Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Not recruitingRare disease

Study on Ravulizumab for Patients with Thrombotic Microangiopathy After Stem Cell Transplant

Verified siteRegistered drug
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

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 Thrombotic Microangiopathy (TMA), which can occur after a Hematopoietic Stem Cell Transplant (HSCT). TMA is a serious condition that affects the small blood vessels and can lead to complications such as low platelet counts, anemia, and organ damage. The study is testing a treatment called Ravulizumab, which is given as an infusion into a vein. This treatment is being compared to a placebo to see how effective it is in treating TMA in adults and adolescents who have undergone HSCT.

The purpose of the study is to assess how well Ravulizumab works in treating TMA. Participants in the study will receive either Ravulizumab or a placebo. The study will last for several months, during which participants will receive regular infusions and have their health monitored closely. The study aims to see if Ravulizumab can help improve symptoms of TMA and prevent further complications.

Throughout the study, participants will be monitored for changes in their health, including any improvements in organ function and overall survival. The study will also track how quickly participants respond to the treatment and if there are any relapses of TMA. This research is important for finding better ways to treat TMA in patients who have had a stem cell transplant.

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, eligibility is confirmed based on specific criteria such as age, recent hematopoietic stem cell transplant (HSCT), and a diagnosis of thrombotic microangiopathy (TMA).

    Participants must be vaccinated against certain infections and may need to follow specific antibiotic guidelines.

  2. Step 2

    Treatment initiation

    The treatment involves the administration of ravulizumab or a placebo. Ravulizumab is given as a solution for infusion through an intravenous route.

    The dosage and frequency of administration are determined by the study protocol.

  3. Step 3

    Monitoring and assessments

    Regular monitoring is conducted to assess the response to treatment. This includes evaluating the response of TMA and any changes in organ function.

    Assessments occur at various intervals, including at 26 weeks and 52 weeks, to track changes from the baseline.

  4. Step 4

    Follow-up period

    During the follow-up period, the study continues to monitor for TMA relapse and overall survival.

    The follow-up period extends to specific time points, such as Day 100, Week 26, and Week 52.

  5. Step 5

    Completion of the study

    The study is estimated to conclude by June 2025, with all data collected and analyzed to determine the efficacy of ravulizumab compared to the placebo.

Who can join the trial?

12 criteria

  • Must be **12 years of age or older** at the time of signing the informed consent form.
  • Must have received a **hematopoietic stem cell transplant (HSCT)** within the past 12 months.
  • Must have a **thrombotic microangiopathy (TMA)** diagnosis, which includes:
    • New onset of **thrombocytopenia** (low platelet count) or not responding to platelet transfusions.
    • Any one of the following signs of **hemolysis** (breakdown of red blood cells):
      • **LDH** (lactate dehydrogenase) levels higher than normal for age.
      • Presence of **schistocytes** (fragmented red blood cells) in blood.
      • **Proteinuria** (protein in urine) on a urine test.
      • New onset of **anemia** (low red blood cell count) or **hypertension** (high blood pressure).
      • Must have HSCT-TMA that continues despite initial treatment for at least 72 hours.
      • Must weigh **30 kg or more** at the time of screening or within 7 days before screening.
      • Must be vaccinated against **meningococcal infections** if possible, following guidelines for immune recovery after HSCT. Participants under 18 should also be revaccinated against **Haemophilus influenzae type b (Hib)** and **Streptococcus pneumoniae** if possible. All participants should receive preventive antibiotics, including protection against **N. meningiditis**, for at least 2 weeks after the meningococcal vaccine. If unable to receive the vaccine, antibiotic protection should continue throughout the treatment and for 8 months after the last dose of **ravulizumab**.
      • Must agree to use **contraception** if applicable, following local regulations for clinical studies.
      • Must be able to provide signed informed consent or assent, agreeing to follow the study's requirements and restrictions.

Who cannot join the trial?

4 criteria

  • Patients who have had a **hematopoietic stem cell transplant** but do not have **thrombotic microangiopathy**. This is a condition where small blood vessels become damaged and form clots.
  • Patients who are not within the specified age range for the study.
  • Patients who are not part of the specified clinical trial groups.
  • Patients who are not considered part of the vulnerable population selected for the study.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Not recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

Ravulizumab is a medication being studied for its effectiveness in treating a condition called thrombotic microangiopathy (TMA) that can occur after a hematopoietic stem cell transplant (HSCT). This medication works by targeting specific proteins in the immune system to help reduce the damage to blood vessels and improve blood flow. The goal of using ravulizumab in this trial is to see if it can help patients recover from TMA more effectively than not using the medication.

What is already known about the treatment

Ravulizumab – This medication is administered intravenously, meaning it is given directly into a vein. It is currently being studied in clinical trials for its effectiveness in treating thrombotic microangiopathy associated with hematopoietic stem cell transplants. Ravulizumab is primarily used to help manage conditions where blood clots form in small blood vessels, leading to organ damage. It works by inhibiting a part of the immune system called the complement system, which can contribute to inflammation and blood clotting. Ravulizumab is classified as a monoclonal antibody, a type of medication designed to target specific proteins in the body.

Investigated diseases

Hematopoietic Stem Cell Transplant-Associated Thrombotic Microangiopathy – This condition occurs after a hematopoietic stem cell transplant, where small blood vessels become damaged and clots form in the vessels. It can lead to reduced blood flow to various organs, causing potential damage. The disease affects multiple systems, including the kidneys, heart, lungs, central nervous system, and gastrointestinal tract. Symptoms may include high blood pressure, low platelet count, and signs of organ dysfunction. The progression of the disease can vary, with some individuals experiencing more severe symptoms than others. It is considered a rare disease, and its impact can be significant on the patient's overall health.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-510107-22-00Protocol codeALXN1210-TMA-313Estimated enrolment144 patientsSponsorAlexion Pharmaceuticals Inc.

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.