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Study of Exagamglogene Autotemcel (CTX001) for Treatment of Severe Sickle Cell Disease Using Modified Stem Cells

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 study focuses on patients with Severe Sickle Cell Disease, a genetic blood disorder that causes red blood cells to become crescent-shaped and rigid, leading to painful episodes and other complications. The main treatment being tested is CTX001 (also known as exagamglogene autotemcel), which is made from a patient's own blood stem cells that have been modified using a gene-editing technique called CRISPR-Cas9. The purpose is to evaluate if this single-dose treatment is safe and effective for people with severe sickle cell disease.

Before receiving the modified cells, patients will be given medications including plerixafor to help collect their blood stem cells, and busulfan to prepare their body for the treatment. The modified stem cells are then given back to the patient through an intravenous infusion. This is a type of cell therapy where the patient's own cells are changed in a laboratory to help them produce a special form of hemoglobin that can prevent the sickling of red blood cells.

After receiving the treatment, patients will be monitored to see how well the modified cells work in their body and if they experience fewer painful crisis events related to their disease. The study will track various aspects of the patient's health, including how well the new cells grow in their body and whether the treatment reduces hospital stays and complications from sickle cell disease.

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

    Initial treatment preparation

    You will undergo evaluation to confirm eligibility for autologous stem cell transplant (using your own stem cells)

    Your medical history will be reviewed, focusing on previous vaso-occlusive crisis events (severe pain episodes related to sickle cell disease)

  2. Step 2

    Cell collection

    You will receive plerixafor by injection under the skin to help release stem cells into your blood

    Your blood stem cells will be collected through a special procedure

    These cells will be modified using CRISPR-Cas9 technology to create the treatment called CTX001

  3. Step 3

    Pre-treatment conditioning

    You will receive busulfan through an intravenous line to prepare your body for the cell therapy

    This medication helps create space in your bone marrow for the new cells

  4. Step 4

    Cell therapy administration

    You will receive a single dose of the modified cells (Casgevy) through an intravenous line

    The modified cells are given as a dispersion for infusion

  5. Step 5

    Post-treatment monitoring

    You will be monitored for successful attachment of the new cells (engraftment)

    Regular blood tests will check your blood cell counts and other markers

    You may need blood transfusions for support during the recovery period

    Monitoring will continue for 24 months to assess the treatment's effectiveness

    The evaluation period begins 60 days after your last blood transfusion

  6. Step 6

    Long-term follow-up

    Your progress will be tracked through regular assessments until July 2025

    Doctors will monitor for any pain episodes or hospitalizations

    Regular blood tests will continue to check treatment effectiveness

    You will complete quality of life questionnaires to assess your well-being

Who can join the trial?

7 criteria

  • Must have a confirmed diagnosis of severe sickle cell disease
  • Must have medical documentation confirming the specific genetic type of severe sickle cell disease
  • Must have experienced at least 2 severe pain crises (periods of intense pain caused by blocked blood vessels) per year in the past 2 years
  • Must be considered suitable for stem cell transplant (a procedure where damaged blood-forming cells are replaced with healthy ones) according to the doctor's assessment
  • Must be either male or female
  • Must be an adolescent or adult (12 years or older)
  • Must not belong to any vulnerable population groups (such as people unable to give informed consent)

Who cannot join the trial?

14 criteria

  • Prior history of stem cell transplantation (a procedure where healthy blood-forming cells replace damaged ones)
  • Known allergies to medications required for the study procedures
  • Active hepatitis B, hepatitis C, or HIV infection (viral infections affecting the liver and immune system)
  • Significant heart, lung, liver or kidney disease
  • Current pregnancy or breastfeeding
  • Active cancer or history of blood cancer
  • Participation in another clinical trial within the past 30 days
  • Unable to undergo required medical procedures due to medical or psychological conditions
  • History of poor response to blood transfusions
  • Severe organ damage related to sickle cell disease
  • Inability to provide informed consent
  • Current substance abuse or addiction
  • Serious psychiatric conditions that could interfere with study compliance
  • Blood disorders other than sickle cell disease
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Investigated drugs

  • CTX001

    is a type of cell therapy that uses the patient's own blood stem cells (called CD34+ cells). These cells are modified using CRISPR-Cas9 technology, which is a gene-editing tool. The modified cells are then given back to the patient as a single infusion. This therapy is designed to help patients with severe sickle cell disease by altering the genes in their blood-forming cells to produce healthy red blood cells instead of the sickle-shaped cells that cause the disease.

  • Busulfan

    is typically used as a conditioning medication before cell therapy. It helps prepare the body to receive the modified stem cells by clearing space in the bone marrow. This allows the new, modified cells to establish themselves and begin producing healthy blood cells.

  • Plerixafor

    is commonly used in stem cell collection procedures. It helps mobilize stem cells from the bone marrow into the bloodstream, making it easier to collect these cells for modification.

What is already known about the treatment

CTX001 - An innovative cell therapy consisting of genetically modified hematopoietic stem cells using CRISPR-Cas9 technology, administered as a single intravenous infusion. This treatment is being investigated for severe sickle cell disease (SCD) and works by editing the patient's own stem cells to produce functional hemoglobin. CTX001 belongs to the class of gene therapy products and represents a potential breakthrough in treating genetic blood disorders by modifying the patient's stem cells at the DNA level to correct the underlying genetic cause of the disease. The therapy involves collecting the patient's blood stem cells, modifying them in a laboratory using CRISPR gene editing technology, and then returning them to the patient's body where they can produce healthy red blood cells.

Investigated diseases

Sickle Cell Disease (SCD) – A genetic blood disorder where red blood cells become crescent-shaped (like a sickle) instead of their normal round shape. This abnormal shape causes red blood cells to break down prematurely and can block small blood vessels. The disease is inherited when both parents pass on the abnormal hemoglobin gene to their child. People with SCD experience episodes called vaso-occlusive crises (VOCs), during which sickle-shaped cells block blood vessels, causing pain and potential organ damage. The condition typically manifests in early childhood and continues throughout life. The disease can cause anemia because the abnormal red blood cells don't last as long as healthy ones.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2024-516067-83-00Protocol codeCTX001-121Estimated enrolment46 patientsSponsorVertex Pharmaceuticals Inc.

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