Gene therapy for rare ‘childhood dementia’ shows promise

An investigational gene therapy for a rare condition which leads to a form of childhood dementia has shown promising early results in a proof-of-concept study.

The Sanfilippo syndrome study was funded by Orchard Therapeutics, sponsored by the University of Manchester and conducted at Manchester University NHS Foundation Trust.

The research found that four out of five patients diagnosed with Sanfilippo have continued to gain cognitive skills in line with development in healthy children after being given the investigational gene therapy, OTL-201.

However, the research team urged caution as the majority of patients have not reached the age of four-to-five years where the most severe stages of disease progression typically present.

Professor Robert Wynn, Chief Investigator on the trial at The Royal Manchester Children’s Hospital, part of Manchester University NHS Foundation Trust (MFT), said:

“These are encouraging results for children living with MPS-IIIA and their families, who currently have no effective treatment options.”

Professor Simon Jones, Clinical Director of NIHR Manchester Clinical Research Facility at Royal Manchester Children’s Hospital, added:

“We hope this therapy will have a positive impact on the lives of our children and their families, improving the symptoms of this devastating disease.”

Sanfilippo syndrome Type A- or Mucopolysaccharidosis Type IIIA (MPS-IIIA)- is a rare genetic metabolism disorder with devastating effects on the central nervous system affecting around 1 in 70,000 children.

Patients with the condition have a mutation in the SGSH gene, causing them to lack an enzyme which normally breaks down large sugar molecules.

These molecules then accumulate in the cells of the body causing irreparable damage to many organs including the brain, causing inflammation and damage to brain tissue.

The investigational gene therapy OTL-201 works by collecting a patient’s own blood stem cells and inserting a working copy of the SGSH gene using a modified virus called a lentiviral vector.

The patient’s modified blood stem cells, which now including a working copy of the SGSH gene, are then given back to the patient.

This enables patients to make this missing SGSH enzyme and provide it throughout the body from blood cells made in the bone marrow.

Leslie Meltzer, Ph.D., chief medical officer of Orchard Therapeutics said:

“These promising early findings continue to show the ability of our HSC gene therapy platform to enable the migration of gene-corrected cells into the central nervous system and the localised delivery of therapeutic enzymes and proteins to the brain to potentially correct neurodegeneration in multiple severe conditions, building on our programs in neurometabolic disorders.

“We are working with our collaborators at The University of Manchester and Royal Manchester Children’s Hospital to continue following patients in this ongoing study and more fully characterise the clinical and safety profile of OTL-201.”