SPN-817 Open-Label Extension Study in Adults With Focal Onset Seizures

Not Applicable

Recruiting

• Conditions: Focal Onset Seizures
• Interventions: Drug: SPN-817

• Registration Number: NCT07141329
• Lead Sponsor: Supernus Pharmaceuticals, Inc.

Brief Summary

This is a Phase 3 open-label extension study to evaluate the long-term safety and efficacy of SPN-817.

Detailed Description

This is a Phase 3, multicenter, open-label extension, one-year, safety, tolerability, and efficacy study in adults who previously completed an applicable double-blind SPN-817 clinical study (including a Phase 2 double-blind study). This study will include a double-blind Dose Titration/Bridging Period of 8-10 weeks in which SPN-817 will be titrated to the participant's maximum tolerated dose based on response. Following the Dose Titration/Bridging Period, participants will enter an Open Label Extension (OLE) Period of 42-44 weeks. When participants finish the OLE Period, they will initiate a Tapering Period (up to 4 weeks) followed by an End-of-Tapering Period video contact (VC) after the last dose of study drug. The duration of study treatment before starting the 4-week Tapering Period will be one year (52 weeks).

Study Timeline

• Study Start: 2025-07-30
• Status Verified: 2025-08
• Study First Submitted: 2025-08-19
• Study First Submitted QC: 2025-08-19
• Last Update Submitted: 2025-08-19
• Study First Posted: 2025-08-26
• Last Update Posted: 2025-08-26
• Primary Completion: 2027-12-31
• Study Completion: 2027-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

1. Completed antecedent SPN-817 double-blind study
2. Taking a stable dosage regimen (maintained during the antecedent study) of at least one antiseizure medication (ASM) and no more than 4 ASMs

Exclusion Criteria

1. Has current nonepileptic events that could be confused by the participant and/or study staff as epileptic seizures
2. Has any suicidal behavior or suicidal ideation related to Item 4 (active suicidal ideation with some intent to act without specific plan) or Item 5 (active suicidal ideation with specific plan and intent) based on the Columbia-Suicide Severity Rating Scale (C-SSRS) assessments in the antecedent study and at Visit 1 or more than one lifetime suicide attempt.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
SPN-817	SPN-817	SPN-817, bid

Primary Outcome Measures

Name	Time	Method
Incidence of treatment-emergent adverse events	Week 1-Week 52	The percent of participants who took at least one dose of SPN-817 and reported at least one adverse event during the 1-year SPN-817 Treatment Period

Secondary Outcome Measures

Name	Time	Method
Proportion of participants experiencing seizure freedom	Baseline and Treatment Period (Week 1-52)	100% reduction in 28-day frequency of focal seizures during the Treatment Period relative to baseline
Percentage of seizure-free days over the 1-year SPN-817 Treatment Period	Week 1-Week 52	The number of seizure-free days reported for each participant divided by the total number of days with seizure data reported, multiplied by 100.
Percent change (PCH) from baseline in quantifiable focal onset seizure frequency per 28 days over the 1-year SPN-817 Treatment Period	Baseline and Treatment Period (Week 1-52)	Percent change in 28-day frequency of quantifiable focal seizures during the 1-year Treatment Period relative to baseline
Proportion of participants experiencing ≥50% reduction in focal seizure frequency per 28 days from baseline	Baseline and Treatment Period (Week 1-52)	Greater than or equal to 50% reduction in 28-day frequency of focal seizures during the 1-year Treatment Period relative to baseline.

Trial Locations

Locations (1)

Medsol Clinical Research Center; 🇺🇸 Port Charlotte, Florida, United States