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Ulonivirine

Phase 1

HIV-1 Infection | Small molecule | Infectious Disease |Merck & Company, Inc.|Last Updated: Aug 24, 2026

Success Probability

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Market & Valuation

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Trial Design

CONTROLLED
Total Trials1
Total Enrollment18

FDA Designations

No designations recorded

Clinical trial landscape

Ulonivirine · 6 trials · 3 indications

Phase 1 6
NCT05093972Ulonivirine (MK-8507) in Participants With Mild or Moderate Hepatic Impairment (MK-8507-014)Hepatic Insufficiency
NOT YET_RECRUITING22 Analytics
NCT07595263A Study of Ulonivirine (MK-8507) and Methadone in Healthy Volunteers (MK-8507-019)Healthy
NOT YET_RECRUITING14 Analytics
NCT07530289A Clinical Study of Ulonivirine (MK-8507) With Atorvastatin and Metformin in Healthy Adults (MK-8507-018)Healthy
COMPLETED12 Analytics
NCT07305831A Clinical Trial to Evaluate the Effect of Ulonivirine (MK-8507) on Heart Rhythm in Healthy Adults (MK-8507-012)Healthy
COMPLETED62 Analytics
NCT07334886A Study of [14C]Ulonivirine ([14C]MK-8507) in Healthy Adults (MK-8507-006)Healthy
COMPLETED8 Analytics
NCT02174159Evaluation of Safety, Tolerability, Pharmacokinetics, and Antiretroviral Activity of Ulonivirine (MK-8507) in Human Immunodeficiency Virus (HIV-1)-Infected Participants (MK-8507-003)HIV-1 Infection
COMPLETED18 Analytics
PHASE1NOT YET_RECRUITING
Ulonivirine (MK-8507) in Participants With Mild or Moderate Hepatic Impairment (MK-8507-014)
Hepatic InsufficiencyUnlock trial analytics
PHASE1NOT YET_RECRUITING
A Study of Ulonivirine (MK-8507) and Methadone in Healthy Volunteers (MK-8507-019)
HealthyUnlock trial analytics
PHASE1COMPLETED
A Clinical Study of Ulonivirine (MK-8507) With Atorvastatin and Metformin in Healthy Adults (MK-8507-018)
HealthyUnlock trial analytics
PHASE1COMPLETED
A Clinical Trial to Evaluate the Effect of Ulonivirine (MK-8507) on Heart Rhythm in Healthy Adults (MK-8507-012)
HealthyUnlock trial analytics
PHASE1COMPLETED
A Study of [14C]Ulonivirine ([14C]MK-8507) in Healthy Adults (MK-8507-006)
HealthyUnlock trial analytics
PHASE1COMPLETED
Evaluation of Safety, Tolerability, Pharmacokinetics, and Antiretroviral Activity of Ulonivirine (MK-8507) in Human Immunodeficiency Virus (HIV-1)-Infected Participants (MK-8507-003)
HIV-1 InfectionUnlock trial analytics

Study Endpoints

Primary Endpoints

Area Under the Plasma Concentration-Time Curve from Dosing to Infinity (AUC0-∞) of Ulonivirine
Predose and 1, 2, 4, 6, 8, 12, 24, 48, 96, 120, 168, 240, 336, and 504 hours postdose

The AUC0-∞ of ulonivirine will be determined in participants with mild or moderate HI and healthy controls.

Area Under the Plasma Concentration-Time Curve from Dosing to Last Measurable Concentration (AUC0-last) of Ulonivirine
Predose and 1, 2, 4, 6, 8, 12, 24, 48, 96, 120, 168, 240, 336, and 504 hours postdose

The AUC0-last of ulonivirine will be determined in participants with mild or moderate HI and healthy controls.

Maximum Plasma Concentration (Cmax) of Ulonivirine
Predose and 1, 2, 4, 6, 8, 12, 24, 48, 96, 120, 168, 240, 336, and 504 hours postdose

The Cmax of ulonivirine will be determined in participants with mild or moderate HI and healthy controls.

Time to Maximum Plasma Concentration (Tmax) of Ulonivirine
Predose and 1, 2, 4, 6, 8, 12, 24, 48, 96, 120, 168, 240, 336, and 504 hours postdose

The Tmax of ulonivirine will be determined in participants with mild or moderate HI and healthy controls.

Apparent Plasma Terminal Half-life (t½) of Ulonivirine
Predose and 1, 2, 4, 6, 8, 12, 24, 48, 96, 120, 168, 240, 336, and 504 hours postdose

The t½ of ulonivirine will be determined in participants with mild or moderate HI and healthy controls.

Apparent Total Clearance from Plasma After Oral Administration (CL/F) of Ulonivirine
Predose and 1, 2, 4, 6, 8, 12, 24, 48, 96, 120, 168, 240, 336, and 504 hours postdose

The CL/F of ulonivirine will be determined in participants with mild or moderate HI and healthy controls.

