Paul Orchard, MD, from the University of Minnesota Medical School, discusses the compassionate use of gene therapy in children with metachromatic leukodystrophy (MLD).

MLD is a lysosomal disorder characterized by the accumulation of sulfatides in cells. This accumulation largely affects myelin producing cells that leads to the progressive destruction of white matter (leukodystrophy) throughout the nervous system.

Affected individuals show progressive deterioration of cognitive ability, motor and sensory functions. Eventually they lose awareness of their surroundings and become unresponsive.

There is currently no treatment available in the United States for this devastating condition but ex vivo autologous hematopoietic stem cell (HSC) gene therapy is available in Europe. In this interview, Dr. Orchard discussed the use of this gene therapy (OTL-200) in three children in the United States and the results observed to date with these children. This data was presented at WORLDSymposium 2023 in Orlando, FL.

As Dr. Orchard noted, three patients with MLD were treated in Minnesota and while the results are preliminary, OTL-200 shows promise as a treatment for patients with MLD early in the disease course, with the potential to be safer than  hematopoietic stem cell transplantation. In addition, levels of arylsulfatase A activity may exceed what can be achieved with hematopoietic stem cell transplantation.

To learn more about MLD and other lysosomal disorders, visit checkrare.com/lysosomal-storage-disorders/