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Study on the Safety and Effectiveness of Pirtobrutinib for Adults with Immune Thrombocytopenia

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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 Immune Thrombocytopenia (ITP), which is a disorder that can lead to easy or excessive bruising and bleeding due to low levels of platelets, the cells that help blood clot. The study is investigating a treatment called Pirtobrutinib, which is taken in tablet form. Pirtobrutinib is being compared to a placebo to understand its safety and effectiveness in treating adults with ITP.

The purpose of the study is to assess how safe and well-tolerated Pirtobrutinib is in people with ITP and to determine the appropriate doses for further research. The study is divided into two phases. In the first phase, participants will receive different doses of Pirtobrutinib to find the safest and most effective dose. In the second phase, the effectiveness of Pirtobrutinib will be compared to a placebo to see if it helps improve platelet counts in participants.

Participants in the study will take the medication orally and will have regular visits to monitor their health and platelet levels. The study aims to see if Pirtobrutinib can help maintain stable platelet counts without the need for additional treatments. The trial will continue until 2027, with the recruitment of participants expected to start in 2025. This research is important for finding new ways to manage and treat ITP effectively.

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 informed about the purpose and procedures involved. This study is designed to investigate the safety and effectiveness of a medication called pirtobrutinib in adults with a condition known as immune thrombocytopenia (ITP).

  2. Step 2

    Phase 1: safety and dosage

    In the first phase, the focus is on assessing the safety of pirtobrutinib and determining the appropriate dosage. You will be given pirtobrutinib in the form of a tablet, which you will take orally. The specific dosage and frequency will be determined by the study team based on your individual needs and responses.

    During this phase, your health will be closely monitored through various tests, including blood tests and heart monitoring, to ensure your safety and to observe how your body responds to the medication.

  3. Step 3

    Phase 2: effectiveness comparison

    In the second phase, the effectiveness of pirtobrutinib will be compared to a placebo, which is a tablet that looks like the medication but does not contain the active ingredient. You may receive either pirtobrutinib or the placebo, and neither you nor the study team will know which one you are receiving.

    The goal is to evaluate how well pirtobrutinib works in improving platelet counts, which are important for blood clotting, in comparison to the placebo.

  4. Step 4

    Regular visits and monitoring

    Throughout the study, you will have regular visits to the study site. These visits will occur every two weeks, where your platelet counts will be checked, and your overall health will be monitored.

    The study team will also assess any side effects you may experience and adjust your treatment as necessary to ensure your safety.

  5. Step 5

    End of study

    The study is expected to continue until June 2027. At the end of the study, the results will be analyzed to determine the safety and effectiveness of pirtobrutinib in treating immune thrombocytopenia.

    You will be informed about the findings and any potential next steps regarding your treatment.

Who can join the trial?

4 criteria

  • Are 18 years of age or older.
  • Have a confirmed diagnosis of primary ITP (Immune Thrombocytopenia, a condition where the immune system attacks and destroys platelets in the blood).
  • Have a documented history of response to at least one previous treatment for ITP.
  • Have not responded to previous treatments for primary ITP.

Who cannot join the trial?

8 criteria

  • Participants cannot join the study if they have any other serious health conditions that might interfere with the study.
  • Participants who are pregnant or breastfeeding are not allowed to participate.
  • Participants who have had a recent major surgery or are planning to have surgery during the study period cannot take part.
  • Participants who are currently using other medications that might interfere with the study treatment are excluded.
  • Participants with a history of allergic reactions to similar medications are not eligible.
  • Participants who have been part of another clinical trial within the last 30 days are not allowed to join.
  • Participants with a history of drug or alcohol abuse within the past year are excluded.
  • Participants who have any condition that, in the opinion of the study doctor, makes them unsuitable for the study are not eligible.
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Investigated drugs

Pirtobrutinib is a medication being studied for its potential to help people with a condition called immune thrombocytopenia (ITP). ITP is a disorder where the immune system mistakenly attacks and destroys platelets, which are cells in the blood that help with clotting. This can lead to easy bruising and bleeding. Pirtobrutinib works by targeting specific proteins in the body that are involved in the immune response. By doing this, it may help to reduce the destruction of platelets and improve the symptoms of ITP. The study is looking at how safe and effective pirtobrutinib is for people with this condition.

What is already known about the treatment

Pirtobrutinib – Pirtobrutinib is administered orally and is currently being studied in clinical trials for its safety and effectiveness in treating adults with Immune Thrombocytopenia (ITP). This medication is in the early stages of research, specifically in Phase 1/2 trials, where its safety and the appropriate dosage are being evaluated. Pirtobrutinib is primarily indicated for ITP, a condition where the immune system mistakenly attacks and destroys platelets, leading to excessive bruising and bleeding. At the molecular level, Pirtobrutinib works by inhibiting a specific protein involved in the immune response, which may help reduce the destruction of platelets. It is classified pharmacologically as a Bruton's tyrosine kinase (BTK) inhibitor, a type of drug that targets specific pathways in the immune system.

Investigated diseases

Immune Thrombocytopenia – Immune Thrombocytopenia is a disorder characterized by a low platelet count, which can lead to easy or excessive bruising and bleeding. The condition occurs when the immune system mistakenly attacks and destroys platelets, which are essential for normal blood clotting. In many cases, the onset is gradual, and symptoms may be mild, such as small red or purple spots on the skin. As the disease progresses, individuals may experience more significant bleeding, such as nosebleeds or bleeding gums. The severity of symptoms can vary widely among individuals, with some experiencing only minor issues and others facing more pronounced bleeding challenges. The condition can affect both children and adults, with varying patterns of progression and symptom severity.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2024-518502-40-00Protocol codeJ2N-MC-JZNZEstimated enrolment71 patientsSponsorEli Lilly & Co.

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