FDA Approval

FDA Expands Casgevy Approval to Children Aged 2 Years and Older With Sickle Cell Disease or Transfusion-Dependent β-Thalassemia

Anthony Calabro, MA

Key Highlights

  • The FDA issued a supplemental approval for exagamglogene autotemcel for patients aged 2 years and older with sickle cell disease with recurrent vaso-occlusive crises or transfusion-dependent β-thalassemia.
  • Exagamglogene autotemcel is a one-time autologous hematopoietic stem cell gene therapy edited using CRISPR/Cas9 technology.
  • In evaluable patients aged 5 years to younger than 12 years with sickle cell disease, all 8 achieved no protocol-defined severe vaso-occlusive crises for at least 12 consecutive months within the first 24 months after infusion.
  • In evaluable patients aged 5 years to younger than 12 years with transfusion-dependent β-thalassemia, 8 of 9 achieved transfusion independence for 12 consecutive months.

On July 1, the FDA issued a supplemental approval for exagamglogene autotemcel (Casgevy, Vertex Pharmaceuticals, Inc) for patients aged 2 years and older with sickle cell disease with recurrent vaso-occlusive crises or transfusion-dependent β-thalassemia. Exagamglogene autotemcel had previously been approved for patients aged 12 years and older with sickle cell disease with recurrent vaso-occlusive crises or transfusion-dependent β-thalassemia. According to the FDA, this is the first gene therapy approved for patients aged 2 years and older with sickle cell disease.

“With today’s decision, pediatric patients as young as 2 years of age can now access a critical additional treatment option to treat these debilitating, life-threatening diseases,” Karim Mikhail, BPharm, MS, Acting Director of the Center for Biologics Evaluation and Research, said in a press release.

Exagamglogene autotemcel consists of a patient’s own autologous hematopoietic stem cells and is administered as a one-time intravenous infusion after full myeloablative conditioning. The cells are edited using CRISPR/Cas9 technology and then engrafted in the bone marrow. In severe sickle cell disease, the treatment increases fetal hemoglobin, helping prevent red blood cells from forming sickle shapes and addressing the underlying cause of disease. In transfusion-dependent β-thalassemia, treatment increases fetal hemoglobin and total hemoglobin levels, eliminating dependence on regular red blood cell transfusions.

Safety and effectiveness in sickle cell disease were evaluated in a clinical trial of 11 patients aged 5 years to younger than 12 years. All 8 patients who were evaluable for efficacy achieved the primary efficacy outcome of VF12, defined as no protocol-defined severe vaso-occlusive crises for at least 12 consecutive months within the first 24 months after infusion.

In transfusion-dependent β-thalassemia, efficacy and safety were evaluated in a trial of 15 patients aged 5 years to younger than 12 years. Eight of 9 efficacy-evaluable patients achieved transfusion independence for 12 consecutive months, with a median duration of 20.1 months. Based on product characteristics and clinical study data, the FDA granted extrapolation to expand the indication to patients aged 2 years and older for both conditions.

The most common adverse reactions were mucositis and febrile neutropenia in patients with sickle cell disease and transfusion-dependent β-thalassemia, and decreased appetite in patients with sickle cell disease. The prescribing information also includes warnings about neutrophil engraftment failure, delayed platelet engraftment, hypersensitivity reactions, and the risk of off-target genome editing.

Exagamglogene autotemcel is administered as a single, one-time dose via intravenous infusion. Full myeloablative conditioning is administered before treatment.

Reference
US Food and Drug Administration. FDA approves first gene therapy for young children with sickle cell disease. Published July 1, 2026. Accessed July 15, 2026. https://www.fda.gov/news-events/press-announcements/fda-approves-first-gene-therapy-young-children-sickle-cell-disease