Vertex’s Gene Therapy Casgevy Shows Strong Efficacy in Younger Children with Blood Disorders

Boston, December 6, 2025

Vertex Pharmaceuticals announced new clinical data demonstrating that its gene-editing therapy Casgevy (exagamglogene autotemcel, exa-cel) produced robust therapeutic benefits in children aged 5 to 11 with severe hereditary blood disorders. The findings represent a major step toward expanding the therapy’s indication to younger pediatric patients.

According to the newly released results, several children with sickle cell disease (SCD) experienced no severe vaso-occlusive crises for at least 12 months following Casgevy infusion, with some remaining crisis-free for nearly two years during extended follow-up.

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Among children with transfusion-dependent β-thalassemia (TDT), all 12 treated patients were able to discontinue blood transfusions entirely, achieving durable transfusion independence — the primary clinical target for TDT therapy.

Casgevy, the first approved CRISPR-based therapy worldwide, is currently authorized for adolescents and adults in multiple regions. The new pediatric findings mark a key advancement in the therapy’s development trajectory, suggesting broad clinical potential across age groups.

Vertex plans to submit regulatory applications for pediatric use in early 2026, supported by a National Priority Voucher that enables an accelerated review pathway.

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Analysts note that approval of Casgevy for younger children would significantly shift the treatment landscape for SCD and TDT, potentially establishing gene editing as a transformative standard of care in pediatric hematology.

Source: Reuters, Vertex’s gene therapy shows promise in younger children with blood disorders, December 6, 2025.