A Clinical Study of Islatravir and Its Interaction With Lamivudine (MK-8591-058)

An Open-Label Study to Evaluate the Effect of Multiple Doses of Lamivudine on the Single Dose Pharmacokinetics of Islatravir in Healthy Participants

The goal of this study is to learn what happens to the medication islatravir (ISL), in a healthy person's body over time--called a pharmacokinetic (PK) study. Researchers want to compare the amount of islatravir in the blood when it is taken alone as a single dose and when it is taken with multiple doses of another medication called lamivudine (3TC).

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Drug: Islatravir (ISL); Drug: Lamivudine (3TC)

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Nebraska
    • Lincoln, Nebraska, United States, 68502
      • Celerion (Site 0001)

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

The key inclusion criteria include but are not limited to the following:

• Is in good health before randomization
• Has a body mass index (BMI) ≥18 and ≤32 kg/m^2

Exclusion Criteria:

The key exclusion criteria include but are not limited to the following:

• 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
• Is a smoker and/or has used nicotine or nicotine-containing products (for example, nicotine patch and electronic cigarette) within 3 months prior to entering the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: ISL and 3TC; During period 1, participants receive a single dose of islatravir (ISL). During Period 2, participants receive multiple once-daily doses of lamivudine (3TC) for 27 days, and a single dose of ISL co-administered with 3TC on day 6.	Drug: Islatravir (ISL); Oral administration of a single dose in period 1 and period 2; Other Names: MK-8591; ISL; Drug: Lamivudine (3TC); Oral administration of multiple daily doses for 27 days; Other Names: 3TC

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peripheral blood mononuclear cell (PBMC) Concentration at 168 hours (C168) of islatravir-triphosphate (ISL-TP )	Blood samples will be collected to determine the C168 of ISL-TP	Predose and at designated timepoints up to 168 hours post dose
PBMC Concentration at 24 Hours (C24) of ISL-TP	Blood samples will be collected to determine the C24 of ISL-TP	Predose and at designated timepoints up to 24 hours post dose
PBMC Area Under the Concentration-Time Curve from Time 0 to Infinity (AUC0-inf) of ISL-TP	Blood samples will be collected to determine the AUC0-inf of ISL-TP	Predose and at designated timepoints up to 840 hours post dose
PBMC Area Under the Concentration-time Curve to Time of Last Measurable Concentration (AUClast) of ISL-TP	Blood samples will be collected to determine the AUClast of ISL-TP	Predose and at designated time points up to 840 hours post dose
PBMC Maximum Concentration (Cmax) of ISL-TP	Blood samples will be collected to determine the Cmax of ISL-TP	Predose and at designated time points up to 840 hours post dose
PBMC Time to Maximum Concentration (Tmax) of ISL-TP	Blood samples will be collected to determine the Tmax of ISL-TP	Predose and at designated time points up to 840 hours post dose
PBMC Apparent Terminal Half-life (t1/2) of ISL-TP	Blood samples will be collected to determine the t1/2 of ISL-TP	Predose and at designated timepoints up to 840 hours post dose

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma C168 of ISL	Blood samples will be collected to determine the C168 of ISL	Predose and at designated timepoints up to 168 hours post dose
Plasma Concentration at 24 Hours (C24) of ISL	Blood samples will be collected to determine the C24 of ISL	Predose and at designated timepoints up to 24 hours post dose
Plasma AUC0-inf of ISL	Blood samples will be collected to determine the AUC0-inf of ISL	Predose and at designated timepoints up to 168 hours post dose
Plasma AUClast of ISL	Blood samples will be collected to determine the AUClast of ISL	Predose and at designated timepoints up to 168 hours post dose
Plasma Cmax of ISL	Blood samples will be collected to determine the Cmax of ISL	Predose and at designated timepoints up to 168 hours post dose
Plasma Tmax of ISL	Blood samples will be collected to determine the Tmax of ISL-TP	Predose and at designated timepoints up to 168 hours post dose
Plasma t1/2 of ISL	Blood samples will be collected to determine the t1/2 of ISL	Predose and at designated timepoints up to 168 hours post dose
Number of Participants Who Experience an Adverse Event (AE)	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. The number of participants who experience an AE will be reported.	Up to approximately 16 weeks
Number of Participants Who Discontinue Study Treatment Due to an AE	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. The number of participants who discontinue study treatment due to an AE will be reported	Up to approximately 10 weeks

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): February 7, 2024
• Primary Completion (Actual): July 14, 2024
• Study Completion (Actual): July 14, 2024

Study Registration Dates

• First Submitted: January 31, 2025
• First Submitted That Met QC Criteria: January 31, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 31, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Anti-Infective Agents; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Nucleic Acid Synthesis Inhibitors; Antiviral Agents; Reverse Transcriptase Inhibitors; Anti-HIV Agents; Anti-Retroviral Agents; Lamivudine; Islatravir
• Other Study ID Numbers: 8591-058; MK-8591-058 (Other Identifier: MSD)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: http://engagezone.msd.com/doc/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