Stoke Therapeutics and Biogen Publish Zorevunersen Study Data

Stoke Therapeutics (STOK) and Biogen (BIIB) announced the publication of data from studies of the investigational medicine zorevunersen in The New England Journal of Medicine, or NEJM. The publication includes results from two completed Phase 1/2a and ongoing open-label extension, or OLE, studies that demonstrate, for the first time, the potential for disease modification in people living with Dravet syndrome. These data showed substantial and durable reductions in seizures and improvements across multiple measures of cognition and behavior that began in the Phase 1/2a treatment period and continued through three additional years of treatment in the OLEs. The effects were shown in people treated with zorevunersen on top of standard of care anti-seizure medicines. The Phase 1/2a studies evaluated single and multiple doses of zorevunersen up to 70 mg with a primary endpoint of safety. Change in major motor seizure frequency was assessed as a secondary endpoint. Substantial reductions in seizures were observed among zorevunersen-treated patients in the Phase 1/2a studies and continued through three years of treatment in the OLEs. The most substantial reductions in seizure frequency were observed among patients treated with initial doses of 70 mg in the Phase 1/2a studies. Changes in neurodevelopment, functioning, clinical status and quality of life for all patients were assessed as additional endpoints in the OLEs using standard clinical assessments. Improvements in communication, motor skills, socialization, daily living and quality of life continued through three additional years of treatment. Zorevunersen has been generally well tolerated across the Phase 1/2a and OLE studies. Eighty-one patients received at least one dose of zorevunersen and were evaluated for safety, and more than 800 doses have been administered across these studies to date. The most common treatment-related adverse event was cerebrospinal fluid protein elevations with a higher incidence observed in the OLE studies. No related clinical manifestations have been observed, although one patient discontinued treatment due to elevated CSF protein levels. All serious adverse events were assessed to be unrelated to zorevunersen except in one patient who experienced suspected unexpected serious adverse reactions.