The U.S. Food and Drug Administration on Tuesday approved an expanded indication for Casgevy, the CRISPR-based gene therapy developed by Vertex Pharmaceuticals and CRISPR Therapeutics, allowing its use in children aged 5 to 11 with severe sickle cell disease. The decision marks the first time a gene-editing therapy has been cleared for use in a pediatric population this young, a milestone that experts say could transform treatment for thousands of children in the United States.

The approval was based on data from the CLIMB SCD-131 pediatric trial, which enrolled 38 children across 12 medical centers in the U.S. and Europe. Results showed that 94% of treated children were free of vaso-occlusive crises for at least 12 months following infusion, with a safety profile consistent with the myeloablative conditioning regimen required before treatment. Vertex CEO Reshma Kewalramani called the approval 'a profound moment for families who have watched their children suffer through repeated pain crises and hospitalizations.'

Sickle cell disease affects approximately 100,000 people in the United States, disproportionately impacting Black and Hispanic communities. While Casgevy was approved for patients aged 12 and older in December 2023, pediatric hematologists had long argued that earlier intervention could prevent cumulative organ damage. Dr. Monica Bhatia, director of the pediatric stem cell transplant program at Columbia University Irving Medical Center, said the expanded approval 'gives us the chance to intervene before these children develop irreversible complications in their lungs, kidneys, and brain.'

The treatment's cost remains a significant barrier. Casgevy carries a list price of $2.2 million per patient, and the intensive hospitalization required for bone marrow conditioning adds substantially to the total expense. Medicaid, which covers a large proportion of sickle cell patients, has been negotiating outcomes-based agreements with Vertex in several states. The Centers for Medicare and Medicaid Services indicated Tuesday that it would issue updated guidance to state Medicaid programs within 60 days to facilitate coverage.

Patient advocacy groups, including the Sickle Cell Disease Association of America, welcomed the decision but cautioned that access gaps remain acute. Only 12 certified treatment centers in the U.S. currently have the infrastructure to administer Casgevy, and wait times already stretch beyond six months for adult patients. 'Approval is not access,' said SCDAA president Beverley Francis-Gibson. 'We need an urgent expansion of qualified centers, particularly in the South, where the burden of this disease is greatest.'

The FDA said it would require Vertex to conduct a 15-year post-market surveillance study to monitor long-term outcomes in pediatric patients, including potential off-target gene-editing effects. The European Medicines Agency is expected to rule on a similar pediatric indication by mid-2026.