LYS-SAF302 Gene Therapy | Type IIIA | Phase II-III | Lysogene

March 9, 2020

Page reviewed by: Dr. Cara O’Neill, FAAP

Page last updated: November 21, 2022

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Update: Nov. 21, 2022

Lysogene recently issued a press released regarding their Type A gene therapy study. In this program, an AAV-10 viral vector gene therapy was injected into the brain tissue of the children. Below are bullet points shared in their recent press release regarding what has been learned so far. You can view the press release directly here.

For children who were treated at under 30 months of age (under 2.5 years), the overall data is showing a better outcome on selected endpoints than what would be expected for the natural course of the disease. Over time and as children continue to grow, more information will be learned about how the treatment may be impacting them. This is encouraging data which holds hope that this specific treatment will provide significant benefit across multiple disease symptoms when administered very early in life.

However, Cure Sanfilippo Foundation is saddened to hear that the endpoints were not able to demonstrate a positive effect of the treatment based on what was measured in children who were treated at an age of 30 months (2.5 years) or older. It is even more difficult for the families who were part of the trial. We offer our support to them.

Cure Sanfilippo Foundation leaders are in communication with Lysogene and hope to learn more about this.

“We believe it is also important to remember that the way treatment impact in a clinical trial is measured may not always reflect more subtle changes that parents may notice in their individual children, said Dr. Cara O’Neill, Foundation Chief Science Officer. “Again, it is our belief that there is more to learn from the children over time. We continue to work in the field to find and develop trial outcome measures (endpoints) that can detect subtle but meaningful changes for our children of all ages, as well as support new treatment strategies through research and additional clinical trials to benefit all.”

Lysogene is hosting a live webcast update on Nov. 23, 2022, at 7:30 a.m. EST for those interested to learn more. Please also feel free to reach out directly at Cure Sanfilippo Foundation. If your child participated in this trial and you have specific questions about your child, you are encouraged to reach out to your trial doctor directly.


Points from Lysogene’s Nov. 18 press release

  • In the cohort of patients enrolled before the age of 30 months, a statistically significant improvement in cognitive development (assessed by BSID-III, Bayley’s Scales of Infant Development, third edition) compared to natural history data was observed. Key secondary efficacy criteria were also achieved in this patient cohort, with improvement or stabilization of cognitive, language and motor developmental age (DA) and lack of decline from baseline in VABS-II (Vineland Adaptive Behavior Scales, second edition) scores and cortical gray matter volumes.
  • In the cohort of patients enrolled at 30 months of age or older, the study did not meet the primary efficacy endpoint of reducing the decline in cognitive developmental quotient (DQ) as compared to natural history data at M24 post-treatment, nor any key secondary efficacy endpoint
  • These results delineate the patient population that would benefit from treatment with LYS-SAF302
  • Safety and tolerability data showed improvement or stabilization of white matter lesions at injection sites at M24 in most patients. The overall safety was compatible with the natural history of MPS IIIA
  • Constructive discussions were initiated with regulatory authorities to define a regulatory path to rapidly advance the clinical development of LYS-SAF302 in the younger patient population with MPS IIIA
  • There is a critical unmet medical need for the treatment of MPS IIIA, given the relentless progression of the disease leading to rapid neurological decline and premature death, and the absence of approved therapies that slow down or modify the disease trajectory
  • Live webcast to be hosted on Wednesday, November 23, 2022 at 1:30 pm CET (Central European Time). Participants can register for the webcast.
Page Last Updated Feb. 15, 2021

LYS-SAF302 is a gene therapy by Lysogene which is intended to deliver a working copy of the SGSH gene to deliver the gene therapy to the patient’s brain. The normal gene is placed inside the shell of a non-disease-causing virus (rhAAV10).

This is a phase 2-3 study to assess the efficacy in improving or stabilizing the neurodevelopmental state of MPS IIIA patients.20 patients are being recruited. There are eight trial locations globally, including four in the United States. The others are in France, Germany, Netherlands, and the United Kingdom.

This trial is currently on clinical hold.

The gene therapy is directly injected into tissue of the brain. This is designed to be a one-time treatment.

Read this clinical trial’s information on, which includes enrollment criteria, trial locations, and study contact information.Read Lysogene’s information about its gene therapy approach.

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