Clinical readout for Dravet syndrome trial part of the collaboration the companies signed in 2025.
An antisense oligonucleotide treatment being co-developed by Biogen and Stoke Therapeutics has become the first drug to demonstrate disease modification potential in a hard-to-treat form of epilepsy.
New clinical data for zorevunersen showed it enabled a significant reduction in the number of seizures in paediatric patients with Dravet syndrome in two initial phase I/IIa trials and ongoing extension studies.
In the initial trial, 81 children were given up to 70mg of zorevunersen, either as a single dose or with multiple doses over a six-month period.
Patients experienced a reduction in the number of seizures by between 59 percent and 91 percent over the first 20 months of the extension studies, persisting over the three years in the extension studies.
By targeting the underlying genetic cause of the disease, zorevunersen has the potential to be the first disease-modifying medicine for the treatment of Dravet syndrome”
These outcomes are notable considering current treatments are ineffective at controlling seizures in most Dravet patients and no therapy is currently available that addresses symptoms. Zorevunersen works by helping to restore correct nerve-cell function.
Dr Barry Ticho, Chief Medical Officer of Stoke Therapeutics, said: “By targeting the underlying genetic cause of the disease, zorevunersen has the potential to be the first disease-modifying medicine for the treatment of Dravet syndrome.”
Lead author of the NEJM publication, Professor Helen Cross, PhD, added: “These data mark a potential turning point in the treatment of Dravet syndrome.
“While reducing seizures is still critical, the improvements in cognition, behaviour and quality of life seen in these studies suggest we may be changing the course of the disease and therefore the lives of patients and their families.”
Zorevunersen is currently being investigated in the ongoing phase III EMPEROR study, results of which are expected to be shared in mid-2027.
The recently published findings are available in the NEMJ.