BEDFORD, Mass. — Stoke Therapeutics reported first-quarter financial results and released new long-term data supporting the potential of its lead investigational medicine, zorevunersen, as a disease-modifying treatment for Dravet syndrome.
The Bedford-based biotechnology company said new four-year data from ongoing Phase 1/2a open-label extension studies showed statistically significant improvements in cognition and behavior at one, two, three and four years of treatment compared with the open-label extension baseline. The company also reported durable reductions in major motor seizure frequency through four years among patients taking standard anti-seizure medicines.
Zorevunersen, which is being developed with Biogen, is designed as a first-in-class potential disease-modifying treatment for Dravet syndrome, a rare genetic epilepsy. Stoke said the therapy has generally been well tolerated, with some patients treated for more than five years across the Phase 1/2a and extension studies.
“These new 4-year OLE data suggest that zorevunersen may change the course of Dravet syndrome by providing children with durable reductions in seizures and the possibility of a more neurotypical development path,” Ian F. Smith, chief executive officer and director of Stoke Therapeutics, said in a statement.
Smith said the company remains on track to complete enrollment of about 150 patients in its pivotal Phase 3 EMPEROR study in June, supporting a data readout in mid-2027. The trial is enrolling patients in the U.S., U.K. and Japan, with additional European enrollment underway in Germany, France, Spain and Italy.
Stoke said approximately 130 patients had been randomized to receive zorevunersen or a sham treatment as of May 5. The remaining patients are moving through an eight-week screening period, with the final patient expected to be randomized in June.
The Phase 3 data are expected to complete the company’s planned rolling New Drug Application submission to the U.S. Food and Drug Administration, which Stoke plans to initiate in the first quarter of 2027. Smith said the company’s financial position is expected to support operations through a potential U.S. launch in early 2028.
Stoke said 93% of patients who completed Phase 1/2a studies continued into one of two open-label extension studies, and 77% remained in the studies as of the four-year data cutoff. More than 850 doses have been administered across the Phase 1/2a and extension studies.
Elevated cerebrospinal fluid protein lab values occurred in about 94% of patients, with 59% classified as treatment-emergent adverse events. The company said no serious or severe clinical manifestations have been associated with the elevations, and there have been no reports of hydrocephalus.
The company also said it continues to advance its broader pipeline. In February, the first patient was dosed in the Phase 1 OSPREY study of STK-002 for autosomal dominant optic atrophy, an inherited optic nerve disorder. Two patients have been dosed so far, with recruitment ongoing at seven sites in the U.K., Germany, Denmark and Austria.
Stoke is also working to identify a clinical candidate this year for SYNGAP1, a severe rare genetic neurodevelopmental disease.
For the quarter ended March 31, Stoke reported $6.2 million in revenue, down from $158.6 million a year earlier. The year-ago period included $150.8 million related to an intellectual property license performance obligation under the company’s Biogen agreement outside the U.S., Canada and Mexico.
The company posted a net loss of $50 million, or 79 cents per share, compared with net income of $112.9 million, or $1.90 per diluted share, a year earlier. Research and development expenses rose to $39.7 million from $32.7 million, while sales, general and administrative expenses increased to $20 million from $14.7 million.
Stoke ended the quarter with $411 million in cash, cash equivalents and marketable securities, which it expects will fund operations into 2028. That total includes $80.7 million raised through selective at-the-market stock sales during the first quarter.
