8-K: Supernus Pharmaceuticals Announces Positive Interim Results for SPN-817 Epilepsy Treatment

Supernus Pharmaceuticals reported promising interim data from a Phase 2a study of SPN-817, showing significant seizure reduction in patients with treatment-resistant epilepsy.

Summary

• Supernus Pharmaceuticals has released interim data from an open-label Phase 2a study of SPN-817 for treatment-resistant seizures.
• The study included 41 enrolled subjects, with 19 completing the maintenance period and 16 of those having focal seizures.
• The median focal seizure reduction was 75% at 3mg to 4mg twice daily doses during the maintenance period and 86% in the open-label extension period.
• In the maintenance period, 81% of subjects with focal seizures had a 30% or more seizure reduction, 63% had a 50% or more reduction, and 19% had a 75% or more reduction.
• Subjects with more severe seizures (greater than 11.3 mean baseline seizures per 28 days) experienced a 74% median reduction in the maintenance period and 86% in the open-label extension period.
• Subjects on three or more anti-seizure medications (ASMs) had a 70% median seizure reduction in the maintenance period and 60% in the open-label extension period.
• Among subjects on three or more ASMs, 100% had a 30% or more seizure reduction, 82% had a 50% or more reduction, and 27% had a 75% or more reduction.
• Overall, the median focal seizure reduction was 58% in the maintenance period and 38% in the open-label extension period across all doses (1mg to 4mg twice daily).
• Cognitive function, assessed by Epitrack, showed improvement or no change in 83% of the 12 subjects with available data.
• SPN-817 was generally safe and well-tolerated, with a 22% discontinuation rate due to adverse events in the titration period and 2.4% in the maintenance period.
• The most common adverse events were consistent with acetylcholinesterase inhibitors, including nausea, diarrhea, headache, dizziness, and decreased appetite.

Sentiment

Score: 8

Explanation: The document presents very positive interim results for SPN-817, showing strong efficacy and acceptable tolerability. The company is moving forward with a Phase 2b study, indicating confidence in the drug's potential. The sentiment is very positive, but tempered by the fact that it is an interim analysis and further studies are needed.

Positives

• SPN-817 shows significant efficacy in reducing seizures, particularly focal seizures, in treatment-resistant epilepsy patients.
• The drug demonstrates a strong response in patients with more severe seizures and those on multiple anti-seizure medications.
• SPN-817 has a manageable safety profile with a low discontinuation rate due to adverse events in the maintenance period.
• Cognitive function was either improved or unchanged in the majority of patients assessed.
• The results support the advancement of SPN-817 into a Phase 2b clinical study.

Negatives

• There was a 22% discontinuation rate due to adverse events during the titration period.
• Some patients experienced adverse events such as nausea, diarrhea, headache, and dizziness, consistent with acetylcholinesterase inhibitors.
• The overall median seizure reduction was lower in the open-label extension period compared to the maintenance period.

Risks

• The study is an open-label Phase 2a study, which may have limitations compared to blinded, controlled trials.
• The adverse event profile, while manageable, could still pose challenges for some patients.
• The long-term efficacy and safety of SPN-817 need to be further evaluated in larger, longer-term studies.
• The company needs to successfully complete and optimize the synthesis process of the synthetic drug and develop a novel dosage form.
• The company needs to improve tolerability during titration.

Future Outlook

Supernus plans to initiate a Phase 2b clinical study of SPN-817 before the end of 2024 and will continue to analyze the data to improve tolerability during titration. Full topline results from the Phase 2a study, excluding the new extension period, are expected in the second half of 2024.

Management Comments

• Jack Khattar, President and CEO of Supernus, stated that the interim analysis provides early, yet strong evidence of the clinical utility of SPN-817 in epilepsy.
• Management believes SPN-817 could offer a novel, differentiated treatment option for patients with hard-to-treat epilepsy.

Industry Context

The announcement is significant as it addresses the unmet need for effective treatments for treatment-resistant epilepsy, a challenging area in neurology. The development of a novel acetylcholinesterase inhibitor for epilepsy could provide a new approach to managing seizures.

Comparison to Industry Standards

• The 75% median focal seizure reduction at the optimal dose in the maintenance period is a strong result compared to many existing anti-epileptic drugs, which often show lower efficacy rates in treatment-resistant populations.
• Many existing anti-epileptic drugs have significant side effect profiles, so the tolerability of SPN-817, with a 2.4% discontinuation rate in the maintenance period, is a positive sign.
• Competitors in the epilepsy space include companies like UCB, Eisai, and Jazz Pharmaceuticals, which offer various anti-epileptic drugs with different mechanisms of action. SPN-817's novel mechanism as an acetylcholinesterase inhibitor could provide a competitive advantage if further studies confirm its efficacy and safety.
• The results are comparable to some of the more effective adjunctive therapies for focal seizures, but further head-to-head trials would be needed to make a definitive comparison.

Stakeholder Impact

• Shareholders are likely to react positively to the promising interim data, potentially increasing the company's stock value.
• Patients with treatment-resistant epilepsy may benefit from a new, potentially more effective treatment option.
• The positive results could enhance the company's reputation and attract potential partners or investors.

Next Steps

• Supernus plans to initiate a Phase 2b clinical study of SPN-817 before the end of 2024.
• The company will continue to analyze the data to improve tolerability during titration.
• Full topline results from the Phase 2a study, excluding the new extension period, are expected in the second half of 2024.

Key Dates

Keywords

SPN-817, epilepsy, seizures, acetylcholinesterase inhibitor, clinical trial, Phase 2a, treatment-resistant, anticonvulsant, neurology, CNS