Vertex gets paediatric FDA okay for Casgevy gene therapy

For the first time, children in the US as young as two with the blood disorders sickle cell disease and beta thalassaemia are eligible for Vertex Pharma's one-shot gene therapy Casgevy.

The FDA has approved use of CRISPR Therapeutics-partnered Casgevy (exagamglogene autotemcel) in this age group for children with SCD and recurrent vaso-occlusive crises (VOCs) – the painful attacks that can accompany the disease – as well as those with transfusion-dependent beta thalassemia (TDT).

The broader label follows the pioneering gene-editing therapy's initial approval for patients aged 12 and over with SCD in 2023, and for TDT in the same age range the following year. The new approval adds another 5,500 children to those eligible in the US for the therapy, said Vertex in a statement.

There are estimated to be around 37,000 people with SCD and TDT in the US and Europe combined.

Last year, almost 150 patients were treated with Casgevy, the first therapy to reach the market based on CRISPR/Cas9 gene-editing technology, with sales of $114 million, of which $54 million came in the last three months of the year.

Haydar Frangoul, medical director of HCA Healthcare's Sarah Cannon Transplant and Cellular Therapy Programme at TriStar Centennial Children's Hospital in the US, said that the approval "offers renewed hope" for children living with SCD and TDT.

"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," he added.

People with SCD and recurrent VOCs in the US have a severely reduced quality of life and a median age of death of approximately 45 years, while the cost of caring for them over their lifespan are estimated to be between $4 and $6 million. The situation is even worse with TDT, with a median age of death of just 37 and lifetime costs of $5 to $5.7 million.

The approval is based on preliminary data from two ongoing, open-label studies – CLIMB-141 and CLIMB-151 – which are testing Casgevy in patients ages 2-11 years with TDT or with SCD and recurrent VOCs.

Vertex's initial application targeted the five to 11 age group, but as trials for children ages two to four were ongoing – and so far there has been consistency in outcomes in clinical trials, regardless of age – the FDA opted to approve the wider age range simultaneously.

The paediatric application for Casgevy was granted a Commissioner's National Priority Voucher (CNPV) by former FDA Commissioner Marty Makary.