Biogen, Stoke dose first patient in phase 3 Dravet syndrome trial

Published 11/08/2025, 12:10
Biogen, Stoke dose first patient in phase 3 Dravet syndrome trial

CAMBRIDGE/BEDFORD, Mass. - Biogen Inc. (NASDAQ:BIIB) and Stoke Therapeutics, Inc. (NASDAQ:STOK) announced Monday that the first patient has been dosed in their global Phase 3 EMPEROR study evaluating zorevunersen for the treatment of Dravet syndrome. According to InvestingPro data, Stoke maintains an excellent financial health score, with a robust current ratio of 8.41 and minimal debt-to-equity of 0.01, positioning the company well for this crucial clinical phase.

Zorevunersen, an investigational antisense oligonucleotide, is being developed as a potential first disease-modifying treatment for Dravet syndrome, a rare genetic epilepsy characterized by severe seizures and neurodevelopmental impairments.

The EMPEROR study will enroll patients aged 2 to 18 years with confirmed SCN1A gene variants. Following an 8-week baseline period, participants will be randomized to receive either zorevunersen or a sham procedure over a 52-week treatment period.

The primary endpoint is change in major motor seizure frequency at week 28, with key secondary endpoints including seizure frequency at week 52 and changes in behavior and cognition as measured by Vineland-3 subdomains.

"Despite treatment with available anti-seizure medicines, no approved medications currently address the underlying cognitive and behavioral aspects of this rare, genetic disease," said Katherine Dawson, Head of the Therapeutics Development Unit at Biogen.

The trial has initiated in the United States, United Kingdom, and Japan, with plans to expand to Europe. Eligible participants will be offered ongoing treatment with zorevunersen in an open-label extension study following completion of the main trial.

Zorevunersen works by increasing NaV1.1 protein production in brain cells from the non-mutated copy of the SCN1A gene. The FDA has granted the drug orphan drug designation, rare pediatric disease designation, and Breakthrough Therapy Designation.

Under their strategic collaboration, Stoke retains exclusive rights for zorevunersen in the United States, Canada, and Mexico, while Biogen receives exclusive commercialization rights for the rest of the world.

The information in this article is based on a press release statement from the companies.

In other recent news, Stoke Therapeutics and Biogen have announced that the first patient has been dosed in their global Phase 3 EMPEROR study evaluating zorevunersen for Dravet syndrome. This trial will assess the investigational antisense oligonucleotide against a sham treatment over 52 weeks, focusing on changes in major motor seizure frequency. Jefferies has initiated coverage on Stoke Therapeutics with a Buy rating, citing the potential of zorevunersen in treating Dravet syndrome, with pivotal trial results anticipated in the latter half of 2027. H.C. Wainwright has also reiterated its Buy rating on Stoke Therapeutics, noting improvements in patient outcomes from an open-label extension study. However, the firm adjusted its price target to $35 from $47, reflecting the timeline for the Phase 3 EMPEROR trial, which is expected to begin in the second quarter of 2025. The trial aims to validate the open-label extension data, highlighting zorevunersen’s potential to reduce seizure frequency and positively impact behavior and cognition. These developments underscore the ongoing interest and investment in Stoke Therapeutics’ efforts to advance treatments for Dravet syndrome.

This article was generated with the support of AI and reviewed by an editor. For more information see our T&C.

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