Lysogene Reports Death of Patient Who Participated in MPS IIIA Gene Therapy Trial

Rare Daily Staff

French biotech Lysogene reported that a patient has died in the AAVance clinical trial, a global phase 2/3 trial of its gene therapy for the treatment of the lysosomal storage disorder mucopolysaccharidosis type IIIA.

Lysogene said the immediate cause of death is currently unknown and additional information is being collected. At this time, there is no evidence that the event is linked to the study drug administration. The company is diligently following per study protocol the 18 patients who have been treated in the clinical trial.

Nineteen of 20 patients had been treated as of early June when the U.S. Food and Drug Administration put a clinical hold on the trial on safety concerns based on observations in some patients of localized findings on MRI images at the intracerebral injection sites that suggested a potential connection to delivery. At the time of the hold, Lysogene said no clinical symptoms had been observed that could be directly attributed to the observed MRI findings.

Lysogene expressed its condolences to the family and said it remains committed to the LYS-SAF302 development program and the Sanfilippo patient community. The company plans to provide further information on the LYS-SAF302 program based on both ongoing data collection and future regulatory status updates.

Mucopolysaccharidosis (MPS IIIA), or Sanfilippo syndrome, is a rare inherited neurodegenerative disease affecting approximately 1 in 100,000 newborns. It is characterized by intractable behavioral problems and developmental regression resulting in early death. It is caused by mutations in the SGSH gene, which encodes an enzyme called Heparan-N-sulfamidase necessary for heparan sulfate (HS) recycling in cells. The disrupted lysosomal degradation and resulting storage of HS and glycolipids such as gangliosides leads to severe neurodegeneration. There are currently no treatment options for patients.

LYS-SAF302 is a second-generation gene therapy designed to deliver a functional copy of the SGSH gene to the brain through a one-time direct-to-central nervous system administration.

In October 2018, Lysogene granted Sarepta Therapeutics exclusive commercial rights to LYS-SAF302 in the United States and markets outside Europe.