Vertex has secured a label expansion through the FDA's Commissioner’s National Priority Voucher (CNPV) program, which allows children as young 2 years of age to receive the gene therapy Casgevy for the one-time treatment of sickle cell disease (SCD) with recurrent vaso-occlusive crises (VOCs) or transfusion-dependent beta thalassemia (TDT).
The groundbreaking therapy, which was co-developed by CRISPR Therapeutics, had already been approved for patients ages 12 and older. The expansion opens the use of Casgevy to an additional 5,500 children in the United States, according to the Boston-based company, giving those patients and their families an opportunity to reduce the risk of organ damage that can result from either disorder.
“Earlier access to the transformative potential of this therapy will allow clinicians and families to consider treatment before years of cumulative damage from these life-shortening diseases take hold,” Haydar Frangoul, M.D., the Medical Director of HCA Healthcare’s Sarah Cannon Transplant and Cellular Therapy Program at TriStar Centennial Children’s Hospital, said in a release.
The expansion is supported in part by results from two ongoing phase 3 trials. In one, which included 11 children between the ages of 5 and 12 with SCD, of the eight patients who were evaluable for efficacy, all achieved the primary endpoint with no severe VOCs for at least 12 straight months, according to a separate approval release from the FDA.
In the other trial of 15 TDT patients in the same age group, eight of the nine who could be evaluated for efficacy achieved the same standard, with a median duration of transfusion independence of 20 months.
Expanding the indication down to 2 years of age was also based on the known characteristics of Casgevy and clinical study data in both indications, Vertex said.
“The remarkable consistency of results across age groups reinforces the potential of Casgevy to deliver durable, transformative benefits to those who have historically had limited options,” Vertex CEO Reshma Kewalramani, M.D., said in Vertex's announcement.
The approval falls under the CNPV program established by former FDA commissioner Marty Makary, M.D., who announced his resignation in May amid a turbulent tenure at the regulator.
The CNPV program was designed to drastically shorten review timelines for certain products and companies aligned with U.S. national interests.
When Casgevy was originally approved in 2023 for SCD, it was hailed as the first medicine developed using the revolutionary CRISPR gene-editing system, which earned its inventors a Nobel Prize in 2020 and holds tantalizing potential to cure other diseases for which there are no current treatments.
On the same day that the FDA originally approved Casgevy, the U.S. regulator also signed off on bluebird bio’s SCD gene therapy Lyfgenia. While uptake has been slow for both treatments—owed in part to their respective prices of $2.2 million and $3.1 million—they are building momentum.
Sales for Casgevy came in at $116 million in 2025 with 64 patients receiving infusions, including 30 in the fourth quarter. In the first three months of this year, Vertex listed Casgevy sales at $43 million. The company added in its report that more than 500 patients have initiated treatment with Casgevy since it reached the market.
Meanwhile in 2025, more than 150 patients finished initial cell collection of Lyfgenia, with more than 100 receiving infusions, according to private Genetix Biotherapeutics, which does not report sales of the treatment. After bluebird was sold last year, private equity companies Carlyle and SK Capital established Genetix. Lyfgenia remains approved for SCD and TDT patients ages 12 and older.