• Decrease in heparan sulfate concentration in cerebrospinal fluid
  • Decrease in GM2 and GM3 ganglioside in cerebrospinal fluid
  • Full data to be presented at the WORLDSymposium™ 2021

PARIS, France I December 28, 2020 I Lysogene (FR0013233475 – LYS) (Paris:LYS), a phase 3 gene therapy platform company targeting central nervous system (CNS) diseases, today reports positive biomarker data from the ongoing AAVance clinical trial with LYS-SAF302 for the treatment of MPS IIIA (NCT03612869).

Changes in heparan sulfate (HS) concentration in cerebrospinal fluid (CSF) are being monitored in patients treated with LYS-SAF302 to provide evidence of in vivo biological activity of the drug and demonstrate proof of concept.

First results show reductions in the concentration of HS in the CSF of all nine patients analyzed so far, at 6 and 12 months after treatment with LYS-SAF302, relative to pre-treatment values. Average reductions were highly statistically significant. In contrast, there were no statistically significant changes in serum HS concentrations following treatment with LYS-SAF302. These results are consistent with the hypothesis that LYS-SAF302 leads to a reduction of HS entering the CSF from the brain parenchyma, with little or no effect on HS-derived oligosaccharides entering the CSF from extra-parenchymal sources, such as choroid plexus or blood.

Furthermore, statistically significant reductions in the secondary storage products GM2 and GM3 ganglioside, which are thought to be possible contributors to neuronal damage in lysosomal storage diseases, were observed in the CSF of treated patients, relative to pre-treatment values.

Ralph Laufer, Chief Scientific Officer at Lysogene said: “These first very encouraging results provide evidence of positive biological responses to LYS-SAF302 treatment in patients enrolled in the AAVance trial. The CNS-specific reduction of the disease biomarker HS is consistent with Lysogene’s unique intra-parenchymal mode of administration, which enables us to deliver the drug directly into the brain, where accumulation of HS causes the predominantly neurological manifestations of MPS IIIA. The reduction in secondary storage products, GM2 and GM3 ganglioside, confirms the biological activity and therapeutic potential of LYS-SAF302. We look forward to confirming these results in additional patients.”

About Lysogene

Lysogene is a gene therapy Company focused on the treatment of orphan diseases of the central nervous system (CNS). The Company has built a unique capability to enable a safe and effective delivery of gene therapies to the CNS to treat lysosomal diseases and other genetic disorders of the CNS. A phase 2/3 clinical trial in MPS IIIA in partnership with Sarepta Therapeutics, Inc. is ongoing and a phase 1/3 clinical trial in GM1 gangliosidosis is in preparation. In accordance with the agreements signed between Lysogene and Sarepta Therapeutics, Inc., Sarepta Therapeutics, Inc. will hold exclusive commercial rights to LYS-SAF302 in the United States and markets outside Europe; and Lysogene will maintain commercial exclusivity of LYS-SAF302 in Europe. Lysogene is also collaborating with an academic partner to define the strategy of development for the treatment of Fragile X syndrome, a genetic disease related to autism. www.lysogene.com.

SOURCE: Lysogene