Bedford, Mass. — Stoke Therapeutics, Inc. said it has completed enrollment of 162 patients in the primary cohort of its Phase 3 EMPEROR study evaluating zorevunersen as a potential disease-modifying treatment for Dravet syndrome.
The biotechnology company expects to report Phase 3 data in the third quarter of 2027. It plans to meet with the U.S. Food and Drug Administration during the second half of 2026 and begin a rolling New Drug Application submission in the first quarter of 2027.
The company expects the EMPEROR data to support completion of the rolling submission during the second half of 2027.
“We have made significant progress across our business this year, including the rapid enrollment of 162 patients into the Phase 3 EMPEROR study and progression of these patients through key study milestones, with the first patients now approaching the end of the 52-week treatment period,” Chief Executive Officer Ian F. Smith said.
Zorevunersen is being developed as a potential first-in-class treatment designed to address the underlying cause of Dravet syndrome, a severe genetic epilepsy.
The primary EMPEROR analysis population includes patients enrolled in the United States, United Kingdom and Japan, where the sham control is administered through lumbar puncture.
As of July 31, about 145 patients had completed Week 8 and received either two 70-milligram loading doses of zorevunersen or sham treatment. About 80 patients had reached Week 24, while approximately 60 had reached Week 28, when the study’s primary endpoint of change in major motor seizure frequency is measured.
The first patients were expected to reach Week 52 in August. Stoke said no patients had discontinued treatment from the study.
“With no treatment discontinuations to date in EMPEROR, and supportive four-year safety and efficacy data from the ongoing open-label extension studies, we have confidence in the potential of zorevunersen to change the course of Dravet syndrome,” Smith said.
Stoke is also enrolling an additional cohort of about 30 patients in Germany, France, Spain and Italy. Screening has closed, and the final patient was expected to enroll in August 2026.
Site activation and screening are underway in China, where zorevunersen recently received Breakthrough Therapy Designation. Enrollment in China is expected to be completed during the second half of 2026.
Data from the European and Chinese cohorts are not planned for inclusion in the company’s U.S. regulatory submission.
Stoke also reported progress in its Phase 1 OSPREY study of STK-002, an investigational treatment for autosomal dominant optic atrophy, an inherited optic nerve disorder.
Dosing has been completed in the first three-patient cohort, with no serious or severe safety events reported. Dosing of the second cohort was expected to begin in August, followed by additional dose-escalation cohorts, subject to safety reviews.
Initial safety and efficacy results are expected during the first half of 2027.
The company is also working to identify a clinical candidate for SYNGAP1-related disorders and expanding its early research into other haploinsufficient diseases, primarily affecting the central nervous system.
Thomas McCauley, Ph.D., joined Stoke as Chief Scientific Officer in July to support the expansion of its RNA medicines research and development pipeline.
For the second quarter, Stoke reported a net loss of $61.6 million, or 93 cents per share, compared with a net loss of $23.5 million, or 40 cents per share, in the same period last year.
Quarterly revenue declined to $9.3 million from $13.8 million. Revenue was generated through the company’s collaboration and licensing agreements with Acadia Pharmaceuticals and Biogen.
Research and development expenses increased to $49.5 million from $25.9 million, primarily because of increased activities and personnel costs related to the advancement of zorevunersen.
Sales, general and administrative expenses rose to $25.3 million from $15.3 million, reflecting higher personnel and commercial launch-readiness spending.
For the first six months of 2026, Stoke reported a net loss of $111.6 million, or $1.73 per share, compared with net income of $89.4 million, or $1.50 per diluted share, a year earlier.
Six-month revenue fell to $15.6 million from $172.4 million. The prior-year period included $150.8 million associated with a Biogen intellectual property licensing obligation.
Stoke had approximately $420 million in cash, cash equivalents and marketable securities, including $354.3 million as of June 30 and $65.7 million in proceeds from a subsequent at-the-market stock sale.
The company said the funds are expected to support operations through a potential U.S. commercial launch of zorevunersen in early 2028.
