Stoke Therapeutics (STOK) investor relations material

Key clinical development updates

• EMPEROR phase III study for Dravet syndrome is enrolling well, with completion of enrollment expected in Q2 and data anticipated by mid-2027.

• The study includes 150-160 lumbar puncture sham control patients, with additional cohorts in Europe and Japan to support regulatory and reimbursement requirements.

• Primary endpoint is seizure reduction at 26 weeks, with secondary endpoints including continuous seizure reduction at 52 weeks and multiple Vineland-3 domains assessing cognition and behavior.

• Longitudinal open-label extension (OLE) data show robust seizure reduction and improvements in cognition and behavior over up to three years, with potential for five-year data at filing.

• Central neuropsychologist raters ensure consistency in Vineland-3 assessments across sites.

Regulatory and labeling strategy

• Breakthrough designation allows for frequent FDA interactions, focusing on demonstrating both seizure reduction and disease-modifying effects on cognition and behavior.

• Labeling strategy leverages Section 14 (CLINICAL STUDIES) to include observed longitudinal data, aiming to differentiate the therapy as more than an anti-seizure medicine.

• The anticipated label is for patients two years and older, aligning with the Breakthrough designation.

• Hierarchical assessment of Vineland-3 domains in the US and composite scoring in Europe are used for secondary endpoints.

Market opportunity and pricing

• Approximately 35,000-40,000 Dravet patients exist in core geographies, with 6,000 immediately addressable upon launch, primarily pediatric and young adult patients.

• Improved genetic testing and ICD-10 coding are expected to increase identification of eligible patients over time.

• Pricing is expected to be benchmarked against other genetically targeted, disease-modifying therapies like SPINRAZA and Vertex CF medicines, rather than traditional anti-seizure drugs.

• Access strategy is designed to ensure broad patient availability, with pricing reflecting the value of disease modification.