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Study of REGN7257 for Adults with Severe Aplastic Anemia Unresponsive to or Relapsed After Immunosuppressive Therapy

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 clinical trial is focused on studying a condition known as severe aplastic anemia. This is a serious blood disorder where the bone marrow fails to produce enough blood cells. The study is investigating a treatment called REGN7257, which is a type of medication known as a monoclonal antibody. Monoclonal antibodies are proteins designed to target specific parts of the immune system. In this case, REGN7257 targets a part of the immune system called the interleukin 2 receptor subunit gamma, which is involved in the body's immune response.

The purpose of the study is to assess the safety and tolerability of REGN7257 in patients whose severe aplastic anemia has not responded to or has returned after standard immunosuppressive therapy. The study is divided into two parts. In the first part, the focus is on understanding how safe and tolerable the treatment is. In the second part, the study also looks at how effective the treatment is in patients whose condition has relapsed after previous treatments.

Participants in the study will receive REGN7257 through an injection into a vein, a method known as intravenous use. The study will monitor participants for any side effects and measure how their condition responds to the treatment over time. The study aims to provide insights into whether REGN7257 can be a beneficial treatment option for those with severe aplastic anemia who have limited options due to the ineffectiveness of other therapies.

The research process

The trial runs in 6 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, including the presence of severe aplastic anemia (SAA) that is either resistant to or has returned after immunosuppressive therapy.

    Hematopoietic stem cell transplantation must not be an available or suitable treatment option, or it must have been declined.

  2. Step 2

    Initial assessment

    An initial assessment is conducted to evaluate liver and kidney function, among other health parameters, to ensure they meet the study's requirements.

  3. Step 3

    Treatment administration

    The treatment involves the administration of REGN7257, a monoclonal antibody targeting the interleukin 2 receptor subunit gamma.

    REGN7257 is provided as a lyophilisate for solution for injection and is administered intravenously.

  4. Step 4

    Monitoring and follow-up

    Throughout the study, regular monitoring is conducted to assess the safety and tolerability of the treatment.

    The incidence of adverse events, including serious adverse events, is recorded.

    The study also evaluates the overall response rate, complete response, and partial response to the treatment.

  5. Step 5

    Evaluation of treatment effects

    Changes in blood cell counts, including lymphocytes, neutrophils, hemoglobin, reticulocytes, and platelets, are measured.

    The study examines changes in immune cell subsets, such as T cells, B cells, and natural killer cells.

  6. Step 6

    Completion of the study

    The study is expected to conclude by July 14, 2026, with ongoing assessments of drug concentrations in serum and the incidence of treatment-emergent anti-drug antibodies.

Who can join the trial?

8 criteria

  • The patient must have **Severe aplastic anemia (SAA)**. This is a condition where the bone marrow does not produce enough blood cells.
  • For Part A of the study, the patient's SAA must be **IST-refractory** or **IST-relapsed**. This means the condition did not improve with or returned after treatment with **immunosuppressive therapy (IST)**.
  • For Part B of the study, the patient's SAA must be **IST-relapsed**. This means the condition returned after treatment with IST.
  • The patient cannot have a **hematopoietic stem cell transplantation (HSCT)** available or suitable as a treatment option, or the patient must have refused this treatment. HSCT is a procedure to replace damaged or destroyed bone marrow with healthy bone marrow stem cells.
  • The patient must have **adequate hepatic and renal function**. This means the liver and kidneys are working well enough, as defined in the study protocol.
  • Other criteria defined in the study protocol must also be met.
  • The study is open to both male and female patients.
  • The study includes patients from certain age groups, which are not specified here.

Who cannot join the trial?

5 criteria

  • Patients who have a different condition than Severe Aplastic Anemia (SAA) cannot participate. SAA is a condition where the bone marrow does not produce enough blood cells.
  • Patients who are not in the age range of 3 to 4 years old are excluded.
  • Patients who are not part of the specific clinical trial group are excluded.
  • Both male and female patients are eligible, so gender is not an exclusion factor.
  • Patients who are considered part of a vulnerable population are not excluded.
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Investigated drugs

REGN7257 is a monoclonal antibody designed to target and block the interleukin 2 receptor subunit gamma (IL2RG). This medication is being studied for its potential to help patients with severe aplastic anemia, a condition where the bone marrow fails to produce enough blood cells. The trial is focused on patients whose condition has not improved with standard immunosuppressive therapy or has worsened after initial improvement. The study aims to determine how safe and tolerable REGN7257 is for these patients and to explore its effectiveness in improving their condition.

What is already known about the treatment

REGN7257 – This medication is administered as an intravenous infusion, meaning it is given directly into the bloodstream through a vein. Currently, REGN7257 is being studied in clinical trials and is not yet widely available in medical practice. It is primarily being investigated for its potential to treat severe aplastic anemia, particularly in patients who have not responded to or have relapsed after immunosuppressive therapy. The drug works by targeting and blocking the interleukin 2 receptor subunit gamma (IL2RG), which plays a role in immune system regulation. REGN7257 is classified as a monoclonal antibody, a type of medication designed to specifically target certain proteins in the body.

Investigated diseases

Severe Aplastic Anemia – Severe aplastic anemia is a rare blood disorder where the bone marrow fails to produce enough blood cells. This condition leads to a deficiency in red blood cells, white blood cells, and platelets. As a result, individuals may experience symptoms such as fatigue, increased risk of infections, and easy bruising or bleeding. The disease can progress as the bone marrow continues to produce fewer blood cells, exacerbating these symptoms. It is often classified as severe when the blood cell counts are extremely low, requiring medical intervention. The condition can be either acquired or inherited, with various factors contributing to its development.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2023-508601-24-00Protocol codeR7257-RAA-1947Estimated enrolment33 patientsSponsorRegeneron Pharmaceuticals Inc.

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