Apparent Volume of Distribution during Terminal Phase (Vz/F) of Ulonivirine
Predose and 1, 2, 4, 6, 8, 12, 24, 48, 96, 120, 168, 240, 336, and 504 hours postdose

The Vz/F of ulonivirine will be determined in participants with mild or moderate HI and healthy controls.

Dose-Normalized Area Under the Plasma Concentration Time Curve From 0-24 Hours Postdose (AUC0-24) of R-Methadone
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
Up to 24 hours post-dose

The AUC0-24 of S-methadone will be determined on Day 1 (methadone) and Day 2 (methadone + ulonivirine).

Area Under the Concentration-Time Curve From Time 0 to Infinity (AUC0-inf) of Atorvastatin
Day 1: Predose and at designated timepoints up to 72 hours post-dose

Blood samples will be collected at multiple time points to determine the AUC0-inf of atorvastatin

AUC0-inf of Metformin
Day 1: Predose and at designated timepoints up to 72 hours post-dose

Blood samples will be collected at multiple time points to determine the AUC0-inf of metformin

Change From Baseline in QT Interval Corrected for Heart Rate (QTc) Following Ulonivirine Administration
Baseline and up to approximately 24 hours

Change from baseline in QTc following ulonivirine administration will be reported.

Plasma Concentration of Ulonivirine at QTc Intervals (Cqtc)
At designated timepoints (up to approximately 24 hours)

Blood samples will be collected to determine the Cqtc of ulonivirine.

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

FE from Urine
At designated timepoints (up to approximately 5 weeks postdose)

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

FE from Feces
At designated timepoints (up to approximately 5 weeks postdose)

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

Cumulative Amount of Radioactivity Recovered from Urine
At designated timepoints (up to approximately 5 weeks postdose)

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

Percent of Total Radioactive Dose Recovered from Urine
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.

Cumulative Amount of Radioactivity Recovered from Feces
At designated timepoints (up to approximately 5 weeks postdose)

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

Percent of Total Radioactive Dose Recovered from Feces
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.

Plasma Ulonivirine: Area Under the Concentration-Time Curve from Time 0 to Time of the Last Concentration (AUC0-last)
At designated timepoints (up to approximately 2 weeks postdose)

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

Plasma Ulonivirine: Area Under the Concentration-Time Curve from Time 0 Extrapolated to Infinity (AUC0-inf)
At designated timepoints (up to approximately 2 weeks postdose)

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

Plasma Ulonivirine: Maximum Observed Concentration (Cmax)
At designated timepoints (up to approximately 2 weeks postdose)

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

Plasma Ulonivirine: Concentration at 168 Hours Postdose (C168)
At approximately 1 week postdose

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

Plasma Ulonivirine: Terminal Half-life (t1/2)
At designated timepoints (up to approximately 2 weeks postdose)

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

Plasma Ulonivirine: Time of Maximum Observed Concentration (Tmax)
At designated timepoints (up to approximately 2 weeks postdose)

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

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

Plasma Total Radioactivity: AUC0-last
At designated timepoints (up to approximately 5 weeks postdose)

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

Plasma Total Radioactivity: AUC0-inf
At designated timepoints (up to approximately 5 weeks postdose)

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

Plasma Total Radioactivity: Cmax
At designated timepoints (up to approximately 5 weeks postdose)

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

Plasma Total Radioactivity: C168
At approximately 1 week postdose

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

Plasma Total Radioactivity: t1/2
At designated timepoints (up to approximately 5 weeks postdose)

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

Plasma Total Radioactivity: Tmax
At designated timepoints (up to approximately 5 weeks postdose)

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

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

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

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

Change from Baseline in Plasma HIV-1 RNA
168 hours (7 days) postdose
Number of Participants with One or More Adverse Experiences
Up to 21 days postdose

