Vertex Casgevy OK'd for Kids as Young as 2 in Sickle Cell, Thalassemia

Vertex Pharmaceuticals won a broader FDA label for its gene-editing therapy Casgevy on Monday, clearing the treatment for children as young as two with sickle cell disease or beta thalassemia. The expanded indication opens a younger patient pool for a drug that launched last year with a label covering patients 12 and older.

Casgevy, developed with CRISPR Therapeutics, is the first approved therapy using CRISPR gene-editing technology. The FDA's decision follows clinical data showing the treatment was safe and effective in the younger age group, Vertex said. The company did not disclose the size of the pediatric trial or specific efficacy rates in its announcement.

The expanded label matters for Vertex's commercial outlook. The initial launch was slow, with analysts at几家 firms citing the complexity of the treatment process – patients must undergo chemotherapy to prepare bone marrow for the edited cells – as a barrier to adoption. Adding younger patients broadens the addressable market at a time when Vertex is also competing with bluebird bio's Lyfgenia, another gene therapy for sickle cell disease.

Sickle cell disease affects roughly 100,000 people in the U.S., mostly Black Americans. Beta thalassemia is less common. Both conditions are genetic blood disorders that cause severe pain, organ damage, and shortened life expectancy. Casgevy works by editing a patient's own stem cells to produce fetal hemoglobin, which compensates for the defective adult hemoglobin.

The treatment carries a wholesale acquisition cost of $2.2 million per patient, though Vertex has said most patients will pay far less through outcomes-based contracts with insurers. The company has not disclosed how many patients have been treated since the initial approval in December 2023.

Vertex shares rose 1.2% in after-hours trading following the announcement. The stock is up roughly 12% year to date.