Focal Onset SeizuresPhase 2NCT07141329
SPN-817 Open-Label Extension Study in Adults With Focal Onset Seizures
A Phase 2 study testing SPN-817 in people with Focal Onset Seizures, run by Supernus Pharmaceuticals, Inc. at 8 sites in 2 countries.
Trial summary
This is a Phase 2b open-label extension study to evaluate the long-term safety and efficacy of SPN-817. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Focal Onset Seizures
- What is being tested?
- SPN-817
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 8 sitesin 2 countries
- Study dates
- 30 Jul 2025to 31 Dec 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Completed antecedent SPN-817 double-blind study
- Taking a stable dosage regimen (maintained during the antecedent study) of at least one antiseizure medication (ASM) and no more than 4 ASMs
Who cannot join
- Has current nonepileptic events that could be confused by the participant and/or study staff as epileptic seizures
- 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.
Trial locations and contacts
8 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
8 sites in 2 countries
United States7 sites
Asheville Neurology Specialists
Asheville, North Carolina, 28806
Ilumina Medical Research
Kissimmee, Florida, 34744
Thomas Jefferson University
Philadelphia, Pennsylvania, 19107
Medsol Clinical Research Center
Port Charlotte, Florida, 33952
University of Rochester Medical Center
Rochester, New York, 14618
Center for Neurosciences
Tucson, Arizona, 85718
Focus Clinical Research
West Hills, California, 91307
About this study
Official title: An Open-Label Extension, One-Year, Safety, and Efficacy Study of SPN-817 in Adults With Focal Onset Seizures
This is a Phase 2b open-label extension study to evaluate the long-term safety and efficacy of SPN-817.
Read the detailed description
This is a Phase 2b, multicenter, open-label extension, one-year, safety, tolerability, and efficacy study in adults who previously completed an applicable double-blind SPN-817 clinical study. This study will include a double-blind Dose Titration/Bridging Period of at least 58 days (8 weeks and 2 days) and up to 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).
- Conditions
- Focal Onset Seizures
- Being tested
- SPN-817
- Keywords
- focal seizures, focal epilepsy, open-label extension, anti-seizure medication
- Medical subject headings
- Seizures, Epilepsies, Partial
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SPN-817Drug
SPN-817 starting at 0.25 mg bid up to 4.00 mg bid
| Study group | Role | What they receive |
|---|---|---|
| SPN-817 | Experimental | SPN-817, bid Receives: Drug: SPN-817 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of treatment-emergent adverse events
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
Measured: Week 1-Week 52
Secondary outcomes (4)
Percent change (PCH) from baseline in focal onset seizure frequency per 28 days over the 1-year SPN-817 Treatment Period
Percent change in 28-day frequency of focal seizures during the 1-year Treatment Period relative to baseline
Measured: Baseline and Treatment Period (Week 1-52)
Proportion of participants experiencing ≥50% reduction in focal seizure frequency per 28 days from baseline
Greater than or equal to 50% reduction in 28-day frequency of focal seizures during the 1-year Treatment Period relative to baseline.
Measured: Baseline and Treatment Period (Week 1-52)
Proportion of participants experiencing seizure freedom
100% reduction in 28-day frequency of focal seizures during the Treatment Period relative to baseline
Measured: Baseline and Treatment Period (Week 1-52)
Percentage of seizure-free days over the 1-year SPN-817 Treatment Period
The number of seizure-free days reported for each participant divided by the total number of days with seizure data reported, multiplied by 100.
Measured: Week 1-Week 52
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Aug 2025
- Study start30 Jul 2025
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Focal Onset SeizuresStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Supernus Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Maciej Gasior, MD, PhD, Study director, Supernus Pharmaceuticals, Inc.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07141329
- Sponsor's protocol ID
- 817P210
- Status last verified
- Oct 2026
- First submitted
- 19 Aug 2025
- Last updated
- 27 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-Label Extension, One-Year, Safety, and Efficacy Study of SPN-817 in Adults With Focal Onset Seizures
- ClinicalTrials.gov ID
- NCT07141329
- Acronym / sponsor ID
- 817P210
- Conditions
- Focal Onset Seizures
- Keywords
- focal seizures, focal epilepsy, open-label extension, anti-seizure medication
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Supernus Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- 30 Jul 2025 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 26 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a Phase 2b open-label extension study to evaluate the long-term safety and efficacy of SPN-817.
Detailed description
This is a Phase 2b, multicenter, open-label extension, one-year, safety, tolerability, and efficacy study in adults who previously completed an applicable double-blind SPN-817 clinical study. This study will include a double-blind Dose Titration/Bridging Period of at least 58 days (8 weeks and 2 days) and up to 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 design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| SPN-817 | Experimental | Drug: SPN-817SPN-817, bid |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Completed antecedent SPN-817 double-blind study
- Taking a stable dosage regimen (maintained during the antecedent study) of at least one antiseizure medication (ASM) and no more than 4 ASMs
Key exclusion criteria (2 listed)
- Has current nonepileptic events that could be confused by the participant and/or study staff as epileptic seizures
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SPN-817SPN-817 starting at 0.25 mg bid up to 4.00 mg bid | Drug | SPN-817 |
Primary outcome
Incidence of treatment-emergent adverse events
Time frame: 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
4 secondary outcomes
Percent change (PCH) from baseline in focal onset seizure frequency per 28 days over the 1-year SPN-817 Treatment Period
Time frame: Baseline and Treatment Period (Week 1-52)
Proportion of participants experiencing ≥50% reduction in focal seizure frequency per 28 days from baseline
Time frame: Baseline and Treatment Period (Week 1-52)
Proportion of participants experiencing seizure freedom
Time frame: Baseline and Treatment Period (Week 1-52)
Percentage of seizure-free days over the 1-year SPN-817 Treatment Period
Time frame: Week 1-Week 52
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Oct 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Maciej Gasior, MD, PhD study director
Supernus Pharmaceuticals, Inc.
8 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing SPN-817 in people with Focal Onset Seizures, run by Supernus Pharmaceuticals, Inc. at 8 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 27 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 8 sites in United States, Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of treatment-emergent adverse events (time frame: Week 1-Week 52). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Oct 2026; AzTrials last refreshed its copy on 7 Nov 2026.