Stoke Therapeutics to Present Data from the Company’s Dravet Syndrome Program at the American Epilepsy Society 2022 Annual Meeting

– Seven abstracts related to the Company’s work in Dravet syndrome will be presented, including data from a combined interim analysis of the Phase 1/2a MONARCH and ADMIRAL studies of STK-001 –

BEDFORD, Mass.--(BUSINESS WIRE)-- 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 that seven abstracts related to the Company’s work in Dravet syndrome have been accepted for presentation at the American Epilepsy Society (AES) 2022 Annual Meeting, taking place December 2 – 6, in Nashville, Tennessee. The company is advancing STK-001 as potentially the first medicine to treat the underlying cause of Dravet syndrome.

“Topline results from a recent interim analysis showed marked reductions in seizure frequency, which support our work to develop STK-001 as potentially the first disease modifying medicine for Dravet syndrome,” said Barry Ticho, M.D., Ph.D., Chief Medical Officer of Stoke Therapeutics. “We look forward to sharing more details from this interim analysis, along with several other presentations with researchers, clinicians and the Dravet syndrome community at the upcoming AES meeting.”

Details for the Company’s poster presentations at AES are as follows:

The same data from a combined analysis of MONARCH and ADMIRAL will be presented in two posters.

• Title: ADMIRAL: A Phase 1/2a UK Study Investigating the Safety and Pharmacokinetics (PK) of STK-001, an Antisense Oligonucleotide (ASO), in Children and Adolescents with Dravet Syndrome (DS) Session Date & Time: Saturday, December 3 at 12:00 PM CST Presenter: Helen Cross, MB ChB, Ph.D., Professor, The Prince of Wales’s Chair of Childhood Epilepsy and Head of the Developmental Neuroscience Programme at University College London Great Ormond Street Institute of Child Health, Honorary Consultant in Paediatric Neurology, President of the International League Against Epilepsy Poster Number: 1.215
• Title: MONARCH Interim Analyses: A Phase 1/2a U.S. Study Investigating Safety and Drug Exposure of STK-001, an Antisense Oligonucleotide (ASO), in Children and Adolescents with Dravet Syndrome (DS) Session Date & Time: Saturday, December 3 at 12:00 PM CST Presenter: Linda Laux​, M.D., Associate Professor of Pediatrics (Neurology and Epilepsy) at Northwestern University Feinberg School of Medicine and Attending Physician at Ann & Robert H. Lurie Children's Hospital of Chicago Poster Number: 1.227

Five additional posters from the Company’s Dravet syndrome program will be presented.

• Title: SWALLOWTAIL: An Open-Label Extension (OLE) Study for Children and Adolescents with Dravet Syndrome (DS) who Previously Participated in a Study of Antisense Oligonucleotide (ASO) STK-001 Session Date & Time: Saturday, December 3 at 12:00 PM CST Presenter: Colin Roberts​, M.D., Director of the Doernbecher Childhood Epilepsy Program at Oregon Health & Science University Poster Number: 1.216
• Title: Utilization of Pharmacokinetic (PK) Model for STK-001 in Patients with Dravet Syndrome (DS) to Predict Pharmacological Active Dose in Clinic Session Date & Time: Saturday, December 3 at 12:00 PM CST Presenter: Meena, Ph.D., Senior Vice President of Bioanalytical, DMPK and Biomarker Development at Stoke Therapeutics Poster Number: 1.134
• Title: Twelve-month Analysis of BUTTERFLY: An Observational Study to Investigate Cognition and Other Non-seizure Comorbidities in Children and Adolescents with Dravet Syndrome (DS) Session Date & Time: Saturday, December 3 at 12:00 PM CST Presenter: Joseph Sullivan, M.D., Professor of Neurology and Pediatrics and Director of the University of California San Francisco Pediatric Epilepsy Center of Excellence Poster Number: 1.228
• Title: Quantitative EEG Analysis Patients with Dravet Syndrome (DS) Treated in the Phase 1/2a MONARCH Study of STK-001, an Antisense Oligonucleotide (ASO) Session Date & Time: Monday, December 5 at 12:00 PM CST Presenter: Kimberly Parkerson, M.D., Ph.D., Vice President, Head of Neurology Clinical Development at Stoke Therapeutics Poster Number: 3.225
• Title: STK-001 Surrogate Restores the Excitability of Parvalbumin-positive Fast-spiking Interneurons in a Mouse Model of Dravet Syndrome Session Date & Time: Monday, December 5 at 12:00 PM CST Presenter: Luis Lopez-Santiago, Ph.D., Associate Research Scientist at University of Michigan Medical School Poster Number: 3.050

About Dravet Syndrome

Dravet syndrome is a severe and progressive genetic epilepsy characterized by frequent, prolonged and refractory seizures, beginning within the first year of life. Dravet syndrome is difficult to treat and has a poor long-term prognosis. Complications of the disease often contribute to a poor quality of life for patients and their caregivers. The effects of the disease go beyond seizures and often include intellectual disability, developmental delays, movement and balance issues, language and speech disturbances, growth defects, sleep abnormalities, disruptions of the autonomic nervous system and mood disorders. The disease is classified as a developmental and epileptic encephalopathy due to the developmental delays and cognitive impairment associated with the disease. Compared with the general epilepsy population, people living with Dravet syndrome have a higher risk of sudden unexpected death in epilepsy, or SUDEP. There are no approved disease-modifying therapies for people living with Dravet syndrome. One out of 16,000 babies are born with Dravet syndrome, which is not concentrated in a particular geographic area or ethnic group.

About STK-001

STK-001 is an investigational new medicine for the treatment of Dravet syndrome currently being evaluated in ongoing clinical trials. Stoke believes that STK-001, a proprietary antisense oligonucleotide (ASO), has the potential to be the first disease-modifying therapy to address the genetic cause of Dravet syndrome. STK-001 is designed to upregulate NaV1.1 protein expression by leveraging the non-mutant (wild-type) copy of the SCN1A gene to restore physiological NaV1.1 levels, thereby reducing both occurrence of seizures and significant non-seizure comorbidities. Stoke has generated preclinical data demonstrating proof-of-mechanism and proof-of-concept for STK-001. STK-001 has been granted orphan drug designation by the FDA and the EMA, and rare pediatric disease designation by the FDA as a potential new treatment for Dravet syndrome.

About Phase 1/2a MONARCH Study (United States)

The MONARCH study is a Phase 1/2a open-label study of children and adolescents ages 2 to 18 who have an established diagnosis of Dravet syndrome and have evidence of a genetic mutation in the SCN1A gene. The primary objectives for the study are to assess the safety and tolerability of STK-001, as well as to determine the pharmacokinetics in plasma and exposure in cerebrospinal fluid. A secondary objective is to assess the efficacy as an adjunctive antiepileptic treatment with respect to the percentage change from baseline in convulsive seizure frequency. Stoke also intends to measure non-seizure aspects of the disease, such as quality of life, as secondary endpoints. Additional information about the MONARCH study can be found at https://www.monarchstudy.com/.

Patients who participated in the MONARCH study and meet study entry criteria are eligible to continue treatment in SWALLOWTAIL, an open-label extension (OLE) study designed to evaluate the long-term safety and tolerability of repeat doses of STK-001. We expect that SWALLOWTAIL will also provide valuable information on the preliminary effects of STK-001 on seizures along with non-seizure aspects of the disease, such as quality of life and cognition.

Enrollment and dosing in SWALLOWTAIL are underway.

About Phase 1/2a ADMIRAL Study (United Kingdom)

The ADMIRAL study is a Phase 1/2a open-label study of children and adolescents ages 2 to