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A study to evaluate the effectiveness of levosimendan in patients with pulmonary hypertension and heart failure with preserved ejection fraction.

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What is this trial about?

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

This study focuses on individuals living with Pulmonary Hypertension, a condition where the blood pressure in the arteries of the lungs is too high, specifically in those who also have Heart Failure with Preserved Ejection Fraction. This type of heart failure occurs when the heart muscle becomes stiff and cannot relax properly to fill with blood between beats, even though the heart's ability to pump blood out remains relatively normal. The purpose of the study is to evaluate the effectiveness and safety of a medication called levosimendan compared to a placebo.

Participants in the study will be assigned to receive either the active medication, levosimendan, or a placebo, which is an inactive substance, through an oral hard gelatin capsule. This assignment is done through a randomized process, meaning it is determined by chance, and a double-blind method, where neither the participants nor the researchers know which substance is being administered. The treatment period lasts for 26 weeks, during which the effects on physical activity and general health are monitored.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Study participation and medication administration

    The 26-week treatment period begins with the administration of either levosimendan or a placebo. levosimendan is provided in hard gelatin capsule form for oral use (taken by mouth).

    The placebo is an immediate-release product used for oral administration that contains no active medicine.

  2. Step 2

    Monitoring and evaluation

    Throughout the 26 weeks, various health measurements are taken to monitor safety and how the body responds. these include physical examinations, checks of vital signs (such as blood pressure), clinical laboratory values (blood tests), and electrocardiograms (ecg), which is a test that records the electrical activity of the heart.

    The heart rate and rhythm are monitored to ensure safety.

    The effectiveness of the treatment is assessed by measuring the 6-minute walk distance, which is a test to see how far a person can walk in six minutes to evaluate physical capacity.

    Health status is also tracked through changes in the nyha functional class, which is a system used to classify the severity of heart failure symptoms, and the kccq-tss, which is a questionnaire used to measure health-related quality of life.

  3. Step 3

    Tracking clinical events

    The study monitors for clinical worsening events during the 26-week period. these events include unplanned hospitalizations related to the heart or lungs, urgent outpatient visits for intravenous (iv) diuretics (medicine given through a vein to help remove excess fluid from the body), or deaths related to cardiovascular conditions.

Who can join the trial?

7 criteria

  • Participants must be men or women aged between 18 and 85 years.
  • Patients must have symptoms categorized as NYHA Class II, III, or ambulatory Class IV, which refers to a system used to classify the severity of heart failure based on how much physical activity causes shortness of breath or fatigue.
  • A diagnosis of WHO Group 2 Pulmonary Hypertension with preserved left ventricular ejection fraction is required. This means there is high blood pressure in the arteries of the lungs caused by issues with the left side of the heart.
  • The diagnosis must be confirmed through a right heart catheterization, which is a procedure where a thin tube is inserted into the heart to measure blood pressure and oxygen levels directly.
  • A recent echocardiogram (an ultrasound of the heart) performed within 45 days must show a left ventricular ejection fraction of 40% or higher. The ejection fraction is a measurement of how much blood the main pumping chamber of the heart pushes out with each beat.
  • Tests must prove the absence of a pulmonary thromboembolism, which is a blood clot that has traveled to the lungs. This must be confirmed by a ventilation-perfusion scan, a specialized imaging test, or a computed tomography pulmonary angiogram, which is a detailed X-ray scan of the lung arteries.
  • During the initial screening and at the start of the study, patients must be able to walk between 100 and 450 meters in a 6-Minute Walk Test, which is a test used to measure how much distance a person can cover on foot in six minutes to assess their physical endurance.

Who cannot join the trial?

