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Neurological & Neuromuscular

Lennox-Gastaut Syndrome (LGS) Clinical Trials and Treatments

Also called LGS, Petit Mal Variant

Lennox-Gastaut Syndrome represents one of the most severe and intractable childhood epilepsies, often emerging from or following infantile spasms (West Syndrome). The characteristic EEG pattern shows slow (1-2.

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About Lennox-Gastaut Syndrome

Lennox-Gastaut Syndrome represents one of the most severe and intractable childhood epilepsies, often emerging from or following infantile spasms (West Syndrome). The characteristic EEG pattern shows slow (1-2.5 Hz) spike-and-wave activity, particularly evident during sleep.

The syndrome is marked by multiple seizure types, with tonic seizures (brief stiffening episodes) being particularly characteristic, often occurring in clusters, especially during sleep. Atonic seizures (drop attacks) can lead to sudden falls and injuries, necessitating protective headgear and environmental modifications. Atypical absence seizures differ from typical absence seizures in their slower onset and offset.

The intellectual disability is usually moderate to severe, with developmental progress typically slowing or reversing after syndrome onset. Behavioral comorbidities including autism spectrum features, anxiety, and sleep disturbances are common. Status epilepticus, with continuous or rapidly recurring seizures, represents a medical emergency.

Common Symptoms of Lennox-Gastaut Syndrome

Recognizing the signs of Lennox-Gastaut Syndrome early can lead to faster diagnosis and better outcomes. Symptoms may vary in severity from person to person. If you or a loved one are experiencing any of the following, consider speaking with a specialist.

  • Multiple seizure types: tonic-clonic, atonic (drop attacks), atypical absence, and focal seizures
  • Frequent clusters of seizures, sometimes hundreds per day
  • Intellectual disability and developmental regression
  • Speech and language delays
  • Behavioral disturbances including hyperactivity, aggression, and mood problems
  • Status epilepticus (prolonged or repeated seizures)

Who Lennox-Gastaut Syndrome Affects

Lennox-Gastaut Syndrome typically manifests between ages 1 and 8 years, with peak onset between 3 and 5 years. It affects males and females equally and occurs across all ethnic and racial groups. While some cases are symptomatic (caused by identified brain abnormalities), many are cryptogenic or idiopathic with no clear underlying cause. Previous history of infantile spasms increases risk.

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Charity funds and drugmaker programs for Lennox-Gastaut Syndrome, checked at the source. Pick your insurance to see what fits.

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    Pays for: Insurance premiums and copays.

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Status as each foundation showed it on September 28, 2026.

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Genetic Testing

Genetic testing can confirm a diagnosis, guide treatment decisions, and identify family members who may be at risk.

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Trusted Lennox-Gastaut Syndrome Resources

Reputable organizations and medical references for learning more about Lennox-Gastaut Syndrome, including disease registries, foundation resources, and clinical guidelines.

Active Clinical Trials for Lennox-Gastaut Syndrome

Use this Lennox-Gastaut Syndrome clinical trial finder to see the 5 studies recruiting patients and 5 opening soon in the United States and worldwide, with eligibility criteria in plain English. These studies play a critical role in advancing care for neurological & neuromuscular conditions and may offer access to treatments not yet widely available. Each trial below is sourced directly from ClinicalTrials.gov, with eligibility criteria translated into plain English to help patients and caregivers evaluate whether a study may be a fit.

TrialsSite mapPipeline timeline

Note: Trial recruitment statuses on ClinicalTrials.gov may not immediately reflect recent FDA decisions, sponsor announcements, or enrollment changes. Always confirm a trial's current status directly with the study coordinator before making plans.

10 active trials worldwide
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NOT YET RECRUITINGPHASE4Recently updatedNCT07728097

A Study to Investigate the Effect of Gradual Titration to Optimize Cannabidiol Treatment in Adults With LGS

Intervention: Cannabidiol Oral Solution

Sponsor: Jazz Pharmaceuticals · Jazz Pharmaceuticals Research UK Limited

This is a Phase 3b/Phase 4 study. The purpose of this study is to learn more about the efficacy of using CBD-OS as an add-on therapy for the treatment of LGS in adults.

Ages 18 Years+1 location
Started Nov 2026Updated 5 days agoEst. Dec 2028 (~2y 3m)
RECRUITINGPHASE3Recently updatedNCT05066217

An Efficacy and Safety Study of Clemizole HCl in Patients With Lennox-Gastaut Syndrome

Intervention: Clemizole HCl, Placebo

Sponsor: Epygenix · Harmony Biosciences Management, Inc.

This is a multicenter, Phase 3, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of clemizole HCL (EPX-100) as adjunctive therapy in children and adult participants with Lennox-Gastaut syndrome (LGS).

Ages 2 Years – 55 Years58 locations
Started Apr 2025Updated 2 weeks agoEst. Nov 2026 (~1 month)
NOT YET RECRUITINGPHASE4Recently updatedNCT06924827

A Study to Investigate the Transition of Children From 'Artisanal" Cannabidiol (CBD) to Epidiolex

Intervention: Epidiolex 100 mg/mL Oral Solution

Sponsor: Elizabeth Donner · Jazz Pharmaceuticals

The goal of this clinical trial is to learn the best way to switch children with Lennox-Gastaut Syndrome (LGS) or Dravet Syndrome (DS) taking 'artisanal' (non pharmaceutical-grade) cannabidiol (CBD) to Epidiolex for treatment of seizures. The main questions it aims to answer are:

Ages 2 Years – 18 Years1 location
Started Jan 2027Updated 2 weeks agoEst. Jan 2028 (~1y 3m)
RECRUITINGRecently updatedNCT05374824

Comparative Effectiveness of Palliative Surgery Versus Additional Anti-Seizure Medications for Lennox-Gastaut Syndrome

Sponsor: Ann & Robert H Lurie Children's Hospital of Chicago

Lennox-Gastaut syndrome is a serious and rare form of epilepsy that begins in infancy and early childhood. Seizures and their consequences need medical attention, emergency encounters, and hospitalizations. Seizures disrupt home life for the patient and for family. Lennox-Gastaut...

Ages up to 26 Years4 locations
Started Apr 2022Updated 1 month agoEst. Dec 2026 (~3 months)
NOT YET RECRUITINGNAUpdated a few months agoNCT07568860

Sleep-Driven Adaptive Neuromodulation in Lennox-Gastaut Syndrome

Intervention: Personalized Adaptive Deep Brain Stimulation Therapy, Conventional Non-Personalized Deep Brain Stimulation Therapy

Sponsor: University of Minnesota

The goal of this clinical trial is to explore a new type of personalized brain stimulation that works during day time and night time hours using the Medtronic Percept Deep Brain Stimulation (DBS) device in patients with Lennox-Gastaut Syndrome. The main question(s) this study aims to answer is:

Ages 18 Years – 65 Years
Started Oct 2026Updated 4 months agoEst. Sep 2030 (~4 years)
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Trial Pipeline

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Data from ClinicalTrials.gov, U.S. National Library of Medicine.
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Related Neurological & Neuromuscular Conditions

Other rare diseases in the neurological & neuromuscular category. Patients with Lennox-Gastaut Syndrome may find relevant research, shared treatment pathways, or overlapping clinical trials among these related conditions.

Companies Developing Lennox-Gastaut Syndrome Treatments

5 pharmaceutical companies have Lennox-Gastaut Syndrome in their rare disease portfolio

Frequently Asked Questions About Lennox-Gastaut Syndrome