A Clinical Trial to Evaluate the Effect of Ulonivirine (MK-8507) on Heart Rhythm in Healthy Adults (MK-8507-012)

A Double-Blind, Placebo-Controlled Trial to Evaluate the Effect of MK-8507 on the QTc Interval in Healthy Adult Participants

Researchers are looking for new treatments for HIV-1 (human immunodeficiency virus type 1) that are safe, well-tolerated, and can be taken less often. HIV-1 is the most common type of HIV, which is a virus that attacks cells of the immune system.

Ulonivirine (MK-8507) is a study medicine designed to treat HIV-1

The goal of this study is to learn if ulonivirine does not increase the QT interval (a measure of heart rhythm on an electrocardiogram) above a certain amount. Researchers also want to learn what happens to the amount of ulonivirine in a healthy person's body over time.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Drug: Moxifloxacin; Drug: Ulonivirine Placebo; Drug: Moxifloxacin Placebo; Drug: Ulonivirine

• Study Type: Interventional
• Enrollment (Actual): 62
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Texas
    • San Antonio, Texas, United States, 78209
      • ICON Early Phase Services (0001)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Is in good health before randomization
• Has body Mass Index (BMI) between 18 and 32 kg/m2, inclusive

Exclusion Criteria:

• Has a history of clinically significant endocrine, gastrointestinal (GI), cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases
• Has history of cancer (malignancy)
• Has positive test(s) for hepatitis B surface antigen (HBsAg), hepatitis C antibodies or human immunodeficiency virus (HIV)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Moxifloxacin 400 mg + Placebo (Arm 1); Participants will receive ulonivirine dose matched placebo + moxifloxacin dose matched placebo OR ulonivirine dose matched placebo + moxifloxacin 400 mg.	Drug: Moxifloxacin; Oral tablet; Drug: Ulonivirine Placebo; Oral tablet; Drug: Moxifloxacin Placebo; Oral tablet
Experimental: Ulonivirine Dose 1 + Placebo (Arm 2); Participants will receive ulonivirine dose matched placebo + moxifloxacin dose matched placebo OR moxifloxacin dose matched placebo + ulonivirine Dose 1.	Drug: Ulonivirine Placebo; Oral tablet; Drug: Moxifloxacin Placebo; Oral tablet; Drug: Ulonivirine; Oral tablet; Other Names: MK-8507; ULO

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following Ulonivirine Administration	Change from baseline in QTc following ulonivirine administration will be reported.	Baseline and up to approximately 24 hours
Plasma Concentration of Ulonivirine at QTc Intervals (Cqtc)	Blood samples will be collected to determine the Cqtc of ulonivirine.	At designated timepoints (up to approximately 24 hours)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following Moxifloxacin Administration	Change from baseline in QTc following moxifloxacin administration will be reported.	Baseline to up to approximately 24 hours
Plasma concentration of Moxifloxacin at QTc intervals (Cqtc)	Blood samples will be collected to determine the Cqtc of moxifloxacin.	At designated timepoints (up to approximately 24 hours)
Maximum Plasma Concentration (Cmax) of Moxifloxacin	Blood samples will be collected to determine the Cmax of moxifloxacin.	At designated timepoints (up to approximately 168 hours)
Area Under the Plasma Concentration-Time Curve From Time 0 to 24 Hours (AUC0-24) of Ulonivirine	Blood samples will be collected to determine the AUC0-24 of ulonivirine.	At designated timepoints (up to 168 hours)
Maximum Plasma Concentration (Cmax) of Ulonivirine	Blood samples will be collected to determine the Cmax of ulonivirine.	At designated timepoints (up to 168 hours)
Time to Maximum Plasma Concentration (Tmax) of Ulonivirine	Blood samples will be collected to determine the Tmax of ulonivirine.	At designated timepoints (up to 168 hours)

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information

Study record dates

Study Major Dates

• Study Start (Actual): January 22, 2026
• Primary Completion (Actual): April 9, 2026
• Study Completion (Actual): April 9, 2026

Study Registration Dates

• First Submitted: December 12, 2025
• First Submitted That Met QC Criteria: December 12, 2025
• First Posted (Actual): December 26, 2025

Study Record Updates

• Last Update Posted (Actual): April 21, 2026
• Last Update Submitted That Met QC Criteria: April 20, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Blood-Borne Infections; Urogenital Diseases; Genital Diseases; Immune System Diseases; Infections; RNA Virus Infections; Virus Diseases; Communicable Diseases; Sexually Transmitted Diseases, Viral; Sexually Transmitted Diseases; Lentivirus Infections; Retroviridae Infections; Immunologic Deficiency Syndromes; HIV Infections; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Fluoroquinolones; 4-Quinolones; Quinolones; Quinolines; Moxifloxacin; ulonivirine
• Other Study ID Numbers: 8507-012; MK-8507-012 (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