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Study on Reduced Dose of Alteplase for Patients with Intermediate-High-Risk Acute Pulmonary Embolism

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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 a condition known as intermediate-high-risk acute pulmonary embolism. This is a serious condition where a blood clot blocks the blood vessels in the lungs, which can lead to severe health issues. The treatment being tested in this study is a medication called ACTILYSE, which contains the active substance alteplase. This medication is used to help dissolve blood clots and is administered through an injection or infusion into the veins. The study also involves a comparison with a placebo, which is a substance with no active medication.

The purpose of the study is to evaluate the effectiveness of a reduced dose of this thrombolytic therapy, which is a treatment that helps break down blood clots, in patients with this type of pulmonary embolism. Participants in the study will receive either the reduced dose of ACTILYSE or a placebo. The study will monitor the participants over a period of 30 days to assess the outcomes, which include the risk of death from any cause, the occurrence of hemodynamic decompensation (a condition where the heart cannot maintain adequate blood flow), or the recurrence of pulmonary embolism.

Throughout the study, researchers will also observe any severe or life-threatening bleeding events and evaluate the overall clinical benefits of the treatment. The study aims to provide valuable insights into whether a lower dose of the medication can effectively treat the condition while minimizing potential side effects. This research is important for improving treatment options for patients with intermediate-high-risk acute pulmonary embolism.

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

    Participation begins after meeting specific criteria, including being 18 years or older and having a confirmed diagnosis of acute pulmonary embolism (PE) with symptoms starting within the last two weeks.

    The condition must be confirmed through specific medical imaging tests, and there must be an elevated risk of early death or complications.

  2. Step 2

    Randomization

    Randomization occurs within 6 hours after confirming certain medical criteria, such as heart function and injury markers.

    This process assigns participants to different treatment groups without choice or preference.

  3. Step 3

    Treatment administration

    Participants receive a reduced dose of thrombolytic therapy, specifically using the medication alteplase.

    The medication is administered intravenously, meaning it is given directly into a vein.

  4. Step 4

    Monitoring and follow-up

    Participants are monitored for 30 days to assess the treatment's effectiveness and any potential side effects.

    The primary focus is on preventing death, hemodynamic issues, or recurrent PE during this period.

  5. Step 5

    Evaluation of outcomes

    The main outcomes evaluated include survival, the occurrence of severe bleeding, and overall clinical benefit.

    These outcomes help determine the success and safety of the treatment.

Who can join the trial?

13 criteria

  • Must be **18 years or older**.
  • Must have an **acute pulmonary embolism (PE)** confirmed by tests, with first symptoms appearing **2 weeks or less** before joining the study. Confirmation can be through:
    • A lung scan showing a mismatch in air and blood flow in the lungs.
    • A **CT scan** or special lung X-ray showing a blockage in a lung artery.
    • PE must be confirmed within **24 hours** before joining the study.
    • Must have a **high risk of early death** or serious heart or lung problems, shown by at least one of these:
      • Blood pressure of **110 mm Hg or lower** for at least 15 minutes.
      • Temporary need for fluids or low-dose medication to raise blood pressure, but stable within 2 hours and maintaining blood pressure of **90 mm Hg or higher** without medication.
      • Breathing rate over **20 breaths per minute** or oxygen level below **90%** while resting and breathing room air.
      • History of **chronic heart failure**, diagnosed or treated in the past 12 months.
      • **Right heart dysfunction** shown by a specific heart measurement (RV/LV diameter ratio greater than 1.0) on an ultrasound or CT scan.
      • **High levels of troponin**, a heart-related protein, in the blood.
      • Must be able to join the study within **6 hours** after the doctor gets the results of the heart tests.
      • Must sign a **consent form** agreeing to participate.
      • Must be covered by a **social security system**.

Who cannot join the trial?

3 criteria

  • Patients who are not diagnosed with **intermediate-high-risk acute pulmonary embolism** cannot participate. This condition involves a blockage in the lung's blood vessels that is considered serious but not the most severe.
  • Patients who are not within the specified age range for the study cannot participate. The study is open to certain age groups only.
  • Patients who are part of a vulnerable population, which means they might need special protection or care, are not eligible to participate.
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Investigated drugs

Thrombolytic Therapy is a treatment used to dissolve dangerous clots in blood vessels, improve blood flow, and prevent damage to tissues and organs. In this clinical trial, a reduced dose of thrombolytic therapy is being tested to see if it is effective for patients with intermediate high-risk acute pulmonary embolism. The goal is to determine if this lower dose can still effectively treat the condition while potentially reducing the risk of side effects associated with higher doses.

What is already known about the treatment

Thrombolytic Therapy – This medication is administered intravenously and is used to dissolve blood clots. It is currently being studied in clinical trials for its effectiveness in treating intermediate-high-risk acute pulmonary embolism. The main therapeutic indication is to reduce the risk of complications from blood clots in the lungs. At the molecular level, it works by activating plasminogen to plasmin, which breaks down fibrin, a key component of blood clots. It is classified as a thrombolytic agent.

Investigated diseases

Acute Pulmonary Embolism – This condition occurs when a blood clot blocks one or more arteries in the lungs. It often originates from clots in the legs, known as deep vein thrombosis, which travel to the lungs. Symptoms can include sudden shortness of breath, chest pain, and coughing, sometimes with blood. The severity of the condition can vary, with intermediate-high-risk cases involving significant strain on the heart and potential for hemodynamic instability. The progression of the disease can lead to complications such as reduced oxygen levels in the blood and damage to lung tissue. Early recognition and management are crucial to prevent further complications.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-511321-54-00Protocol codeP160924Estimated enrolment800 patientsSponsorAssistance Publique Hopitaux De Paris

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