Vertex's gene therapy shows promise in younger children with blood disorders

By Sriparna Roy

Dec 6 (Reuters) - Vertex Pharmaceuticals VRTX.O said on Saturday its gene therapy helped children aged between 5 and 11 years with sickle cell disease to be free of painful events and allowed those with another blood disorder that requires frequent blood transfusions to be transfusion-free for at least 12 consecutive months.

This supports the potential for the therapy to treat the blood disorders in a younger patient population and will help Vertex expand the use of Casgevy, which is currently approved for patients 12 years and older with sickle cell disease or transfusion-dependent beta thalassemia (TDT).

"These results — the first clinical data ever presented on any genetic therapy for children ages 5-11 years with SCD — again demonstrate the transformative potential of Casgevy," said Vertex Chief Medical Officer Carmen Bozic.

Casgevy is based on the Nobel Prize-winning CRISPR gene editing technology, which uses molecular "scissors" to trim faulty parts of genes that can then be disabled or replaced with new strands of normal DNA.

The company will begin filing to global regulators in the first half of next year. It has received a Commissioner's National Priority Voucher for Casgevy in the 5-11 year age group, which will accelerate the health regulator's review.

In a late-stage trial, four children with SCD who were dosed with Casgevy with sufficient follow-up were free from vaso-occlusive crises for at least 12 consecutive months. The longest period without these events reached about two years, the company said.

Vaso-occlusive crises, a key hallmark of the inherited blood disorder, are caused by blockages of blood vessels by sickled red blood cells and result in severe and debilitating pain.

After infusion with Casgevy, 12 patients with TDT were transfusion free, with the longest duration being just under two years.

A patient with TDT died from pneumonia and multi-organ failure due to severe veno-occlusive disease, a liver condition, related to a pre-transplant treatment that uses the chemotherapy drug busulfan.

The results were presented at the American Society of Hematology Annual Meeting.

(Reporting by Sriparna Roy in Bengaluru; Editing by Alan Barona)

((Sriparna.Roy@thomsonreuters.com))