Stoke Therapeutics (STOK) Q3 2026 earnings review
Stoke clears FDA trial hurdle, but its cash burn climbs
Stoke Therapeutics, a developer of genetic medicines for severe epilepsy and eye diseases, cleared a key regulatory hurdle while its spending climbed. Chief executive Ian F. Smith said the Food and Drug Administration agreed on how to score thinking and behavior in the Phase 3 zorevunersen trial, where about 110 of 162 patients have passed the main 28-week checkpoint with zero dropouts. Meanwhile, quarterly operating costs rose 65% from a year ago to $89 million as the company hired commercial staff, leaving $359 million in cash.
| EMPEROR patients past Week 28 | ~110 of 162 0 treatment dropouts to date |
|---|---|
| Quarterly net loss | $73.6M widened 92% from a year ago |
| Cash and marketable securities | $358.8M ~$61M burned in Q3 by our math |
| Cash runway outlook | Unchanged funds operations into early 2028 |
⚖️ Verdict: 🟢 Bullish
The story got better because the FDA agreement removes uncertainty over how the trial's key behavioral goal will be judged, and perfect patient retention strengthens the study's statistical power. One caution: burning about $61 million this quarter by our math leaves cash running out in early 2028, right when the commercial launch is supposed to start.
The question now is whether zorevunersen can prove a clear behavioral benefit over a sham procedure within 52 weeks while cash lasts. Either the four-part cognition score hits statistical significance and supports a premium launch, or a narrow seizure-only result forces a tougher commercial rollout with a depleted bank account. The third-quarter 2027 trial readout will settle it.
🐂 Bull Case
FDA Agreement Settles the Cognition Scoring Rule
Stoke is testing zorevunersen, an experimental genetic medicine for Dravet syndrome, a childhood epilepsy that causes severe seizures and mental delays. To win a broad approval label, the company wants to prove the drug improves thinking and daily behavior as well as seizures. Until now, regulators had not agreed on how to score those behavioral changes in the Phase 3 EMPEROR trial.
"Our NDA planning is on track following our recent discussion with the FDA," chief executive Ian F. Smith said. After the meeting, the agency agreed that the biotechnology group will measure Week 52 behavior using "a multicomponent assessment of four Vineland-3 subdomains" covering expressive communication, receptive communication, personal skills and interpersonal relationships.
This agreement removes a major regulatory hurdle because averaging the four scores into one number prevents a single lagging skill from failing the whole test. Stoke will now begin sending data to the agency throughout the first half of 2027 to speed up its full application in the second half.
What to watch: the start of data submissions to the FDA in the first half of 2027. Keeping that schedule will confirm that manufacturing and early safety files meet the agency's standards.
Zero Dropouts as Two-Thirds Pass Main Checkpoint
The Phase 3 EMPEROR trial enrolled 162 children across the United States, the United Kingdom and Japan by June 2026. Each patient receives either zorevunersen or a sham procedure via spinal injection over 52 weeks, with the main seizure test measured at Week 28. Meanwhile, the company is presenting five-year open-label data at medical conferences to prepare doctors for an early 2028 launch.
- Patients past the Week 28 main seizure checkpoint: about 110 of 162, or 68% by our math, up from 60 in July
- Patients finished with all 52 weeks: about 20, with 100% choosing to stay on the drug in the extension study
- Patient dropouts across the entire study: 0, plus 39 extra patients enrolled across Europe and China
"All 20 of these patients are continuing into the open-label extension period of the study and to date, no patients have discontinued treatment," Smith said. Zero dropouts matter because the trial was designed assuming 15% of patients would quit, so keeping everyone gives the study much stronger statistical power.
What to watch: the patient completion count at the fourth-quarter update in early 2027. Passing 140 patients through Week 28 without dropouts will lock in the statistical cushion for the primary seizure readout.
Eye Disease Trial Reaches Potentially Active Doses
Beyond epilepsy, the Bedford, Massachusetts-based company is developing STK-002 for autosomal dominant optic atrophy (ADOA), an inherited nerve disorder that causes progressive blindness. The Phase 1 OSPREY trial tests rising single doses of the medicine across eight European clinics. Stoke finished dosing the first two patient groups and started the third group, which it expects to complete by the end of 2026.
This step matters because the company stated that cohorts three and four "have the potential to reach therapeutic levels of dosing". That means the upcoming readout in the first half of 2027 can test whether STK-002 actually improves vision rather than just checking safety.
What to watch: initial safety and vision results from the third and fourth dose groups in the first half of 2027. Early signs of vision stabilization would give the company a second valuable medicine before the Dravet trial reads out.
🐻 Bear Case
Cash Cushion Stops Right at the Launch Line
Stoke ended September with $358.8 million in cash and marketable securities, which it expects to fund operations "into early 2028". That date is also when the company hopes to launch zorevunersen in the United States. Adding the $65.7 million stock sale in July to June's $354.3 million balance shows the drug developer burned $61.2 million in the third quarter by our math.
