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Study on Carisbamate for Treating Seizures in Children and Adults with Lennox-Gastaut Syndrome

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What is this trial about?

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

This clinical trial is focused on studying Lennox-Gastaut syndrome (LGS), a type of epilepsy that causes multiple types of seizures and developmental delays in children and adults. The study is testing a treatment called Carisbamate, also known by its code name YKP509, which is taken as an oral suspension. The purpose of the study is to evaluate how effective and safe Carisbamate is when used alongside other treatments to reduce the number of specific seizures, such as tonic, atonic, and tonic-clonic seizures, in people with LGS.

Participants in the study will be randomly assigned to receive either Carisbamate or a placebo, which looks like the treatment but does not contain the active medicine. The study will be conducted in a double-blind manner, meaning neither the participants nor the researchers will know who is receiving the actual treatment or the placebo. This helps ensure that the results are unbiased. The study will include both children and adults aged 4 to 55 years who have been diagnosed with LGS. Participants will continue their current anti-seizure medications while taking part in the study.

The trial will last for a period of time during which participants will be monitored for changes in the frequency of their seizures. There is also an optional open-label extension, where all participants can receive Carisbamate after the initial study period. The main goal is to see if Carisbamate can significantly reduce the number of drop seizures, which are seizures that can lead to falls or injuries. Participants and their caregivers will be asked to keep a diary of seizures to help track any changes during the study.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, the participant will be randomly assigned to receive either the medication carisbamate or a placebo. The placebo is a substance with no active medication, used for comparison.

    The study is designed to be double-blind, meaning neither the participant nor the researchers will know who is receiving the actual medication or the placebo during the trial.

  2. Step 2

    Baseline period

    Before starting the treatment, there is a 4-week baseline period. During this time, the participant's current seizure frequency will be recorded. This helps to establish a baseline for comparison during the treatment phase.

  3. Step 3

    Treatment phase

    The treatment phase involves taking the assigned oral suspension, either carisbamate or placebo, as an adjunctive treatment. This means it is taken in addition to the participant's current anti-seizure medications.

    The dosage and frequency of the medication will be determined by the study protocol and monitored by the study team. The participant will continue this treatment for the duration specified in the study.

  4. Step 4

    Monitoring and assessments

    Throughout the study, the participant's seizure frequency and any side effects will be closely monitored. This includes regular visits to the study site for assessments.

    The primary goal is to evaluate the change in the number of drop seizures, which are seizures that can lead to falls or injuries.

  5. Step 5

    End of double-blind period

    At the end of the double-blind treatment period, the participant's response to the treatment will be evaluated. This includes assessing the percentage change in seizure frequency compared to the baseline period.

  6. Step 6

    Optional open-label extension

    Participants may have the option to enter an open-label extension phase. In this phase, all participants receive the actual medication, carisbamate, and continue to be monitored for safety and efficacy.

Who can join the trial?

15 criteria

  • The patient must have a documented history of **Lennox-Gastaut syndrome (LGS)**, which includes having more than one type of seizure, with at least one being an atonic or tonic seizure.
  • The patient must have a history of an **electroencephalogram (EEG)**, a test that measures brain activity, showing specific patterns for LGS.
  • The patient must have a history of **developmental delay**, which means slower development in skills compared to others of the same age.
  • The patient can be male or female.
  • The patient must be between 4 and 55 years old at the time of giving consent to participate.
  • The patient must have been younger than 11 years old when LGS started.
  • The patient must have had at least 8 **drop seizures** during a 4-week period before starting the study. Drop seizures are seizures that can cause a fall or injury.
  • The patient must be taking 1 to 4 **anti-seizure medications (ASMs)** at a stable dose for at least 4 weeks before the study starts.
  • If the patient is not taking a specific medication called Epidiolex, they may take other approved cannabidiol products, which are substances derived from cannabis.
  • Any special diets or devices used to help with seizures must be stable for 4 weeks before the study and remain stable during the study.
  • Parents or caregivers must be able to keep accurate records of the patient's seizures.
  • If the patient can have children, they must use an acceptable method of birth control during the study and for a short time after.
  • The patient and/or their caregiver must be willing and able to give informed consent to participate in the study.
  • The patient and their caregiver must be willing and able to follow all study requirements, according to the investigator's opinion.
  • The patient can have a history of COVID-19 vaccination.

Who cannot join the trial?

7 criteria

  • Patients who do not have a diagnosis of Lennox-Gastaut syndrome (LGS) cannot participate. LGS is a type of epilepsy that causes different kinds of seizures.
  • Patients who are younger than 4 years old or older than 55 years old cannot participate.
  • Patients who are not experiencing drop seizures cannot participate. Drop seizures are a type of seizure where a person suddenly loses muscle strength and may fall.
  • Patients who are not able to take the study medication or have allergies to it cannot participate.
  • Patients who are pregnant or breastfeeding cannot participate.
  • Patients who have other serious health conditions that might interfere with the study cannot participate.
  • Patients who are currently participating in another clinical trial cannot participate.
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Investigated drugs

Carisbamate (YKP509) is being studied as an additional treatment for seizures in people with Lennox-Gastaut Syndrome, a condition that causes severe seizures. The trial aims to see if Carisbamate can help reduce the number of drop seizures, which include tonic, atonic, and tonic-clonic seizures, in both children and adults.

What is already known about the treatment

Carisbamate – Carisbamate is administered orally and is currently being studied in clinical trials as an adjunctive treatment for seizures associated with Lennox-Gastaut syndrome (LGS) in both children and adults. It is not yet widely used in medical practice, as it is still under investigation for its efficacy and safety. The main therapeutic indication for carisbamate is to reduce the number of drop seizures, which include tonic, atonic, and tonic-clonic seizures. At the molecular level, carisbamate is believed to work by modulating neurotransmitter activity in the brain, although the exact mechanism is not fully understood. It is classified pharmacologically as an anticonvulsant.

Investigated diseases

Lennox-Gastaut Syndrome – Lennox-Gastaut Syndrome (LGS) is a severe form of epilepsy that typically begins in childhood. It is characterized by multiple types of seizures, including tonic, atonic, and tonic-clonic seizures, which can lead to sudden falls. The syndrome often results in developmental delays and cognitive impairment. Seizures in LGS are usually difficult to control and may occur frequently. The condition is associated with a slow spike-and-wave pattern on an electroencephalogram (EEG). LGS can be caused by various factors, including brain malformations, genetic disorders, or brain injuries.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-506616-41-00Protocol codeYKP509C003Estimated enrolment242 patientsSponsorSk Life Science Inc.

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