Sio Gene Therapies Announces First Patient Dosed in High-Dose Cohort of AXO-AAV-GM1 Clinical Trial in Patients with GM1 Gangliosidosis

NEW YORK and RESEARCH TRIANGLE PARK, N.C., Dec. 02, 2020 (GLOBE NEWSWIRE) — Sio Gene Therapies Inc. (NASDAQ: SIOX), a clinical-stage company focused on developing gene therapies to radically transform the lives of patients with neurodegenerative diseases, today announced that the first patient has been dosed in the high-dose cohort of the Phase 1/2 (“Stage 1”) study for Type I (infantile) and Type II (late infantile and juvenile onset) GM1 gangliosidosis.

“AXO-AAV-GM1 is the only gene therapy in the clinic targeting patients with Type I and Type II GM1 gangliosidosis, a devastating and fatal pediatric disease,” said Gavin Corcoran, M.D., Chief R&D Officer of Sio. “The initiation of the high-dose cohort builds on evidence of extension of survival in naturally-occurring GM1 disease animal models and encouraging clinical data from an expanded access study conducted by a National Human Genome Research Institute (NHGRI) team led by our principal investigator, Dr. Cynthia Tifft at the National Institutes of Health’s (NIH) Clinical Center. Our team and academic partners are dedicated to improving the lives of children affected by this devastating disease, and we look forward to reporting topline data from the low-dose cohort before year end.”

The Phase 1/2 study (NCT03952637) is designed to evaluate the safety, tolerability, and potential efficacy of AXO-AAV-GM1 delivered intravenously in patients with Type I and Type II GM1 gangliosidosis.

• The low-dose cohort evaluated 1.5×1013 vg/kg AXO-AAV-GM1 gene therapy in a total of five Type II (juvenile) patients. Six-month follow-up data from the low-dose cohort are expected by the end of 2020.
• The high-dose cohort is evaluating a dose of 4.5×1013 vg/kg AXO-AAV-GM1 gene therapy.

AXO-AAV-GM1 has received both Orphan Drug Designation and Rare Pediatric Disease Designation and is the only gene therapy in clinical development for both Type I and Type II GM1 gangliosidosis.

GM1 gangliosidosis is a progressive and fatal pediatric lysosomal storage disorder caused by mutations in the GLB1 gene that cause impaired production of the β-galactosidase enzyme. Currently, there are no approved treatment options for GM1 gangliosidosis. In 2019, Sio reported clinically meaningful improvements from baseline to six-month follow-up for the first GM1 Type II child dosed with low-dose AXO-AAV-GM1 gene therapy under an expanded access protocol.