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Study on the Safety and Effectiveness of CTX001 for Children with Severe Sickle Cell Disease Using Exagamglogene Autotemcel, Busulfan, and Plerixafor

Verified siteRegistered drugNo 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 severe sickle cell disease, a condition where red blood cells become misshapen and can block blood flow, causing pain and other serious problems. The study is testing a new treatment called CTX001, which involves using a special technique known as CRISPR-Cas9 gene editing. This technique modifies the patient's own blood stem cells to help them produce healthier red blood cells. The goal is to see if a single dose of CTX001 can safely and effectively reduce the complications associated with severe sickle cell disease in children.

Participants in the study will receive a single dose of CTX001 through an infusion, which is a way of delivering the treatment directly into the bloodstream. The study will monitor the participants over time to see if the treatment helps reduce the number of painful episodes and hospital visits related to sickle cell disease. The study will also look at the safety of the treatment by checking for any side effects or changes in health markers like blood counts and vital signs.

The trial aims to find out if CTX001 can help children with severe sickle cell disease by reducing the frequency of painful crises and improving their overall health. The study will track the participants' progress for several months to gather information on how well the treatment works and how safe it is. This research could lead to new ways to manage and treat sickle cell disease in the future.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    The trial begins with an initial assessment to confirm eligibility. This includes a diagnosis of severe sickle cell disease (SCD) and a history of at least two severe vaso-occlusive crises (VOCs) per year for the previous two years.

    Eligibility also requires a failure of hydroxyurea treatment unless intolerant, and suitability for an autologous stem cell transplant.

  2. Step 2

    Medication preparation

    The preparation phase involves the administration of plerixafor through a subcutaneous injection. This medication helps mobilize stem cells from the bone marrow into the bloodstream.

  3. Step 3

    Stem cell collection

    Stem cells are collected from the bloodstream. These cells will be modified using CRISPR-Cas9 technology to create CTX001, which is intended to treat SCD.

  4. Step 4

    Conditioning treatment

    A conditioning treatment with busulfan is administered intravenously. This step prepares the body to receive the modified stem cells by reducing the number of existing bone marrow cells.

  5. Step 5

    CTX001 infusion

    The modified stem cells, now called CTX001, are infused back into the body through an intravenous route. This is a single-dose treatment aimed at addressing the underlying cause of SCD.

  6. Step 6

    Post-infusion monitoring

    After the infusion, monitoring begins to evaluate the effectiveness and safety of the treatment. This includes checking for any severe VOCs and other health indicators.

    The primary goal is to achieve a period of at least 12 consecutive months without severe VOCs, starting 60 days after the last red blood cell transfusion.

  7. Step 7

    Long-term follow-up

    Long-term follow-up continues for up to 24 months to assess the reduction in VOCs and hospitalizations, as well as other health metrics such as fetal hemoglobin levels and overall hemoglobin concentrations.

    Safety and tolerability are also evaluated through regular health checks and laboratory tests.

Who can join the trial?

5 criteria

  • The patient must have a diagnosis of severe sickle cell disease (SCD). This means they have a specific type of blood disorder.
  • The patient should have a history of at least two severe VOCs events per year for the previous two years before joining the study. VOCs are painful episodes that occur when blood flow is blocked.
  • The patient must have experienced hydroxyurea (HU) failure, unless they cannot tolerate HU. Hydroxyurea is a medication used to treat SCD, and failure means it did not work well for them.
  • The patient should be eligible for an autologous stem cell transplant according to the investigator's judgment. This means they can receive a transplant using their own stem cells.
  • The study is open to both male and female patients.

Who cannot join the trial?

7 criteria

  • Patients who do not have severe sickle cell disease (SCD) cannot participate. Sickle cell disease is a condition where red blood cells, which carry oxygen around the body, are shaped like a sickle or crescent, causing blockages and pain.
  • Patients who are not within the specified age range for the study cannot participate. The study is for pediatric subjects, meaning children.
  • Patients who are not able to provide consent or whose guardians cannot provide consent cannot participate.
  • Patients who have other medical conditions that might interfere with the study cannot participate.
  • Patients who are pregnant or breastfeeding cannot participate.
  • Patients who have participated in another clinical trial recently may not be eligible.
  • Patients who have had a recent blood transfusion or are on certain medications may not be eligible.
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Investigated drugs

CTX001 is a treatment being studied for its effectiveness in children with severe sickle cell disease. It involves using the patient's own stem cells, which are modified using a technology called CRISPR-Cas9. This modification aims to correct the genetic defect that causes sickle cell disease, potentially reducing symptoms and complications associated with the condition.

What is already known about the treatment

CTX001 – CTX001 is administered as a single dose of autologous CRISPR-Cas9 modified CD34+ human hematopoietic stem and progenitor cells, delivered through an intravenous infusion. It is currently being studied in clinical trials, specifically in a Phase 3 study, to assess its safety and effectiveness in treating severe sickle cell disease in pediatric patients. The main therapeutic indication for CTX001 is severe sickle cell disease, a genetic disorder that affects hemoglobin in red blood cells. At the molecular level, CTX001 works by using CRISPR-Cas9 technology to edit the patient's own stem cells, aiming to correct the genetic mutation responsible for the disease. It falls under the pharmacological classification of gene therapy, as it involves modifying the patient's genetic material to treat the condition.

Investigated diseases

Sickle Cell Disease – Sickle cell disease is a genetic blood disorder characterized by the production of abnormal hemoglobin, known as hemoglobin S. This causes red blood cells to become rigid and shaped like a sickle, leading to blockages in blood vessels. These blockages can result in episodes of pain, known as vaso-occlusive crises, and can damage organs over time. The disease can also cause anemia, as the sickle-shaped cells break down more quickly than normal red blood cells. Over time, individuals with sickle cell disease may experience complications such as infections, delayed growth, and vision problems. The severity of symptoms can vary widely among individuals.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IIITrial ID2024-513978-22-00Protocol codeVX21-CTX001-151Estimated enrolment13 patientsSponsorVertex Pharmaceuticals Inc.

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