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Study on the Effects of Riociguat in Patients with Early Pulmonary Vascular Disease

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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 effects of a medication called Riociguat on a condition known as pulmonary vascular disease. This disease affects the blood vessels in the lungs and can lead to a more serious condition called pulmonary arterial hypertension, which is high blood pressure in the lungs' arteries. The purpose of the study is to explore how Riociguat can help patients with early signs of this disease.

Participants in the study will be randomly assigned to receive either Riociguat or a placebo. The study will last for 24 weeks, during which time the effects of the medication on the blood vessels in the lungs will be closely monitored. The study aims to see if Riociguat can reduce the resistance in the lung's blood vessels, which is a measure of how hard the heart has to work to pump blood through the lungs.

Throughout the study, several aspects of the participants' health will be assessed, including changes in their ability to exercise, their heart function, and their overall quality of life. The study is designed to be double-blind, meaning neither the participants nor the researchers will know who is receiving the actual medication and who is receiving the placebo, to ensure unbiased results. This trial is being conducted in multiple centers across different countries to gather comprehensive data on the safety and effectiveness of Riociguat for treating early pulmonary vascular disease.

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

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes reviewing medical history and recent right-heart catheterization results, which should not be older than one month, unless there have been no significant clinical changes.

    Eligibility is based on specific criteria related to early pulmonary vascular disease, including measurements of pulmonary arterial pressure and resistance.

  2. Step 2

    Randomization

    Participants are randomly assigned to receive either the study medication, riociguat, or a placebo. This process is double-blind, meaning neither the participant nor the study team knows which treatment is being administered.

  3. Step 3

    Medication administration

    The study medication, riociguat, is provided in the form of a film-coated tablet. It is taken orally. The exact dosage and frequency are determined by the study protocol and are administered consistently throughout the trial period.

  4. Step 4

    Treatment period

    The treatment period lasts for 24 weeks. During this time, participants continue to take the assigned medication and attend regular study visits for monitoring and assessment.

  5. Step 5

    Monitoring and assessments

    Throughout the trial, various health parameters are monitored, including changes in pulmonary vascular resistance, cardiac index, total pulmonary resistance, lung diffusion capacity, walking distance, and quality of life.

    These assessments help determine the efficacy and safety of the treatment.

  6. Step 6

    End of treatment evaluation

    At the end of the 24-week treatment period, a final evaluation is conducted to assess changes from baseline in the monitored health parameters.

    This evaluation provides data on the primary and secondary endpoints of the study.

Who can join the trial?

6 criteria

  • Both male and female patients can participate.
  • Patients must have early pulmonary vascular disease. This means either:
    • A mean pulmonary arterial pressure (mPAP) of 25 mmHg or more, with pulmonary vascular resistance (PVR) between 2 and less than 3 WU, and pulmonary arterial wedge pressure (PAWP) of 15 mmHg or less. This is known as group I PAH according to guidelines.
    • Or, mPAP between 21 and less than 25 mmHg, with PVR of 2 WU or more, and PAWP of 15 mmHg or less, associated with connective tissue disease or as an idiopathic/heritable form.
    • Patients should be treatment naïve, meaning they have not received specific medication for pulmonary arterial hypertension (PAH).
    • Patients can be on other treatments like oral anticoagulants, diuretics, digitalis, calcium channel blockers, or oxygen supplementation, as long as these were started at least 1 month before a specific test called right-heart catheterization.
    • The results from the right-heart catheterization test must not be older than 1 month at the first visit. This test measures the pressure in the heart and lungs. The time frame can be extended to 6 months if there have been no significant changes in the patient's condition.

Who cannot join the trial?

4 criteria

  • Patients who have a different condition than the one being studied, which is **pulmonary vascular disease**. This is a condition affecting the blood vessels in the lungs.
  • Patients who are not within the specified age range for the study.
  • Patients who belong to a group that is not included in the study.
  • Patients who are part of a vulnerable population that the study does not include.
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Investigated drugs

Riociguat (MK-4836) is a medication being studied for its potential to treat early pulmonary vascular disease, which can be an early sign of pulmonary arterial hypertension. The trial aims to see how this medication affects the resistance in the blood vessels of the lungs over a period of 24 weeks. Riociguat works by helping to relax and widen the blood vessels, which may improve blood flow and reduce the workload on the heart.

What is already known about the treatment

Riociguat – Riociguat is administered orally in tablet form. It is currently being studied in clinical trials for its effectiveness and safety in treating early pulmonary vascular disease, which can lead to pulmonary arterial hypertension. The main therapeutic indication for riociguat is to reduce pulmonary vascular resistance. At the molecular level, riociguat works by stimulating an enzyme called soluble guanylate cyclase, which helps relax blood vessels and improve blood flow. It is classified pharmacologically as a soluble guanylate cyclase stimulator.

Investigated diseases

Pulmonary Vascular Disease – This condition involves the blood vessels in the lungs, where they become narrowed, blocked, or damaged. As the disease progresses, it can lead to increased pressure in the pulmonary arteries, known as pulmonary hypertension. This increased pressure makes it harder for the heart to pump blood through the lungs, which can cause the heart to work harder and eventually weaken. Symptoms may include shortness of breath, fatigue, and chest pain, which can worsen over time. The disease can affect the ability to exercise and perform daily activities. It is often considered a rare disease, requiring specialized medical attention.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-509695-42-00Protocol code2020-01RCTEstimated enrolment70 patientsSponsorThoraxklinik Heidelberg gGmbH

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