Secondary Endpoints

Percentage of Participants with an Adverse Event (AE)
Up to 21 days
Dose-Normalized Maximum Plasma Concentration (Cmax) of R-Methadone
Up to 24 hours post-dose
Dose-Normalized Plasma Concentration 24 Hours Postdose (C24) of R-Methadone
24 hours post-dose
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Panel A: Mild HIEXPERIMENTALParticipants with mild HI receive a single oral dose of ulonivirine 400 mg on Day 1.
Panel B: Moderate HIEXPERIMENTALParticipants with moderate HI receive a single oral dose of ulonivirine 400 mg on Day 1.
Panel C: Healthy ControlsACTIVE_COMPARATORHealthy matched control participants receive a single oral dose of ulonivirine 400 mg on Day 1.
Methadone + UlonivirineEXPERIMENTALParticipants 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.
Atorvastatin + metformin + ulonivirineEXPERIMENTALIn Period 1, participants will receive atorvastatin and metformin. In Period 2, participants will receive atorvastatin, metformin, and ulonivirine.
Moxifloxacin 400 mg + Placebo (Arm 1)EXPERIMENTALParticipants will receive ulonivirine dose matched placebo + moxifloxacin dose matched placebo OR ulonivirine dose matched placebo + moxifloxacin 400 mg.
Ulonivirine Dose 1 + Placebo (Arm 2)EXPERIMENTALParticipants will receive ulonivirine dose matched placebo + moxifloxacin dose matched placebo OR moxifloxacin dose matched placebo + ulonivirine Dose 1.
[14C]UlonivirineEXPERIMENTALAll participants receive a single oral dose of \[14C\]ulonivirine on Day 1.
Panel A: Ulonivirine 600 mgEXPERIMENTALSingle oral dose of ulonivirine 600 mg (supplied as 10 mg and 100 mg tablets) administered after an overnight fast
Panel B: Ulonivirine 150 mgEXPERIMENTALSingle oral dose of ulonivirine 150 mg (supplied as 10 mg and 100 mg tablets) administered after an overnight fast
Panel C: Ulonivirine <=600 mgEXPERIMENTALSingle oral dose of ulonivirine \<=600 mg mg (supplied as 10 mg and 100 mg tablets) administered after an overnight fast. Inclusion of Panel C in the study, and the dose selected, will be decided pending evaluation of results for Panels A and B.

Interventions

NameTypeDescription
UlonivirineDRUGFour ulonivirine 100 mg tablets (total dose 400 mg) taken by mouth.
MethadoneDRUGOral (per local guidelines)
AtorvastatinDRUGOral tablet
MetforminDRUGOral tablet
MoxifloxacinDRUGOral tablet
Ulonivirine PlaceboDRUGOral tablet
Moxifloxacin PlaceboDRUGOral tablet
[14C]UlonivirineDRUGOral Solution
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Eligibility Criteria

Age Range18 Years to 75 Years
SexALL
Healthy VolunteersYes

Inclusion Criteria: Mild and Moderate HI (Panels A and B): * Has a diagnosis of chronic (\>6 months), stable HI with features of cirrhosis due to any etiology (stability of hepatic disease should correspond to no acute episodes of illness within the previous 2 months due to deterioration in hepati...

Countries:United States
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Recent Changes (Last 90 Days)

LOWAug 24, 2026NCT07595263lastUpdatePostDate: changed
LOWAug 24, 2026NCT07595263lastUpdatePostDate: changed
MEDIUMJul 17, 2026NCT05093972primaryCompletionDate: changed
MEDIUMJul 17, 2026NCT05093972primaryCompletionDate: changed
MEDIUMJul 17, 2026NCT05093972primaryCompletionDate: changed
MEDIUMJul 16, 2026NCT07530289TRIAL_REMOVED: changed
MEDIUMJul 16, 2026NCT07530289TRIAL_REMOVED: changed
MEDIUMJul 16, 2026NCT07530289TRIAL_REMOVED: changed
LOWJun 23, 2026NCT07595263startDate: changed
LOWJun 23, 2026NCT07595263startDate: changed
HIGHJun 16, 2026NCT07530289Status: ACTIVE_NOT_RECRUITING → COMPLETED
HIGHJun 16, 2026NCT07530289Status: ACTIVE_NOT_RECRUITING → COMPLETED
HIGHJun 16, 2026NCT07530289Status: ACTIVE_NOT_RECRUITING → COMPLETED
HIGHJun 16, 2026NCT07530289Status: ACTIVE_NOT_RECRUITING → COMPLETED

Frequently asked questions about Ulonivirine

What is Ulonivirine used for?

Ulonivirine is an investigational small molecule being studied for use in HIV-1 infection, as well as in healthy volunteers and people with hepatic insufficiency. It is currently in Phase 1 clinical development and is not yet approved by the FDA.

Who makes Ulonivirine?

Ulonivirine is being developed by Merck & Company, Inc., which trades on the New York Stock Exchange under the ticker MRK. The drug is in Phase 1 clinical trials for infectious disease indications.

What phase is Ulonivirine in?

Ulonivirine is in Phase 1 clinical development. It is an investigational drug, meaning it has not been approved by the FDA and is still being evaluated in early-stage clinical trials for safety and other characteristics.

What clinical trials is Ulonivirine in?

Ulonivirine has four clinical trials listed on ClinicalTrials.gov. Three are completed: NCT07305831, a heart rhythm study in healthy adults; NCT07334886, a radiolabeled study in healthy males; and NCT07530289, a drug interaction study with atorvastatin and metformin. One trial, NCT07595263, is not yet recruiting and will study Ulonivirine with methadone in healthy volunteers.

Is Ulonivirine the same as MK-8507?

Yes, Ulonivirine is also known as MK-8507. Clinical trial records refer to the drug by both names, such as in the study titles for NCT07305831 and NCT07334886, which list Ulonivirine (MK-8507).