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Discontinuing vs Continuing Riociguat in Chronic Thromboembolic Pulmonary Hypertension Patients After Successful Balloon Pulmonary Angioplasty

Verified siteRegistered drugNo placebo
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What is this trial about?

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

The investigation focuses on chronic thromboembolic pulmonary hypertension, a condition where blood clots cause high pressure in the lungs’ arteries, leading to strain on the heart. Participants have previously undergone balloon pulmonary angioplasty, a procedure that uses a small balloon to open narrowed lung vessels, and are being treated with the oral medication riociguat. The purpose of the study is to estimate the risk of clinical worsening when the drug is stopped compared with continuing it after a successful angioplasty.

After successful angioplasty, eligible individuals are divided into two groups: one continues taking riociguat and the other stops the medication. Both groups are followed for at least twelve months, with regular clinic visits to monitor health status. Simple tests include a walking test that measures how far a person can walk in six minutes (6‑minute walk distance) and questionnaires that assess daily functioning and quality of life, such as the EQ-5D-5L and disease‑specific EmPHasis‑10. Blood tests for a heart‑stress marker (NT-proBNP) and routine checks of heart function are also performed.

During the follow‑up period, any serious events such as death, hospitalization because of worsening lung pressure, right heart failure, need for a lung transplant, use of intravenous diuretics or inotropic support, or requirement of medication called prostanoids are recorded. The study aims to provide information on whether stopping riociguat after a successful procedure is safe or if continuing the medication offers better protection against these serious outcomes.

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 study visit

    After joining the study, you will meet the study team and give written consent to take part.

    You will undergo baseline measurements that include the 6‑minute walk distance, assessment of who functional class (a rating of symptom severity), a blood test for nt‑probnp (a marker of heart strain), and questionnaires that evaluate quality of life (eq‑5d‑5l and emphasis‑10).

    Additional heart pressure measurements may be performed to record your condition before treatment.

  2. Step 2

    Start riociguat medication

    You will receive tablets of riociguat with a dose of 7.5 mg.

    The medication is taken by mouth as instructed by the study team and is continued daily until the study directs otherwise.

  3. Step 3

    Balloon pulmonary angioplasty procedure

    You will undergo balloon pulmonary angioplasty, a catheter‑based procedure that opens narrowed lung arteries.

    The procedure is performed after you have been on riociguat and is considered successful when the targeted arteries are reopened.

  4. Step 4

    Randomization to continuation or discontinuation

    Following a successful angioplasty, you will be randomly assigned to either keep taking riociguat or stop the medication.

    If you are assigned to discontinue, the drug will be withdrawn under medical supervision.

  5. Step 5

    Regular follow‑up visits

    You will return for study visits at month 3, month 6, month 12, and every 6 months thereafter.

    Each visit includes repeat measurements of the 6‑minute walk distance, reassessment of who functional class, a new nt‑probnp blood test, and the same quality‑of‑life questionnaires.

    Additional heart pressure measurements may be taken, and you will be asked about any signs of clinical worsening such as hospitalization, worsening heart failure, need for lung transplantation, need for intravenous medications, or a decline of 15 % or more in the walk distance combined with a higher functional class.

  6. Step 6

    Final study assessment

    After at least 12 months of follow‑up, you will complete a final visit that repeats all baseline assessments.

    The information collected will be used to compare outcomes between those who continued and those who stopped riociguat.

Who can join the trial?

7 criteria

  • You must sign a written agreement called informed consent that shows you understand the study and agree to either stop or keep taking the medication.
  • You must be an adult, age 18 years or older.
  • You must have been diagnosed with chronic thromboembolic pulmonary hypertension (CTEPH) that cannot be fixed with surgery, or you still have high blood pressure in the lungs after a surgery called pulmonary endarterectomy (PEA), and you must have reached certain health goals after a procedure called balloon pulmonary angioplasty (BPA). These goals are: your activity level is in World Health Organization functional class I or II (meaning little or no limitation in daily activities); your lung blood‑vessel resistance (pulmonary vascular resistance, PVR) is less than 3 Wood units (a measure of how hard the heart works to push blood through the lungs); and your average pressure in the pulmonary artery (mean pulmonary artery pressure, mPAP) is below 30 mmHg.
  • You must have taken the medication riociguat alone (no other medicines for this condition) for at least 6 months, and the dose must have been stable (unchanged) for at least the last 3 months.
  • Your most recent BPA treatment must have been performed at least 6 months before you join the study.
  • You must be able to walk at least 150 meters in a six‑minute walk test (TM6 ≥ 150 m), which measures your exercise capacity.
  • If you are a woman who could become pregnant, you must use a highly effective birth‑control method.

