WEDNESDAY, July 8, 2026 (HealthDay News) -- The U.S. Food and Drug Administration has issued a supplemental approval for Casgevy (exagamglogene autotemcel) for patients aged 2 years and older with either sickle cell disease (SCD) with recurrent vaso-occlusive crises (VOCs) or transfusion-dependent β thalassemia (TDT). Casgevy was previously approved for the treatment of patients 12 years and older with SCD with recurrent VOCs or TDT and is now the first gene therapy approved for patients aged 2 years and older. Therapy consists of autologous hematopoietic stem cells, administered as a one-time single dose via intravenous infusion. Cells are edited using CRISPR/Cas9 genome editing technology and then engrafted in the body's bone marrow.The safety and effectiveness of Casgevy in patients aged 5 years to <12 years with SCD were evaluated in a clinical trial that included 11 patients. All eight patients evaluable for efficacy achieved the primary efficacy outcome of no protocol-defined severe VOCs for at least 12 consecutive months within the first 24 months after infusion with Casgevy. For TDT, the efficacy and safety of Casgevy in patients 5 years to <12 years of age were evaluated in 15 patients. Of the nine patients evaluable for efficacy, eight achieved transfusion independence for 12 consecutive months; median duration of transfusion independence was 20.1 months.Based on the product characteristics and available clinical study data, extrapolation to the younger pediatric population was supported, extending the indication to patients aged 2 years and older for both conditions."These disorders carry a heavy burden for children and their families, affecting growth, development, and long-term health in profound ways," Megha Kaushal M.D., from the FDA Center for Biologics Evaluation and Research, said in a statement. "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 and gives these children a meaningful chance at a healthier future."Supplemental approval of Casgevy was granted to Vertex Pharmaceuticals.More Information.Sign up for our weekly HealthDay newsletter