Orchard Therapeutics has reported results from the first Sanfilippo type A patient treated in their "ex vivo autologous hematopoietic stem cell gene therapy" clinical trial. The therapy involves taking the patient's own blood stem cells and using a virus to deliver a healthy copy of the faulty gene into the cells. These cells are then transplanted back into the child. The blood cells are then able to produce the SGSH enzyme that is missing in Sanfilippo type A patients. The aim is for the enzyme to be delivered to the brain from the bloodstream.
Three months after the experimental treatment the company reported that it was generally well-tolerated. The amount of SGSH was measured in the blood at levels higher than seen in healthy individuals. This is important because bone marrow transplants from donors have been previously tried as a treatment for Sanfilippo, but they were largely unsuccessful because the cells did not produce enough of the enzyme to effectively treat the brain.
Levels of heparan sulfate, the damaging substance that builds up in children with Sanfilippo, also returned into the normal range in urine. No data is yet available on the impact on cognitive function or other symptoms of the disease.
Three patients have so far been treated in the ongoing clinical trial, which is being sponsored and conducted by The University of Manchester (UoM) and funded by Orchard.