In a landmark decision, the FDA approved Casgevy, developed by Vertex Pharmaceuticals and CRISPR Therapeutics, making it the first therapy using CRISPR gene editing to reach the market. The treatment works by editing patients' own blood stem cells to produce functional hemoglobin, eliminating the painful vaso-occlusive crises that characterize sickle cell disease.
Clinical trials showed that 29 of 31 patients who received the therapy were free of severe vaso-occlusive episodes for at least 12 months post-treatment. The one-time procedure involves collecting stem cells, editing them ex vivo with CRISPR-Cas9, and reinfusing them after myeloablative conditioning.
While the approval marks a transformative moment for gene therapy, challenges remain: the treatment costs approximately $2.2 million, requires intensive hospital stays, and the long-term effects of gene editing are still being studied.