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HealthyPhase 1NCT07334886

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

A Phase 1 study testing [14C]Ulonivirine in people with Healthy, run by Merck Sharp & Dohme LLC at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

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. Read more about this study

Who is it for?
Ages 18 to 55 years, men onlyHealthy volunteers can take part
Conditions the study is for
Healthy
What is being tested?
[14C]Ulonivirine
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
8 participants
Where
1 siteUnited States
Study dates
17 Sep 2025to 11 Nov 2025
Phase
Phase 1
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 55 years
  • Men only
  • Healthy volunteers accepted
  • Adult

Who may be able to join

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

Who cannot join

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

Trial locations and contacts

1 site in 1 country.

United States1 site

  • Fortea CRU Madison (Site 002)

    Madison, Wisconsin, 53704

Other trials in United States

About this study

Official title: 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.

Conditions
Healthy
Being tested
[14C]Ulonivirine

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • [14C]UlonivirineDrug

    Also called [14C]ULO, [14C]MK-8507

    Oral Solution

Study groups in NCT07334886
Study groupRoleWhat they receive
[14C]UlonivirineExperimentalAll participants receive a single oral dose of [14C]ulonivirine on Day 1.
Receives: Drug: [14C]Ulonivirine

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Cumulative Percentage of Total Radioactivity Recovered (FE) from Urine and Feces

    Urine and fecal samples will be collected to determine the cumulative percentage of radioactivity recovered from both urine and feces.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  2. FE from Urine

    Urine samples will be collected to determine the percent of total radioactivity recovered from urine.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  3. FE from Feces

    Fecal samples will be collected to determine the percent of total radioactivity recovered from feces.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  4. Cumulative Amount of Radioactivity Recovered from Urine

    Urine samples will be collected to determine the cumulative amount of radioactivity recovered from urine.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  5. Percent of Total Radioactive Dose Recovered from Urine

    Urine samples will be collected to determine the percent of the total radioactive dose recovered from urine.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  6. Cumulative Amount of Radioactivity Recovered from Feces

    Fecal samples will be collected to determine the cumulative amount of radioactivity recovered from feces.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  7. Percent of Total Radioactive Dose Recovered from Feces

    Fecal samples will be collected to determine the percent of the total radioactive dose recovered from feces.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  8. Plasma Ulonivirine: Area Under the Concentration-Time Curve from Time 0 to Time of the Last Concentration (AUC0-last)

    Plasma samples will be collected to determine the AUC0-last of ulonivirine.

    Measured: At designated timepoints (up to approximately 2 weeks postdose)

  9. Plasma Ulonivirine: Area Under the Concentration-Time Curve from Time 0 Extrapolated to Infinity (AUC0-inf)

    Plasma samples will be collected to determine the AUC0-inf of ulonivirine.

    Measured: At designated timepoints (up to approximately 2 weeks postdose)

  10. Plasma Ulonivirine: Maximum Observed Concentration (Cmax)

    Plasma samples will be collected to determine the Cmax of ulonivirine.

    Measured: At designated timepoints (up to approximately 2 weeks postdose)

  11. Plasma Ulonivirine: Concentration at 168 Hours Postdose (C168)

    Plasma samples will be collected to determine the C168 of ulonivirine.

    Measured: At approximately 1 week postdose

  12. Plasma Ulonivirine: Terminal Half-life (t1/2)

    Plasma samples will be collected to determine the t1/2 of ulonivirine.

    Measured: At designated timepoints (up to approximately 2 weeks postdose)

  13. Plasma Ulonivirine: Time of Maximum Observed Concentration (Tmax)

    Plasma samples will be collected to determine the Tmax of ulonivirine.

    Measured: At designated timepoints (up to approximately 2 weeks postdose)

  14. Ratio of Ulonivirine to Total Plasma Radioactivity: AUC0-last (ulonivirine)/ AUC0-last (total radioactivity)

    Plasma samples will be collected to determine the ratio of ulonivirine to total plasma radioactivity: AUC0-last (ulonivirine)/ AUC0-last (total radioactivity)

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  15. Plasma Total Radioactivity: AUC0-last

    Plasma samples will be collected to determine the AUC0-last of total radioactivity.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  16. Plasma Total Radioactivity: AUC0-inf

    Plasma samples will be collected to determine the AUC0-inf of total radioactivity.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  17. Plasma Total Radioactivity: Cmax

    Plasma samples will be collected to determine the Cmax of total radioactivity.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  18. Plasma Total Radioactivity: C168

    Plasma samples will be collected to determine the C168 of total radioactivity.

    Measured: At approximately 1 week postdose

  19. Plasma Total Radioactivity: t1/2

    Plasma samples will be collected to determine the t1/2 of total radioactivity.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  20. Plasma Total Radioactivity: Tmax

    Plasma samples will be collected to determine the Tmax of total radioactivity.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  21. Total Number of Metabolites in Plasma that Represent at least 10% of the Dose of Radioactivity

    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.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  22. Total Number of Metabolites in Urine that Represent at least 10% of the Dose of Radioactivity

    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.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

  23. Total Number of Metabolites in Feces that Represent at least 10% of the Dose of Radioactivity

    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.

    Measured: At designated timepoints (up to approximately 5 weeks postdose)

Secondary outcomes (2)

  1. Number of Participants Who Experience an Adverse Event (AE)

    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.

    Measured: Up to approximately 5 weeks

  2. Number of Participants Who Discontinue the Study Due to an AE

    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.

    Measured: Up to approximately 5 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted12 Jan 2026
  2. Study start17 Sep 2025
  3. Primary completion11 Nov 2025
  4. Study completion11 Nov 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Basic science
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
8 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07334886
Sponsor's protocol ID
8507-006
Other IDs
MK-8507-006
Status last verified
Dec 2025
First submitted
31 Dec 2025
Last updated
12 Jan 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing [14C]Ulonivirine in people with Healthy, run by Merck Sharp & Dohme LLC at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 12 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Cumulative Percentage of Total Radioactivity Recovered (FE) from Urine and Feces (time frame: At designated timepoints (up to approximately 5 weeks postdose)). The study lists 23 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07334886.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Jan 2026.

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