Clinical Characteristics and Treatment Experience of Individuals with SCN8A Developmental and Epileptic Encephalopathy (SCN8A-DEE): Findings from an Online Caregiver Survey

ABSTRACT Purpose: SCN8A developmental epileptic encephalopathy (SCN8A-DEE) is a rare and severe genetic epilepsy syndrome characterized by early-onset developmental delay, cognitive impairment, and intractable seizures. Variants in the SCN8A gene are associated with a broad phenotypic spectrum and variable disease severity. A caregiver survey, solicited by the advocacy group The Cute Syndrome Foundation (TCSF), was conducted to gather information on the demographics/disease presentation, seizure history, and treatment of patients with SCN8Arelated epilepsies. Methods: A 36-question online survey was developed to obtain de-identified data from caregivers of children with SCN8A-related epilepsy. The survey included questions on genetic diagnosis, disease manifestations/comorbidities, seizure severity/type, current/prior use of antiseizure medicines (ASMs), and best/worst treatments per caregiver perception. Results: In total, 116 survey responses (87 USA, 12 Canada, 12 UK, 5 Australia) were included in the quantitative analysis. Generalized tonic/clonic was the most common seizure type at onset and time of survey; absence and partial/focal seizures were also common. Most patients (77%) were currently taking [≥]2 ASMs; 50% had previously tried and stopped [≥]4 ASMs. Sodium channel blockers (oxcarbazepine, phenytoin, lamotrigine) provided the best subjective seizure control and quality of life. Conclusion: The SCN8A-DEE patient population is heterogeneous and difficult to treat, with high seizure burden and multiple comorbidities. The high proportion of patients who previously tried and stopped ASMs indicates a large unmet treatment need. Further collaboration between families, caregivers, patient advocates, clinicians, researchers, and industry can increase awareness and understanding of SCN8A-related epilepsies, improve clinical trial design, and potentially improve patient outcomes.