New hope for Hard-to-Treat seizures: phase 3 trial launches

NCT ID NCT06719141

Disease control Sponsor: Longboard Pharmaceuticals Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Sep 16, 2026 · Updated 5 times

Summary

This study tests an experimental drug called LP352 to see if it can safely reduce seizures in children and adults with developmental and epileptic encephalopathies (DEE), a group of severe epilepsy syndromes. About 320 participants will receive either LP352 or a placebo, and researchers will track changes in seizure frequency over several months. The goal is to find a better treatment option for people whose seizures are not controlled by current medications.

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Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

367 people

The number who actually took part.

Started

Nov 2024

Expected to finish

Nov 2026

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

2 to 65 years

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Participants who are characterized as having Lennox-Gastaut Syndrome (LGS) must fulfill all of the following criteria: * Onset of seizures at ≤8 years old * History of tonic/tonic-atonic seizures plus at least 1 of the following seizure type(s): atypical absence, atonic, myoclonic, focal impaired awareness, generalized tonic-clonic, nonconvulsive status epilepticus, or epileptic spasms * Presence of developmental plateauing or regression * History of electroencephalogram (EEG) showing generalized slow (\<2.5 Hertz \[Hz\]) spike-and-wave complexes * Participants who are characterized as having DEE (Other) must fulfill all of the following criteria: * Does not meet criteria for LGS * Onset of seizures at ≤5 years old * Presence of developmental plateauing or regression * History of multiple seizure types * History of interictal EEG background showing diffuse or multifocal slowing (with or without epileptiform activity) * The participant has a current occurrence of at least 1 of the following countable motor seizure types: generalized tonic-clonic, tonic (bilateral), clonic (bilateral), atonic (bilateral) with truncal/leg involvement, focal motor (including hemiclonic), and focal to bilateral tonic-clonic. * The participant has demonstrated an average of at least 4 countable motor seizures per month for each of the 3 months prior to Screening. * The participant has been taking 1 to 4 antiseizure medications (ASMs) at a stable dose for at least 4 weeks prior to Screening. * The participant, parent, or caregiver is willing and able (in the judgment of the investigator) to comply with completion of the diaries throughout the study. * The participant must be willing and able to provide written informed consent; in instances where the participant is unable to provide consent, an appropriate legal representative. Exclusion Criteria: * The participant has a diagnosis of Dravet Syndrome (DS) or has a mutation of the Sodium channel protein type 1 subunit alpha (SCN1A) gene consistent with DS. * The participant has been admitted to a medical facility for treatment of status epilepticus requiring mechanical ventilation within 3 months prior to Screening. * The participant has a neurodegenerative disorder as indicated by magnetic resonance imaging or genetic testing. * The participant has an acquired lesion/injury unrelated to the primary etiology that could contribute as a secondary cause of seizures. * The participant is receiving exclusionary medications. * The participant is currently using any cannabis product or cannabidiol that is not in oral solution/capsule/tablet form, not obtained from a government-approved dispensary, or contains ≥50% Delta-9-tetrahydrocannabinol (THC). * The participant has unstable, clinically significant neurologic (other than the disease being studied; eg, recurrent strokes), psychiatric, cardiovascular (eg, pulmonary arterial hypertension, cardiac valvulopathy, orthostatic hypotension/tachycardia), pulmonary, hepatic, renal, metabolic, gastrointestinal, urologic, immunologic, hematopoietic, or endocrine disease or other abnormality which may impact the ability of the participant to participate or potentially confound the study results. * The participant is unable or unwilling to comply with any of the study requirements or timelines.

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Conditions

The condition(s) this trial relates to.

developmental and epileptic encephalopathy epilepsy Lennox-Gastaut syndrome neurodevelopmental disorder visual epilepsy

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Developmental and epileptic encephalopathy

Contacts and locations

Locations

AP-HM- Hôpital de La Timone

Marseille, 13005, France
AP-HP - Hôpital universitaire Necker-Enfants malades

Paris, 75015, France
AP-HP - Hôpital universitaire Robert-Debré

Paris, 75019, France
Arkansas Children's Hospital - Cardiology Clinic

Little Rock, Arkansas, 72202-3500, United States
Austin Hospital

Heidelberg, Victoria, 3084, Australia
Azienda Ospedaliera Universitaria Integrata Verona - Centro Fibrosi Cistica di Verona (CFC Verona)

