A study testing gene therapy with Dream01 and imatinib for patients with severe sickle cell disease to improve red blood cell production

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What is this study about?

This study involves sickle cell disease, a serious inherited blood disorder that affects red blood cells and can cause severe pain episodes, organ damage, and other complications. The study will test a treatment called DREAM01, which is a type of gene therapy. Gene therapy is a treatment that works by modifying a patient’s own cells to correct the genetic problem causing the disease. In this approach, special blood-forming cells called CD34+ cells are collected from the patient, modified in a laboratory using a lentiviral vector (a tool that delivers corrected genetic material into the cells), and then given back to the patient through an intravenous infusion, which means the cells are returned into the bloodstream through a vein. Some patients may also receive imatinib before the gene therapy if they have severe inflammation detected during the initial evaluation phase.

The purpose of this study is to evaluate whether this gene therapy treatment is safe and effective for patients with sickle cell disease, both with and without prior imatinib treatment. The study will examine whether the treatment can restore normal red blood cell production by correcting the genetic defect that causes the abnormal hemoglobin (the protein in red blood cells that carries oxygen) found in sickle cell disease. The modified cells are designed to produce a corrected form of hemoglobin and also include a component that specifically targets the defective hemoglobin to reduce its production.

During the study, patients will undergo several evaluations to monitor the effectiveness and safety of the treatment. This includes measuring various blood parameters related to anemia and the breakdown of red blood cells, checking the function of different organs that may be affected by the disease such as the brain, heart, kidneys, liver, and lungs, and assessing iron levels in the body. The study will also track the frequency of painful episodes that require hospitalization, the need for blood transfusions, and changes in the patient’s physical abilities and quality of life. Patients will be followed for an extended period after receiving the treatment to carefully monitor outcomes and any potential side effects. The treatment involves a preparation phase where patients receive conditioning therapy to prepare their body for the infusion of the modified cells.

1 Initial screening and preparation

Your medical history will be reviewed to confirm the diagnosis of sickle cell disease (a condition where red blood cells have an abnormal shape) through blood tests that analyze hemoglobin types and genetic testing.

A bone marrow aspiration will be performed to collect a sample of bone marrow for evaluation.

Your overall health status will be assessed using the Karnovsky/Lansky performance score, which measures your ability to perform daily activities. This score must be at least 60%.

Various tests will be conducted to evaluate the function of different organs, including the brain, eyes, heart, kidneys, liver, lungs, bones, and muscles.

Tests will be performed to assess iron overload in your body, including blood tests for ferritin levels and magnetic resonance imaging of the liver and heart.

Your fertility will be evaluated through appropriate tests based on your sex, which may include hormone level measurements and ultrasound examinations.

Physical ability tests will be conducted, including a 6-minute walk test, vertical jump test, and exercise capacity assessment.

Questionnaires will be provided to evaluate your quality of life and fatigue levels.

If severe inflammation is detected during this phase, you may be assigned to receive imatinib treatment before the gene therapy procedure.

2 Imatinib treatment (if applicable)

If you are assigned to receive imatinib based on inflammation levels detected during screening, this medication will be administered before the gene therapy.

Imatinib is an anti-inflammatory medication that will be taken orally (by mouth).

The specific dosage, frequency, and duration of imatinib treatment will be determined by the medical team based on your individual condition.

3 Collection of stem cells

Your own stem cells (specifically CD34+ cells, which are special cells found in bone marrow that can develop into blood cells) will be collected from your body.

These cells will be processed and modified in a laboratory using a specialized technique involving a lentiviral vector (a tool used to introduce genetic material into cells).

The modification involves introducing a corrected version of the hemoglobin gene and a specialized molecule called microRNA that targets the defective hemoglobin in your cells.

This process aims to enable your body to produce normal red blood cells.

4 Conditioning treatment

Before receiving the modified stem cells, you will undergo a conditioning treatment to prepare your body for the transplant.

This treatment prepares your bone marrow to accept the modified cells.

5 Infusion of modified stem cells

The modified stem cells, called DREAM01, will be given back to you through intravenous infusion (administered directly into a vein).

The product is prepared as a dispersion for infusion.

This is a single infusion procedure.

6 Post-infusion monitoring and recovery

After receiving the modified stem cells, you will be closely monitored for safety and effectiveness of the treatment.

Blood tests will be performed regularly to measure the percentage of corrected hemoglobin and the amount of genetic modification in your cells over time.

The number and severity of vaso-occlusive events (episodes where blood flow is blocked due to abnormally shaped red blood cells causing pain and organ damage) will be tracked. This evaluation will begin 60 days after your last red blood cell transfusion.

The need for blood transfusions and the number of red blood cell units required will be monitored.

Blood tests will be conducted to assess markers of hemolysis (breakdown of red blood cells) and anemia, including total hemoglobin, reticulocytes, lactate dehydrogenase, haptoglobin, free plasma heme, bilirubin, and erythropoietin levels.

Organ function will be evaluated through biological, functional, and imaging tests for the brain, eyes, heart, kidneys, liver, lungs, bones, and muscles.

