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

NCT07334886 | Completed Phase 1 FDA Drug

• 2 other identifiers: 8507-006MK-8507-006
• Study Type: interventional
• Target: 8
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Healthy

Outcome Measures

Primary Outcomes (23)

• 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.

  At designated timepoints (up to approximately 5 weeks postdose)

• FE from Urine

  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

  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

  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

  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

  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

  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)

  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)

  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)

  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)

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

  At approximately 1 week postdose

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

  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)

  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)

  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

  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

  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

  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

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

  At approximately 1 week postdose

• Plasma Total Radioactivity: t1/2

  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

  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

  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

  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

  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 Outcomes (2)

• Number of Participants Who Experience an Adverse Event (AE)

  Up to approximately 5 weeks

• Number of Participants Who Discontinue the Study Due to an AE

  Up to approximately 5 weeks

Study Arms (1)

[14C]Ulonivirine

EXPERIMENTAL

All participants receive a single oral dose of \[14C\]ulonivirine on Day 1.

Drug: [14C]Ulonivirine

Interventions

[14C]Ulonivirine DRUG

Oral Solution

Also known as: [14C]ULO, [14C]MK-8507

[14C]Ulonivirine

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

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

You may not qualify if:

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

Sponsors & Collaborators

• Merck Sharp & Dohme LLC: lead

Study Sites (1)

Fortea CRU Madison (Site 002)

Madison, Wisconsin, 53704, United States

Location

Related Links

• Merck Clinical Trials Information

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: December 31, 2025
• First Posted: January 12, 2026
• Study Start: September 17, 2025
• Primary Completion: November 11, 2025
• Study Completion: November 11, 2025
• Last Updated: January 12, 2026

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will share

Locations

US (1)