Single-Dose Islatravir in Moderate Hepatic Impairment (MK-8591-030)

July 8, 2025 updated by: Merck Sharp & Dohme LLC

An Open-Label, Single-Dose Study to Evaluate the Pharmacokinetics of Islatravir (MK-8591) in Participants With Moderate Hepatic Impairment

This is an open-label, single-dose study of the plasma pharmacokinetics (PK), safety, and tolerability of islatravir (ISL, MK-8591), and the intracellular PK of ISL triphosphate (ISL-TP) in male and female adult participants with moderate hepatic impairment and in healthy matched control participants.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
12

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Florida
      • Miami, Florida, United States, 33014
        • Clinical Pharmacology of Miami ( Site 0001)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 71 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

Healthy Control Participants:

  • Is in good health based on medical history, physical examination, vital sign (VS) measurements and electrocardiograms (ECGs) performed prior to randomization
  • Is in good health based on laboratory safety tests obtained at the screening visit and prior to administration of the initial dose of study drug.
  • Has a body mass index (BMI) ≥18.5 and ≤40 kg/m2

Hepatic Impairment Participants:

  • Has a diagnosis of chronic (> 6 months), stable (no acute episodes of illness within the previous 2 months due to deterioration in hepatic function) hepatic insufficiency with features of cirrhosis due to any etiology
  • Has a score on the Child-Pugh scale ranging from 7 to 9 (moderate hepatic insufficiency) at screening
  • With the exception of hepatic impairment, is in generally good health
  • Has a BMI ≥ 18.5 and ≤ 40 kg/m2

Healthy and Hepatic Impairment Participants:

  • Males : uses contraception according to local regulations
  • Females: is not pregnant or breastfeeding and one of the following applies:
  • Is not a woman of childbearing potential (WOCBP) OR
  • Is a WOCBP and uses an acceptable contraceptive method
  • A WOCBP with negative highly sensitive pregnancy test within 24 hours of study intervention

Exclusion Criteria:

  • Has a history of clinically significant endocrine, gastrointestinal, cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases
  • Is mentally or legally incapacitated, has significant emotional problems at the time of prestudy (screening) visit or expected during the conduct of the study or has a history of clinically significant psychiatric disorder of the last 5 years
  • Has a history of cancer (malignancy)
  • Has a history of significant multiple and/or severe allergies, or has had an anaphylactic reaction or significant intolerability (ie, systemic allergic reaction) to prescription or non-prescription drugs or food
  • Has known hypersensitivity to the active substance or any of the excipients of the study drug
  • Is positive for hepatitis B surface antigen, hepatitis C antibodies, HIV-1 or HIV-2
  • Had major surgery, donated or lost 1 unit of blood (approximately 500 mL) within 4 weeks prior to the prestudy (screening) visit
  • Is unable to refrain from or anticipates the use of any medication, including prescription and nonprescription drugs or herbal remedies beginning approximately 2 weeks (or 5 half-lives) prior to study drug administration, throughout the study, until the poststudy visit
  • Has participated in another investigational study within 4 weeks (or 5 half-lives, whichever is greater) prior to the prestudy (screening) visit
  • Has a QTc interval >470 for males or >480 ms for females, has a history of risk factors for Torsades de Pointes (eg, heart failure/cardiomyopathy or family history of long QT syndrome), has uncorrected hypokalemia or hypomagnesemia, is taking concomitant medications that prolong the QT/QTc interval
  • Is not considered low risk of having HIV infection
  • Is a smoker or user of electronic cigarettes and/or has used nicotine or nicotine-containing products (eg, nicotine patch) within 3 months of screening
  • Consumes greater than 3 glasses of alcoholic beverages per day
  • Consumes more than 6 caffeinated beverages per day
  • Is a regular user of illicit drugs or has a history of drug abuse within 2 years
  • Presents any concern to the investigator regarding safe study participation
  • Is unwilling to comply with study restrictions
  • Is or has an immediate family member who is investigational site or Sponsor staff directly involved with this study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Moderate Hepatic Impairment
Participants receive a single dose of ISL 60 mg.
Drug: Islatravir
Two ISL 30 mg capsules taken by mouth.
Other Names:
  • MK-8591
Experimental: Healthy Controls
Participants receive a single dose of ISL 60 mg.
Drug: Islatravir
Two ISL 30 mg capsules taken by mouth.
Other Names:
  • MK-8591

