Biogen, Stoke presents data from Phase 1/2a, OLE studies of zorevunersen

Biogen (BIIB) and Stoke Therapeutics (STOK) announced data from Phase 1/2a and open-label extension, OLE, studies of zorevunersen that support the potential for zorevunersen to be the first disease-modifying medicine for Dravet syndrome. Findings were presented at the 36th International Epilepsy Congress, IEC, in Lisbon, Portugal. Data support the EMPEROR Phase 3 study of zorevunersen that is now underway to further evaluate this investigational antisense oligonucleotide. The Phase 1/2a studies evaluated single and multiple doses of zorevunersen up to 70 mg with a primary endpoint of safety. Effects on major motor seizure frequency were evaluated as a secondary endpoint. A dose relationship was demonstrated among patients treated with multiple doses of zorevunersen. Patients treated with an initial 2 or 3 doses of 70 mg experienced the most substantial reductions in seizures. A median reduction in seizures of 84.8% and a median increase of eight seizure-free days per 28 days were observed at 3 months after the last dose. Patients who received initial 70 mg doses of zorevunersen in the Phase 1/2a studies also showed the most substantial improvements in quality-of-life outcomes as measured by the EuroQol Visual Analog Scale, a component of the Euro-Qol-5D Youth. Following treatment in the Phase 1/2a studies, 94% of eligible patients continued treatment in the OLEs. Through three years, 77% of these patients remain in the studies. Overall, reductions in major motor seizure frequency were sustained through three years of treatment in the OLE studies. The most substantial reductions in seizure frequency were observed among patients treated with initial doses of 70 mg in the Phase 1/2a studies.