SIOX Stock: Why It Increased Today

By Amit Chowdhry ● Oct 21, 2021
  • The stock price of Sio Gene Therapies Inc (NASDAQ: SIOX) increased by over 14% pre-market today. This is why it happened.

The stock price of 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 – increased by over 14% pre-market today. Investors are responding positively to the company presenting positive interim data from the company’s 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, in an oral presentation at the European Society of Gene & Cell Therapy (ESGCT) Virtual Congress 2021, held from October 19-22, 2021. These follow-up data from five Type II (late-infantile to juvenile) patients in the low-dose cohort and the initial two Type II patients in the high-dose cohort demonstrate an encouraging safety profile and a consistent dose-response in disease biomarkers across the evaluation period.

These are the key findings

— Generally well-tolerated at both low and high doses with the majority of adverse events considered mild to moderate

1.) To date, there have been no reported serious adverse events attributed to gene therapy in any patients

2.) To date, there have been no adverse events leading to study withdrawal in any patients

a.) No liver-related adverse events required clinical intervention or had associated clinical sequelae

b.) No clinically relevant changes were observed in complement factors, platelet count, or other liver function tests

— Data demonstrate a dose-dependent improvement in key biomarkers of disease activity: β-galactosidase enzyme activity in the serum and GM1 ganglioside activity in the CSF

1.) Serum β-galactosidase activity achieved a normal range, increasing by 12x and 17x pre-treatment levels, respectively, in both patients in the high-dose cohort at six months

a.) All 5 patients in the low-dose cohort saw a 1.3-2.3x increase in the same timeframe

2.) Levels of CSF GM1 ganglioside, the toxic substrate which accumulates in patients with GM1 gangliosidosis and which is associated with disease activity were normalized in both patients in the high-dose cohort with 42% and 72% reductions, respectively, at six months

a.) In the low-dose cohort, a 18-49% decrease was seen in four out of five patients, and a 19% increase in a single patient was seen in the same timeframe

b.) GM1 ganglioside levels were below baseline in all five low-dose patients at 12 months

— MRI assessment of total brain volume and ventricular volume, which decrease and increase respectively in the natural history of the disease, showed the following in the low-dose cohort at 12 months:

1.) Total brain volume (excluding ventricles) was maintained within ± 5% in all five patients

2.) Ventricular volume remained within ± 15% in four patients and increased by 104% in one patient

— There was no clinical evidence of overt disease progression in four of five low-dose patients at 12 months and both high-dose patients at six months as assessed by measures of development including the Vineland-3 Adaptive Behavior and Upright and Floor Mobility scales

Upcoming Milestones:

First Half of 2022: Expect to provide data updates from Stage 1 of the study, including both Type I (early-infantile) and Type II patients, at future scientific conferences

First Half of 2022: Expect to engage with the FDA to review Stage 1 data and discuss the next steps for clinical development

KEY QUOTES:

“Our team continues to lead the industry in the development of a new, potentially disease-modifying therapeutic option for GM1 gangliosidosis. We are extremely proud of these data, representing our broadest dataset generated thus far, which support a dose response and a favorable safety and tolerability profile at both low and high doses. We observed dose-dependent responses in two key biomarkers, serum β-galactosidase and cerebrospinal fluid (CSF) GM1 ganglioside, including normalization of both biomarkers in the high-dose cohort. Taken together, six out of seven patients show no evidence of overt disease progression at the latest timepoint assessed, and we now have a better understanding of the clinical measures that may serve as important indicators of efficacy. Based on the results of this ongoing study, we are working on the continued development of AXO-AAV-GM1 and plan to engage the FDA to discuss further development, recognizing that there is currently no approved therapy available for GM1 patients.”

— Gavin Corcoran, M.D., Chief R&D Officer of Sio Gene Therapies

“I have dedicated my career to the care of patients with GM1 gangliosidosis and to research efforts in the search for a functional cure. The biomarker dose response and favorable safety profile is a remarkable finding for the gene therapy field. I am excited about the potential impact that AXO-AAV-GM1 may have on the lives of these children and their families. I look forward to seeing the longer-term data, where we may have a chance to see not only durable disease stabilization, but possibly even improvement.”

— Dr. Cynthia Tifft, Deputy Clinical Director of the National Human Genome Research Institute (NHGRI) and study Principal Investigator

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