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Study on the Safety and Effectiveness of Emtricitabine and Tenofovir Alafenamide for HIV-1 Prevention in Men and Transgender Women at Risk

Fast replyRegistered drugNo placebo
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What is this trial about?

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

This clinical trial is focused on studying the prevention of HIV-1 infection in men and transgender women who have sex with men and are at risk of contracting the virus. The study will use a medication called Descovy, which is a combination of two active substances: emtricitabine and tenofovir alafenamide. These substances are taken together in the form of film-coated tablets.

The purpose of the study is to evaluate the safety and effectiveness of this medication when taken once daily as a preventive measure, also known as pre-exposure prophylaxis. Participants in the study will be randomly assigned to receive either the medication or a placebo. The study will follow participants for a minimum of 48 weeks, with at least half of the participants being followed for 96 weeks. During this time, the study will monitor the occurrence of HIV-1 infections among participants.

Throughout the study, various health assessments will be conducted, including checks on bone health and kidney function. These assessments will help determine any changes in the body that may occur as a result of taking the medication. The study aims to provide valuable information on how well the medication works in preventing HIV-1 infection and its safety for long-term use.

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

    Joining the study

    Upon joining the study, participants will be randomly assigned to receive either the study medication or a placebo. This process is double-blind, meaning neither the participant nor the study team will know which one is being administered.

  2. Step 2

    Medication administration

    Participants will take a film-coated tablet called Descovy, which contains the active substances emtricitabine and tenofovir alafenamide. The tablet is taken orally once daily.

    The duration of the medication administration is a minimum of 48 weeks, with at least 50% of participants continuing for 96 weeks.

  3. Step 3

    Regular follow-up visits

    Participants will attend regular follow-up visits to monitor their health and the effectiveness of the medication. These visits will include various tests and assessments to ensure safety and efficacy.

    The primary goal is to assess the rates of HIV-1 infection among participants.

  4. Step 4

    Health assessments

    Health assessments will include tests for bone mineral density (BMD) at the hip and spine, renal function, and other relevant health markers.

    These assessments will occur at specific intervals, such as Week 48 and Week 96, to track any changes from the baseline.

  5. Step 5

    Completion of the study

    Upon completion of the study period, participants will undergo a final evaluation to assess the overall outcomes and any long-term effects of the medication.

    The study is estimated to conclude by September 29, 2027.

Who can join the trial?

13 criteria

  • Must be HIV-1 negative, meaning you do not have the HIV-1 virus.
  • Must be a man who has sex with men (MSM) or a transgender woman (TGW) who was male at birth.
  • Must meet at least one of the following conditions:
    • Had condomless anal intercourse with at least two different male partners in the past 12 weeks. These partners must either have HIV or their HIV status is unknown.
    • Have a documented history of syphilis in the past 24 weeks. Syphilis is a sexually transmitted infection.
    • Have a documented history of rectal gonorrhea or chlamydia in the past 24 weeks. These are sexually transmitted infections.
    • Must be at least 18 years old.
    • Must have an estimated glomerular filtration rate (eGFR) of at least 60 mL/min. This is a measure of how well your kidneys are working.
    • Must have adequate liver and blood function:
      • AST and ALT levels should be no more than 2.5 times the upper limit of normal. These are liver enzymes.
      • Total bilirubin should be no more than 1.5 mg/dL, or normal direct bilirubin. Bilirubin is a substance made during the breakdown of red blood cells.
      • Absolute neutrophil count should be at least 1000/mm3. Neutrophils are a type of white blood cell.
      • Platelets should be at least 75,000/mm3. Platelets help with blood clotting.
      • Hemoglobin should be at least 10 g/dL. Hemoglobin is a protein in red blood cells that carries oxygen.
      • Must be willing and able to comply with study procedures.

Who cannot join the trial?

4 criteria

  • Participants cannot join if they are not men who have sex with men (MSM) or transgender women (TGW) who have sex with men.
  • Participants must be male; females are not eligible.
  • Participants must be within the specified age range for the study.
  • Participants cannot join if they are part of a vulnerable population, which means groups that might need special protection or care.
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Investigated drugs

  • Emtricitabine

    is a medication used to help prevent HIV infection. It works by blocking a specific enzyme that the virus needs to multiply. By doing this, it helps to lower the amount of virus in the body and reduces the risk of getting HIV when taken regularly as part of a prevention plan.

  • Tenofovir Alafenamide

    is another medication used to prevent HIV infection. It also works by blocking the virus from multiplying in the body. This medication is often used in combination with other drugs to provide a stronger defense against the virus, helping to keep the virus at bay and reduce the risk of infection.

What is already known about the treatment

Emtricitabine and Tenofovir Alafenamide (F/TAF) – This medication is taken as a pill once a day and is used to help prevent HIV-1 infection in men and transgender women who have sex with men and are at risk of getting HIV. It is currently being studied in clinical trials to ensure it is safe and effective for this purpose. The medication works by blocking a key enzyme that the HIV virus needs to multiply, which helps to prevent the virus from spreading in the body. It belongs to a group of drugs known as antiretrovirals, which are used to manage and prevent HIV infections.

Investigated diseases

Human Immunodeficiency Virus Type 1 (HIV-1) Infection – HIV-1 is a virus that attacks the immune system, specifically targeting CD4 cells, which are crucial for immune defense. As the virus replicates, it gradually depletes these cells, weakening the immune system over time. Initially, individuals may experience flu-like symptoms, but as the infection progresses, it can lead to more severe immune system damage. Without intervention, the body becomes increasingly vulnerable to opportunistic infections and certain cancers. The progression of the disease can vary, with some individuals remaining asymptomatic for years. Monitoring and managing the infection is essential to prevent further immune system deterioration.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2022-501763-40-00Protocol codeGS-US-412-2055Estimated enrolment5 000 patientsSponsorGilead Sciences Inc.

sourced from the EU Clinical Trials Register and site verification

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