US approves first gene therapy for children with rare genetic disease

London: The U.S. health regulator on Monday approved UK-based Orchard Therapeutics' gene therapy to treat children with metachromatic leukodystrophy (MLD), making it the first approved treatment in the United States for the rare, hereditary disease.

Orchard, which was acquired by Japanese pharmaceutical firm Kyowa Kirin for $477.6 million last year, said it will provide details on the pricing and availability of the therapy later in the week.

The one-time therapy, branded as Lenmeldy in the U.S., is approved for children in certain stages of disease progression, the Food and Drug Administration (FDA) said.

The approval was based on data from 37 children who received Lenmeldy in two open-label clinical trials, whose results showed that the therapy significantly reduced the risk of severe motor impairment or death compared with untreated children.

The regulator also flagged potential risk of blood cancer associated with the treatment, along with formation of blood clots or a type of swelling of brain tissues.

MLD, which affects the brain and nervous system, is characterised by the buildup of certain fatty substances in the cells, and leads to loss of motor and cognitive function and early death.

The disease is estimated to affect one in every 40,000 individuals in the United States, according to the FDA.

Before Orchard was acquired, TD Cowen analyst Yaron Werber had estimated peak sales of $300 million globally for the therapy, with annual sales of less than $70 million till 2025. The brokerage no longer covers Orchard.

The therapy is approved in the European Union and sold under the brand name Libmeldy.

(Reporting by Mariam Sunny in Bengaluru; Editing by Sriraj Kalluvila and Devika Syamnath)