Verona, 37126, Italy
Azienda Ospedaliero-Universitaria Meyer - Ospedale dei Bambini

Florence, Tuscany, 50139, Italy
BC Children's Hospital (British Columbia Children's Hospital)

Vancouver, British Columbia, V6H 3V4, Canada
Barnabas Health - Institute of Neurology and Neurosurgery

Livingston, New Jersey, 07039-5817, United States
Bernu Kliniska Universitates Slimnica (BKUS) (University Children's Hospital)

Riga, LV-1004, Latvia
Capital Medical University-Beijing Children's Hospital

Beijing, Beijing Municipality, 100045, China
Cardiff and Vale University Health Board - University Hospital of Wales (UHW) - Noah's Ark Childr...

Cardiff, East Wales, CF14 4XW, United Kingdom
Centre Hospitalier Universitaire (CHU) de Toulouse - Hopital de Psychiatrie

Toulouse, Occitanie, 31059, France
Centre Hospitalier Universitaire de Lyon - Hôpital Pierre Wertheimer

Bron, 69500, France
Centro Hospitalar Universitario de Santo Antonio - Centro Materno Infantil do Norte (CMIN)

Porto, 4050, Portugal
Child Neurology Consultants of Austin - Austin

Austin, Texas, 78731-3157, United States
Children's Healthcare of Atlanta (CHOA)

Atlanta, Georgia, 30329-2311, United States
Children's Hospital Colorado - Heart Institute

Aurora, Colorado, 80045-7106, United States
Children's Hospital Los Angeles (CHLA)

Los Angeles, California, 90027-6062, United States
Children's National Hospital - Children's National Heart Center

Washington D.C., District of Columbia, 20010-2916, United States
Chu de Rennes - Centre d'Evaluation et de Traitement de la Douleur de l'Adulte et de l'Enfant

Villejuif, Île-de-France Region, 94800, France
Clinical Center Kragujevac

Kragujevac, Sumadijski Okrug, 34000, Serbia
Consultants in Epilepsy & Neurology, PLLC

Boise, Idaho, 83702-5029, United States
Cook Children's Jane and John Justin Neurosciences Center

Fort Worth, Texas, 76104-2710, United States
Dokkyo Medical University Hospital

Mibu-Machi, Tochigi, 321-0293, Japan
Epilepsie-Zentrum Bodensee

Ravensburg, 88214, Germany
Epilepsiezentrum Kleinwachau gemeinnützige GmbH

Radeberg, Saxony, 01454, Germany
Faculdade de Medicina de Sao Jose do Rio Preto-SP (FAMERP)

São José do Rio Preto, São Paulo, 15090-000, Brazil
Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta

Milan, 20133, Italy
Fondazione Mondino, IRCCS Istituto Neurologico Nazionale a Carattere Scientifico

Pavia, 27100, Italy
Fudan University - Children's Hospital

Shanghai Shi, Shanghai Municipality, 201102, China
Fukuoka Children's Hospital (FCH)

Fukuoka, Fukuoka, 813-0017, Japan
Gesellschaft fuer Epilepsieforschung e.V.

Bielefeld, North Rhine-Westphalia, 33617, Germany
Great Ormond Street Hospital for Children NHS Foundation Trust

London, WC1N 3JH, United Kingdom
Guangzhou Medical University-The Second Affiliated Hospital

Guangzhou, Guangdong, 510260, China
Hokkaido University Hospital

Sapporo, Hokkaido, 060-8648, Japan
Hospital Infantil Universitario Nino Jesus (HIUNJS)

Madrid, 28009, Spain
Hospital Pediátrico de Coimbra

Coimbra, 3000-602, Portugal
Hospital Regional Universitario de Malaga - Hospital General

Málaga, 29010, Spain
Hospital Ruber Internacional

Madrid, 28034, Spain
Hospital Sant Joan de Deu Barcelona (HSJDB)

Esplugues de Llobregat, Barcelona, 08950, Spain
Hospital Universitari Vall d'Hebron

Barcelona, 08035, Spain
Hospital Universitari i Politecnic La Fe de Valencia (Hospital La Fe Bulevar Sur)