20 criteria

  • You cannot join if you have certain types of Pulmonary Hypertension (high blood pressure in the lung arteries) that fall into specific medical categories known as WHO Groups 1, 3, 4, or 5.
  • You are excluded if an echocardiogram (an ultrasound of the heart) shows specific heart muscle or lining problems, such as hypertrophic cardiomyopathy (thickened heart muscle), restrictive cardiomyopathy (stiff heart muscle), constrictive pericarditis (inflammation that prevents the heart from filling properly), cardiac amyloidosis (buildup of abnormal proteins in the heart), or infiltrative cardiomyopathy (heart muscle affected by substances that seep into the tissue).
  • You cannot participate if you had heart surgery to repair or replace the aortic valve or mitral valve in the last 24 months, or if you have a surgery planned for these valves in the next 24 months.
  • You are excluded if an echocardiogram shows significant valve disease, specifically mitral regurgitation (blood leaking backward through the mitral valve) at a high grade, mitral stenosis (narrowing of the mitral valve), aortic regurgitation (blood leaking backward through the aortic valve) at a certain grade, or aortic stenosis (narrowing of the aortic valve).
  • You cannot join if your recent blood tests show hemoglobin (a protein in red blood cells that carries oxygen) levels below 10 g/dL.
  • You are excluded if your liver tests, specifically ALT, AST, or total bilirubin (indicators of liver health), are more than three times the upper limit of normal.
  • You cannot participate if your ECG (a test that records the electrical activity of the heart) shows a QT interval (the time it takes for the heart muscle to recharge between beats) that is too long, measured using a specific formula, unless you have a specific heart rhythm condition like a bundle branch block or a paced rhythm (heartbeat controlled by a device).
  • You are excluded if your platelet count (cells that help blood clot) is below 75,000/mm3.
  • You cannot join if you have physical issues that might affect breathing, such as congenital abnormalities (birth defects) of the lungs, chest, or diaphragm, having had a pneumonectomy (removal of part or all of a lung), or having received radiation therapy to the lungs or middle of the chest.
  • You are excluded if there is recent evidence of significant underlying lung disease.
  • You cannot participate if you had a pulmonary thromboembolism (a blood clot in the lung) in the last 12 months, confirmed by special imaging scans.
  • You are excluded if you have certain heart-related conditions, such as untreated coronary artery disease (narrowing of the heart's blood vessels) or acute coronary syndrome (a sudden reduction of blood flow to the heart).
  • You cannot join if you had a coronary artery bypass graft (surgery to redirect blood flow around blocked arteries) or a percutaneous coronary intervention (a procedure to open blocked heart arteries) within the last 180 days.
  • You are excluded if you have an uncontrolled heart rate caused by atrial fibrillation or atrial flutter (irregular or rapid heart rhythms).
  • You cannot participate if you have a history of untreated, life-threatening arrhythmia (irregular heartbeat) or if you are expected to receive a heart transplant or a ventricular assist device (a mechanical pump to help the heart).
  • You are excluded if you are scheduled to get a pacemaker (a small device that regulates the heartbeat) or if you received one within the last 30 days.
  • You cannot join if you had a myocardial infarction (a heart attack) caused by heart artery disease within the last 180 days.
  • You are excluded if you have uncontrolled systemic hypertension (high blood pressure throughout the body) with a top number (systolic blood pressure) higher than 170 mmHg.
  • You cannot participate if you had a stroke within the last 90 days.
  • You are excluded if your systolic blood pressure (the pressure in your arteries when your heart beats) is lower than 100 mmHg during your initial checks.
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Investigated drugs

Levosimendan is a medication taken by mouth that is being studied to see how well it helps people with pulmonary hypertension who also have heart failure. It is intended to improve the patient's ability to walk and overall physical function.

What is already known about the treatment

  • Levosimendan

    This medication is taken orally in the form of a hard gelatin capsule. It is currently being studied in clinical trials to help treat high blood pressure in the lungs for patients who also have heart failure. It works by helping the heart muscle contract more strongly and by relaxing the blood vessels to improve blood flow. This drug is classified as a calcium sensitizer and a vasodilator.

  • Placebo

    This is an inactive substance administered orally in the same way as the study medication. It is used in clinical research as a control to compare the effects of the actual drug being tested. Since it contains no active ingredients, it has no medicinal effect on the body or its molecular processes. This substance is used as a standard tool in clinical trials to ensure the results are caused by the medication itself.

Investigated diseases

Pulmonary hypertension with heart failure with preserved ejection fraction - This condition occurs when there is high blood pressure in the arteries that connect the heart to the lungs. At the same time, the left side of the heart becomes stiff and cannot relax properly between beats. This stiffness prevents the heart from filling with enough blood to pump effectively. As the disease progresses, the increased pressure in the lung vessels makes it harder for the heart to move blood through the body. This can lead to a buildup of fluid and increased strain on the heart muscles.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522475-28-00Protocol codeTNX-103-07Estimated enrolment569 patientsSponsorTenax Therapeutics Inc.

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