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Ulonivirine

Phase 2

Hepatic Insufficiency | Small molecule | Gastrointestinal |Merck & Company, Inc.|Trials Updated: Jul 16, 2026

Ulonivirine development status

Highest phase Phase 2 (NCT04564547)
Phase scored for MRKPhase 1
Registered trials 7 across 1 sponsor since Jun 2014

Ulonivirine target and mechanism

ModalitySmall molecule

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

Success Probability

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Market & Valuation

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Trial Design

ACTIVE_CONTROLLED
Total Trials3
Total Enrollment76

FDA Designations

No designations recorded

Ulonivirine clinical trials

Ulonivirine · 3 trials · 3 indications

Phase 1 3
NCT05093972Ulonivirine (MK-8507) in Participants With Mild or Moderate Hepatic Impairment (MK-8507-014)Hepatic Insufficiency
NOT YET_RECRUITING22 Analytics
NCT06619678A Study of MK-8507 and Islatravir (MK-8591) in Healthy Adult Participants (MK-8507-016)Healthy
COMPLETED36 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
PHASE1COMPLETED
A Study of MK-8507 and Islatravir (MK-8591) in Healthy Adult Participants (MK-8507-016)
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.

Area Under the Concentration-Time Curve from Time 0 to Infinity (AUC0-Inf) of Islatravir Metabolite
At designated timepoints (up to approximately 43 days)

Blood samples will be collected to determine the AUC0-Inf of Islatravir metabolite.

Area Under the Concentration-Time Curve from Time 0 to 168 hours (AUC0-168hrs) of Islatravir Metabolite
At designated timepoints (up to approximately 168 hours)

Blood samples will be collected to determine the AUC0-168hrs of Islatravir metabolite.

Maximum Concentration (Cmax) of Islatravir Metabolite
At designated timepoints (up to approximately 43 days)

Blood samples will be collected to determine Cmax of Islatravir metabolite.

Plasma Concentration at 168 Hours (C168) of Islatravir Metabolite
At designated timepoints (up to approximately 168 hours)

Blood samples will be collected to determine the C168 of Islatravir metabolite.

Time to Maximum Concentration (Tmax) of Islatravir Metabolite
At designated timepoints (up to approximately 43 days)

Blood samples will be collected to determine the Tmax of Islatravir metabolite.

Apparent Terminal Half-life (t1/2) of Islatravir Metabolite
At designated timepoints (up to approximately 43 days)

Blood samples will be collected to determine the t1/2 of Islatravir metabolite.

AUC0-Inf of Islatravir
At designated timepoints (up to approximately 22 days)

Blood samples will be collected to determine the AUC0-Inf of Islatravir.

AUC0-168hrs of Islatravir
At designated timepoints (up to approximately 7 days)

Blood samples will be collected to determine the AUC0-168hrs of Islatravir.

Cmax of Islatravir
At designated timepoints (up to approximately 22 days)

Blood samples will be collected to determine Cmax of Islatravir.

C168 of Islatravir
At designated timepoints (up to approximately 168 hours)

Blood samples will be collected to determine the C168 of Islatravir.

Tmax of Islatravir
At designated timepoints (up to approximately 22 days)

Blood samples will be collected to determine the Tmax of Islatravir.

t1/2 of Islatravir
At designated timepoints (up to approximately 22 days)

Blood samples will be collected to determine the t1/2 of Islatravir.

Apparent clearance (CL/F) of Islatravir
At designated timepoints (up to approximately 22 days)

Blood samples will be collected to determine the CL/F of Islatravir.

Apparent Volume of Distribution During Terminal Phase (Vd/F) of Islatravir
At designated timepoints (up to approximately 22 days)

Blood samples will be collected to determine the Vd/F of Islatravir.

AUC0-168hrs of MK-8507
At designated timepoints (up to approximately 7 days)

Blood samples will be collected to determine the AUC0-168hrs of MK-8507.

Cmax of MK-8507
At designated timepoints (up to approximately 15 days)

Blood samples will be collected to determine Cmax of MK-8507.

C168 of MK-8507
At designated timepoints (up to approximately 168 hours)

Blood samples will be collected to determine the C168 of MK-8507.

Tmax of MK-8507
At designated timepoints (up to approximately 15 days)

Blood samples will be collected to determine the Tmax of MK-8507.

t1/2 of MK-8507
At designated timepoints (up to approximately 15 days)

Blood samples will be collected to determine the t1/2 of MK-8507.

CL/F of MK-8507
At designated timepoints (up to approximately 15 days)

Blood samples will be collected to determine the CL/F of MK-8507.

Vd/F of MK-8507
At designated timepoints (up to approximately 15 days)

Blood samples will be collected to determine the Vd/F of MK-8507.

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
Number of Participants Who Experience an Adverse Event (AE)
Up to approximately 5 months
Number of Participants Who Discontinue Study Treatment Due to an AE
Up to approximately 5 months
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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.
Islatravir+MK-8507EXPERIMENTALPeriod 1: Participants receive single dose of Islatravir on Day 1. Period 2: Participants receive single dose of MK-8507 on Days 1 and Days 8. Period 3: Participants receive single dose of Islatravir and single dose of MK-8507 on Day 1, 7 days after the Day 8 dose of MK-8507, during Period 2. Participants will receive additional MK-8507 single doses on Days 8, 15, 22, and 29.
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.
MK-8507DRUGOral administration
IslatravirDRUGOral administration
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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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Frequently asked questions about Ulonivirine

What is Ulonivirine used for?

Ulonivirine is an investigational small molecule being studied for the treatment of HIV-1 infection. It is also being evaluated in people with mild or moderate hepatic impairment. It has not been approved for any indication and remains in Phase 1 clinical development.

Who is developing Ulonivirine?

Ulonivirine is being developed by Merck & Company, Inc., which trades under the ticker MRK. Merck is running the clinical program for the drug, including the Phase 1 studies in HIV-1 infection and in hepatic insufficiency.

What phase is Ulonivirine in?

Ulonivirine is in Phase 1 clinical development. It is an investigational agent and has not been approved by the FDA or any other regulatory authority. The program includes one completed Phase 1 trial and one Phase 1 trial in hepatic impairment.

What clinical trials is Ulonivirine in?

Ulonivirine has been studied in two Phase 1 trials. NCT02174159 evaluated safety, tolerability, pharmacokinetics, and antiretroviral activity in HIV-1 infected participants and is completed. NCT05093972 is evaluating Ulonivirine in participants with mild or moderate hepatic impairment.

Is Ulonivirine the same as [14C]Ulonivirine?

Yes, [14C]Ulonivirine is an alternative name for Ulonivirine. The carbon-14 labeled form is used in study work, and both names refer to the same investigational compound being developed by Merck for HIV-1 infection and hepatic insufficiency.

How many participants have been enrolled in Ulonivirine trials?

Across the Ulonivirine clinical program, 22 participants are planned or enrolled in the hepatic impairment study, and 18 participants were enrolled in the completed HIV-1 study. The trials are Phase 1 and include adult participants aged 18 years and older.