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One-Year Open-Label Extension Study Evaluating Safety and Efficacy of Huperzine A as Adjunctive Therapy in Adults with Focal Onset Seizures

Investigational
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The condition being examined is Focal Onset Seizures, a type of seizure that starts in one specific part of the brain and can cause brief periods of altered awareness or movements. The trial uses an oral capsule containing the experimental compound SPN-817 and includes matching placebo capsules during the initial adjustment phase.

The aim is to evaluate the safety and tolerability of the medication when added to existing seizure medicines over a period of one year, as an adjunctive treatment, meaning it is taken in addition to the person's current anti‑seizure drugs.

Participants will begin with a short period of dose adjustment using the matching placebo capsules, after which they will receive the active drug daily for twelve months. Throughout the year, they will attend regular clinic visits where blood tests, blood pressure checks, a heart test called a electrocardiogram (ECG), and a questionnaire known as the Columbia‑Suicide Severity Rating Scale (C‑SSRS) will be completed to monitor health and any side effects.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline Screening and Enrollment

    After joining the study, you will complete a baseline assessment that includes a review of your medical history, laboratory tests, measurement of vital signs, a 12‑lead electrocardiogram (ECG), and the Columbia‑Suicide Severity Rating Scale (C‑SSRS) questionnaire.

    These assessments establish your starting condition before any study medication is taken.

  2. Step 2

    Start of Dose Titration/Bridging Period

    You will begin taking placebo capsules that match the appearance of the study drug capsules.

    The specific dose, frequency, and length of this titration period are not provided in the available information.

  3. Step 3

    Transition to Active Treatment (SPN‑817)

    After the titration/bridging period, you will start receiving SPN‑817 as an additional therapy for focal onset seizures.

    Details about the exact dosage, how often the medication is taken, and the duration of each dose are not specified in the source data.

  4. Step 4

    Ongoing Safety Monitoring

    Throughout the one‑year study, you will attend scheduled visits where the same laboratory tests, vital signs measurements, ECG, and C‑SSRS assessments performed at baseline will be repeated.

    Any treatment‑emergent adverse events (TEAEs) you experience will be recorded and evaluated at each visit.

  5. Step 5

    End‑of‑Study Assessment

    Approximately one year after starting the study medication, a final visit will be conducted to evaluate overall safety and tolerability of SPN‑817.

    The final assessment will include the same laboratory, vital sign, ECG, and C‑SSRS measurements used during the study.

Who can join the trial?

5 criteria

  • You have focal onset seizures – seizures that begin in one specific area of the brain.
  • You have finished the earlier SPN-817 double‑blind study, which was a trial where neither you nor the doctors knew which treatment was being given.
  • You are currently taking at least one antiseizure medication (ASM) and no more than four, and the dose has stayed the same (a stable dosage regimen) since the previous study.
  • You are an adult (generally 18 years of age or older).
  • You can be either male or female.

Who cannot join the trial?

2 criteria

  • Having episodes that seem like seizures but are not caused by epilepsy (these are called nonepileptic events) and could be mistaken by you or the study staff as real seizures.
  • Having any thoughts of harming yourself or a plan to do so, or having tried to harm yourself in the past, as measured by a standard questionnaire called the C-SSRS (Columbia‑Suicide Severity Rating Scale).
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Investigated drugs

Huperzine A is a plant‑derived compound that is being tested as an additional (adjunct) medicine for adults who have focal onset seizures. In this study participants take the medication by mouth in capsule form. The goal is to see if adding Huperzine A to their usual seizure medicines is safe over a year and whether it helps reduce seizure frequency or severity. The researchers will monitor participants for any side effects and track how well the seizures are controlled while they are using Huperzine A.

What is already known about the treatment

  • Huperzine A

    This medication is supplied as oral capsules that are swallowed with water. It is currently an experimental product that is not approved as a prescription drug, but it is widely discussed in research as a dietary supplement for memory problems. The main use being studied is to help adults with focal onset seizures as an additional therapy, and it has also been examined for memory loss in conditions like Alzheimer’s disease. Huperzine A works by blocking the enzyme that breaks down acetylcholine, so more of this brain chemical stays available, and it is classified as a natural acetylcholinesterase inhibitor.

  • Placebo

    The placebo is provided in capsule form that looks the same as the active drug but contains no active ingredient. It is used only as a control to compare the effects of the real medication in the trial and has no therapeutic purpose. Because it contains no drug, it is not classified as a medication and has no status in medical literature beyond its role in research studies.

Investigated diseases

Focal Onset Seizures - Focal onset seizures start in a specific area of the brain and cause symptoms that reflect the function of that region, such as tingling, visual changes, or unusual feelings. The electrical disturbance may remain confined to the original area, producing brief episodes that stop on their own. In some cases the activity spreads to adjacent regions, leading to larger seizures that can affect consciousness or cause more noticeable movements. The frequency and intensity of the episodes can vary over time, sometimes increasing in number or duration. Patients may notice a pattern of triggers or warning signs before a seizure occurs.
Trial detailsLast updated 22 Oct 2026
Age18+ yearsPhasePhase IITrial ID2026-526361-15-00Protocol code817P210Estimated enrolment63 patientsSponsorSupernus Pharmaceuticals Inc.

sourced from the EU Clinical Trials Register and site verification

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