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Study on the Safety and Effectiveness of TAK-755 (Apadamtase Alfa) for Patients with Severe Congenital Thrombotic Thrombocytopenic Purpura (cTTP)

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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 rare blood disorder called Congenital Thrombotic Thrombocytopenic Purpura (cTTP), also known as Upshaw-Schulman Syndrome or hereditary thrombotic thrombocytopenic purpura. This condition is characterized by the formation of small blood clots throughout the body, which can lead to various health issues. The study is testing a treatment called TAK-755, also known as recombinant ADAMTS13 (rADAMTS13), which is a protein-based medication designed to help manage this condition.

The purpose of the study is to evaluate the long-term safety and tolerability of TAK-755 in patients with severe cTTP. Participants in the study will receive the treatment either as a regular preventive measure or as needed when symptoms occur. The treatment is administered as a powder and solvent for solution, which is then injected either under the skin (subcutaneous use) or directly into a vein (intravenous use). The study aims to monitor any side effects or adverse events that may arise from the treatment over an extended period.

Participants who have previously been involved in related studies or are new to this treatment will be included. The study will continue until 2027, allowing researchers to gather comprehensive data on the effectiveness and safety of TAK-755 in managing cTTP. This research is crucial for understanding how well the treatment works in preventing and managing the symptoms of this rare 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

    Joining the study

    Upon joining the study, the patient will be informed about the trial's purpose, which is to evaluate the long-term safety and tolerability of the drug TAK-755 (also known as rADAMTS13).

    The patient will be required to provide informed consent, confirming their understanding and agreement to participate in the study.

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to confirm the patient's eligibility. This includes verifying the diagnosis of severe congenital ADAMTS-13 deficiency and ensuring no severe signs of thrombotic thrombocytopenic purpura (TTP) are present.

    The patient will undergo a series of tests, including a pregnancy test for females of childbearing potential, to ensure safety during the trial.

  3. Step 3

    Treatment administration

    The patient will receive TAK-755 as a powder and solvent for solution for injection. The administration can be either subcutaneous (under the skin) or intravenous (into a vein), depending on the specific requirements of the treatment plan.

    The frequency and dosage of the medication will be determined based on whether the patient is in the prophylactic or on-demand treatment group.

  4. Step 4

    Ongoing monitoring

    Throughout the study, the patient will be regularly monitored for any treatment-emergent adverse events (TEAEs) or serious adverse events (SAEs).

    Regular check-ups will be scheduled to assess the patient's health status and the effectiveness of the treatment.

  5. Step 5

    Completion of the study

    The study is expected to continue until January 19, 2027. Upon completion, the patient's overall health and response to the treatment will be evaluated.

    The patient will be informed of the study's findings and any implications for their future treatment.

Who can join the trial?

10 criteria

  • The patient must have completed a previous study called TAK-755 Phase 3 (Study 281102) in a specific group called the prophylactic cohort.
  • The patient or their legal representative must have signed a consent form if they are 18 years or older, or an assent form if they are younger than 18.
  • The patient must be between 0 and 70 years old at the time of screening.
  • The patient must have a condition called severe congenital ADAMTS-13 deficiency, which means they have very low levels of a specific protein in their blood.
  • The patient should not show severe signs of a condition called TTP, which includes having a low platelet count (less than 100,000 per microliter) and high levels of a substance called LDH in the blood.
  • Patients aged 16 and older must have a Karnofsky score of 70% or higher, which is a way to measure their ability to perform daily activities. Patients younger than 16 must have a Lansky score of 80% or higher, which is a similar measure for children.
  • If the patient is a female who can have children, she must have a negative pregnancy test before starting the study and agree to use effective birth control during the study.
  • Sexually active males must use effective contraception during the study and for at least 16 days after the last dose of the study medication.
  • The patient must be willing and able to follow the study's requirements.
  • The patient must be negative for hepatitis C virus (HCV) or, if positive, their condition must be stable.

Who cannot join the trial?

7 criteria

  • Patients who have any other serious medical condition that might interfere with the study.
  • Patients who are currently participating in another clinical trial.
  • Patients who have had a recent major surgery or are planning to have surgery during the study period.
  • Patients who have a known allergy to the study medication or any of its ingredients.
  • Patients who are pregnant or breastfeeding.
  • Patients who have a history of drug or alcohol abuse.
  • Patients who are unable to comply with the study procedures or follow-up visits.
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Investigated drugs

TAK-755: This medication, also known by its code names BAX930 or SHP655, is being studied for its safety and effectiveness in treating people with a rare blood disorder called severe congenital thrombotic thrombocytopenic purpura (cTTP). This condition, also known as Upshaw-Schulman Syndrome or hereditary thrombotic thrombocytopenic purpura, causes blood clots to form in small blood vessels throughout the body. TAK-755 is designed to help prevent and treat these blood clots by replacing a missing enzyme in the blood, which is crucial for breaking down large protein molecules that can cause clotting. The study aims to see how well patients tolerate the medication over a long period and to monitor any side effects that may occur.

What is already known about the treatment

TAK-755 – TAK-755 is administered intravenously, meaning it is given directly into a vein. It is currently being studied in clinical trials for its safety and effectiveness in treating severe congenital thrombotic thrombocytopenic purpura (cTTP), a rare blood disorder. The medication works by replacing a missing enzyme called ADAMTS-13, which helps regulate blood clotting. TAK-755 is classified as a recombinant enzyme replacement therapy, aiming to prevent or reduce the frequency of blood clotting episodes in affected individuals.

Investigated diseases

Congenital Thrombotic Thrombocytopenic Purpura (cTTP) – This is a rare genetic disorder characterized by the formation of small blood clots throughout the body. These clots can lead to a low platelet count, which is known as thrombocytopenia. The disease is caused by a deficiency of the enzyme ADAMTS13, which normally helps to regulate blood clotting. Without enough of this enzyme, large molecules called von Willebrand factor accumulate and cause excessive clotting. Symptoms can include fatigue, bruising, and neurological issues due to restricted blood flow. The condition is present from birth and can vary in severity among individuals.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-513839-24-00Protocol codeTAK-755-3002Estimated enrolment75 patientsSponsorBaxalta Innovations GmbH

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