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Study on the Effects of MK-5475 for Adults with Pulmonary Arterial 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 Pulmonary Arterial Hypertension (PAH). PAH is a type of high blood pressure that affects the arteries in the lungs and the right side of the heart. The study includes various forms of PAH, such as idiopathic PAH, which occurs without a known cause, heritable PAH, which is passed down through families, and PAH that is associated with other conditions like connective tissue disease, HIV infection, or congenital heart disease. The treatment being tested in this study is called MK-5475, which is administered as an inhalation powder. The study also involves a comparison with a placebo to evaluate the effectiveness and safety of MK-5475.

The purpose of the study is to assess how well MK-5475 works in reducing the resistance in the blood vessels of the lungs and improving the distance participants can walk in six minutes. The study is divided into two phases. In the first phase, the focus is on the change in pulmonary vascular resistance, which is a measure of the pressure in the lung arteries, after 12 weeks of treatment. In the second phase, the study looks at the change in the six-minute walk distance after 12 weeks and again after 24 weeks. Participants will be randomly assigned to receive either MK-5475 or a placebo, and neither the participants nor the researchers will know who is receiving which treatment until the study is completed.

Throughout the study, participants will be monitored for any side effects or adverse events. The study aims to provide valuable information on the potential benefits and risks of using MK-5475 for treating PAH. This research could lead to new treatment options for individuals living with this challenging condition.

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

    Upon joining the study, you will be randomly assigned to receive either the study medication, MK-5475, or a placebo. A placebo is a substance with no active medication, used to compare the effects of the actual drug.

  2. Step 2

    Medication administration

    You will receive the medication in the form of an inhalation powder. This means you will inhale the medication through your mouth using a special device.

    The exact dosage and frequency of administration will be provided by the study team. It is important to follow these instructions carefully throughout the study.

  3. Step 3

    Regular assessments

    Throughout the study, you will undergo regular assessments to monitor your health and the effects of the medication. These assessments may include physical exams, blood tests, and other evaluations as needed.

    One key assessment is the 6-minute walk distance test, which measures how far you can walk in six minutes. This test will be conducted at various points during the study to evaluate your physical capacity.

  4. Step 4

    Monitoring and follow-up

    Your progress will be closely monitored by the study team. You will be asked to report any side effects or changes in your health during the study.

    The study aims to evaluate the effect of MK-5475 on pulmonary vascular resistance and your ability to perform physical activities over a period of 12 weeks.

  5. Step 5

    Completion of the study

    At the end of the study period, you will have a final assessment to determine the overall effects of the medication.

    The study team will provide you with information about the results and any further steps if necessary.

Who can join the trial?

10 criteria

  • Must have Pulmonary Arterial Hypertension (PAH) in one of these groups: Idiopathic PAH, Heritable PAH, Drug and toxin-induced PAH, PAH associated with connective tissue disease, HIV infection, or congenital heart disease.
  • Must have a diagnosis of PAH confirmed by a test called right heart catheterization (RHC), which measures the pressure in the heart and lungs.
  • The RHC test must show:
    • Mean pulmonary artery pressure (mPAP) of 25 mmHg or higher.
    • Pulmonary vascular resistance (PVR) of 3 Wood units or more.
    • Pulmonary capillary wedge pressure (PCWP) or left ventricular end diastolic pressure (LVEDP) of 15 mmHg or less.
    • Must have symptoms classified by the World Health Organization (WHO) as Class II to IV, which indicates the severity of the condition.
    • Must be able to walk between 150 and 500 meters in a 6-minute walk test, which will be done twice: once at the start and once before randomization.
    • Must be on a stable treatment plan for PAH that is specific to the condition.
    • Must have a Body Mass Index (BMI) between 18.5 and 40 kg/m², which is a measure of body fat based on height and weight.
    • Both male and female participants are eligible.

Who cannot join the trial?

9 criteria

  • Patients with any other type of pulmonary hypertension that is not listed in the study.
  • Patients who have had a heart attack or stroke in the last 6 months.
  • Patients with severe liver disease.
  • Patients with severe kidney disease.
  • Patients who are pregnant or breastfeeding.
  • Patients who have a history of drug or alcohol abuse in the past year.
  • Patients who are currently participating in another clinical trial.
  • Patients who have a known allergy to the study medication or its ingredients.
  • Patients with any condition that the study doctors believe would make it unsafe for them to participate.
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Investigated drugs

MK-5475 is a medication being studied for its potential to help people with pulmonary arterial hypertension, a condition where the blood pressure in the lungs is too high. This medication is being tested to see if it can lower the resistance in the blood vessels of the lungs, which might help improve how well the heart and lungs work together. The study also looks at whether this medication can help people walk longer distances in six minutes, which is a way to measure how well someone can do physical activities. The goal is to see if MK-5475 can make it easier for people with this condition to breathe and be active.

What is already known about the treatment

MK-5475 – MK-5475 is administered to patients in a clinical trial setting to treat pulmonary arterial hypertension (PAH), a condition characterized by high blood pressure in the arteries of the lungs. This medication is currently being studied in a Phase 2/3 clinical trial to assess its effectiveness and safety. The main therapeutic goal is to reduce pulmonary vascular resistance and improve exercise capacity, as measured by a 6-minute walk test. MK-5475 works at the molecular level by targeting pathways that relax and widen blood vessels in the lungs, thereby lowering blood pressure. It is classified pharmacologically as a treatment for cardiovascular conditions, specifically targeting pulmonary hypertension.

Investigated diseases

Pulmonary Arterial Hypertension (PAH) – Pulmonary arterial hypertension is a condition characterized by high blood pressure in the arteries that supply the lungs. It begins with the narrowing of these arteries, which increases resistance to blood flow and forces the heart to work harder to pump blood through the lungs. Over time, this increased workload can lead to the enlargement and weakening of the right side of the heart. Symptoms often include shortness of breath, fatigue, chest pain, and swelling in the legs and ankles. The disease can progress to cause significant limitations in physical activity. PAH can be idiopathic, heritable, or associated with other conditions such as connective tissue disease, HIV infection, or congenital heart disease.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2022-500877-15-00Protocol codeMK-5475-007Estimated enrolment189 patientsSponsorMerck Sharp & Dohme LLC

sourced from the EU Clinical Trials Register and site verification

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