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Investigating LP352 for treating seizures in children and adults with developmental and epileptic encephalopathies

A Phase 3, Randomized, Double-Blind, Placebo-Controlled, Multicenter Study to Investigate the Efficacy, Safety, and Tolerability of LP352 in the Treatment of Seizures in Children and Adults With Developmental and Epileptic Encephalopathies

PHASE3 · Longboard Pharmaceuticals · NCT06719141

This study is testing a new medication called LP352 to see if it can help reduce seizures in children and adults with developmental and epileptic encephalopathies like Lennox-Gastaut Syndrome.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment320 (estimated)
Ages2 Years to 65 Years
SexAll
SponsorLongboard Pharmaceuticals (industry)
Locations109 sites (Little Rock, Arkansas and 108 other locations)
Trial IDNCT06719141 on ClinicalTrials.gov

What this trial studies

This study, known as the DEEp OCEAN Study, is a double-blind, randomized, placebo-controlled, multicenter investigation aimed at evaluating the efficacy, safety, and tolerability of LP352 in managing seizures associated with developmental and epileptic encephalopathies (DEE). Participants will undergo a structured process that includes screening, a titration period, a maintenance phase, and a taper period, with the entire study lasting approximately 24 months. The study specifically targets individuals with Lennox-Gastaut Syndrome and other forms of DEE, focusing on their unique seizure profiles and developmental challenges.

Who should consider this trial

Good fit: Ideal candidates include children and adults diagnosed with Lennox-Gastaut Syndrome or other forms of developmental and epileptic encephalopathies who meet specific seizure onset and EEG criteria.

Not a fit: Patients who do not have developmental and epileptic encephalopathies or those whose seizures do not meet the study's inclusion criteria may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new treatment option for patients suffering from severe seizures associated with developmental and epileptic encephalopathies.

How similar studies have performed: Other studies investigating treatments for Lennox-Gastaut Syndrome and related conditions have shown promise, indicating that this approach may be beneficial.

Eligibility criteria

Show full inclusion / exclusion criteria 
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.

Where this trial is running

Little Rock, Arkansas and 108 other locations

+59 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Developmental and Epileptic Encephalopathy, Developmental and epileptic encephalopathy, LP352, Seizures, Bexicaserin, Antiseizure medications, Epilepsy, Lennox-Gastaut Syndrome

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.