Sio Gene Therapies Inc. announced dosing of the first Type I, or early infantile, patient in the low-dose cohort of its ongoing Phase 1/2 study of AXO-AAV-GM1, its adeno-associated viral vector (AAV)9-based gene therapy candidate for the treatment of GM1 gangliosidosis. No serious adverse events considered by the investigators to be related to AXO-AAV-GM1 have been observed following the administration of GM1 gene therapy, and additional screening and enrollment of Type I patients is ongoing. The clinical study is designed to evaluate the safety, tolerability, and potential efficacy of AXO-AAV-GM1 delivered intravenously in children with early infantile, or Type I, and late infantile and juvenile, or Type II, GM1 gangliosidosis. Stage 1 is a dose-escalation study in which the low-dose cohort is evaluating 1.5x1013 vg/kg and the high-dose cohort is evaluating a dose of 4.5x1013 vg/kg in both disease sub-types. Target enrollment of eight late infantile and juvenile-onset (Type II) patients across the low- and high-dose cohorts was recently completed and up to three Type I patients each in the low-dose and high dose cohorts are expected to be enrolled. 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 FDA-approved treatment options for GM1 gangliosidosis.