A Phase 3 interventional study of LP352 in Developmental and Epileptic Encephalopathy, sponsored by Longboard Pharmaceuticals. Enrolling by invitation at 88 sites in 17 countries. Open to participants aged 2 Years to 66 Years. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by Longboard Pharmaceuticals (part of H. Lundbeck A/S) · Phase 3, Interventional, and Treatment
This (DEEp OLE Study) is a multicentre, open-label study to investigate the long-term safety, efficacy, tolerability, and pharmacokinetics (PK) of LP352 in the treatment of seizures in children and adults with DEE who completed Study LP352-301 or LP352-302. The study consists of 3 main phases: Screening, Titration period and Maintenance period, followed by a Taper period and Follow-Up. The total duration of the study will be approximately 14 months.
766 studies on the registry are indexed under Seizures; 136 are open to participants now.
This study's planned enrollment of 324 is above the median of 64 across 519 interventional studies indexed under Seizures.
Browse Seizures studies →Longboard Pharmaceuticals is the lead sponsor of 6 studies on the registry; 2 are open to participants now.
First submitted after Longboard Pharmaceuticals became part of H. Lundbeck A/S.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will be titrated up to highest tolerated dose of LP352 during the Titration period (Visit 1 - Visit 3), followed by maintenance period (Visit 4 - Visit 14) and then taper/down titration period (Visit 15 - Visit 17).
Drug: LP352
LP352 will be administered orally or through G-tube/ percutaneous endoscopic gastrostomy (PEG) tube.
Also known as: Bexicaserin
Number of participants reporting Treatment emergent adverse events (TEAEs) and serious adverse events (SAEs) and AEs leading to discontinuation
An AE is defined as any untoward medical occurrence in a participant enrolled into this study, regardless of its causal relationship to the study drug. A treatment-emergent AE is defined as any event that is not present before exposure to study drug or any event or condition that is already present that worsens in either intensity or frequency after exposure to study drug. An SAE is defined as any event that: Results in death; Is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization. "Inpatient hospitalization" includes admission to an emergency room for observation and/or treatment that would have been insufficient in an outpatient setting; results in persistent or significant disability/incapacity; Is a congenital anomaly/birth defect or is an important medical event. An adverse event of special interest (AESI) is an AE or SAE is defined as an AE or SAE of scientific or medical concern specific to the sponsor's product or program.
Time frame: Up to 61 Weeks
Number of Participants With Clinically Significant Changes in Chemistry parameters
Time frame: Up to 61 Weeks
Number of Participants With Clinically Significant Changes in Hematology parameters
Time frame: Up to 61 Weeks
Number of Participants With Clinically Significant Changes in Urinalysis
Time frame: Up to 61 Weeks
Number of participants with clinically significant changes in vital signs
Time frame: Up to 61 Weeks
Number of participants with clinically significant changes in physical examinations
Time frame: Up to 61 Weeks
Number of participants with clinically significant changes in growth parameters
Time frame: Up to 61 Weeks
Number of participants with clinically significant changes in electrocardiogram (ECG) parameters
Time frame: Up to 61 Weeks
Number of participants with postive responses to Columbia-Suicide Severity Rating Scale (C-SSRS)
C-SSRS was developed by researchers at Columbia University as a tool to help systematically assess suicidal ideation and behavior. It is composed of questions addressing suicidal ideation and suicidal behavior, as well as self-injurious behavior without suicidal intent. The tool will be administered by a trained operator/interviewer (investigator or designee) via interview with the participant at the study time points. If the participant is unable to complete the C-SSRS due to developmental status, the participant's legally acceptable representative may not complete the C SSRS. In these cases, the investigator may use clinical judgment to assess both the participant's status regarding suicidality and ability to complete the scale, both of which must then be documented in the source document.
Time frame: Up to 61 Weeks
Number of participants with positive responses to Patient Health Questionnaire-9 (PHQ-9) and Question 9
The PHQ-9 is a multipurpose instrument for Screening, diagnosing, monitoring, and measuring the severity of depression. The scale is an easy-to-use participant questionnaire that is a self-administered version of the Primary Care Evaluation of Mental Disorders diagnostic instrument for common mental disorders. The PHQ-9 is the depression module, which scores each of the 9 Diagnostic and Statistical Manual of Mental Disorders IV, Text Revision criteria as "0" (not at all) to "3" (nearly every day). It has been validated for use in primary care. Participants with a depression score of greater than 9 (mild) on the PHQ-9 scale or a positive response to Question 9 should be excluded from the study. When there is a positive response to PHQ-9 Question 9 post randomization, the investigator should determine whether an AE has occurred.
Time frame: Up to 61 Weeks
Frequency Percent Change in Countable Motor Seizures During Treatment Compared to Baseline
The percent change from Baseline in countable motor seizure frequency during Treatment will be calculated as (countable motor seizure frequency during Treatment) - (countable motor seizure frequency during Baseline \[Visit 1 of LP352-301 and LP352-302\]) ÷ seizure frequency during Baseline \[Visit 1 of LP352-301 and LP352-302\]) × 100
Time frame: Baseline and up to 55 weeks
Percentage of participants with ≥ 50% Reduction in countable motor seizures during Treatment compared to Baseline [Visit 1 of LP352-301 and LP352-302]
Time frame: Baseline and up to 55 weeks
Frequency Percent Change in Countable Motor Seizures during Maintenance compared to Baseline [Visit 1 of LP352-301 and LP352-302]
Time frame: Baseline and up to 55 weeks
Plan to share: Undecided
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Bexicaserin