Who Owns Casgevy?

The therapy's scientific basis is a discovery about hemoglobin genetics. Researchers found that some people carry natural mutations in a gene called BCL11A that keep their fetal hemoglobin switched on into adulthood, protecting them from sickle cell disease and beta thalassemia even when they inherit the causative mutations. Editing BCL11A to reactivate fetal hemoglobin offered a route to a functional cure.

Vertex and CRISPR Therapeutics began their collaboration in 2015 to pursue this approach. The treatment process collects a patient's own blood stem cells, edits them ex vivo using CRISPR/Cas9 to disable BCL11A, destroys the remaining bone marrow with chemotherapy, and reinfuses the edited cells, which then produce healthy fetal hemoglobin.

Clinical results published in the New England Journal of Medicine showed the therapy eliminating vaso-occlusive crises in nearly all sickle cell patients and freeing almost all thalassemia patients from transfusion dependence. On November 16, 2023, the UK's MHRA authorized Casgevy, making it the first CRISPR-based medicine approved anywhere in the world. The FDA followed on December 8, 2023, for sickle cell disease, and added transfusion-dependent beta thalassemia in January 2024.

Commercial rollout has been deliberately slow because delivery is complex. Patients must be treated at authorized treatment centers capable of cell collection, conditioning chemotherapy, and long hospitalization. In FY2025, 64 patients received Casgevy infusions while 147 began the first cell collection step, generating $115.8 million in revenue. Vertex estimates approximately 60,000 patients with severe disease are or could become eligible across approved geographies, including about 37,000 in North America and more than 23,000 in the Middle East.