FDA Expands CRISPR Gene Therapy to Children as Young as Two

The FDA has cleared Casgevy, the world's first CRISPR-based gene therapy, for children as young as two years old — opening access for 5,500 additional American children with sickle cell disease and beta-thalassemia.

The U.S. Food and Drug Administration has cleared the world's first CRISPR-based gene therapy for use in children as young as two years old, an expansion that places a potentially curative treatment within reach of approximately 5,500 additional American children before years of accumulated organ damage can narrow their options.

Casgevy (exagamglogene autotemcel), developed by Vertex Pharmaceuticals in partnership with CRISPR Therapeutics, was previously approved only for patients aged 12 and older. The July 1 supplemental approval extends the indication to any patient aged two and above with either sickle cell disease with recurrent vaso-occlusive crises, or transfusion-dependent beta-thalassemia.

The therapy works by collecting a patient's own blood-forming stem cells, editing them with CRISPR/Cas9 to disable the BCL11A gene that suppresses fetal hemoglobin production, and then reinfusing the edited cells. The result: red blood cells produce high levels of fetal hemoglobin — typically 40 to 50 percent — which does not sickle or polymerize the way adult sickle hemoglobin does.

The pediatric approval rests on data from two Phase 3 trials. In the sickle cell trial, all eight evaluable children achieved the primary endpoint of freedom from severe pain crises for at least 12 consecutive months — a 100 percent efficacy rate. In the beta-thalassemia trial, eight of nine evaluable patients achieved transfusion independence, with a median duration of 20.1 months.

The treatment is not without significant tradeoffs. The myeloablative chemotherapy required before infusion is gonadotoxic, meaning very young patients face permanent infertility with no option to preserve eggs or sperm beforehand. The 2.2 million dollar price tag also remains a barrier — as of February 2026, only about 64 patients globally had received Casgevy despite more than 75 authorized U.S. treatment centers.

Still, with sickle cell disease causing strokes, progressive kidney failure, chronic pain, and a life expectancy shortened by more than 20 years, the calculus for families is shifting. For the first time, a toddler diagnosed with sickle cell disease no longer has to wait until adolescence for access to a therapy capable of preventing the disease's worst outcomes.

Sources: TechTimes, Vertex PR via Las Vegas Sun