8-K: Stoke Therapeutics Receives FDA Breakthrough Therapy Designation and Announces Positive Clinical Trial Data for Zorevunersen in Dravet Syndrome

Stoke Therapeutics announced it has received Breakthrough Therapy Designation from the FDA for zorevunersen and released positive data from its clinical trials showing substantial reductions in seizure frequency and improvements in cognition and behavior for patients with Dravet syndrome.

Summary

• Stoke Therapeutics has received Breakthrough Therapy Designation from the FDA for zorevunersen, a treatment for Dravet syndrome.
• Clinical trial data shows that zorevunersen has led to substantial and sustained reductions in convulsive seizure frequency.
• Patients treated with zorevunersen experienced an 85% reduction in seizure frequency at 3 months and 74% at 6 months post-last dose in the Phase 1/2a study.
• In the open-label extension study, patients sustained at least a 50% median reduction in seizure frequency each month, with an 87% median reduction at month eight.
• Patients also showed continuous improvements in cognition and behavior over two years of treatment.
• Zorevunersen was generally well-tolerated across the studies, with the most common treatment-related adverse events being CSF protein elevations and procedural vomiting.
• The company plans to provide an update on its Phase 3 registrational plans by the end of the year.

Sentiment

Score: 9

Explanation: The document conveys a highly positive sentiment due to the Breakthrough Therapy Designation and strong clinical data showing significant improvements in patients with Dravet syndrome. The potential for zorevunersen to be a disease-modifying therapy is a major positive.

Positives

• The Breakthrough Therapy Designation from the FDA may expedite the development and review process for zorevunersen.
• Clinical data shows substantial and durable reductions in seizure frequency, with an 87% median reduction at month eight in the OLE study.
• Patients experienced continuous improvements in multiple measures of cognition and behavior.
• Zorevunersen has been generally well-tolerated across the studies.
• The data supports the company's proposed Phase 3 registrational study regimen.

Negatives

• Some patients experienced treatment-emergent adverse events, including CSF protein elevations and procedural vomiting.
• One patient discontinued treatment in the OLE due to elevated CSF protein.
• A greater incidence of CSF protein elevation was observed in the OLEs, with 79% of patients having at least one CSF protein value >50 mg/dL, although no clinical manifestations were observed.

Risks

• The company's ability to advance, obtain regulatory approval, and commercialize zorevunersen is subject to risks and uncertainties.
• Regulatory authorities may interpret data differently and request additional information or change their guidance.
• Receiving Breakthrough Therapy Designation does not guarantee faster development or regulatory approval.
• The company's ability to fund development activities and achieve development goals is subject to risks.
• Global business, political, and macroeconomic conditions could impact the company's operations.

Future Outlook

The company plans to provide an update on its Phase 3 registrational plans by the end of the year and is moving forward with discussions with regulatory agencies regarding the Phase 3 study.

Management Comments

• Shamim Ruff, Chief Regulatory Affairs Officer, stated that the Breakthrough Therapy designation is supported by promising clinical data that suggests zorevunersen has the potential to demonstrate substantial improvement over current treatments for Dravet syndrome.
• Mary Anne Meskis, Executive Director, Dravet Syndrome Foundation, expressed encouragement by the FDA's shared sense of urgency for the development of innovative new medicines.
• Joseph Sullivan, M.D., FAES, noted that the substantial and durable reductions in seizures, as well as the continuous gains in multiple measures of behavior and cognition through 2 years in patients treated in these studies have never been seen before in studies of Dravet syndrome.
• Barry Ticho, M.D., Ph.D., Chief Medical Officer of Stoke Therapeutics, stated that the new long-term data give a more complete and convincing picture of the potential for zorevunersen as a disease-modifying medicine.

Industry Context

This announcement is significant in the context of Dravet syndrome, a severe and difficult-to-treat genetic epilepsy, as there are currently no approved disease-modifying therapies. The positive clinical data and Breakthrough Therapy Designation position zorevunersen as a potential first-in-class treatment.

Comparison to Industry Standards

• Current treatments for Dravet syndrome primarily focus on managing symptoms, such as seizures, with anti-seizure medications.
• Zorevunersen is being developed as a disease-modifying therapy, aiming to address the underlying genetic cause of the disease, which is a novel approach compared to existing treatments.
• The reported 87% median reduction in seizure frequency at month eight in the OLE study is a significant improvement compared to the outcomes typically seen with standard anti-seizure medications.
• The continuous improvements in cognition and behavior observed in the clinical trials are also notable, as these are areas where current treatments often fall short.
• Companies like GW Pharmaceuticals (now part of Jazz Pharmaceuticals) with Epidiolex have shown success in reducing seizure frequency, but zorevunersen aims to go further by addressing the underlying cause of the disease.

Stakeholder Impact

• Shareholders may see a positive impact due to the positive clinical data and Breakthrough Therapy Designation.
• Patients with Dravet syndrome and their families may benefit from a potential new treatment option.
• Employees of Stoke Therapeutics may be motivated by the progress of zorevunersen.
• The medical community may see a new approach to treating Dravet syndrome.

Next Steps

• The company plans to provide an update on its Phase 3 registrational plans by the end of the year.
• The company will host a virtual event for investors and analysts on December 9 to discuss Dravet syndrome and zorevunersen.
• Discussions with the FDA and other global regulatory agencies regarding a global, randomized, controlled Phase 3 registrational study of zorevunersen continue to progress.

Key Dates

Keywords

Dravet syndrome, zorevunersen, Breakthrough Therapy Designation, seizure reduction, cognition, RNA medicine, clinical trials, antisense oligonucleotide, STK-001, FDA