Radiopaque Matrix MK-8591 Implant in Participants at Low-Risk for Human Immunodeficiency Virus Type 1 (HIV-1) Infection (MK-8591-043)

A Phase 2a, Double-Blind, Placebo-Controlled Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of a Radiopaque Matrix MK-8591 Implant in Participants at Low-Risk for HIV-1 Infection

Status

Withdrawn

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05115838

Enrollment

Registered

2021-11-10

Start date

2024-01-04

Completion date

2025-10-02

Last updated

2023-11-24

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Human Immunodeficiency Virus, HIV

Brief summary

The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (PK) of an islatravir (ISL)-eluting implant. Participants will receive an implant placed in the upper arm for approximately 52 weeks with 8 weeks of follow-up in the Base Study. A subset of participants will also receive a second implant for an additional 12 weeks before 8 weeks of follow-up in the Substudy.

Interventions

DRUGIslatravir

ISL 47, 52, or 57 mg implantable rod placed subdermally on the upper arm.

DRUGPlacebo

Placebo implantable rod placed subdermally on the upper arm.

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

TRIPLE (Subject, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to 55 Years

Healthy volunteers

Yes

Inclusion criteria

* Is in good health * Is confirmed human immunodeficiency virus (HIV)-uninfected * Is at low risk of HIV infection * For males, uses contraception in accordance with local regulations regarding contraception use for those participating in clinical trials * For females, is not pregnant or breastfeeding and one of the following applies: * Is not a participant of childbearing potential (POCBP) * Is a POCBP and uses an acceptable contraception method or is abstinent

Exclusion criteria

* Has an active diagnosis of hepatitis (B or C) due to any cause * Has a history of malignancy ≤5 years before signing informed consent * Has a history or current evidence of any condition that might confound study results or interfere with study participation * Has a history of keloid in upper arm or presence of tattoo, scar, or other physical finding that could interfere with implant placement (the contralateral arm may be used if the findings are limited to 1 arm) * Is taking or is expected to take immunosuppressants during the study

Design outcomes

Primary

Measure	Time frame	Description
Percentage of participants with ≥1 adverse events (AEs)	Up to 60 weeks	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.
Percentage of participants withdrawing from study treatment due to adverse event (AE)	Up to 52 weeks	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.

Secondary

Measure	Time frame	Description
Plasma concentration of islatravir (ISL) 12 weeks after placement of an ISL-eluting implant (ISL C12weeks)	Week 12	Plasma ISL C12weeks will be determined.
Plasma concentration of islatravir (ISL) 52 weeks after placement of an ISL-eluting implant (ISL C52weeks)	Week 52	Plasma ISL C52weeks will be determined.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026