The US health regulator FDA (Food and Drug Administration) approved the first genetic therapy to treat children with rare genetic disease.
The FDA on Monday approved the gene therapy of UK based Orchard Therapeutics to treat children with MLD (Metachromatic Leukodystrophy). This is the first authorized treatment for the rare, hereditary diseases in the United States.
Orchard Therapeutics was acquired by Japanese pharmaceutical company Kyowa Kirin last year for $477.6 million. It said that they will provide the details of the therapy’s pricing and availability later in the week.
The FDA said that the one time therapy, branded as Lenmeldy in the U.S., is authorized for children in certain stages of disease progression.
The authorization of therapy on the basis of the data from 37 children, who received Lenmeldy in two label clinical trials. The results of the clinical trials showed that the therapy notably lessened the risk of this severe motor impairment or death in comparison with the untreated children.
The FDA also underlines the probable risk of blood cancer that was related to the treatment, along with formation of blood clots or a type of swelling of brain tissues known as encephalitis.
According to NIH, MLD (Metachromatic Leukodystrophy) also known as globoid cell leukodystrophy. This is one of a group of genetic disorders. MLD is characterized by the toxic buildup of lipids such as fatty materials like oils and waxes and other storage materials in the cells in the white matter of the central nervous and peripheral nerves. The buildup of storage materials damages the growth or development of the myelin sheath (fatty covering that acts as an insulator around the nerve fibers). People with MLD have mutations in the ARSA or PSAP genes, which causes a deficiency of the enzyme arylsulfatase A and decreases the ability to break down sulfatides (essential components of the myelin sheath). Excess of sulfatides can be toxic to the nervous system, they progressively destroy the myelin producing cells and leading to nervous system impairment.
According to the FDA, the disease is assessed to affect one in every 40,000 individuals in the US.
The authorized Lenmeldy is a one time, single dose infusion, which is prepared from the patient's own hematopoietic stem cells. The stem cells are taken from the patient and they are modified by adding a functional copy of the ARSA gene. These modified stem cells are transplanted back into the patient where they attach and multiply within the bone marrow. The altered stem cells supply myeloid (immune cells that produce the ARSA enzyme) to the body, which aids to break down the deleterious build up of sulfatides and may cease the development of MLD. Before this treatment, patients must go through a high dose chemotherapy. It is a procedure that removes cells from the bone marrow so they can be substituted with the modified cells in Lenmeldy.
Prior to Orchard acquisition, Yaron Werber, TD Cowen analyst had calculated peak sales of $300 million globally for the therapy, with annual turnover of less than $70 million till 2025 and the brokerage no more covers Orchard.
The therapy is also authorized in the European Union and it is sold under the brand name Libmeldy.
References:
1. https://www.ninds.nih.gov/health-information/disorders/metachromatic-leukodystrophy
(Input from various sources)
(Rehash/Lavanya Beeraboina/MSM)
