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Study on Gene Therapy for Patients with RAG1-Deficient Severe Combined Immunodeficiency Using RAG1-LV-CD34+ Cells

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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 a rare genetic disorder known as severe combined immunodeficiency (SCID), specifically caused by a defect in the Recombinase Activating Gene 1 (RAG1). SCID is a condition where the immune system is severely weakened, making it difficult for the body to fight off infections. The study is testing a new treatment called RAG1-LV-CD34+ cells, which involves using a patient's own blood stem cells that have been genetically modified to correct the RAG1 defect. These modified cells are then given back to the patient through an infusion, which is a way of delivering the treatment directly into the bloodstream.

The purpose of the study is to see if this gene therapy is safe and feasible for patients with RAG1-deficient SCID. Participants in the study will receive the gene therapy and will be monitored closely to ensure their safety and to observe how well the treatment works. The study will look at various outcomes, such as the ability of the immune system to recover and function properly, the overall health and survival of the participants, and any potential side effects that may occur.

Throughout the study, researchers will track the participants' progress over time, including their immune system's response to the treatment and any changes in their health. The study aims to provide valuable information on the potential of this gene therapy to improve the lives of individuals with RAG1-deficient SCID. Participants will be followed for a period of time to gather comprehensive data on the long-term effects and benefits of the treatment.

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

    Initial assessment

    Eligibility for the trial is confirmed through genetic analysis, ensuring a diagnosis of RAG1-deficient severe combined immunodeficiency (SCID).

    Additional criteria include specific blood cell counts, age requirements, and the absence of a suitable donor match.

  2. Step 2

    Preparation for treatment

    The patient undergoes a preparatory regimen, which includes the administration of medications such as busulfan and fludarabine. These medications help prepare the body for the upcoming infusion.

  3. Step 3

    Infusion of gene-corrected cells

    The patient receives an infusion of RAG1-LV-CD34+ cells through an intravenous route. This involves the use of a lentiviral vector to introduce a corrected version of the RAG1 gene into the patient's own stem cells.

  4. Step 4

    Monitoring and follow-up

    The patient is monitored for safety and effectiveness of the treatment. This includes checking for successful cell generation, overall survival, and any adverse events.

    Regular assessments are conducted to evaluate T cell reconstitution, thymic function, and the presence of naive T cells. The patient's immune system function and quality of life are also monitored.

  5. Step 5

    Long-term follow-up

    The patient continues to be monitored for up to 15 years to assess long-term outcomes, including the rate of infections and overall health status.

Who can join the trial?

7 criteria

  • The patient must have a condition called **RAG1-deficient SCID**, which is confirmed by a genetic test.
  • The patient must have a low number of **T cells** in their blood. T cells are a type of white blood cell important for the immune system. Specifically, they should have less than 300 T cells per microliter of blood, or less than 1 **naïve T cell** per microliter. Naïve T cells are a type of T cell that has not yet encountered an infection.
  • The patient must be younger than 2 years old.
  • The patient must be at least 8 weeks old by the time they receive certain medications called **busulfan** and **fludarabine**.
  • There must be no available **HLA-matched donor**. This means there is no sibling or unrelated donor who matches the patient's tissue type perfectly.
  • The patient's parent or guardian must sign a form giving permission for the patient to participate in the study. This is called **informed consent**.
  • The patient must be able to return to the local center where they received a type of treatment called **HSCT** (hematopoietic stem cell transplant) for follow-up visits during the 2-year study and for a 15-year long-term review.

Who cannot join the trial?

2 criteria

  • Patients who do not have a genetic defect in the **Recombinase Activating Gene 1 (RAG1)**. This gene is important for the immune system to work properly.
  • Patients who do not have **severe combined immunodeficiency (SCID)**. This is a condition where the immune system does not work well, making it hard to fight infections.
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Investigated drugs

Autologous Hematopoietic Stem Cell Gene Therapy is a treatment that uses a patient's own stem cells. These stem cells are collected and then modified in a laboratory to correct a genetic defect. In this trial, the stem cells are treated with a special vector that carries a corrected version of the RAG1 gene. After the modification, the stem cells are returned to the patient's body to help restore their immune system function. This therapy is specifically designed for patients with RAG1-deficient severe combined immunodeficiency (SCID).

What is already known about the treatment

Autologous Hematopoietic Stem Cell Gene Therapy – This therapy is administered through the infusion of genetically modified stem cells into the patient's bloodstream. It is currently being studied in clinical trials, specifically for its feasibility and safety in treating severe combined immunodeficiency (SCID) caused by a genetic defect in the Recombinase Activating Gene 1 (RAG1). The main therapeutic indication is for patients with RAG1-deficient SCID. The therapy works by using a lentiviral vector to introduce a corrected version of the RAG1 gene into the patient's own stem cells, allowing for the production of functional immune cells. It is classified under gene therapy, focusing on correcting genetic defects at the molecular level.

Investigated diseases

Severe Combined Immunodeficiency (SCID) due to RAG1 Deficiency – This is a rare genetic disorder characterized by a severe defect in both the T- and B-lymphocyte systems, which are crucial components of the immune system. The condition arises from mutations in the Recombinase Activating Gene 1 (RAG1), leading to an inability to effectively fight off infections. Infants with this condition often present with recurrent infections, failure to thrive, and other complications due to the lack of functional immune cells. The disease progresses as the immune system remains severely compromised, making affected individuals highly susceptible to infections. Without intervention, the immune deficiency persists, impacting overall health and development.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase ITrial ID2023-510204-50-00Protocol codeRAG1Estimated enrolment11 patientsSponsorVideja B.V.

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