Skip to content

MK8591-024: Oral ISL QM as PrEP in MSM and TGW at High Risk for HIV-1 Infection

A Phase 3, Randomized, Active-Controlled, Double-Blind Clinical Study to Evaluate the Efficacy and Safety of Oral Islatravir Once-Monthly as Preexposure Prophylaxis in Cisgender Men and Transgender Women Who Have Sex With Men, and Are at High Risk for HIV-1 Infection

Status
Active, not recruiting
Phases
Phase 3
Study type
Interventional
Source
PACTR
Registry ID
PACTR202109759050023
Enrollment
1500
Registered
2021-09-13
Start date
2021-06-01
Completion date
Unknown
Last updated
2026-01-27

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

Conditions

HIV/AIDS

Interventions

Placebo to FTCTDF
FTCTDF

Sponsors

MSD Pty Ltd.
Lead Sponsor

Eligibility

Sex/Gender
All

Inclusion criteria

Inclusion criteria: 1. Is confirmed HIV-uninfected based on negative HIV-1/HIV-2 test result before randomization. 2. Is sexually active with male (assigned male sex at birth) or transgender female partners defined as having anal sexual intercourse with a man or TGW at least once in the past month. 3. Is at high risk for sexually acquiring HIV-1 infection based on self-report of at least 1 of the following: Condomless receptive anal intercourse in the 6 months prior to screening occurring outside a mutually monogamous HIV seronegative concordant relationship,More than 5 partners (anal intercourse) in the 6 months prior to screening (regardless of condom use and HIV serostatus, as reported by the enrollee),Any unprescribed stimulant drug use in the 6 months prior to screening,Rectal or urethral gonorrhea or chlamydia or incident syphilis in the 6 months prior to screening.4.Is cisgender male or transgender female (assigned male sex at birth), and =16 years of age at the time of providing informed consent/assent. 5.The participant (or legally acceptable representative) has provided documented informed consent /assent for the study. 6.Has no plans to relocate or travel away from the site for =4 consecutive weeks during study participation

Exclusion criteria

Exclusion criteria: 1. Has hypersensitivity or other contraindication to any component of the study interventions as determined by the investigator. 2. Has active HBV infection (defined as HBsAg-positive or HBV DNA positive). 3. Has known current or chronic history of liver disease (eg, nonalcoholic or alcoholic steatohepatitis) or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome, asymptomatic gallstones, or cholecystectomy), unless the participant has stable liver function tests and no evidence of hepatic synthetic dysfunction. 5. Has a history or current evidence of any condition (including active tuberculosis infection), therapy, laboratory abnormality or other circumstance (including drug or alcohol abuse or dependence) that might, in the opinion of the investigator, confound the results of the study or interfere with the participant’s participation for the full duration of the study, such that it is not in the best interest of the participant to enroll. 6. Has taken cabotegravir at any time (past or current). Is currently receiving or is anticipated to require any prohibited therapies outlined in Section 6.5 of the study protocol from 30 days prior to Day 1 through the duration of the study.

Design outcomes

Primary

MeasureTime frame
1. Confirmed HIV-1 infection 2. AEs and AEs leading to discontinuation of study intervention

Secondary

MeasureTime frame
Confirmed HIV-1 infection

Countries

South Africa

Contacts

Public ContactZoe Nell

Clinical Research Director

zoe.nell@merck.com+270116553307

Outcome results

None listed

Source: PACTR (via WHO ICTRP) · Data processed: Feb 4, 2026