FDA Approves First Treatment for Metachromatic Leukodystrophy in Children

The FDA has approved Lenmeldy (atidarsagene autotemcel), the first FDA-approved gene therapy indicated for “the treatment of children with pre-symptomatic late infantile, pre-symptomatic early juvenile or early symptomatic early juvenile metachromatic leukodystrophy (MLD).”

MLD is “a debilitating, rare genetic disease affecting the brain and nervous system…caused by a deficiency of an enzyme called arylsulfatase A (ARSA), leading to a buildup of sulfatides (fatty substances) in the cells. This buildup causes damage to the central and peripheral nervous system, manifesting with loss of motor and cognitive function and early death. It is estimated that MLD affects one in every 40,000 individuals in the United States. There is no cure for MLD, and treatment typically focuses on supportive care and symptom management.”

Lenmeldy, the “first FDA-approved treatment option for children who have this rare genetic disease,” is a “one-time, individualized single-dose infection made from the patient’s own hematopoietic (blood) stem cells (HSCs), which have been genetically modified to include functional copies of the ARSA gene. The stem cells are collected from the patient and modified by adding a functional copy of the ARSA gene. The modified stem cells are transplanted back into the patient where they engraft (attach and multiply) within the bone marrow. The modified stem cells supply the body with myeloid (immune) cells that produce the ARSA enzyme, which helps break down the harmful build-up of sulfatides and may stop the progression of MLD.”

Data was collected from 37 children to determine Lenmeldy’s safety and effectiveness. In children with MLD, “treatment with Lenmeldy significantly reduced the risk of severe motor impairment or death compared with untreated children.” All of the children treated with Lenmeldy were alive at 6 years of age compared to only 58% of children who went untreated. 71% of treated children were able to walk without assistance at age 5, and 85% of the children treated had normal language and performance IQ scores, “which has not been reported in untreated children.”

The FDA’s website has the news release.