells you otherwise.
- Assignment
- Not applicable
- Masking
- No masking
Methadone + Ulonivirine
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
Ulonivirine DRUG
Oral Tablet
Methadone DRUG
Oral (per local guidelines)
What researchers are measuring
Outcome measures describe what is being studied. They are not proof that a treatment works.
Primary measures
Dose-Normalized Area Under the Plasma Concentration Time Curve From 0-24 Hours Postdose (AUC0-24) of R-Methadone
Time frame: Up to 24 hours post-dose
The AUC0-24 of R-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Dose-Normalized AUC0-24 of S-Methadone
Time frame: Up to 24 hours post-dose
The AUC0-24 of S-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Secondary measures
Dose-Normalized Maximum Plasma Concentration (Cmax) of R-Methadone
Time frame: Up to 24 hours post-dose
The Cmax of R-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Dose-Normalized Plasma Concentration 24 Hours Postdose (C24) of R-Methadone
Time frame: 24 hours post-dose
The C24 of R-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Time to Maximum Plasma Concentration (Tmax) of R-Methadone
Time frame: Up to 24 hours post-dose
The Tmax of R-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Dose-Normalized Cmax of S-Methadone
Time frame: Up to 24 hours post-dose
The Cmax of S-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Dose-Normalized C24 of S-Methadone
Time frame: 24 hours post-dose
The C24 of S-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Tmax of S-Methadone
Time frame: Up to 24 hours post-dose
The Tmax of S-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Dose-Normalized AUC0-24 of Total Methadone
Time frame: Up to 24 hours post-dose
The AUC0-24 of total methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Dose-Normalized Cmax of Total Methadone
Time frame: Up to 24 hours post-dose
The Cmax of total methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Dose-Normalized C24 of Total Methadone
Time frame: 24 hours post-dose
The C24 of total methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Tmax of Total Methadone
Time frame: Up to 24 hours post-dose
The Tmax of total methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).
Number of Participants With Adverse Events (AEs) Following Methadone + Ulonivirine Coadministration
Time frame: Up to 16 Days
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants experiencing an AE following coadministration of methadone and ulonivirine will be presented.
Number of Participants Discontinuing Study Therapy Due to AEs Following Coadministration of Methadone and Ulonivirine
Time frame: Up to 16 Days
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants discontinuing study therapy due to an AE following coadministration of methadone and ulonivirine will be presented.
Review the complete result tables and limitations in the official record.
Open official results ↗Research locations (1)
The overall study status and a local site’s status can differ. Confirm that location’s availability before traveling.
1 locations
Pinnacle Research Group ( Site 0002)Anniston, Alabama, United StatesStatus unknown
Study team and timeline
- Lead sponsor
- Merck Sharp & Dohme LLC
- Study start
- Aug 17, 2026 Actual
- Primary completion
- Sep 29, 2026 Actual
- Study completion
- Sep 29, 2026 Actual
- First posted
- May 19, 2026 Actual
- Last updated
- Nov 10, 2026 Actual
Official study contacts
No central contact is listed. Check the locations and the official record.
Official study title
A Clinical Trial to Study the Effect of a Single Dose of Ulonivirine on the Pharmacokinetics of Methadone
Ask Wellness Clinical Research
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Source: ClinicalTrials.gov API v2. Information is submitted by sponsors and investigators. NLM does not approve the safety or science of all listed studies. Registry disclaimer.
Retrieved: Nov 12, 2026 · Last registry update: Nov 10, 2026