Karen Bean, Health Economist at Orchard Therapeutics, discusses a recent study comparing the effect of gene therapy in treated versus untreated sibling pairs with early-onset metachromatic leukodystrophy (MLD).
MLD is a rare genetic condition characterized by the accumulation of sulfatides in cells, especially of the nervous system. This accumulation results in progressive destruction of white matter of the brain. Affected individuals experience progressive deterioration of intellectual functions and motor skills, such as the ability to walk. They also develop loss of sensation in the extremities, incontinence, seizures, paralysis, inability to speak, blindness, and hearing loss. Eventually they lose awareness of their surroundings and become unresponsive. This condition is caused by genetic changes in the ARSA and PSAP genes.
Atidarsagene autotemcel (arsa-cel) is a gene therapy approved by the U.S. Food and Drug Administration (FDA) for the treatment of children with MLD. The treatment is a one-time, individualized single-dose infusion made from the patient’s hematopoietic stem cells that have been modified to include functional copies of the ARSA gene.
The goal of this analysis was to compare the clinical outcomes for age-matched arse-cel treated versus untreated natural history cohort sibling pairs. In total, 25 patients treated pre-symptomatically had a sibling in the natural history cohort.
Results of the analysis included an observation that 86.4% of age-matched sibling pairs had differencesgreater than four levels in the seven level gross motor function assessments (GMFC-MLD) in favor of arsa-cel. Additionally, the mean difference in total GMFM-88 score for all sibling pairs was 76.3, also in favor of arsa-cel. These results emphasize the importance of early-diagnosis and access to treatment for all early-onset patients with MLD.
To learn more about MLD and other rare metabolic disorders, visit https://checkrare.com/diseases/metabolic-disorders/