Valencia, 46026, Spain
Hospital Universitario Vithas Madrid La Milagrosa

Madrid, 28010, Spain
Hospital Universitario de Navarra

Pamplona, Navarre, 31008, Spain
Hospital Vithas Malaga

Málaga, 29016, Spain
Hospital de la Santa Creu I Sant Pau

Barcelona, 8041, Spain
Hôpital Roger Salengro

Lille, Nord, 59000, France
Hôpital de Hautepierre - Les Hôpitaux Universitaires de Strasbourg

Strasbourg, 67098, France
Institut za Zdravstvenu Zastitu Majke i Deteta Srbije Dr Vukan Cupic

Belgrade, Beograd, 11070, Serbia
Instituto Nacional de Pediatria (INP) (National Institute of Pediatrics)

Mexico City, Mexico City, 04530, Mexico
Instituto de Neurologia de Curitiba (INC)

Curitiba, Paraná, 81210-310, Brazil
International University of Health and Welfare - Narita Hospital

Narita-shi, Chiba, 286-8520, Japan
Istituto Giannina Gaslini (Ospedale Pediatrico IRCCS) - Centro Malattie Rare

Genoa, 16147, Italy
Le Bonheur Children's Hospital - Outpatient Center

Memphis, Tennessee, 38105-4625, United States
London Health Sciences Centre (LHSC)

London, Ontario, N6A 5W9, Canada
Massachusetts General Hospital (MGH)

Boston, Massachusetts, 02114, United States
Mayo Clinic - Children's Center - Rochester

Rochester, Minnesota, 55905-0001, United States
Mid-Atlantic Epilepsy and Sleep Center - Bethesda

Bethesda, Maryland, 20817-1844, United States
Moinhos de Vento Hospital (Hospital Moinhos de Vento) (HMV)

Porto Alegre, Rio Grande do Sul, 90035-001, Brazil
MultiCare Health System

Tacoma, Washington, 98415-0299, United States
NHS Greater Glasgow and Clyde-Glasgow Clinical Research Facility - Queen Elizabeth University Hos...

Glasgow, South Western Scotland, G51 4TF, United Kingdom
NW FL Clinical Research Group, LLC

Gulf Breeze, Florida, 32561-4495, United States
NYU Langone Health-NYU Comprehensive Epilepsy Center

New York, New York, 10016-4852, United States
National Center of Neurology and Psychiatry-National Center Hospital

Kodaira-shi, Tokyo-To, 187-8551, Japan
National Hospital Organization Nishi-Niigata Chuo National Hospital

Niigata, 950-2074, Japan
National Hospital Organization Shizuoka Institute of Epilepsy and Neurological Disorders

Shizuoka, 420-0953, Japan
Nicklaus Children's Hospital (Miami Children's Hospital)

Miami, Florida, 33155-3009, United States
Northeast Regional Epilepsy Group - Morristown

Morristown, New Jersey, 07960-6092, United States
Northwestern Memorial Hospital

Chicago, Illinois, 60611-2908, United States
Northwestern University - Ann & Robert H. Lurie Children's Hospital of Chicago - Center for Cance...

Chicago, Illinois, 60611-2991, United States
Okayama University Hospital

Okayama, Okayama-ken, 700-8558, Japan
Oregon Health & Science University - Blood Brain Barrier and Neuro-Oncology Program

Portland, Oregon, 97239-3098, United States
Osaka City General Hospital

Osaka, Osaka, 534-0021, Japan
Ospedale Pediatrico Bambino Gesu - Gianicolo

Rome, 00165, Italy
Pediatric Epilepsy & Neurology Specialists (PENS)

Tampa, Florida, 33609-4191, United States
Peking University First Hospital (Beida Hospital)

Beijing, Beijing Municipality, 100034, China
Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS) - Instituto Do Cerebro Do Rio Grand...