Iron overload will be assessed through ferritin levels and magnetic resonance imaging of the liver and heart. Any specific treatments such as chelation therapy or phlebotomy will be documented.

Fertility assessments will be repeated based on your sex.

Physical ability and capacity will be evaluated through the 6-minute walk test, vertical jump test, physical ability questionnaires, and cardiopulmonary exercise testing.

Quality of life will be assessed using standardized questionnaires.

7 Long-term follow-up

Monitoring will continue for up to 24 months after the infusion of modified stem cells to evaluate long-term safety and effectiveness.

If you are sexually active, you must use a double-barrier contraception method for at least 12 months following the infusion, and potentially longer as determined by the medical team.

Regular assessments will continue to track the reduction in disease-related complications and overall health status.

Who Can Join the Study?

You must be between 5 and 35 years old
You must have a diagnosis of HbSS, which is a specific type of sickle cell disease confirmed by blood tests and genetic testing
You must agree to have a bone marrow aspiration, which is a procedure where a small sample of bone marrow is taken with a needle for testing
You must have severe sickle cell disease with at least one of the following serious complications: at least 3 pain crises requiring hospital admission while on hydroxyurea or transfusions in the past 2 years, a severe acute chest syndrome requiring intensive care unit admission, at least 2 episodes of acute chest syndrome with one occurring while on hydroxyurea, painful prolonged erections lasting more than 3 hours at least twice in the past year or recurring at least once weekly while on treatment, or specific heart findings on ultrasound
You must have either failed treatment with hydroxyurea, which is a medication used to treat sickle cell disease, or not responded adequately to this medication
Your Karnovsky or Lansky performance score must be at least 60%, which is a measure of how well you can perform daily activities and take care of yourself
If you are a woman who can become pregnant, you must use two effective methods of birth control, including one insertable device, injection, patch, or birth control pill combined with a barrier method like a condom, during the study and for at least 12 months after treatment
If you are a man who is sexually active with women, you must use two methods of birth control including a condom plus another method used by your partner, and agree not to donate sperm during the study and for at least 12 months after treatment
You must be able to provide informed consent, which means you understand the study and agree to participate, or if you are a minor, your parent or guardian must provide consent
You must have social security coverage

Who Cannot Join the Study?

The study does not list specific exclusion criteria, which means the research team will determine who cannot participate based on individual medical evaluation and the study’s safety requirements
Patients who do not have severe sickle cell disease (a serious blood disorder where red blood cells become abnormally shaped) cannot participate
Patients whose age falls outside the specified age groups for this study cannot participate
Patients who are not healthy enough to undergo stem cell transplant (a procedure where special cells that make blood are given to replace damaged ones) may not be eligible
Patients who have certain infections or medical conditions that would make the gene therapy (treatment that modifies genes to fix disease) unsafe cannot participate
Patients who cannot safely receive the preparatory treatment needed before the transplant may be excluded
Patients with severe organ damage that would prevent safe treatment may not be eligible
Patients who are pregnant or breastfeeding cannot participate due to potential risks to the baby

Where you can join this trial?

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Other Sites

Site Name	City	Country	Status
Hopital Beaujon	Clichy	France
Geyusy Hjcpoxpsuhz Ukvsmthvlicll Prtsv Pwntvwsenps Eo Nmidlsytflbv	Paris	France

Trial status

Country	Status	Recruitment Start
France	Recruiting	01.01.2026

Trial locations

Investigated drugs:

Imatinib

DREAM01 is a gene therapy treatment designed for people with sickle cell disease. This treatment involves collecting a patient’s own blood stem cells (called CD34+ cells) and modifying them in a laboratory using a special carrier called a lentiviral vector. The modified cells are designed to produce a corrected version of the hemoglobin beta gene, which helps make healthy red blood cells, and also include a microRNA that targets the defective hemoglobin. After the cells are modified, they are transplanted back into the patient to help restore normal red blood cell production and reduce symptoms of sickle cell disease.

Imatinib is an anti-inflammatory medication that may be given to some patients before they receive the gene therapy treatment if they have severe inflammation detected during the screening phase of the study. This medication helps to reduce inflammation in the body.

Investigated diseases:

Sickle cell disease

Sickle Cell Disease – Sickle cell disease is a genetic blood disorder that affects the shape and function of red blood cells. In this condition, red blood cells become abnormally shaped like a crescent or sickle instead of their normal round shape. These sickle-shaped cells are rigid and sticky, which causes them to block blood flow in small vessels throughout the body. When blood flow is blocked, it leads to painful episodes called vaso-occlusive events, where tissues and organs do not receive enough oxygen. The disease causes ongoing destruction of red blood cells, leading to anemia, which means the body does not have enough healthy red blood cells to carry oxygen effectively. Over time, the repeated blocking of blood vessels and lack of oxygen can affect various organs including the brain, eyes, heart, kidneys, liver, lungs, bones, and muscles.

Trial ID:

2025-521257-17-00

Protocol code:

APHP241664

Trial Phase:

Phase I and Phase II (Integrated) – First administration to humans

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A study testing gene therapy with Dream01 and imatinib for patients with severe sickle cell disease to improve red blood cell production

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?