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Area Under the Curve From Time 0 to Infinity (AUC0-inf) of Islatravir (ISL) in Plasma
Time Frame: Pre-dose, 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Participants were treated with ISL, and blood samples were collected from pre-dose up to 168 hours post-dose to determine the concentration of plasma ISL. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
Pre-dose, 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Area Under the Curve From Time 0 to Last Sampling Time (AUC0-last) of ISL in Plasma
Time Frame: Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Participants were treated with ISL, and blood samples were collected from pre-dose up to 168 hours post-dose to determine the concentration of plasma ISL. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Maximum Concentration (Cmax) of ISL in Plasma
Time Frame: Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Participants were treated with ISL, and blood samples were collected from pre-dose up to 168 hours post-dose to determine the concentration of plasma ISL. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Time to Maximum Concentration (Tmax) of ISL in Plasma
Time Frame: Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Participants were treated with ISL, and blood samples were collected from pre-dose up to 168 hours post-dose to determine the concentration of plasma ISL. The Tmax of plasma ISL was expressed as a median.
Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Apparent Terminal Half-Life (t½) of ISL in Plasma
Time Frame: Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Participants were treated with ISL, and blood samples were collected from pre-dose up to 168 hours post-dose to determine the concentration of plasma ISL. The Geometric Coefficient of Variation was expressed as a percent (%CV), and is calculated from the square root of corresponding estimated variance obtained for each population in fixed effect model multiplied by 100.
Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Apparent Total Clearance (CL/F) of ISL in Plasma
Time Frame: Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Participants were treated with ISL, and blood samples were collected from pre-dose up to 168 hours post-dose to determine the concentration of plasma ISL. The Geometric Coefficient of Variation was expressed as a percent (%CV), and is calculated from the square root of corresponding estimated variance obtained for each population in fixed effect model multiplied by 100.
Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Apparent Volume of Distribution During Terminal Phase (Vz/F) of ISL in Plasma
Time Frame: Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose
Participants were treated with ISL, and blood samples were collected from pre-dose up to 168 hours post-dose to determine the concentration of plasma ISL. The Geometric Coefficient of Variation was expressed as a percent (%CV), and is calculated from the square root of corresponding estimated variance obtained for each population in fixed effect model multiplied by 100.
Pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 36, 48, 72, 96, 120, and 168 hours post-dose

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Concentration at 24 Hours Post Dose (C24) of ISL-TP in PBMC
Time Frame: 24 hours post-dose
Participants were treated with ISL and peripheral blood samples were collected at 24 hours post-dose to determine the concentration of ISL-TP in PBMCs. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
24 hours post-dose
Concentration at 168 Hours Post Dose (C168) of ISL-TP in PBMC
Time Frame: 168 hours post-dose
Participants were treated with ISL and peripheral blood samples were collected at 168 hours post-dose to determine the concentration of ISL-TP in PBMCs. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
168 hours post-dose
Concentration at 672 Hours Post Dose (C672) of ISL-TP in PBMC
Time Frame: 672 hours post-dose
Participants were treated with ISL and peripheral blood samples were collected at 672 hours post-dose to determine the concentration of ISL-TP in PBMCs. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
672 hours post-dose
Percentage of Participants With an Adverse Event (AE)
Time Frame: Up to 28 days
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention.
Up to 28 days
Percentage of Participants Who Discontinued From the Study Due to an AE
Time Frame: Up to 28 days
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention.
Up to 28 days
AUC0-inf of ISL Triphosphate (ISL-TP) in Peripheral Blood Mononuclear Cells (PBMC)
Time Frame: Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
Participants were treated with ISL, and peripheral blood samples were collected from pre-dose up to 672 hours post-dose to determine the concentration of ISL-TP in PBMCs. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
AUC0-last of ISL-TP in PBMC
Time Frame: Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
Participants were treated with ISL and peripheral blood samples were collected from pre-dose up to 672 hours post-dose to determine the concentration of ISL-TP in PBMCs. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
Cmax of ISL-TP in PBMC
Time Frame: Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
Participants were treated with ISL and peripheral blood samples were collected from pre-dose up to 672 hours post-dose to determine the concentration of ISL-TP in PBMCs. The 95% confidence interval was derived from a fixed effects model performed on natural log-transformed values.
Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
Tmax of ISL-TP in PBMC
Time Frame: Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
Participants were treated with ISL and peripheral blood samples were collected from pre-dose up to 672 hours post-dose to determine the concentration of ISL-TP in PBMCs. The Tmax of ISL-TP was expressed as a median.
Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
T1/2 of ISL-TP in PBMC
Time Frame: Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose
Participants were treated with ISL, and peripheral blood samples were collected from pre-dose to 672 hours post-dose to determine the concentration of ISL-TP in PBMCs. The Geometric Coefficient of Variation was expressed as a percent (%CV), and is calculated from the square root of corresponding estimated variance obtained for each population in fixed effect model multiplied by 100.
Predose and 4, 24, 48, 96, 168, 240, 336, 408, 504, and 672 hours post-dose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Merck Sharp & Dohme LLC

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 5, 2020

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 13, 2021

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 13, 2021

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 14, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 14, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 17, 2020

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 17, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 8, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 8591-030
  • MK-8591-030 (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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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