Porto Alegre, Rio Grande do Sul, 90610-970, Brazil
Prince of Wales Hospital (POWH)

Randwick, New South Wales, 2031, Australia
Queensland Children's Hospital (Lady Cilento Children's Hospital)

Brisbane, Queensland, 4101, Australia
Rare Disease Research, LLC. (RDR)

Atlanta, Georgia, 30329, United States
Research Institute of Orlando LLC

Orlando, Florida, 32806, United States
Royal Brisbane and Women's Hospital (RBWH)

Brisbane, Queensland, 4006, Australia
Saitama Prefectural Children's Medical Center

Saitama-shi, Saitama, 330-8777, Japan
Shenzhen Children's Hospital

Shenzhen Shi, Guangdong, 518026, China
Stanford University - Stanford School of Medicine - Pulmonary and Cystic Fibrosis Center

Palo Alto, California, 94304-1511, United States
Sydney Children's Hospital - Randwick

Randwick, New South Wales, 2031, Australia
The Alfred Hospital

Melbourne, Victoria, 3004, Australia
The Children's Hospital-Westmead - Heart Centre for Children

Westmead, New South Wales, 2145, Australia
The Hospital for Sick Children (SickKids)

Toronto, Ontario, M5G 1X8, Canada
The Newcastle upon Tyne Hospitals NHS Foundation Trust - Royal Victoria Infirmary (RVI)

Newcastle upon Tyne, North East, NE1 4LP, United Kingdom
The Royal Children's Hospital (RCH) Melbourne

Parkville, Victoria, 3052, Australia
The University of Texas Medical School at Houston - UT Gastroenterology

Houston, Texas, 77030-1517, United States
UCSF Benioff Children's Hospitals - San Francisco

San Francisco, California, 94158, United States
Unidade Local de Saude Santa Maria, E.P.E (ULSSM)

Lisbon, 1649-035, Portugal
Universidade Estadual de Campinas (UNICAMP) - Hospital das Clinicas (HC)

Campinas, São Paulo, 13083-888, Brazil
Universidade de Sao Paulo (USP) - Hospital das Clinicas da Faculdade de Medicina (HCFMUSP) - Inst...

São Paulo, 05403-903, Brazil
Universidade de Sao Paulo (USP)-Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto ...

Ribeirão Preto, São Paulo, 14051-260, Brazil
Universita Cattolica del Sacro Cuore - Fondazione Policlinico Universitario A Gemelli - Centro pe...

Rome, 00168, Italy
Universitaetsklinikum Schleswig-Holstein (UKSH) - Campus Kiel - Klinik fuer Psychosomatik und Psy...

Kiel, Schleswig-Holstein, 24105, Germany
Universitair Medisch Centrum Utrecht - Polikliniek Oogheelkunde

Utrecht, 3584 CX, Netherlands
Universitair Ziekenhuis Antwerpen (UZA)

Edegem, Antwerp, 2650, Belgium
Universitaire Ziekenhuizen Leuven - Campus Gasthuisberg

Leuven, Flemish Brabant, 3000, Belgium
University College London Hospitals NHS Foundation Trust (UCLH)

London, NW1 2PG, United Kingdom
University Health Network-Toronto Western Hospital - Krembil Neuroscience Centre (KNC)

Toronto, Ontario, M5T 2S8, Canada
University Hospital Southampton NHS Foundation Trust-Southampton General Hospital (SGH)

Southampton, South East, SO16 6YD, United Kingdom
University Hospitals Birmingham (UHB) NHS Foundation Trust - Queen Elizabeth Hospital Birmingham

Birmingham, West Midlands, B15 2WB, United Kingdom
University of Belgrade-Faculty of Medicine - Clinic of Neurology and Psychiatry for Children and ...

Belgrade, Beograd, 112112, Serbia
University of California Los Angeles (UCLA) - David Geffen School of Medicine - Global Health Pro...

Los Angeles, California, 90095, United States
University of Iowa Health Care Medical Center (University of Iowa Hospitals & Clinics)

Iowa City, Iowa, 52242-1009, United States
University of Miami Medical Group (UMMG)

Miami, Florida, 33136-2117, United States
University of South Florida (USF) - Tampa Campus

Tampa, Florida, 33620, United States
Universitätsklinikum Bonn

Bonn, North Rhine-Westphalia, 53127, Germany
Universitätsklinikum Frankfurt - Klinikum der Goethe-Universität

Frankfurt am Main, Hesse, 60596, Germany
Univerzitetski Klinicki Centar Srbije - Klinika za Neurologiju

Belgrade, Beograd, 11000, Serbia
Wuhan Children's Hospital

Wuhan, Hubei, 430016, China

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