Stoke Therapeutics Presents Data from a Combined Interim Analysis of the Phase 1/2a MONARCH and ADMIRAL Studies of STK-001 in Children and Adolescents with Dravet Syndrome at the American Epilepsy Society (AES) 2022 Annual Meeting

Stoke Therapeutics, Inc. (Nasdaq: STOK), a biotechnology company dedicated to addressing the underlying cause of severe diseases by upregulating protein expression with RNA-based medicines, today announced highlights from presentations related to the ongoing clinical development of STK-001, the first potential new medicine to treat the underlying cause of Dravet syndrome. A total of seven posters will be presented at the American Epilepsy Society (AES) 2022 Annual Meeting, December 2-6. Dravet syndrome is a severe and progressive genetic epilepsy characterized by frequent, prolonged and refractory seizures beginning within the first year of life. The disease is classified as a developmental and epileptic encephalopathy due to the developmental delays and cognitive impairment associated with the disease.

“Dravet syndrome is a complex and devastating disease that presents challenges for clinicians, patients and their caregivers,” said Barry Ticho, Ph.D., M.D., Chief Medical Officer of Stoke Therapeutics. “To curb the seizures, patients typically take multiple anti-seizure medicines which often produce additional challenges and side effects that impact their quality of life and overall health. STK-001 represents an entirely new approach to treatment, one that aims to treat the syndrome, not just the seizures. At the highest dose level, we observed a 55% median reduction in convulsive seizure frequency, with all but one patient responding to treatment with STK-001. Demonstrating this level of effect in highly refractory patients, who have already taken multiple standard anti-seizure medicines, including fenfluramine, has not been seen before.”

Topline data from a combined interim analysis of the Phase 1/2a MONARCH and ADMIRAL studies showed single and multiple doses of STK-001 up to 45mg were well-tolerated. Reductions in seizure frequency were observed among patients who received multiple doses of STK-001 (20mg, 30mg, 45mg). The effects were more evident at the highest dose (45mg) and in younger patients and were observed on top of standard treatments. Half of the patients in these studies were taking four or more anti-seizure medicines, including fenfluramine.

An interim analysis of six patients treated with three doses of 45mg was presented and showed:

• A 55% median reduction from baseline in convulsive seizure frequency from Day 29 after the first dose to three months after receiving the last dose.
• Reductions from baseline in convulsive seizure frequency in 5/6 (83%) patients.
• A greater than 50% reduction in convulsive seizure frequency in 4/6 (67%) patients.
• Reductions in seizure frequency began after the first dose and continued with additional treatment, consistent with the anticipated mechanism of action of STK-001.

The interim safety analysis of patients treated in MONARCH and ADMIRAL showed that 27% (15/55) of patients experienced a treatment-emergent adverse event (TEAE) that was related to study drug. All adverse events related to study drug were mild to moderate in severity. No TEAEs led to study drug withdrawal.