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Title: Study of LP352 (bexicaserin) oral solution versus placebo for treating seizures in children and adults with Developmental and Epileptic Encephalopathies

Fast replyInvestigationalNo placebo
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What is this trial about?

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

This study focuses on Developmental and Epileptic Encephalopathies (DEE), a group of severe conditions that cause frequent seizures and affect brain development. The research evaluates a new medication called LP352 (bexicaserin), which is given as an oral solution. The study aims to determine if this medication can effectively reduce seizures in children and adults with this condition.

The study uses LP352 or placebo in the form of an oral solution, which can be given through the mouth or through a feeding tube. Participants will take the medication or placebo for approximately 17 weeks. The maximum daily dose of the medication is 36 milligrams, and participants will continue taking their regular anti-seizure medications during the study.

The research focuses on people who experience various types of seizures, including tonic seizures (stiffening of muscles), atonic seizures (sudden loss of muscle strength), focal seizures (seizures that start in one part of the brain), and tonic-clonic seizures (convulsions with both stiffening and jerking). The study particularly includes people with Lennox-Gastaut Syndrome, a severe form of epilepsy that begins in childhood.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial phase

    You will be monitored for your current countable motor seizures to establish a baseline measurement.

    You must maintain your current dose of 1-4 antiseizure medications (ASMs) that you have been taking for at least 4 weeks.

  2. Step 2

    Treatment assignment

    You will be randomly assigned to receive either Bexicaserin or a placebo solution.

    The medication will be administered as an oral solution, which can be taken by mouth, through a nasogastric tube, or through a feeding tube.

  3. Step 3

    Maintenance period

    Your seizure frequency will be monitored and compared to your baseline measurements.

    You or your caregiver will need to maintain a diary to record seizure activity throughout the study period.

    The study will measure changes in the frequency of your countable motor seizures, which include:

    - Generalized tonic-clonic seizures

    - Bilateral tonic seizures

    - Bilateral clonic seizures

    - Bilateral atonic seizures affecting trunk or legs

    - Focal motor seizures

    - Focal to bilateral tonic-clonic seizures

  4. Step 4

    Monitoring period

    The study will track if you achieve a 50% or greater reduction in seizure frequency compared to your baseline period.

    Regular assessments will continue throughout the treatment period to monitor your response to the medication.

Who can join the trial?

12 criteria

  • Must have Lennox-Gastaut Syndrome (LGS) with:
    • Seizures starting before age 8
    • History of tonic seizures (sudden muscle stiffening) and at least one other type of seizure
    • Signs of slowing or loss of developmental skills
    • OR must have other Developmental and Epileptic Encephalopathy (DEE) with:
      • Seizures starting before age 5
      • Multiple types of seizures
      • Signs of slowing or loss of developmental skills
      • Must have at least one type of countable seizure that involves physical movement
      • Must experience at least 4 countable seizures per month in the last 3 months
      • Must be taking 1-4 anti-seizure medications with stable doses for at least 4 weeks
      • Must be able to maintain a seizure diary throughout the study (can be done by caregiver)
      • Must provide informed consent (if unable, legal representative can provide consent and participant must agree to participate)
      • Both males and females can participate

Who cannot join the trial?

14 criteria

  • Age below 2 years or above 65 years
  • History of status epilepticus (a prolonged seizure lasting more than 5 minutes or multiple seizures without regaining consciousness) within the past 3 months
  • Currently taking more than 4 anti-seizure medications (drugs used to control epilepsy)
  • Presence of severe liver or kidney disease
  • Pregnancy or breastfeeding
  • Participation in another clinical trial within the past 30 days
  • History of substance abuse within the past year
  • Unstable medical condition that could interfere with study participation
  • Known allergy or sensitivity to the study medication or its components
  • Unable to comply with study procedures or follow-up visits
  • Major surgery planned during the study period
  • Significant heart problems or abnormal heart rhythm
  • History of severe psychiatric disorders
  • Use of prohibited medications that might interact with the study drug
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Investigated drugs

Based on the provided data, there is only one active medication in this trial: LP352 is an investigational medication being studied for treating seizures in people with developmental and epileptic encephalopathies. This medication is being tested to see if it can help reduce the frequency of motor seizures in both children and adults who have these conditions. It is still in the research phase (Phase 3) and its effectiveness and safety are being evaluated.

What is already known about the treatment

LP352 - A novel investigational medication being studied in Phase 3 clinical trials for the treatment of seizures in patients with Developmental and Epileptic Encephalopathies (DEE). The drug is being evaluated in a randomized, double-blind, placebo-controlled study to assess its efficacy in reducing countable motor seizures in both children and adults. While the specific mechanism of action and administration route are not detailed in the source data, this experimental therapeutic agent represents a potential new treatment option for patients with DEE, a severe group of epilepsy disorders that typically begin in early childhood and are often resistant to conventional antiepileptic medications.

Investigated diseases

Developmental and Epileptic Encephalopathy (DEE) - A group of severe brain disorders that begin in early childhood and are characterized by frequent seizures and abnormal brain development. The condition affects the child's cognitive and developmental progress, often causing delays in reaching developmental milestones. Seizures in DEE typically occur frequently and can take various forms, with motor seizures being a common manifestation. The electrical activity in the brain is severely disrupted, leading to ongoing epileptic activity that interferes with normal brain function. The condition can be caused by various genetic mutations or structural changes in the brain.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-516412-17-00Protocol codeLP352-301Estimated enrolment283 patientsSponsorLongboard Pharmaceuticals Inc.

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

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