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A Study to Test How Safe Budoprutug Is and How Well It Works in Patients with Immune Thrombocytopenia

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This study involves people with Immune Thrombocytopenia, a condition where the body's defense system mistakenly attacks and destroys blood cells called platelets that help blood to clot. When platelet counts become too low, people may experience unusual bleeding or bruising. The treatment being tested is called budoprutug, which is a medicine given through a needle into a vein. This medicine works by targeting specific cells in the body's defense system that may be causing the low platelet counts.

The purpose of the study is to find out if budoprutug is safe and well-tolerated in people with this condition, and to see how it affects the body. The study will also look at how the medicine moves through the body over time and whether it can help increase platelet counts. During the study, participants will receive different amounts of budoprutug to help determine which dose works best. Doctors will monitor participants closely to check for any unwanted effects and to measure changes in platelet counts and other blood cells.

Throughout the study, participants will have regular visits where blood samples will be taken to measure platelet levels and other substances in the blood. The study will track how many participants achieve improved platelet counts and whether those taking steroids at the start might be able to stop this treatment. The study will continue for several years to gather information about the long-term effects of budoprutug in people with this blood disorder.

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

    Initial treatment period

    At the start of the study, you will receive budoprutug, which is given through a vein in your arm. This is called an intravenous infusion, meaning the medication flows slowly into your bloodstream through a needle placed in a vein.

    The medication comes as a liquid solution prepared for infusion. The dose you receive will depend on which group you are assigned to, as the study is testing different dose levels to find the safest and most effective amount.

    If you are currently taking corticosteroids (medications that reduce inflammation and suppress the immune system) or thrombopoietin agonists (medications that help your body make more platelets), you must remain on a stable dose throughout this period. This means your dose should not change by more than 20 percent during the 14 days before you receive your first dose of the study medication.

  2. Step 2

    Monitoring and assessments

    Throughout the study, your medical team will regularly check your platelet count. Platelets are small blood cells that help your blood clot and stop bleeding. In immune thrombocytopenia, your body does not have enough platelets.

    Blood samples will be taken at regular intervals to measure how the medication is working in your body. These tests will check your platelet levels and other important blood components.

    Your healthcare team will also monitor your B-cells, which are a type of white blood cell. Specifically, they will measure CD20+ B-cells to see how the medication affects these cells over time.

    Blood tests will measure levels of immunoglobulins (IgG, IgM, and IgA), which are proteins that your immune system produces to fight infections.

  3. Step 3

    Week 12 evaluation

    By week 12 of the study, your response to the treatment will be evaluated. The medical team will determine if you have achieved a stable, partial, or complete response based on your platelet counts.

    A stable response means your platelet count reaches at least 30,000 per microliter on at least two separate occasions, with at least 7 days between measurements, within a 30-day period.

    A partial response means your platelet count reaches at least 50,000 per microliter using the same measurement criteria.

    A complete response means your platelet count reaches at least 100,000 per microliter using the same measurement criteria.

    If you were taking steroids at the beginning of the study, the medical team will assess whether you are able to stop taking them.

  4. Step 4

    Safety monitoring throughout the study

    Throughout your participation, any side effects or health changes you experience will be carefully recorded and evaluated. These are called treatment-emergent adverse events.

    The medical team will assess whether any side effects are related to the study medication, how severe they are, and how long they last.

    Your body may develop anti-drug antibodies, which means your immune system creates proteins against the study medication. Blood tests will check for these antibodies at various times during the study.

    Regular blood tests will monitor your liver function, kidney function, and overall blood health to ensure the medication is safe for you.

  5. Step 5

    Continued follow-up

    After the initial treatment and evaluation periods, you will continue to be monitored to see how long the effects of the medication last and to track any delayed side effects.

    Your platelet counts will continue to be measured over time to see if the treatment has a lasting effect on your condition.

    The medical team will track changes in your B-cell counts and immunoglobulin levels throughout the extended follow-up period.

Who can join the trial?

6 criteria

  • You must be older than 18 years at the time you agree to join the study
  • Your platelet count (number of blood cells that help with clotting) must be less than 30,000 per microliter even though you have tried at least one treatment before. This low platelet count must be confirmed by two separate blood tests done at least 5 days apart, but not more than 14 days apart
  • Your blood clotting tests must show results that are not too high. Specifically, your partial thromboplastin time (a test measuring how long it takes blood to clot) and prothrombin time (another clotting test) must be less than 1.5 times the highest normal value. Your total bilirubin (a substance in blood that shows liver function) must also be less than 1.5 times the highest normal value unless you have a condition called Gilbert's syndrome. Your international normalized ratio (a standardized clotting test) must be less than 1.5
  • Your blood cell counts, liver function, and kidney function must be adequate
  • If you are taking corticosteroids (medicines that reduce inflammation and immune system activity) or thrombopoietin agonists (medicines that help increase platelet production), your dose must have stayed mostly the same (changed by less than 20 percent) over the 14 days before starting the study drug. If you are taking corticosteroids, the dose should not be more than 1 milligram per kilogram of methylprednisolone (or an equivalent medicine) for 2 weeks before starting the study drug
  • You must have been diagnosed with primary ITP (a condition where your immune system destroys your own platelets, and it is not caused by another disease or condition)

Who cannot join the trial?

3 criteria

  • The study information provided does not contain specific exclusion criteria, which are reasons why a patient cannot participate in the research
  • Typically, clinical trials have rules about who cannot join, but these details were not included in the available study information
  • Without the specific exclusion criteria listed, it is not possible to provide the reasons why someone with Immune Thrombocytopenia (a condition where the body's defense system mistakenly attacks and destroys platelets, which are blood cells that help stop bleeding) might not be able to participate in this particular study
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Investigated drugs

Budoprutug (also known as TNT119) is an investigational medication being studied for the treatment of immune thrombocytopenia (ITP), a condition where the immune system destroys blood platelets, leading to low platelet counts and increased risk of bleeding. This medication is being tested to see if it is safe and well-tolerated at different dose levels, and to understand how it works in the body and whether it may help improve platelet counts in people with ITP.

What is already known about the treatment

Budoprutug – Budoprutug is an experimental medication currently being studied in early-phase clinical trials for the treatment of Immune Thrombocytopenia (ITP), a condition where the immune system mistakenly destroys blood platelets, leading to increased bleeding risk. The drug is administered under medical supervision as part of a dose-finding study to determine the safest and most effective amount to give patients. While the exact way budoprutug works at the cellular level is being investigated, it is designed to help restore normal platelet counts by targeting specific molecules involved in the immune system's attack on platelets. As this medication is still in the experimental phase, it is not yet approved for general medical use and is only available through participation in clinical trials.

Investigated diseases

Immune Thrombocytopenia – Immune thrombocytopenia is a blood disorder in which the immune system mistakenly attacks and destroys platelets, which are cell fragments necessary for normal blood clotting. The condition occurs when the body produces antibodies against its own platelets, leading to their premature removal from the bloodstream. As platelet counts drop below normal levels, patients may experience easy bruising, small red or purple spots on the skin called petechiae, and prolonged bleeding from cuts. The disease can develop suddenly or gradually over time, and its severity varies from person to person. Some individuals may have very low platelet counts but experience few symptoms, while others may have bleeding complications even with moderately reduced platelet levels. The condition can affect both children and adults, and may occur without any identifiable trigger or following infections or other immune system challenges.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase ITrial ID2024-519745-30-01Protocol codeTNT119-ITP-201Estimated enrolment24 patientsSponsorClimb Bio Inc.

sourced from the EU Clinical Trials Register and site verification

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