Gene therapy clinical trials


Abeona Therapeutics gene therapy for Sanfilippo types A and B

Abeona Therapeutics is conducting clinical trials of gene therapy for Sanfilippo types A and B and currently has sites in the USA, Spain and Australia (type A only). The first trial for Sanfilippo type A started in the USA in May 2016 and the first Australian patients were treated at Adelaide’s Women’s and Children’s Hospital in 2017.

The program is the result of a unique collaboration between patient groups and researchers at Nationwide Children’s Hospital in Ohio together with Abeona. The phase I/II trial was funded by international patient groups, including the Sanfilippo Children's Foundation.

Participants in the clinical trials are administered the gene therapy product intravenously (into the bloodstream). The gene therapy consists of a virus (AAV9) which has the ability to cross the blood-brain-barrier to deliver a healthy copy of the gene that is faulty in Sanfilippo Types A or B.

Encouraging results have been reported – the gene therapy appears to be safe and reductions in heparan sulfate, the toxic substance that builds up in children with Sanfilippo, have been seen in both the urine and the cerebral spinal fluid (CSF). The liver and spleen, which are enlarged in children with Sanfilippo, has reduced.

Further updates were provided at the 2021 WORLD Symposium and American Academy of Neurology annual meeting in April 2021. In total, 20 Sanfilippo type A patients have been treated in this clinical trial so far. Unfortunately, no cognitive improvements have been seen in older patients. However, 3 children who were treated below the age of 2.5 years are showing trajectories of cognitive development that are in line with typical children without Sanfilippo Syndrome. This is particularly encouraging considering that they are now at an age where development would be expected to have slowed. 5 more children in this young age group have now been treated and data is being gathered to confirm these results. Abeona have indicated that they will be consulting with the USA Food & Drug Administration to discuss next steps towards approval of the treatment.

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Lysogene gene therapy trial for Sanfilippo type A

Lysogene was founded by Karen Aiach, mother of a Sanfilippo Type A child in Paris, France. In 2013, Lysogene successfully completed a Phase I/II clinical trial for its gene therapy product SAF-301: four children affected by Sanfilippo Type A were administered a gene therapy product directly into the brain. This involved surgery to inject virus (AAVrh10) carrying a healthy copy of the SGSH gene directly into the brain (intra-cerebral injection).

The Phase I/II trial concluded with good safety results and promising indicators of efficacy. Some alterations have been made to the gene therapy product, now named LYS-SAF302, and a Phase II/III trial has begun. It is expected the trial will recruit 20 Sanfilippo Type A patients at sites in the USA, France, UK, Germany and the Netherlands, more details of the trial are available here.

In June 2020, Lysogene announced that their clinical trial has been put on hold by the FDA due to localized MRI findings at injection sites. At the time of the announcement, 19 of the planned 20 participants had been recruited and treated, and these participants will continue to be monitored.

At the 2021 WORLD conference, interim results from the 19 patients treated so far were presented and indicated that the treatment has been well tolerated with no serious adverse events other than the MRI findings which are not associated with any clinical symptoms. While the cognitive development data is still to be analysed, the team have shown a reduction of heparan sulphate and other secondary storage molecules in the CSF that is sustained for at least 12 months following treatment.


Esteve Sanfilippo Type A gene therapy trial

Pharmaceutical company Esteve is currently recruiting for a Phase I/II gene therapy clinical trial in Barcelona for Sanfilippo Type A.

The treatment approach consists of a single injection into the cerebrospinal fluid of a virus (AAV9) carrying a healthy copy of the SGSH cerebral spinal fluid (CSF) (Intracerebroventricular (ICV) injection). They plan to recruit six patients for this initial clinical trial.

Esteve is also developing a similar gene therapy approach for Sanfilippo type B, but this is not yet in clinical trial.

For more information, visit Esteve's Sanfilippo program

Gene therapy for Sanfilippo type C

In November 2018 Phoenix Nest Inc. acquired rights to the Sanfilippo type C gene therapy developed by Dr. Brian Bigger at the University of Manchester.  This approach involves gene therapy using an AAV vector delivered to the brain intracerebrally by a neuro-surgical procedure. A clinical trial is currently being planned.


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