Biogen and Stoke Therapeutics Announce Publication of Two-Year Natural History Data Demonstrating the Severity of Dravet Syndrome, Including Frequent Seizures and Significant Cognitive and Behavioral Impairments

Core Insights - The BUTTERFLY study highlights the significant impact of Dravet syndrome on children's neurodevelopment and functioning, indicating a need for new disease-modifying treatments [1][3][5] Company Overview - Biogen Inc. is a leading biotechnology company focused on innovative science to develop new medicines and create value for shareholders [8] - Stoke Therapeutics specializes in RNA medicine aimed at restoring protein expression, with its lead candidate zorevunersen under evaluation for Dravet syndrome [10] Study Findings - The BUTTERFLY study involved children and adolescents aged 2 to 18, assessing the effects of Dravet syndrome on neurodevelopment over two years [2][7] - Results showed that neurodevelopment plateaued at approximately two years of age, leading to a widening gap compared to neurotypical peers [5] - Major motor seizure frequency increased by 10.6% over the study period, with an average of 14.3 seizures per 28 days at baseline [5] Disease Characteristics - Dravet syndrome is characterized by recurrent seizures and significant cognitive and behavioral impairments, primarily caused by mutations in the SCN1A gene [4][6] - Over 90% of patients continue to experience seizures despite treatment with available anti-seizure medicines, leading to a poor quality of life [4][6] Future Implications - The findings from the BUTTERFLY study provide a baseline for understanding the potential impact of future disease-modifying therapies for Dravet syndrome [3][5]