The US FDA approved Casgevy, a cell-based gene therapy, for the treatment of patients 12 years of age and older with transfusion-dependent beta-thalassemia, an inherited disorder characterised by life-long anemia requiring frequent blood transfusions. To produce Casgevy, patients’ hematopoietic (blood) stem cells are modified by genome editing utilising novel CRISPR/Cas9 technology. The modified blood stem cells are transplanted back into the patient where they engraft (attach and multiply) within the bone marrow and increase the production of fetal hemoglobin (HbF), a type of hemoglobin that facilitates oxygen delivery and decreases the severity of anemia. The most common side effects were mouth sores, febrile neutropenia (fever associated with a low level of certain white blood cells), and decreased appetite. This application received Fast Track and Regenerative Medicine Advanced Therapy (RMAT) designations.
The approval signifies a second FDA-approved indication for Casgevy, as the product was also recently approved for the treatment of sickle cell disease in patients 12 years and older.