Vertex Casgevy wins landmark FDA approval for toddlers with SCD and TDT

USA—The FDA has broadened the approval of Vertex Pharmaceuticals’ Casgevy to include a one-time gene-editing treatment for children two years and older suffering from sickle cell disease (SCD) with frequent vaso-occlusive crises (VOCs) or transfusion-dependent beta thalassemia (TDT).

The decision makes Casgevy the first approved CRISPR-based gene-editing therapy available for children this young with either inherited blood disorder.

The approval was granted through the FDA’s Commissioner’s National Priority Voucher (CNPV) programme, which accelerates the review of medicines that address major public health priorities.

The expanded label is expected to make about 5,500 additional children in the United States eligible for treatment.

Casgevy was previously approved only for patients aged 12 years and older. Vertex is also pursuing similar label expansions in the United Kingdom and Saudi Arabia.

Clinical trial results support broader use

Casgevy, developed by Vertex Pharmaceuticals and CRISPR Therapeutics, became the world’s first FDA-approved medicine based on CRISPR/Cas9 genome-editing technology in December 2023.

The therapy uses a patient’s own blood-forming stem cells, which are edited to increase production of fetal haemoglobin (HbF).

Higher HbF levels help red blood cells carry oxygen more effectively and reduce complications associated with both diseases.

Sickle cell disease is caused by mutations in the HBB gene that produce rigid, sickle-shaped red blood cells capable of blocking blood vessels.

Transfusion-dependent beta thalassemia, meanwhile, limits the body’s ability to produce healthy haemoglobin, leaving patients reliant on regular blood transfusions.

The FDA based its decision on Phase III clinical trial data involving younger children.

In the SCD study, all eight patients evaluated for efficacy remained free of vaso-occlusive crises for at least 12 consecutive months after treatment.

In the beta thalassemia trial, eight of the nine evaluable patients achieved transfusion independence for at least one year, with a median transfusion-free period of 20 months.

Karim Mikhail, Acting Director of the FDA’s Center for Biologics Evaluation and Research, said the approval gives children as young as two access to an important treatment option for two severe, life-threatening genetic diseases.

Haydar Frangoul, Medical Director of HCA Healthcare’s Sarah Cannon Transplant and Cellular Therapy Program, added that earlier treatment could help prevent years of cumulative organ damage.

Commercial growth continues

Vertex President and Chief Executive Officer Reshma Kewalramani said the consistent outcomes across age groups strengthen confidence in Casgevy’s ability to deliver durable, long-term benefits.

Casgevy carries a list price of £1.65 million (US$2.26 million) per patient in the UK, although England’s NHS provides the therapy at no cost to eligible patients through a reimbursement agreement.

In the United States, approximately 90% of eligible patients have secured reimbursed access.

The therapy generated US$116 million in global sales during 2025 from 64 patient infusions and contributed US$43 million in first-quarter 2026 revenue.

More than 500 patients have started treatment since launch.

Casgevy competes with Lyfgenia, a gene therapy approved only for patients aged 12 years and older and priced at US$3.1 million per treatment.

Vertex expands rare disease portfolio

The latest approval comes as Vertex broadens its presence beyond cystic fibrosis and gene editing.

This week, the company announced plans to acquire Crinetics Pharmaceuticals for approximately US$10 billion, adding rare endocrine disorders to its portfolio and strengthening its long-term rare disease strategy.