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Study on Isatuximab for Treating Pure Red Cell Aplasia in Patients with Major ABO Mismatch After Stem Cell Transplantation

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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 Pure Red Cell Aplasia (PRCA), which can occur after a type of stem cell transplant called allogeneic hematopoietic stem cell transplantation. This condition happens when there is a major mismatch in blood types between the donor and the recipient, leading to a lack of red blood cells. The study is testing a treatment using a medication called isatuximab, which is a type of protein known as a monoclonal antibody. This medication is designed to target and help manage the condition by potentially reducing the time it takes for the body to start producing its own red blood cells again.

The purpose of the study is to evaluate how effective isatuximab is in treating PRCA compared to standard supportive care, which may include treatments like blood transfusions. Participants in the study will receive the medication through an infusion, which means it will be given directly into a vein. The study will follow participants over a period of time to see how quickly they can become independent of transfusions and to monitor any side effects or changes in their quality of life.

Throughout the study, researchers will collect information on various factors, such as the number of blood transfusions needed, levels of certain proteins in the blood, and any side effects experienced. The study aims to provide valuable insights into whether isatuximab can help improve outcomes for patients with PRCA after 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

    Participation begins after meeting specific criteria, including being 15 years or older, having undergone a specific type of stem cell transplant, and experiencing a condition called pure cell red aplasia (PCRA).

    Consent is required, and for those under 18, consent from both parents is necessary.

  2. Step 2

    Randomization

    Participants are randomly assigned to either receive the treatment with isatuximab or to a control group receiving supportive care.

    This occurs around six months after the transplant.

  3. Step 3

    Treatment phase

    If assigned to the treatment group, isatuximab is administered through an intravenous infusion.

    The frequency and duration of the treatment are determined by the study protocol.

  4. Step 4

    Monitoring and assessments

    Regular assessments are conducted to monitor the number of red blood cell transfusions, ferritin levels, and any adverse events.

    Quality of life is evaluated at specific intervals, including 60 days, 100 days, and several months post-transplant.

  5. Step 5

    End of study

    The study aims to determine the time to achieve transfusion independence and other health outcomes.

    The estimated end date for the study is March 20, 2027.

Who can join the trial?

7 criteria

  • Must be 15 years or older.
  • Must have received an allogeneic hematopoietic stem cell transplantation with a major ABO mismatch. This means a type of stem cell transplant from a donor where the blood types are not fully compatible.
  • Must have PRCA, which is a condition where you need regular red blood cell transfusions 60 days after the transplant. Your reticulocyte count, which are young red blood cells, should be under 10 G/L, even though your donor cells are working well and your white blood cells and platelets have recovered.
  • No return or worsening of the original disease.
  • Must use contraception during the trial. Women of childbearing age and men must use effective birth control during treatment and for at least 5 months after the last dose. Men should also not donate sperm during this time.
  • Must have health insurance coverage.
  • Must have signed a written informed consent. If under 18, both parents must sign.

Who cannot join the trial?

5 criteria

  • Patients who have not experienced a **major ABO mismatch** after a **stem cell transplant**. A major ABO mismatch occurs when the blood types of the donor and recipient are not compatible.
  • Patients who have not been diagnosed with **pure cell red aplasia (PRCA)**. PRCA is a condition where the body stops producing red blood cells.
  • Patients who are not part of the age groups specified for the study. The study includes certain age ranges, so patients outside these ranges cannot participate.
  • Patients who are not willing or able to follow the study procedures and requirements.
  • Patients who are not able to provide informed consent, which means they understand the study and agree to participate.
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Investigated drugs

Isatuximab is a monoclonal antibody used in this trial to treat a condition called pure red cell aplasia (PRCA) that can occur after a stem cell transplant. It works by targeting a specific protein on the surface of certain cells, which helps the immune system to attack and destroy these cells. This treatment aims to reduce the time it takes for PRCA to resolve in patients who have undergone an allogeneic hematopoietic stem cell transplant.

What is already known about the treatment

Isatuximab – Isatuximab is administered intravenously, meaning it is given directly into a vein through an IV. It is currently being studied in clinical trials for its effectiveness in treating pure red cell aplasia (PRCA) that occurs due to a major ABO mismatch after allogeneic hematopoietic stem cell transplantation. The main therapeutic indication for isatuximab in this context is to reduce the time it takes for PRCA to resolve. At the molecular level, isatuximab works by targeting and binding to a specific protein called CD38 on the surface of certain cells, which helps the immune system to attack and destroy these cells. It is classified pharmacologically as a monoclonal antibody.

Investigated diseases

Pure Red Cell Aplasia – This condition is characterized by a significant reduction in the production of red blood cells, leading to anemia. It occurs when the bone marrow fails to produce enough red blood cells, while the production of white blood cells and platelets remains normal. In the context of major ABO mismatch after allogeneic hematopoietic stem cell transplantation, the body's immune response can target and destroy red blood cell precursors. This results in a lack of mature red blood cells, causing symptoms such as fatigue and pallor. The condition can persist until the immune system stabilizes and stops attacking the red blood cell precursors.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-514351-14-00Protocol codeAPHP200067Estimated enrolment90 patientsSponsorAssistance Publique Hopitaux De Paris

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