CTX001 is a treatment that uses a patient’s own blood stem cells, which are modified using a technology called CRISPR/Cas9. This modification aims to help people with certain blood disorders, like transfusion-dependent beta-thalassemia or severe sickle cell disease, by potentially increasing the levels of a specific type of hemoglobin in their blood. The goal is to improve the patient’s condition by reducing the need for blood transfusions or alleviating symptoms associated with these diseases.

Transfusion-dependent β-thalassemia – This is a genetic blood disorder characterized by reduced production of hemoglobin, leading to severe anemia. Individuals with this condition require regular blood transfusions to manage their symptoms and maintain adequate hemoglobin levels. Over time, the need for transfusions can lead to complications such as iron overload, which may affect various organs. The disease is caused by mutations in the HBB gene, affecting the production of the beta-globin chain of hemoglobin. Symptoms often appear in early childhood and can include fatigue, weakness, and pale skin. Management focuses on maintaining hemoglobin levels and monitoring for complications.

Severe sickle cell disease – This is a genetic disorder affecting hemoglobin, the molecule in red blood cells that carries oxygen. It is characterized by the presence of abnormal hemoglobin, known as hemoglobin S, which causes red blood cells to become rigid and sickle-shaped. These sickle-shaped cells can block blood flow, leading to pain episodes known as vaso-occlusive crises. Over time, the disease can cause damage to organs and increase the risk of infections. Symptoms typically begin in early childhood and can include anemia, pain, and swelling in the hands and feet. The condition is inherited in an autosomal recessive pattern, meaning both copies of the gene in each cell have mutations.