Stem cell therapy clinical trials

Orchard Therapeutic's stem cell-based gene therapy program for Sanfilippo Types A and B

Dr Brian Bigger from The University of Manchester has developed an "autologous ex-vivo gene therapy" for Sanfilippo types A and B. It works by taking the patient's own stem cells (from the blood or bone marrow) and using a virus to deliver a healthy copy of the faulty gene (SGSH for Type A or NAGLU for Type B). These cells are then transplanted back into the body.  

Bone marrow transplants have been previously tried as a treatment for Sanfilippo, but they were largely unsuccessful because the cells did not produce enough of the enzyme that is missing. This approach aims to boost the amount of enzyme produced by the transplanted cells and has the advantage that the patient’s own cells are used, lowering the risk of transplant rejection.

The University of Manchester has signed a licensing agreement with Orchard Therapeutics to bring its stem cell gene therapy program to human clinical trial.  

In May 2019 it was announced that a two-year-old boy with Sanfilippo Type A received this experimental therapy in Manchester, under what is called a “Specials” licence. Results were presented at the WORLD Conference in Orlando in February 2020 showing increase in SGSH enzyme activity in the blood and reduction of GAGs in the urine, CSF and plasma. No cognitive testing results were presented but it was reported that the boy was doing well.

Following this, Orchard Therapeutics launched a full trial at Royal Manchester Children’s Hospital. At the 2021 WORLD conference, Orchard Therapeutics presented the results to date for the first three Sanfilippo type A patients who have received this experimental therapy. All three were aged under 2 years at the time of treatment. Treatment has been well-tolerated and the cells have been incorporated well following transplantation. Results from these patients following transplantation indicate much higher enzyme levels in the blood compared to healthy individuals. Also, the presence of GAGs (heparan sulphate and other complex molecules) in the urine fell to normal levels. Data on cognitive development is still to come. More information on these results can be found in the second part of this media release.

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