The US Food and Drug Administration (FDA) has granted approval to Orchard Therapeutics' Lenmeldy (atidarsagene autotemcel) gene therapy for use in children with specific forms of metachromatic leukodystrophy (MLD).
This is the first FDA approval for a gene therapy addressing pre-symptomatic late infantile, early juvenile or early symptomatic early juvenile MLD.
Lenmeldy is a single-use, personalised infusion, utilising the patient's genetically modified hematopoietic stem cells (HSCs) to halt disease progression.
The gene therapy involves collecting HSCs from the patient and modifying them to include functional copies of the ARSA gene.
The modified cells are re-introduced into the patient's bone marrow where they engraft and produce immune cells that can break down sulfatides, the substances that accumulate harmfully in MLD.
Patients must have previously received high-dose chemotherapy to prepare the bone marrow for the modified cells.
The efficacy and safety of the therapy were evaluated based on data from 37 children who participated in two single-arm, open-label clinical trials and an expanded access programme.
Severe motor impairment-free survival, defined as the time from birth to the first appearance of locomotion loss, loss of sitting without support, or mortality, was the primary measure of efficacy.
All children in the treated group with pre-symptomatic late infantile MLD were alive at six years old, in contrast to only 58% in the natural history group.
71% of treated children could walk unassisted at five years of age.
85% of treated children maintained normal language and performance IQ scores, a result not observed in untreated children.
Those with pre-symptomatic early juvenile and early symptomatic early juvenile MLD exhibited a deceleration in motor and cognitive disease progression.
FDA Center for Biologics Evaluation and Research director Peter Marks stated: “This is the first FDA-approved treatment option for children with this rare genetic disease.
“We remain committed to advancing scientific and regulatory principles that enable the efficient development and review of safe, effective and innovative products that have the potential to change patients’ lives.”
