1st Patient Dosed in Trial of Gene Therapy, OTL-201, for Sanfilippo Type A

Orchard Therapeutics announced the dosing of a first patient in a clinical trial evaluating its investigational cell-based gene therapy OTL-201 for Sanfilippo syndrome type A.

OTL-201’s safety, tolerability, and efficacy is being investigated in the open-label, Phase 1/2 study (NCT04201405) taking place at Manchester University NHS Foundation Trust in the U.K. This proof-of-concept study is recruiting between three to five patients, ages 3 months to 2 years.  More information can be found here.

Sanfilippo syndrome type A, also known as mucopolysaccharidosis type IIIA (MPSIIIA), is caused by mutations in the SGSH gene resulting in a deficiency in the enzyme sulfamidase. This deficiency leads to a toxic accumulation of heparan sulfate and other long sugar molecules inside cells of the brain and other tissues, eventually resulting in cell death.

OTL-201 is a cell-based gene therapy in which patients’ own (autologous) blood-forming (hematopoietic) stem cells are genetically modified to carry a working version of the SGSH gene. Following the harvesting of the cells, a modified, harmless virus is used to introduce the gene into cells, which are then returned to patients.

The trial will assess the therapy’s efficacy by measuring the levels of sulfamidase in white blood cells (leukocytes).

Additional goals include overall survival, changes in cognition and behavior, improvements in quality of life, and changes in levels of heparan sulphate concentration in cerebrospinal fluid (CSF, which surrounds the brain and spinal cord), plasma, and urine.

Participants will be followed for three years after receiving the gene therapy.

Results of this trial will help to inform further clinical development of hematopoietic stem cell-based gene therapies for Sanfilippo type A.

“I am very encouraged that we, together with our research and clinical collaborators in Manchester, could achieve this important milestone in our efforts to develop a gene therapy for MPS-IIIA despite the current, challenging global health circumstances,” Bobby Gaspar, MD, PhD, Orchard’s CEO, said in a press release.

The U.S. Food and Drug Administration (FDA) granted OTL-201 a rare pediatric disease designation as a potential Sanfilippo type A treatment. This designation helps to support its development, and may make the therapy eligible for priority review should it be submitted for approval.

“This study adds to Orchard’s clinical pipeline of HSC gene therapies for the treatment of severe neurometabolic disorders and further demonstrates the potential of our platform approach,” Gaspar added.