- Total operating expenses: $88.6 million, up 64.9% from a year ago and up 18.5% from last quarter
- Research and development costs: $59.8 million, up 58.7% from a year ago (up 177 percentage points of revenue)
- Sales, general and administrative costs: $28.7 million, up 79.3% from a year ago on "growth in personnel and launch readiness expenses"
Management says it is building the team to realize the drug's full potential, but the math leaves no cash cushion for the actual launch. At the third-quarter burn rate, current funds last 5.9 quarters by our math, meaning any clinical delay or commercial buildout will require selling more shares.
What to watch: fourth-quarter operating expenses and cash burn in the full-year report. A quarterly burn above $65 million would pull the funding deadline into 2027.
Dravet Trial Readout Remains a Single-Product Risk
Despite early progress in the eye program, Stoke's business still rests on the third-quarter 2027 readout of zorevunersen in Dravet syndrome. While the FDA agreed on the four-part Vineland-3 scoring method for thinking and behavior, those skills must show a clear gain over a sham procedure inside just 52 weeks. Earlier open-label studies had no sham group to control for caregiver expectations.
This matters because the company is already spending $28.7 million a quarter on overhead and launch preparations before knowing the Phase 3 result. If the drug lowers seizures at Week 28 but misses the Week 52 cognition score, insurers could resist paying a premium genetic-medicine price.
What to watch: the top-line EMPEROR readout in the third quarter of 2027. The gap between drug and sham on the combined Vineland-3 score will decide whether zorevunersen wins a disease-modifying label.
Risks this quarter didn't answer
Four standing questions received no new figures in the third-quarter earnings release because detailed footnotes wait for the quarterly filing.
- Biogen and Acadia revenue split: total revenue was $11.3 million, and the quarterly filing's collaboration note will show how much came from Biogen cost sharing.
- Spinal-fluid protein levels: elevated in 94% of extension patients at the first-quarter update, and any new safety cut at medical meetings would test tolerability.
- Infant and adult Dravet studies: previously planned to start by late 2026, and the fourth-quarter update will show if dosing began.
- SYNGAP1 candidate selection: still in lead optimization with no target date, and naming a clinical candidate would move the early pipeline forward.
💲 Other KPIs
Total deferred revenue — upfront payments from partners Biogen and Acadia that Stoke has not yet earned — fell 23.7% from last quarter and 24.5% from a year ago by our math. The balance drained by $3.4 million this quarter, faster than the $2.5 million drop in the second quarter, as existing partner prepayments wind down.
The diluted share count rose 16.6% from a year ago and 3.6% from the second quarter. The biotech company sold shares through its at-the-market stock facility in the first quarter and again in July, raising cash to pay for the Phase 3 Dravet trial while diluting existing shareholders.
Revenue from licensing and research partnerships with Biogen and Acadia grew 5.9% from a year ago and rose 20.7% from the second quarter. Because Biogen reimburses a portion of zorevunersen development costs, higher clinical trial spending this quarter lifted the reimbursement revenue.
🔮 Guidance
Unchanged. Management expects its $358.8 million in cash and marketable securities to fund operations into early 2028. By our math, after burning $61.2 million of its $420.0 million post-July cash pile this quarter, the company has about 5.9 quarters of funding left at the current spending pace.
Unchanged. The company still expects top-line results from the 162-patient Phase 3 Dravet syndrome study in the third quarter of 2027. That schedule matches the 52-week treatment period following the completion of enrollment in June 2026.
Unchanged. Stoke plans to submit sections of its drug application throughout the first half of 2027 and finish the filing in the second half of 2027 after the third-quarter trial readout.
Unchanged on the readout window, with new cohort dates. The company will finish dosing the third group of eye-disease patients by the end of 2026, dose the fourth group in early 2027, and report initial safety and vision data in the first half of 2027.
❓ Key Questions
What will the commercial launch cost in 2028?
Cash is projected to last into early 2028, right when the U.S. launch begins, and third-quarter cash burn reached $61.2 million by our math. Investors need to know how management plans to fund the first year of sales.
Did the FDA agree to include open-label extension data?
The release confirmed the four-subdomain Vineland-3 scoring method for the 52-week blinded trial, but it did not say whether the FDA will allow five-year open-label data on the drug's prescribing label.
How much of Q3 revenue came from Biogen?
Total collaboration revenue was $11.3 million in the release, without the partner split. The quarterly filing's footnote will show whether Biogen cost-sharing stayed above $5 million as trial costs rose.
When will the infant and adult Dravet studies start?
Last quarter management planned to start studies in children under two and in adults by the end of 2026, but the third-quarter release did not mention either trial.