Who cannot join the trial?

21 criteria

  • If you are already taking other pulmonary hypertension medicines besides riociguat, such as drugs that block endothelin receptors, phosphodiesterase‑5 inhibitors, prostanoids, or prostacyclin receptor agonists.
  • If you have serious lung disease that makes breathing difficult, shown by lung tests (FEV₁ less than 60% of normal, FEV₁/FVC less than 65%, or total lung capacity less than 60% of normal) or known conditions like emphysema or interstitial lung disease.
  • If you have severe liver problems, identified by a Child‑Pugh score of B or C or liver enzyme levels more than three times the normal upper limit.
  • If you have severe kidney problems, measured by a creatinine clearance of 30 mL/min/1.73 m² or lower.
  • If you have left‑sided heart failure with a left ventricular ejection fraction (the percentage of blood the heart pumps out) lower than 40%.
  • If you are currently taking or plan to take organic nitrates, medicines often used for chest pain.
  • If you are using drugs that strongly increase the activity of the liver enzyme CYP3A4 (examples: rifabutin, rifampicin, carbamazepine, phenobarbital, phenytoin, St. John’s wort).
  • If you are taking medicines that strongly block transport proteins called P‑glycoprotein (P‑gp) or breast cancer resistance protein (BCRP), such as lopinavir/ritonavir.
  • If you are in prison or otherwise deprived of liberty by a court decision.
  • If you are under psychiatric care and cannot give your own consent.
  • If a court has appointed a guardian or similar legal protector for you.
  • If you are taking strong CYP3A4 inhibitors (examples: ketoconazole, itraconazole, voriconazole, clarithromycin, telithromycin, nefazodone, ritonavir, saquinavir) or moderate inhibitors that affect both CYP3A4 and CYP2C9 (examples: fluconazole, amiodarone) or a combination of moderate inhibitors of these enzymes.
  • If you are unable to give informed consent.
  • If you are not covered by the national health‑insurance/social security system.
  • If you have a history of life‑threatening hemoptysis (coughing up more than 100 mL of blood in 24 hours) or have had a bronchial artery embolization procedure to stop such bleeding.
  • If you are pregnant, breastfeeding, or plan to become pregnant during the study.
  • If you have other serious illnesses that are expected to shorten your life to less than 12 months, such as active cancer that has spread.
  • If you have a problem with excessive alcohol use, as judged by the study doctor.
  • If any condition or situation might make it difficult for you to follow the study rules.
  • If you are already participating in another interventional clinical trial or are still in the waiting period after finishing one.
  • If you have post‑capillary pulmonary hypertension, defined by a pulmonary artery wedge pressure (PAWP) greater than 15 mmHg.
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Investigated drugs

Riociguat is an oral medication that helps relax and widen the blood vessels in the lungs. By doing this, it lowers the pressure that builds up in the lungs in a condition called chronic thromboembolic pulmonary hypertension (CTEPH). In this study, patients who have already had a successful balloon pulmonary angioplasty are either asked to keep taking riociguat or to stop it, so researchers can see how stopping the drug affects their health over at least a year.

Balloon pulmonary angioplasty (BPA) is a minimally invasive procedure used to treat CTEPH. A thin tube with a tiny balloon at its tip is guided through the blood vessels to the narrowed areas in the lungs. The balloon is then inflated to open the blocked vessels, improving blood flow and reducing pressure in the lungs. In this trial, BPA is performed first, and then the study looks at what happens when patients continue or discontinue riociguat after the procedure.

What is already known about the treatment

riociguat - Riociguat is taken as an oral tablet, usually 7.5 mg once or twice daily. It is an approved medication that is widely referenced in current medical literature for treating certain types of high blood pressure in the lungs. The drug is used mainly for chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension, helping to lower pressure and improve exercise capacity. It works by stimulating the enzyme soluble guanylate cyclase, which raises levels of a relaxing signal in blood‑vessel walls, and it is classified as a soluble guanylate cyclase stimulator (a vasodilator).

Investigated diseases

Chronic thromboembolic pulmonary hypertension - It is a condition where scarred blood clots block the arteries that carry blood from the heart to the lungs, raising pressure in those vessels. The blockage makes the right side of the heart work harder to push blood through the lungs. Over time the heart muscle can become enlarged and less able to pump effectively. As pressure continues to rise, symptoms such as shortness of breath and tiredness may gradually increase. The disease usually progresses slowly, with the blocked areas potentially expanding and further increasing vascular pressure.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2026-525351-81-00Protocol codeAPHP251608Estimated enrolment150 patientsSponsorAssistance Publique Hopitaux De Paris

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