Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Recruiting

Study on Acyclovir for Patients with Herpes Simplex Virus Reactivation in the Throat on Mechanical Ventilation with One or No Organ Failure

Verified siteRegistered drugNo placebo
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

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

This clinical trial is focused on patients who are in the Intensive Care Unit (ICU) and are receiving help to breathe through a machine, known as mechanical ventilation. These patients have a reactivation of the Herpes simplex virus (HSV) in their throat and have one or no organ failures. The study is investigating the use of a medication called acyclovir, which is a powder that is mixed into a solution for injection, to see if it can help reduce the risk of death in these patients. The trial will compare the effects of acyclovir with a placebo to determine its effectiveness.

The purpose of the study is to find out if treating these patients with acyclovir can lower the chances of dying within 60 days. Participants in the study will receive either acyclovir or a placebo through an intravenous (IV) injection, which means the medication is given directly into a vein. The treatment will last for up to 14 days. During the study, doctors will monitor the patients' health, including how long they need mechanical ventilation, their stay in the ICU, and any changes in their condition.

Throughout the study, various health indicators will be checked, such as the presence of HSV in the throat and any signs of lung infections or other complications. The study aims to provide valuable information on whether acyclovir can be a beneficial treatment for patients with HSV reactivation in the ICU, potentially improving their chances of recovery and reducing the length of their hospital stay.

The research process

The trial runs in 6 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, eligibility is confirmed based on specific criteria such as age, mechanical ventilation duration, and HSV throat reactivation.

    Consent is required from the patient or a designated representative.

  2. Step 2

    Randomization

    Participants are randomly assigned to receive either the treatment with aciclovir or a placebo.

    This process ensures that the study results are unbiased.

  3. Step 3

    Treatment administration

    The treatment involves the administration of aciclovir through intravenous infusion.

    The dosage is 500 mg, prepared as a powder for solution for injection.

    The frequency and duration of administration are determined by the study protocol.

  4. Step 4

    Monitoring and assessments

    Regular assessments are conducted to monitor health status, including the SOFA score and other health indicators.

    These assessments occur at specified intervals: days 1, 3, 5, 7, 10, 14, 21, and 28 post-randomization.

  5. Step 5

    Evaluation of outcomes

    The primary outcome is the mortality rate at day 60 post-randomization.

    Secondary outcomes include day-90 mortality, duration of mechanical ventilation, and incidence of HSV-related conditions.

  6. Step 6

    Completion of study participation

    Participation concludes after the final assessments and evaluations are completed.

    The study aims to determine the effectiveness of aciclovir in reducing mortality and improving health outcomes.

Who can join the trial?

6 criteria

  • Must be **18 years old** or older.
  • Must be on **invasive mechanical ventilation** for at least 96 hours and expected to continue for at least 48 more hours. This means a machine is helping you breathe.
  • Must have **HSV reactivation in the throat**. This is confirmed by a test called PCR that checks for the presence of the herpes virus in a throat swab.
  • Must have **1 or no organ failures**. Organ failure is when an organ is not working properly, and it is measured by a score called SOFA. A score of 3 or 4 indicates organ failure.
  • Must have **written consent** from you, a close relative, or a trusted person you have previously appointed. In emergencies, there might be a different procedure for consent.
  • Must be **covered by social security**.

Who cannot join the trial?

7 criteria

  • Patients who are not in the Intensive Care Unit (ICU).
  • Patients who are not on invasive mechanical ventilation. This means they are not using a machine to help them breathe through a tube.
  • Patients who do not have HSV throat reactivation. This refers to the reactivation of the herpes simplex virus in the throat.
  • Patients with more than one organ failure. Organ failure means that an organ, like the heart or kidneys, is not working properly.
  • Patients who are younger than 18 years old or older than 65 years old.
  • Patients who are not male or female.
  • Patients who are not considered part of a vulnerable population. This means they are not in a group that might need special protection or care.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

Acyclovir is a medication used in this trial to treat patients who are intubated and mechanically ventilated. It is specifically aimed at those who have a reactivation of the Herpes simplex virus in the throat and have one or fewer organ failures. The goal of using acyclovir in this trial is to reduce the mortality rate of these patients by day 60.

What is already known about the treatment

Acyclovir – Acyclovir is administered orally or intravenously, depending on the severity of the condition. It is currently well-established in medical literature as an antiviral medication primarily used to treat infections caused by the herpes simplex virus. The main therapeutic indication for acyclovir in this context is to reduce mortality in patients in intensive care units who are mechanically ventilated and have herpes simplex virus reactivation in the throat with one or no organ failures. At the molecular level, acyclovir works by inhibiting the viral DNA polymerase enzyme, which prevents the virus from replicating. It is classified pharmacologically as an antiviral agent.

Investigated diseases

Herpes Simplex Virus Throat Reactivation – This condition occurs when the herpes simplex virus, which typically causes cold sores, becomes active again in the throat. It is often seen in patients who are critically ill and require mechanical ventilation in an intensive care unit (ICU). The virus can cause inflammation and discomfort in the throat, potentially complicating the patient's recovery. Reactivation is more likely when the immune system is weakened, such as during severe illness or stress. The condition can lead to further complications if not managed properly, but it primarily affects the throat area.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-505510-26-00Protocol codeAPHP220800Estimated enrolment246 patientsSponsorAssistance Publique Hopitaux De Paris

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

ClinicalTrials.eu

Every clinical trial in Europe, in plain language.

Explore the full ecosystem of clinical research in Europe.

Search trials

Legal notice · Published by CTIN POLAND sp. z o.o., ul. rtm. Witolda Pileckiego 67/109, 02-781 Warsaw, Poland · KRS 0001111334 · REGON 528919042 · NIP 9512598637

© 2026 Clinical Trials EU – European Clinical Trials Information Network

GDPR compliance, ISO 9001 and ISO 27001 certified (LL-C Certification)

On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).