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Study on Long-Term Safety of Soticlestat for Patients with Dravet or Lennox-Gastaut Syndromes

Verified siteInvestigationalNo placebo
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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 the long-term safety and tolerability of a medication called soticlestat for individuals with Dravet Syndrome and Lennox-Gastaut Syndrome. These are both rare forms of epilepsy that begin in childhood and are characterized by frequent seizures. The medication, known by its code name TAK-935, is being tested as an additional treatment to standard care, which may include anti-seizure medications, vagus nerve stimulation, or specific diets like the ketogenic or modified Atkins diet.

The purpose of the study is to assess how well patients tolerate soticlestat over a long period. Participants in the study will take the medication in tablet form by mouth. The study will last up to 52 weeks, during which time participants will be monitored for any side effects and changes in their health. The study will also look at changes in seizure frequency and other health indicators, such as growth and development in children.

This trial is an extension of previous studies, meaning it includes participants who have already been involved in earlier research phases. The study aims to provide more information on the long-term use of soticlestat, helping to determine its safety and effectiveness as a treatment option for those living with Dravet Syndrome and Lennox-Gastaut Syndrome.

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

    Joining the study

    Participation begins after enrollment in a previous phase 3 study of soticlestat and completion of at least 12 weeks of treatment.

    Eligibility requires no serious adverse effects related to the study drug that would make continued use unsafe.

  2. Step 2

    Medication administration

    Soticlestat is administered orally in tablet form.

    The medication is used as an additional treatment for Dravet Syndrome or Lennox-Gastaut Syndrome.

  3. Step 3

    Monitoring and assessments

    Regular monitoring includes checking for any side effects and conducting laboratory tests and heart evaluations.

    Changes in height, weight, and other health indicators are tracked throughout the study.

  4. Step 4

    Seizure tracking

    Participants or their caregivers maintain a daily seizure diary to record seizure frequency and intensity.

    This information helps assess the effectiveness of soticlestat in reducing seizures.

  5. Step 5

    Study duration

    The study is expected to continue until December 21, 2025.

    Participants are required to comply with all study procedures for the duration of the trial.

Who can join the trial?

5 criteria

  • The patient must have been part of a previous phase 3 study for the drug soticlestat and received at least 12 weeks of treatment with it. They should not have had any serious or severe side effects from the drug that would make it unsafe to continue.
  • The doctor believes that the patient could benefit from taking soticlestat.
  • The patient, or their parent or caregiver, must be able to understand and follow the study's requirements. This includes completing assessments, keeping a daily record of seizures, and taking the study drug as directed. If the patient lives in a care facility, the main caregivers there should also be able to follow these requirements.
  • The patient, or their parent or legal guardian, must be willing and able to read, understand, and sign a consent form before starting the study. They must also be able to follow the study's requirements, as mentioned above.
  • Female patients who can have children must have a negative pregnancy test and agree to use effective birth control during the study and for 30 days after the last dose of the study drug. Effective birth control methods include using two forms of protection, like a condom and a diaphragm, or using certain hormonal methods. Abstaining from sex can also be considered if it is a regular lifestyle choice.

Who cannot join the trial?

5 criteria

  • Patients who do not have **Dravet Syndrome** or **Lennox-Gastaut Syndrome** cannot participate. These are specific types of epilepsy.
  • Patients who are not within the specified age range cannot participate. The age range is typically defined in the study details.
  • Patients who are not able to follow the study's treatment plan, which includes additional therapies like **vagus nerve stimulation** (a treatment that uses electrical impulses to help control seizures), **ketogenic diet** (a high-fat, low-carbohydrate diet), or **modified Atkins diet** (a similar diet with more protein), cannot participate.
  • Patients who are not able to safely take the study medication, **soticlestat**, cannot participate. This medication is being tested for its safety and how well it is tolerated.
  • Patients who are part of a vulnerable population, which may include those who cannot give informed consent or have other special considerations, may not be eligible.
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Investigated drugs

  • Soticlestat

    is a medication being studied for its long-term safety and tolerability when used as an additional treatment for individuals with Dravet Syndrome or Lennox-Gastaut Syndrome. These are types of epilepsy that are difficult to control. Soticlestat is used alongside other standard treatments to help manage seizures in these conditions.

  • ASMs (Anti-Seizure Medications)

    are a group of drugs used to help control seizures in people with epilepsy. In this trial, they are used in combination with soticlestat to see how well they work together in managing seizures for those with Dravet Syndrome or Lennox-Gastaut Syndrome.

  • Vagus Nerve Stimulation

    is a therapy that involves using a device to send electrical impulses to the vagus nerve in the neck. This can help reduce the frequency and intensity of seizures in some people with epilepsy. It is used in this trial as part of the standard care alongside soticlestat.

  • Ketogenic Diet

    is a high-fat, low-carbohydrate diet that can help control seizures in some people with epilepsy. It is used in this trial as part of the standard care to see how it works with soticlestat in managing seizures.

  • Modified Atkins Diet

    is a variation of the ketogenic diet that is also high in fat and low in carbohydrates. It is used in this trial as part of the standard care to evaluate its effectiveness in combination with soticlestat for controlling seizures in individuals with Dravet Syndrome or Lennox-Gastaut Syndrome.

What is already known about the treatment

Soticlestat – Soticlestat is administered orally and is currently being studied in clinical trials as an adjunctive therapy for Dravet Syndrome and Lennox-Gastaut Syndrome. It is in the phase 3 stage of clinical trials, focusing on its long-term safety and tolerability. The medication is primarily indicated for use in individuals with these specific types of epilepsy. Soticlestat works by inhibiting an enzyme involved in the production of certain neurosteroids, which are believed to play a role in seizure activity. It is classified as an antiepileptic drug.

Investigated diseases

  • Dravet Syndrome

    Dravet Syndrome is a rare, severe form of epilepsy that begins in infancy. It is characterized by prolonged seizures that are often triggered by fever or hot temperatures. As the child grows, other types of seizures may develop, including myoclonic and absence seizures. The condition can also lead to developmental delays, speech impairment, and motor difficulties. Children with Dravet Syndrome may experience behavioral challenges and have an increased risk of sudden unexplained death in epilepsy (SUDEP). The syndrome is often resistant to many types of epilepsy medications.

  • Lennox-Gastaut Syndrome

    Lennox-Gastaut Syndrome is a complex, rare form of epilepsy that typically appears in early childhood. It is marked by multiple types of seizures, including tonic and atonic seizures, which can cause sudden falls. Children with this syndrome often have intellectual disabilities and developmental delays. The condition is known for its resistance to treatment and can significantly impact daily life. Seizures in Lennox-Gastaut Syndrome can be frequent and severe, leading to injuries. The syndrome may also cause behavioral problems and difficulties with learning and social interaction.

Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2022-502802-34-00Protocol codeTAK-935-3003Estimated enrolment377 patientsSponsorTakeda Development Center Americas Inc.

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