---
title: A Study of Doravirine and Islatravir as a Single Entity or Combination Therapy and the Effect of Food in Healthy Adult Participants (MK-8591A-055)
nct_id: NCT06719570
overall_status: COMPLETED
phase: PHASE1
sponsor: Merck Sharp & Dohme LLC
study_type: INTERVENTIONAL
primary_condition: Healthy
countries: United States
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT06719570.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT06719570"
ct_last_update_post_date: 2024-12-06
last_seen_at: "2026-05-12T07:04:49.185Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# A Study of Doravirine and Islatravir as a Single Entity or Combination Therapy and the Effect of Food in Healthy Adult Participants (MK-8591A-055)

**Official Title:** An Open-Label Study to Evaluate the Effect of a High-Fat Meal on the Pharmacokinetics of Doravirine/Islatravir (100 mg/0.25 mg) Fixed-dose Combination Tablet and to Compare the Pharmacokinetics of Doravirine/Islatravir to Doravirine and Islatravir Single Entities in Healthy Adult Participants

**NCT ID:** [NCT06719570](https://clinicaltrials.gov/study/NCT06719570)

## Key Facts

- **Status:** COMPLETED
- **Phase:** PHASE1
- **Study Type:** INTERVENTIONAL
- **Target Enrollment:** 24
- **Lead Sponsor:** Merck Sharp & Dohme LLC
- **Conditions:** Healthy
- **Start Date:** 2024-01-23
- **Completion Date:** 2024-03-15
- **CT.gov Last Update:** 2024-12-06

## Brief Summary

The purpose of this study is to learn what happens to MK-8591A in a person's body over time. Researchers will compare what happens to MK-8591A in the body when it is given with and without food.

## Eligibility

- **Minimum age:** 19 Years
- **Maximum age:** 55 Years
- **Sex:** ALL
- **Healthy Volunteers:** Yes

```
Inclusion Criteria:

Inclusion Criteria include, but are not limited to:

* Has a body mass index (BMI) ≥ 18.0 and ≤ 32.0 kg/m\^2
* Is medically healthy with no clinically significant medical history, physical examination, clinical laboratory profiles, vital signs, and electrocardiograms (ECGs)

Exclusion Criteria:

Exclusion Criteria include, but are not limited to:

* Has a history or presence of clinically significant endocrine, gastrointestinal, cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases
* Has a history of cancer (malignancy)
```

## Arms

- **MK-8591A Sequence 1A** (EXPERIMENTAL) — Participants will receive Doravine/Islatravir (DOR/ISL) fixed-dose combination (FDC) tablet under fasting conditions followed by a DOR/ISL FDC tablet under fed conditions followed by a single dose Doravine tablet and a single dose Islatravir capsule under fasting conditions.
- **MK-8591A Sequence 2A** (EXPERIMENTAL) — Participants will receive DOR/ISL FDC tablet under fasting conditions followed by a single dose DOR tablet and a single dose ISL capsule under fasting conditions followed by DOR/ISL FDC tablet under fed conditions.
- **MK-8591A Sequence 1B** (EXPERIMENTAL) — Participants will receive DOR/ISL FDC tablet under fed conditions followed by a DOR/ISL FDC tablet under fasting conditions followed by a single dose DOR tablet and a single dose ISL capsule under fasting conditions.
- **MK-8591A Sequence 2B** (EXPERIMENTAL) — Participants will receive DOR/ISL FDC tablet under fed conditions followed by a single dose DOR tablet and a single dose ISL capsule under fasting condition followed by a DOR/ISL FDC tablet under fasting conditions.
- **MK-8591A Sequence 1C** (EXPERIMENTAL) — Participants will receive a single dose DOR tablet and a single dose ISL capsule under fasting conditions followed by DOR/ISL FDC tablet under fasting conditions followed by followed by a DOR/ISL FDC tablet under fed conditions.
- **MK-8591A Sequence 2C** (EXPERIMENTAL) — Participants will receive a single dose DOR tablet and a single dose ISL capsule under fasting conditions followed by DOR/ISL FDC tablet under fed conditions followed by followed by a DOR/ISL FDC tablet under fasting conditions.

## Interventions

- **MK-8591A** (DRUG) — Fixed dose combination tablet
- **Islatravir** (DRUG) — Oral capsule
- **Doravine** (DRUG) — Oral tablet

## Primary Outcomes

- **Area under the curve from time 0-infinity (AUC0-inf) of DOR** _(time frame: At designated time points up to ~30 days)_ — AUC0-inf is a measure of plasma drug concentration from time 0 to infinity and is estimated as the area under the plot of plasma concentration against time 0 to infinity after drug administration. Blood samples collected at designated time points will be used to determine the AUC0-inf of DOR.
- **Area under the curve from time 0 to last measurable concentration (AUC0-last) of Doravine** _(time frame: At designated time points up to ~30 days)_ — AUC0-last is defined as the area under the concentration-time curve from time 0 to time of last measurable concentration of DOR. Blood will be collected at designated time points to determine the AUC0-last of DOR.
- **Maximum plasma concentration (Cmax) of doravine** _(time frame: At designated time points up to ~30 days)_ — Cmax is the maximum concentration of the drug observed in plasma. Blood samples collected at designated time points will be used to determine Cmax of DOR.
- **Plasma concentration at 24 hours postdose (C24) of DOR** _(time frame: At designated time points up to ~24 hours postdose)_ — C24 is the concentration at 24 hours postdose of the drug observed in plasma. Blood samples collected at 24 postdose will be used to determine C24 of DOR.
- **AUC0-inf of ISL** _(time frame: At designated time points up to ~30 days)_ — AUC0-inf is a measure of plasma drug concentration and time 0 to infinity and is estimated as the area under the plot of plasma concentration against time 0 to infinity after drug administration. Blood samples collected at designated time points will be used to determine the AUC0-inf of ISL.
- **AUC0-last of ISL** _(time frame: At designated time points up to ~30 days)_ — AUC0-last is defined as the area under the concentration-time curve from time zero to time of last measurable concentration of ISL. Blood will be collected at designated time points to determine the AUC0-last of ISL.
- **Cmax of ISL** _(time frame: At designated time points up to ~30 days)_ — Cmax is the maximum concentration of the drug observed in plasma. Blood samples collected at designated time points will be used to determine Cmax of ISL.

## Secondary Outcomes

- **Number of participants who experienced an adverse event (AE)** _(time frame: Up to ~44 days)_
- **Number of participants who discontinued study intervention due to an AE** _(time frame: Up to ~30 days)_

## Locations (1)

- Celerion (Site 0001), Lincoln, Nebraska, United States

## Recent Field Changes (last 30 days)

- `status.overallStatus` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.phases` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.maxAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `outcomes.secondary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `locations.celerion (site 0001)|lincoln|nebraska|united states` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT06719570.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT06719570*  
*This page is a raw mirror with no AI summary, no editorial enrichment, and no Parkinson's-specific filtering.*