On December 8, 2023, the FDA approved the first cell-based gene therapies for the treatment of sickle cell disease (SCD) in patients 12 years and older—Vertex’s CASGEVY and Bluebird’s LYFGENIA. SCD is a group of inherited blood disorders affecting approximately 100,000 people in the U.S. and inducing a median life expectancy of 45 years. The two approved therapies are made from a patient’s own blood stem cells which are extracted from the body, modified, and administered back to the patient as a single-dose infusion following chemotherapy. Peter Marks, M.D., Ph.D., director of the FDA’s Center for Biologics Evaluation and Research stated, “These approvals represent an important medical advance with the use of innovative cell-based gene therapies to target potentially devastating diseases and improve public health.”
Vertex’s CASGEVY (exagamglogene autotemcel [exa-cel]) is also the first FDA-approved therapy employing the use of CRISPR/Cas9 gene editing technology. CRISPR/Cas9 technology works by modifying specific regions of a patient’s DNA thereby altering the production of certain proteins important to bodily functions. CRISPR Therapeutics supported Vertex in the development, manufacturing, and commercialization of CASGEVY, and will receive certain payments from Vertex in conjunction with the FDA approval. CASGEVY has previously been granted conditional marketing authorization in Great Britain and Bahrain, and is currently under review by the European Medicines Agency and the Saudi Food and Drug Agency.
Bluebird’s LYFGENIA (lovotibeglogene autotemcel), on the other hand, uses a lentiviral vector to effect a genetic modification to a patient’s stem cells. As a result, a functional β-globin gene is permanently added to the patient’s stem cells resulting in durable production of hemoglobin with anti-sickling properties.
Patients receiving CASGEVY and LYFGENIA will be followed in long-term studies to evaluate the safety and effectiveness of the therapies.