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Study Comparing Bomedemstat and Hydroxycarbamide for Patients with Essential Thrombocythemia

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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 called Essential Thrombocythemia, which is a type of blood disorder where the body produces too many platelets. Platelets are small blood cells that help with clotting, and having too many can lead to problems like blood clots or bleeding. The study is comparing two treatments: Bomedemstat, also known by its code name MK-3543, and Hydroxycarbamide, which is also known as Hydroxyurea. These medications are being tested to see how effective and safe they are for people who have not received any previous treatment to reduce their platelet count.

The purpose of the study is to compare the effectiveness of Bomedemstat to Hydroxycarbamide in managing Essential Thrombocythemia. Participants in the study will be randomly assigned to receive either Bomedemstat, Hydroxycarbamide, or a placebo. The study will last for a period of up to 36 months, during which participants will take the medication orally in the form of capsules. Throughout the study, participants will be monitored regularly to assess their response to the treatment and to check for any side effects.

This trial aims to provide valuable information on which treatment might be more beneficial for managing Essential Thrombocythemia. By participating, individuals contribute to research that could improve future treatment options for this condition. The study is designed to ensure the safety and well-being of all participants, with regular check-ups and assessments conducted by healthcare professionals.

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, the participant is confirmed to have a diagnosis of essential thrombocythemia based on specific criteria. The participant must not have received any prior treatment for this condition.

  2. Step 2

    Randomization

    The participant is randomly assigned to receive either bomedemstat (MK-3543) or hydroxyurea. This process is double-blind, meaning neither the participant nor the researchers know which treatment is being administered.

  3. Step 3

    Treatment administration

    The participant takes the assigned medication orally in the form of a hard capsule. The specific dosage and frequency are determined by the study protocol and are followed throughout the trial.

  4. Step 4

    Monitoring and assessments

    Regular monitoring is conducted to assess the participant's response to the treatment. This includes evaluating the durable clinicohematologic response and other health indicators.

    Participants are also assessed for any changes in symptoms and overall health status using specific forms and questionnaires.

  5. Step 5

    Completion of the study

    The study is estimated to conclude by May 14, 2029. Upon completion, the participant's overall health and response to the treatment are thoroughly evaluated.

Who can join the trial?

7 criteria

  • Must have a diagnosis of Essential Thrombocythemia (ET), which is a condition where the body makes too many blood cells called platelets, based on specific medical guidelines.
  • Must have a bone marrow fibrosis score of Grade 0 or Grade 1. This means the bone marrow, where blood cells are made, is in a healthy or slightly affected state.
  • Must not have received any previous treatment aimed at reducing blood cell production for their ET.
  • If the participant has HIV (a virus that affects the immune system), it must be well controlled with medication.
  • If the participant has tested positive for Hepatitis B (a liver infection), they must have been on treatment for at least 4 weeks and have no detectable virus in their blood.
  • If the participant has a history of Hepatitis C (another liver infection), the virus must not be detectable in their blood.
  • Both male and female participants are eligible to join the study.

Who cannot join the trial?

3 criteria

  • Patients with medical conditions other than Essential thrombocythemia cannot participate. Essential thrombocythemia is a condition where the body produces too many blood platelets, which are cells that help with blood clotting.
  • Patients who are not within the specified age range cannot participate. The age range includes adults and older adults.
  • Patients who are part of a vulnerable population cannot participate. A vulnerable population includes groups of people who may have a higher risk of harm or exploitation.
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Investigated drugs

  • Bomedemstat (MK-3543)

    is a medication being studied for its effectiveness and safety in treating essential thrombocythemia, a condition characterized by an overproduction of platelets in the blood. This medication is being compared to another treatment to see how well it works in managing the disease.

  • Hydroxyurea

    is a medication commonly used to treat essential thrombocythemia. It helps to reduce the number of platelets in the blood, which can help prevent complications associated with the condition. In this study, it serves as a comparison to evaluate the effectiveness of bomedemstat.

What is already known about the treatment

  • Bomedemstat

    Bomedemstat is administered orally and is currently being studied in clinical trials for its effectiveness in treating essential thrombocythemia, a condition characterized by an overproduction of platelets. It is not yet widely used in medical practice, as it is still under investigation. The medication works by inhibiting an enzyme involved in the production of blood cells, thereby reducing platelet levels. Bomedemstat is classified as a small molecule inhibitor targeting specific pathways in blood cell production.

  • Hydroxyurea

    Hydroxyurea is taken orally and is a well-established medication used in the treatment of essential thrombocythemia, among other conditions. It is widely recognized in medical literature and practice for its ability to reduce high platelet counts. The drug works by interfering with DNA synthesis, which slows down the production of blood cells. Hydroxyurea is classified as an antineoplastic agent, commonly used in managing blood disorders.

Investigated diseases

Essential thrombocythemia – This is a chronic blood disorder characterized by the overproduction of platelets by the bone marrow. It often progresses slowly and may not cause symptoms initially. Over time, individuals may experience headaches, dizziness, or vision changes due to increased blood viscosity. Some people may also develop blood clots or bleeding issues. The condition can lead to complications such as an enlarged spleen or changes in blood cell counts. It is considered a type of myeloproliferative neoplasm, which involves the abnormal growth of blood cell precursors.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-505232-36-00Protocol codeMK-3543-007Estimated enrolment396 patientsSponsorMerck Sharp & Dohme LLC

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