Stoke Therapeutics Q1 Earnings Call Highlights

Key Points

• Stoke Therapeutics said its lead drug zorevunersen showed durable seizure reductions and improved cognition/behavior in four-year extension data, supporting a potential disease-modifying effect in Dravet syndrome.
• The company expects to finish enrollment in the Phase 3 EMPEROR trial in June and remains on track for a mid-2027 data readout, with a potential U.S. launch targeted for late 2027 or early 2028 if the program succeeds.
• Stoke ended the quarter with $411 million in cash, which it says should fund operations through the Phase 3 readout and a potential launch, while it also raised $80.7 million via its at-the-market equity program.

Stoke Therapeutics NASDAQ: STOK said its lead investigational therapy zorevunersen continued to show durable seizure reductions and improvements in measures of cognition and behavior in four-year open-label extension data, while the company remains on track to complete enrollment in its pivotal Phase 3 EMPEROR study in June.

On the company’s first-quarter 2026 business and financial update call, Chief Executive Officer Ian Smith said Stoke has seen increased awareness over the past 12 to 18 months around both Dravet syndrome and the potential role of zorevunersen, an investigational antisense oligonucleotide designed to address the underlying cause of the disease.

Smith said the company is preparing for a potential U.S. launch in late 2027 or early 2028, contingent on successful Phase 3 data and regulatory approval. He added that Stoke expects to begin a rolling New Drug Application submission in the first quarter of 2027, with Phase 3 data expected to complete the submission in mid-2027.

Four-Year Data Show Continued Seizure Reductions

Chief Medical Officer Dr. Barry Ticho reviewed new top-line four-year data from Stoke’s ongoing Phase 1/2 open-label extension studies. Of the 81 patients who received at least one dose of zorevunersen in the Phase 1/2 studies, 75, or 93%, continued into the extension studies, receiving zorevunersen on top of standard anti-seizure medicines.

Ticho said approximately 77% of patients remained in the studies at the time of the four-year data cut. In patients initially treated with one, two or three 70 mg doses before entering the extension studies, median reductions in major motor seizure frequency ranged from 59% to 91% through month 28 compared with Phase 1/2 baseline.

The company said the latest four-year data also showed statistically significant improvements in five Vineland-3 subdomains compared with open-label extension baseline at years one, two, three and four. Vineland-3 is used to assess behavioral outcomes across domains such as communication, motor skills, socialization and daily living.

Ticho said the findings provide support for the potential disease-modifying effect of zorevunersen, noting that Dravet syndrome is associated with severe neurodevelopmental consequences in addition to seizures.

“These data suggest that zorevunersen may durably reduce seizure frequency and lead to improvements in cognition and behavior in patients whose neurodevelopment generally stagnates around the age of two,” Ticho said.

Safety Profile Remains Consistent

Ticho said Stoke now has more than five years of clinical data across the Phase 1/2 and extension studies, with more than 850 doses administered. He said no new safety findings have emerged and zorevunersen continues to be generally well-tolerated.

Elevated cerebrospinal fluid protein lab values occurred in approximately 94% of patients, with 59% classified as treatment-emergent adverse events. Ticho said no serious or severe clinical manifestations have been associated with the CSF protein elevations, and there have been no reports of hydrocephalus.

Phase 3 EMPEROR Study Nears Enrollment Completion

Stoke’s Phase 3 EMPEROR study is a global, double-blind, sham-controlled trial of zorevunersen in Dravet syndrome. The company plans to enroll approximately 150 patients in the U.S., U.K. and Japan, where sham is administered via lumbar puncture. Ticho said data from those patients are expected to be used for the U.S. NDA submission.

As of May 5, approximately 130 patients had been randomized to zorevunersen or sham, and approximately 18 had completed the week 28 visit, which is tied to the study’s primary endpoint of change in seizure frequency. Ticho said no patients had discontinued treatment in EMPEROR to date, and approximately 91 had received two loading doses of 70 mg of zorevunersen or sham.

The study will remain blinded for the full 52-week treatment period because secondary endpoints measuring cognition and behavior will be assessed at week 52. Stoke expects the final patient in the U.S., U.K. and Japan cohort to be randomized in June, keeping the company on track for a Phase 3 readout in mid-2027.

The company is also enrolling a European cohort where sham will be administered by needle prick. Ticho said at least 20 patients are planned for enrollment in Europe, but the cohort is not planned for the NDA submission. Screening in Europe is underway, with 15 of 16 sites active, and enrollment is expected to be completed in the third quarter.

Commercial Planning Focuses on Concentrated U.S. Market

Chief Patient Officer Jason Hoitt said Stoke estimates there are about 38,000 patients with Dravet syndrome across the seven major markets where the EMPEROR study is running, including approximately 16,000 in the U.S. He said the company estimates approximately 6,000 U.S. patients will be addressable at the time of a potential launch, based in part on patients under age 25 who are likely under pediatric care and claims analyses of diagnosed patients.

Hoitt said the U.S. Dravet population is concentrated, with about 70% of patients seen by roughly 1,200 healthcare providers and approximately 124 sites of care. He added that Stoke expects to pursue a lean commercial infrastructure given the rare disease market’s concentration.

During the question-and-answer session, Hoitt said payers have indicated they would evaluate the totality of the zorevunersen data, including longitudinal data, rather than relying solely on label language. He said Stoke plans to deploy national account directors in the second half of 2026 to begin payer education through pre-approval information exchange presentations.

Smith and Hoitt also discussed the company’s goal of including long-term open-label extension data in the zorevunersen label if approved. Smith said the data would be shared with the FDA and could help inform physicians about the medicine’s safety and efficacy in chronic use.

Cash Position Supports Phase 3 Readout and Potential Launch

Chief Financial Officer Thomas Leggett said Stoke ended the first quarter with $411 million in cash, cash equivalents and marketable securities. The company expects that balance to fund operations through a potential U.S. launch in late 2027 or early 2028.

During the quarter, Stoke raised $80.7 million in net proceeds through its at-the-market program by selling approximately 2.6 million shares of common stock to what Leggett described as high-quality fundamental investors.

Leggett said the company continues to invest in advancing its clinical work, preparing for potential commercialization, advancing its pipeline and maintaining a strong financial position. Smith said the company is funded well beyond the Phase 3 readout and through a potential U.S. launch of zorevunersen.

About Stoke Therapeutics NASDAQ: STOK

Stoke Therapeutics, headquartered in Bedford, Massachusetts, is a clinical-stage biopharmaceutical company focused on developing genetic medicines to upregulate protein production for the treatment of rare neuromuscular and neurological disorders. Founded in 2014, the company applies its proprietary Targeted Augmentation of Nuclear Gene Output (TANGO™) platform to design antisense oligonucleotides that selectively modulate RNA splicing and enhance expression of functional proteins.

The company's lead program, STK-001, is an antisense oligonucleotide therapy designed to increase production of the sodium channel protein SCN1A and is currently in clinical development for Dravet syndrome, a severe childhood-onset epilepsy.

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