Casgevy, the world's first CRISPR gene-editing therapeutic co-developed by Vertex Pharmaceuticals and CRISPR Therapeutics, has announced positive results from its Phase 3 clinical trials in pediatric patients. According to CLIMB-151 and CLIMB-141 clinical data presented at the American Society of Hematology (ASH) 2025, safety and therapeutic efficacy similar to that observed in adults were confirmed in pediatric patients aged 5 to 11. Casgevy works by editing hematopoietic stem cells collected from the bone marrow of patients with beta-thalassemia and sickle cell disease using CRISPR-Cas9 technology, then reinfusing them. Clinical results showed a significant reduction in the number of blood transfusions for treated pediatric patients, with some no longer requiring transfusions at all. Long-term follow-up also indicated that the therapeutic effect was maintained for over a year. The FDA already approved Casgevy for adults in December 2023, and an expansion of its indication is anticipated following the success of these pediatric trials. The European Medicines Agency (EMA) is also conducting a similar review. The industry views the expansion of Casgevy's pediatric indication as a new milestone for gene-editing therapeutics. However, with treatment costs reaching up to $3.1 million (approximately 4.1 billion Korean Won), improving accessibility remains a challenge. Source: