Washington - The US Food and Drug Administration has granted approval for two gene therapies designed to treat sickle cell disease (SCD) in individuals aged 12 years and older.

In an official statement, the FDA revealed that Casgevy, a cell-based gene therapy, has been approved for individuals aged 12 and above with recurring vaso-occlusive crises associated with sickle cell disease. Notably, Casgevy is the first FDA-approved therapy incorporating CRISPR/Cas9, a genome editing technology.

Another gene therapy, Lyfgenia, has received approval for patients aged 12 years and above with sickle cell disease and a history of vaso-occlusive events. This cell-based gene therapy employs a lentiviral vector for genetic modification. According to the FDA, Lyfgenia involves genetically modifying the patient's blood stem cells to produce HbAT87Q, a gene-therapy-derived hemoglobin that functions similarly to hemoglobin A found in individuals without sickle cell disease. Red blood cells containing HbAT87Q have a lower risk of sickling, preventing blood vessel obstruction. The modified stem cells are then administered to the patient.

The FDA Director of the Center for Biologics Evaluation and Research, Peter Marks, MD, PhD, emphasized the significance of these approvals, characterizing them as a crucial medical advancement. Vertex Pharmaceuticals Inc. received approval for Casgevy, while Bluebird Bio Inc. secured approval for Lyfgenia.

Marks commented in the statement, "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." He added that the FDA's commitment to fostering the development of safe and effective treatments for severe health conditions underpinned the rigorous evaluations of scientific and clinical data.

Sickle cell disease, a collection of inherited blood disorders, affects around 100,000 people in the US, primarily among African Americans and, to a lesser extent, Hispanic Americans. The condition results from a mutation in hemoglobin, causing red blood cells to assume a crescent or "sickle" shape. This abnormal shape leads to blood vessel constriction, reduced oxygen delivery to tissues, and severe pain and organ damage known as vaso-occlusive events (VOEs) or vaso-occlusive crises (VOCs), as outlined by the FDA. Recurrent crises can pose life-threatening risks and result in significant disabilities or premature death.