Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Not recruitingRare disease

Study of Ravulizumab for Children with Thrombotic Microangiopathy After Stem Cell Transplant

Verified siteRegistered drugNo placebo
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 medical procedure known as Hematopoietic Stem Cell Transplantation (HSCT). TMA is a serious condition that affects the blood vessels and can lead to complications in various organs. The study is specifically for children from 1 month to under 18 years of age who have developed TMA following HSCT.

The treatment being tested in this study is a medication called Ravulizumab, which is given in addition to the best supportive care available. Ravulizumab is administered through an infusion, which means it is delivered directly into the bloodstream through a vein. The purpose of the study is to evaluate how effective Ravulizumab is in treating children with TMA after they have undergone HSCT.

Participants in the study will receive Ravulizumab and will be monitored over a period of time to see how their condition responds to the treatment. The study will look at various outcomes, such as how quickly the TMA responds to the treatment, any changes in organ function, and overall survival rates. The study aims to provide valuable information on the potential benefits of using Ravulizumab for treating TMA in pediatric patients following HSCT.

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 or their legally authorized representative must provide signed informed consent. This includes understanding and agreeing to comply with the study's requirements and restrictions.

  2. Step 2

    Screening period

    During the screening period, eligibility is confirmed. Participants must be between 28 days and less than 18 years old, have received a hematopoietic stem cell transplant (HSCT) within the past 12 months, and have a diagnosis of thrombotic microangiopathy (TMA) that persists for at least 72 hours after initial management.

    Participants must weigh at least 5 kg and be vaccinated against meningococcal infections, if feasible. Prophylactic antibiotics are administered according to institutional guidelines.

  3. Step 3

    Treatment administration

    The treatment involves the administration of ravulizumab, a medication given through an intravenous infusion. The specific dosage and frequency are determined by the study protocol and the participant's condition.

    Participants receive ravulizumab in addition to best supportive care, which includes measures to manage symptoms and improve quality of life.

  4. Step 4

    Monitoring and follow-up

    Participants are monitored for their response to the treatment, focusing on the resolution of TMA symptoms. This includes assessing changes in organ function and overall health.

    The study tracks the time to TMA response, any relapses, overall survival, and other health indicators over a period of up to one year.

  5. Step 5

    End of study participation

    The study is estimated to conclude by May 30, 2025. Participants will have completed their involvement in the study by this date, unless otherwise specified by the study protocol.

Who can join the trial?

12 criteria

  • Participants must be at least 28 days old and younger than 18 years at the time of signing the informed consent.
  • Participants should have received a hematopoietic stem cell transplant (HSCT) within the past 12 months at the time of screening.
  • Participants must have a thrombotic microangiopathy (TMA) diagnosis, which includes:
    • New onset of low platelet count or resistance to platelet transfusion.
    • Any one of the following signs of hemolysis (breakdown of red blood cells):
      • High levels of lactate dehydrogenase (LDH), an enzyme, above the normal range for age.
      • Presence of schistocytes, which are fragmented red blood cells, in a blood test.
      • Presence of proteinuria, which means protein in the urine, on a urine test.
      • New onset of anemia or high blood pressure.
      • Participants must have HSCT-TMA that lasts for at least 72 hours after initial treatment of any triggering condition.
      • Participants must weigh at least 5 kg at screening or within 7 days before the start of the screening period.
      • Participants must follow local regulations regarding the use of contraception if applicable.
      • Participants should be vaccinated against meningococcal infections if possible, following national guidelines for immune recovery after HSCT. They should also be re-vaccinated against Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae if possible. All participants should receive preventive antibiotics according to guidelines, including protection against N. meningitidis for at least 2 weeks after meningococcal vaccination. If they cannot receive the vaccine, they should receive antibiotics for the entire treatment period and for 8 months after the last dose of the study medication.
      • Participants or their legally authorized representative must be able to provide signed informed consent, agreeing to follow the study requirements and restrictions.

Who cannot join the trial?

8 criteria

  • Patients who have had a hematopoietic stem cell transplant (a procedure to replace damaged or destroyed bone marrow with healthy bone marrow stem cells) and are experiencing thrombotic microangiopathy (a condition where small blood vessels become blocked or damaged) cannot participate.
  • Patients who are not within the specified age range for the study cannot participate.
  • Patients who do not meet the health requirements set by the study cannot participate.
  • Patients who are unable to follow the study procedures or attend required visits cannot participate.
  • Patients who are currently participating in another clinical trial cannot participate.
  • Patients who have certain medical conditions that could interfere with the study cannot participate.
  • Patients who are pregnant or breastfeeding cannot participate.
  • Patients who have a history of allergic reactions to the study medication cannot 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.

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 used in this clinical trial to treat children with a condition called thrombotic microangiopathy (TMA) that occurs after a hematopoietic stem cell transplant (HSCT). This medication works by blocking certain proteins in the blood that can cause inflammation and damage to blood vessels, which are common issues in TMA. The goal of using ravulizumab in this study is to see if it can help improve the health of children affected by this condition when used alongside the best supportive care available.

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 in children. Ravulizumab works by inhibiting a part of the immune system called the complement system, which can help reduce inflammation and prevent damage to blood vessels. It is classified as a complement inhibitor and is being explored for its potential to improve outcomes in patients with this specific condition.

Investigated diseases

Hematopoietic Stem Cell Transplant-Associated Thrombotic Microangiopathy (HSCT-TMA) – 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 patients experiencing a more rapid onset of symptoms. Monitoring and managing the condition is crucial to prevent further complications.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IIITrial ID2023-507850-33-00Protocol codeALXN1210-TMA-314Estimated enrolment47 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.