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Study on the Effects of Riociguat and Macitentan in Patients with Inoperable Chronic Thromboembolic Pulmonary Hypertension

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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 Chronic Thromboembolic Pulmonary Hypertension (CTEPH), which is a type of high blood pressure affecting the lungs and heart. The study is specifically for patients with CTEPH that cannot be treated with surgery. The trial will explore the effects of a treatment using two medications, riociguat and macitentan, compared to the standard treatment which includes riociguat and a placebo. Macitentan is a medication that comes in the form of a film-coated tablet and is taken orally.

The purpose of the study is to compare the effectiveness of the dual medication treatment against the standard single medication treatment in reducing the resistance in the blood vessels of the lungs. Participants in the study will be newly diagnosed and have not received previous treatment for CTEPH. The study will involve taking the medications and undergoing various assessments over a period of time to monitor changes in the condition.

Throughout the study, participants will have their lung function and overall health monitored, including their ability to walk a certain distance in six minutes, their quality of life, and other health indicators. The study aims to provide insights into whether the dual medication approach offers better outcomes for patients with inoperable CTEPH compared to the standard treatment.

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 assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes a review of medical history and a series of tests to confirm the diagnosis of inoperable chronic thromboembolic pulmonary hypertension (CTEPH).

    Tests may include a ventilation-perfusion lung scan, digital subtraction pulmonary angiography, and CT pulmonary angiography to confirm the diagnosis.

  2. Step 2

    Right-heart catheterization

    A right-heart catheterization is performed within 12 weeks prior to the screening visit or during the screening period. This test measures the pressure in the pulmonary artery and assesses the severity of pulmonary hypertension.

  3. Step 3

    Medication administration

    Participants are randomly assigned to receive either a dual oral treatment or a standard-of-care monotherapy. The dual treatment includes riociguat and macitentan, while the monotherapy includes riociguat and a placebo.

    The medications are taken orally. The dosage and frequency are determined by the study protocol and are monitored by the study team.

  4. Step 4

    Monitoring and follow-up

    Participants are monitored regularly throughout the study. This includes assessments of pulmonary vascular resistance (PVR), six-minute walk distance (6MWD), and other health indicators.

    Follow-up visits are scheduled to track progress and any changes in symptoms or health status.

  5. Step 5

    End of study evaluation

    At the end of the study, a final evaluation is conducted. This includes measuring the primary endpoint, which is the change in pulmonary vascular resistance at rest at week 16.

    Secondary endpoints, such as changes in six-minute walk distance and quality of life, are also assessed.

Who can join the trial?

12 criteria

  • Must provide a signed informed consent, which means agreeing to participate after understanding the study details.
  • Must be a male or female aged between 18 and 80 years.
  • Must have been newly diagnosed with **CTEPH** (Chronic Thromboembolic Pulmonary Hypertension) and not have received any treatment for it. The condition must be considered inoperable, meaning surgery is not possible, but the patient is eligible for a procedure called **balloon pulmonary angioplasty**. This decision is made by a team of specialists.
  • Must have symptoms of **pulmonary hypertension** (high blood pressure in the lungs) classified as **WHO FC II** or higher, which indicates the severity of symptoms.
  • The diagnosis must be confirmed using at least two of the following tests: a **ventilation-perfusion lung scan**, **digital subtraction pulmonary angiography (DSA)**, or **CT pulmonary angiography (CTPA)**.
  • Must have confirmation that surgery is not possible based on a **CTPA scan** and/or **DSA**.
  • Must have had a **right-heart catheterization (RHC)**, a test to measure the pressure in the heart and lungs, within 12 weeks before or during the screening. The results must show:
    • Mean pulmonary artery pressure (**mPAP**) of 25 mmHg or higher.
    • **Pulmonary artery wedge pressure (PAWP)** or left ventricular end diastolic pressure of 15 mmHg or lower.
    • **Pulmonary vascular resistance (PVR)** at rest of 400 dyn.sec.cm-5 or higher.
    • Must have been on blood-thinning medication, such as vitamin K antagonists, direct oral anticoagulants, unfractionated heparin, or low molecular weight heparin, for at least 3 months before the baseline RHC.
    • Must be able to walk at least 50 meters in a 6-minute walk test (**6MWD**).
    • Women who can have children must have a negative pregnancy test before treatment and agree to use reliable birth control from the start of the study until one month after stopping the study treatment.

Who cannot join the trial?

8 criteria

  • Patients who have had surgery to treat their condition cannot participate.
  • Patients who have already received treatment for their condition are not eligible.
  • Patients with other serious health problems that could interfere with the study are excluded.
  • Pregnant or breastfeeding women cannot take part in the study.
  • Patients who are unable to follow the study procedures or take the study medication as directed are not eligible.
  • Patients who are participating in another clinical trial at the same time are excluded.
  • Patients with a history of drug or alcohol abuse that could affect their ability to participate are not eligible.
  • Patients with allergies to the study medications or similar drugs cannot participate.
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Investigated drugs

  • Riociguat

    is a medication used to treat pulmonary hypertension. It works by relaxing and widening the blood vessels in the lungs, which helps to lower blood pressure and improve blood flow. In this trial, it is used as part of both the dual oral treatment and the standard-of-care monotherapy.

  • Macitentan

    is a medication that helps to manage pulmonary hypertension by blocking certain substances in the body that cause blood vessels to narrow. This action helps to reduce blood pressure in the lungs and improve the ability to exercise. In this trial, it is used in combination with riociguat as part of the dual oral treatment.

What is already known about the treatment

  • Riociguat

    Riociguat is administered orally in tablet form. It is currently used in medicine for treating certain types of pulmonary hypertension, including inoperable chronic thromboembolic pulmonary hypertension (CTEPH). The main therapeutic indication is to improve exercise capacity and delay clinical worsening in patients with CTEPH. Riociguat works by stimulating the enzyme soluble guanylate cyclase, which increases the levels of cyclic guanosine monophosphate (cGMP), leading to relaxation of the pulmonary arteries and reduction of blood pressure in the lungs. It is classified as a soluble guanylate cyclase stimulator.

  • Macitentan

    Macitentan is taken orally in tablet form. It is used in the treatment of pulmonary arterial hypertension to improve exercise ability and delay disease progression. The medication works by blocking endothelin receptors, which helps to relax and widen the blood vessels, reducing the blood pressure in the lungs. Macitentan is classified as an endothelin receptor antagonist.

Investigated diseases

Inoperable Chronic Thromboembolic Pulmonary Hypertension – This disease is characterized by high blood pressure in the lungs' arteries due to blood clots that have not been surgically removed. Over time, these clots can lead to increased resistance in the pulmonary arteries, making it difficult for the heart to pump blood through the lungs. As the condition progresses, patients may experience symptoms such as shortness of breath, fatigue, and chest pain. The disease can lead to a decrease in exercise capacity and overall quality of life. It is considered inoperable when surgical removal of the clots is not possible. Management focuses on reducing symptoms and improving the patient's ability to perform daily activities.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-513672-17-00Protocol codeAPHP201037Estimated enrolment96 patientsSponsorAssistance Publique Hopitaux De Paris

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