A Study of [14C]Ulonivirine ([14C]MK-8507) in Healthy Adults (MK-8507-006)

December 31, 2025 updated by: Merck Sharp & Dohme LLC

A Study to Investigate the Absorption, Metabolism, and Excretion of [14C]Ulonivirine in Healthy Adults

The goal of this study is to learn how [14C]ulonivirine moves through a healthy person's body over time. Researchers will study how [14C]ulonivirine is absorbed by the body, broken down by the body, and how it leaves the body.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
8

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Locations

  • United States
    • Wisconsin
      • Madison, Wisconsin, United States, 53704
        • Fortea CRU Madison (Site 002)

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Key Inclusion Criteria include but are not limited to:

  • Is in good health
  • Has a body mass index (BMI) of 18 to 32 kg/m^2

Key Exclusion Criteria include but are not limited to:

  • Has a history of cancer
  • Has positive tests for hepatitis B surface antigen, hepatitis C antibodies or human immunodeficiency virus antibody

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: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: [14C]Ulonivirine
All participants receive a single oral dose of [14C]ulonivirine on Day 1.
Drug: [14C]Ulonivirine
Oral Solution
Other Names:
  • [14C]ULO
  • [14C]MK-8507

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Cumulative Percentage of Total Radioactivity Recovered (FE) from Urine and Feces
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Urine and fecal samples will be collected to determine the cumulative percentage of radioactivity recovered from both urine and feces.
At designated timepoints (up to approximately 5 weeks postdose)
FE from Urine
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Urine samples will be collected to determine the percent of total radioactivity recovered from urine.
At designated timepoints (up to approximately 5 weeks postdose)
FE from Feces
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Fecal samples will be collected to determine the percent of total radioactivity recovered from feces.
At designated timepoints (up to approximately 5 weeks postdose)
Cumulative Amount of Radioactivity Recovered from Urine
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Urine samples will be collected to determine the cumulative amount of radioactivity recovered from urine.
At designated timepoints (up to approximately 5 weeks postdose)
Percent of Total Radioactive Dose Recovered from Urine
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Urine samples will be collected to determine the percent of the total radioactive dose recovered from urine.
At designated timepoints (up to approximately 5 weeks postdose)
Cumulative Amount of Radioactivity Recovered from Feces
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Fecal samples will be collected to determine the cumulative amount of radioactivity recovered from feces.
At designated timepoints (up to approximately 5 weeks postdose)
Percent of Total Radioactive Dose Recovered from Feces
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Fecal samples will be collected to determine the percent of the total radioactive dose recovered from feces.
At designated timepoints (up to approximately 5 weeks postdose)
Plasma Ulonivirine: Area Under the Concentration-Time Curve from Time 0 to Time of the Last Concentration (AUC0-last)
Time Frame: At designated timepoints (up to approximately 2 weeks postdose)
Plasma samples will be collected to determine the AUC0-last of ulonivirine.
At designated timepoints (up to approximately 2 weeks postdose)
Plasma Ulonivirine: Area Under the Concentration-Time Curve from Time 0 Extrapolated to Infinity (AUC0-inf)
Time Frame: At designated timepoints (up to approximately 2 weeks postdose)
Plasma samples will be collected to determine the AUC0-inf of ulonivirine.
At designated timepoints (up to approximately 2 weeks postdose)
Plasma Ulonivirine: Maximum Observed Concentration (Cmax)
Time Frame: At designated timepoints (up to approximately 2 weeks postdose)
Plasma samples will be collected to determine the Cmax of ulonivirine.
At designated timepoints (up to approximately 2 weeks postdose)
Plasma Ulonivirine: Concentration at 168 Hours Postdose (C168)
Time Frame: At approximately 1 week postdose
Plasma samples will be collected to determine the C168 of ulonivirine.
At approximately 1 week postdose
Plasma Ulonivirine: Terminal Half-life (t1/2)
Time Frame: At designated timepoints (up to approximately 2 weeks postdose)
Plasma samples will be collected to determine the t1/2 of ulonivirine.
At designated timepoints (up to approximately 2 weeks postdose)
Plasma Ulonivirine: Time of Maximum Observed Concentration (Tmax)
Time Frame: At designated timepoints (up to approximately 2 weeks postdose)
Plasma samples will be collected to determine the Tmax of ulonivirine.
At designated timepoints (up to approximately 2 weeks postdose)
Ratio of Ulonivirine to Total Plasma Radioactivity: AUC0-last (ulonivirine)/ AUC0-last (total radioactivity)
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Plasma samples will be collected to determine the ratio of ulonivirine to total plasma radioactivity: AUC0-last (ulonivirine)/ AUC0-last (total radioactivity)
At designated timepoints (up to approximately 5 weeks postdose)
Plasma Total Radioactivity: AUC0-last
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Plasma samples will be collected to determine the AUC0-last of total radioactivity.
At designated timepoints (up to approximately 5 weeks postdose)
Plasma Total Radioactivity: AUC0-inf
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Plasma samples will be collected to determine the AUC0-inf of total radioactivity.
At designated timepoints (up to approximately 5 weeks postdose)
Plasma Total Radioactivity: Cmax
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Plasma samples will be collected to determine the Cmax of total radioactivity.
At designated timepoints (up to approximately 5 weeks postdose)
Plasma Total Radioactivity: C168
Time Frame: At approximately 1 week postdose
Plasma samples will be collected to determine the C168 of total radioactivity.
At approximately 1 week postdose
Plasma Total Radioactivity: t1/2
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Plasma samples will be collected to determine the t1/2 of total radioactivity.
At designated timepoints (up to approximately 5 weeks postdose)
Plasma Total Radioactivity: Tmax
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Plasma samples will be collected to determine the Tmax of total radioactivity.
At designated timepoints (up to approximately 5 weeks postdose)
Total Number of Metabolites in Plasma that Represent at least 10% of the Dose of Radioactivity
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Plasma samples will be collected at pre-specified timepoints and used to determine the total number of metabolites that represent at least 10% of the dose of radioactivity. Metabolites will be determined using liquid scintillation and high-resolution mass spectrometry.
At designated timepoints (up to approximately 5 weeks postdose)
Total Number of Metabolites in Urine that Represent at least 10% of the Dose of Radioactivity
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Urine samples will be collected at pre-specified timepoints and used to determine the total number of metabolites that represent at least 10% of the dose of radioactivity. Metabolites will be determined using liquid scintillation and high-resolution mass spectrometry.
At designated timepoints (up to approximately 5 weeks postdose)
Total Number of Metabolites in Feces that Represent at least 10% of the Dose of Radioactivity
Time Frame: At designated timepoints (up to approximately 5 weeks postdose)
Fecal samples will be collected at pre-specified timepoints and used to determine the total number of metabolites that represent at least 10% of the dose of radioactivity. Metabolites will be determined using liquid scintillation and high-resolution mass spectrometry.
At designated timepoints (up to approximately 5 weeks postdose)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of Participants Who Experience an Adverse Event (AE)
Time Frame: Up to approximately 5 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of the study intervention, whether or not considered related to the study intervention.
Up to approximately 5 weeks
Number of Participants Who Discontinue the Study Due to an AE
Time Frame: Up to approximately 5 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of the study intervention, whether or not considered related to the study intervention.
Up to approximately 5 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Merck Sharp & Dohme LLC

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 17, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 11, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 11, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 31, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 31, 2025

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 12, 2026

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 31, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 8507-006
  • MK-8507-006 (Other Identifier: MSD)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

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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