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Study of MK-8527 taken once monthly compared to emtricitabine/tenofovir taken daily for HIV-1 prevention

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial focuses on preventing HIV-1 infection using two different medications. The study compares a new experimental drug called MK-8527 taken once monthly with a combination of emtricitabine and tenofovir taken daily. The purpose is to determine if the new monthly medication is as effective and safe as the daily treatment in preventing HIV-1 infection.

The study uses film-coated tablets that contain either the active medications or placebo. Participants will receive either MK-8527 once per month or the combination of emtricitabine and tenofovir once per day. The study will monitor how well these medications prevent HIV-1 infection and evaluate their safety over time.

During the study, participants will take their assigned medication as directed and attend regular medical visits. The medications are taken by mouth, and the study team will track any health changes that occur. The study will look at how many people develop HIV-1 infection while taking the medications and monitor any side effects that may occur.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial medication assignment

    You will be randomly assigned to receive either MK-8527 taken once monthly or emtricitabine/tenofovir taken daily

    Both medications are taken orally in the form of film-coated tablets

    The purpose is to prevent HIV-1 infection

  2. Step 2

    Treatment period

    If assigned to MK-8527: Take one tablet once per month

    If assigned to emtricitabine/tenofovir: Take one tablet daily

    The treatment period will continue from September 2025 through October 2027

  3. Step 3

    Regular health monitoring

    Regular HIV-1/HIV-2 testing will be conducted to confirm negative status

    Your health status will be monitored for any side effects

    Medical staff will track and document any health-related events that occur during the study

  4. Step 4

    Safety assessment

    Any side effects will be documented and evaluated

    If side effects occur, the medical team will assess whether it is safe to continue the medication

    You may need to stop taking the study medication if significant side effects occur

  5. Step 5

    Study completion

    The study will conclude in October 2027

    Final HIV testing and health evaluations will be conducted

    Your participation will end after the final assessment

Who can join the trial?

11 criteria

  • Must test negative for HIV-1 and HIV-2 during screening
  • Must be one of the following:
    • A cisgender man (person whose gender identity matches their birth sex)
    • A transgender woman (person assigned male at birth who identifies as female)
    • A transgender man (person assigned female at birth who identifies as male)
    • A gender nonbinary person (person who does not identify exclusively as male or female)
    • Must have had at least one of these experiences:
      • Unprotected receptive anal sex in the past 12 months (not including sex with a committed monogamous partner)
      • Receptive anal sex with 2 or more partners in the past 3 months (with or without protection)
      • Had gonorrhea or chlamydia (infections) in the rectum or urethra, or new syphilis infection in the past 6 months
      • Used stimulant drugs during sexual activity in the past 3 months
      • Must be at least 16 years old
      • Must weigh at least 35 kilograms (approximately 77 pounds)

Who cannot join the trial?

15 criteria

  • Positive test result for HIV-1 (Human Immunodeficiency Virus type 1)
  • Known allergy or sensitivity to any components of the study medications
  • Active or chronic hepatitis B infection (liver inflammation caused by hepatitis B virus)
  • Significant kidney problems or decreased kidney function
  • Current pregnancy or breastfeeding
  • History of bone disorders or significant bone loss
  • Active, untreated sexually transmitted infections
  • Use of certain medications that could interact with study drugs
  • History of serious medical conditions that could interfere with study participation
  • Participation in another clinical trial within the past 30 days
  • History of poor compliance with medical treatments
  • Active substance abuse or dependence
  • Mental health conditions that could affect ability to follow study procedures
  • Abnormal laboratory test results that indicate health issues
  • High risk of complications based on medical history
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Investigated drugs

  • MK-8527

    is an experimental medication taken once a month by mouth to help prevent HIV-1 infection in people who are at risk of getting HIV. This is known as pre-exposure prophylaxis (PrEP).

  • FTC/TDF

    (emtricitabine/tenofovir disoproxil fumarate) is a daily oral medication currently used to prevent HIV infection. It's a combination of two medications that work together to reduce the risk of getting HIV-1 when taken regularly.

What is already known about the treatment

  • MK-8527

    An investigational oral medication being studied for HIV-1 prevention (pre-exposure prophylaxis, or PrEP), administered once monthly. This novel compound is currently undergoing Phase 3 clinical trials to evaluate its efficacy and safety compared to the daily FTC/TDF regimen. The medication represents a potential breakthrough in HIV prevention by offering a more convenient dosing schedule than current daily preventive options.

  • FTC/TDF

    A combination medication (emtricitabine/tenofovir disoproxil fumarate) taken once daily as an oral tablet for HIV-1 prevention. This established medication works by blocking an enzyme called reverse transcriptase that HIV needs to multiply, serving as a proven pre-exposure prophylaxis (PrEP) treatment. It is currently considered the standard of care for HIV prevention and is being used as the active control in clinical trials of newer preventive medications.

Investigated diseases

HIV (Human Immunodeficiency Virus) Infection - A viral infection that affects the immune system by targeting CD4 cells, which help the body fight infections. The virus can spread through direct contact with certain body fluids from a person infected with HIV. Initially, a person may experience flu-like symptoms during the acute phase, followed by a period with no obvious symptoms. Without intervention, the virus continues to multiply and gradually weakens the immune system over time. The virus specifically attacks T cells (also called CD4 cells), which are crucial for maintaining the body's defense system.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-520610-58-00Protocol codeMK-8527-011Estimated enrolment4 700 patientsSponsorMerck Sharp & Dohme LLC

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