WASHINGTON, D.C. — The U.S. Food and Drug Administration has expanded approval of the gene therapy Casgevy to include children as young as 2 with sickle cell disease or transfusion-dependent beta thalassemia, giving younger patients access to the first gene-editing treatment approved for these inherited blood disorders.
The decision broadens Casgevy’s previous approval, which covered patients aged 12 and older with sickle cell disease accompanied by recurrent vaso-occlusive crises or transfusion-dependent beta thalassemia.
The expanded indication marks the first gene therapy approved for children ages 2 and older with sickle cell disease, a condition that causes red blood cells to deform and can trigger severe pain episodes and organ damage.
“With today’s decision, pediatric patients as young as 2 years of age can now access a critical additional treatment option to treat these debilitating, life-threatening diseases,” Karim Mikhail, acting director of the FDA’s Center for Biologics Evaluation and Research, said in a statement.
Casgevy, developed by Vertex Pharmaceuticals, uses the CRISPR/Cas9 gene-editing platform to modify a patient’s own blood stem cells. The one-time treatment increases production of fetal hemoglobin, helping prevent red blood cells from taking on the sickle shape associated with the disease.
For patients with transfusion-dependent beta thalassemia, the therapy is designed to raise hemoglobin levels and reduce or eliminate the need for regular blood transfusions.
The FDA based its decision on clinical data involving pediatric patients between the ages of 5 and 12. In a trial involving children with sickle cell disease, all eight patients evaluated for efficacy experienced no severe vaso-occlusive crises for at least 12 consecutive months within the first two years after treatment.
In a separate study involving children with transfusion-dependent beta thalassemia, eight of nine evaluable patients achieved transfusion independence for at least 12 consecutive months, with a median duration of 20.1 months.
“Grounded in the scientific evidence that earlier treatment reduces the risk of lasting end-organ damage, making this therapy available to younger patients opens a critical window for intervention,” Megha Kaushal, acting deputy director of the Office of Therapeutic Products and a pediatric hematologist, said in a statement.
The approval was granted 53 days after the application was filed and was the eighth authorization issued under the FDA Commissioner’s National Priority Voucher pilot program, which aims to accelerate reviews for therapies addressing significant unmet medical needs.
Casgevy previously received Orphan Drug, regenerative medicine advanced therapy and Fast Track designations from the FDA.
The therapy carries risks associated with the stem cell transplant process and gene editing, including mucositis, febrile neutropenia, delayed platelet recovery and the possibility of unintended genetic changes outside the targeted DNA sequence, according to prescribing information.
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