Developmental and Epileptic EncephalopathyPhase 2NCT05626634
Open-label, Long-term Safety Study of LP352 in Subjects With Developmental and Epileptic Encephalopathy
A Phase 2 study testing LP352, bexicaserin in people with Developmental and Epileptic Encephalopathy and Dravet Syndrome, run by Longboard Pharmaceuticals at 28 sites in 2 countries.
Trial summary
The objective of this study is to assess the long-term safety, tolerability, and efficacy of adjunctive therapy of LP352 in subjects with developmental and epileptic encephalopathies who completed participation in Study LP352-201. Read more about this study
- Who is it for?
- Ages 12 to 65 years
- Conditions the study is for
- Developmental and Epileptic Encephalopathy, Dravet Syndrome, Lennox-Gastaut Syndrome
- What is being tested?
- LP352, bexicaserin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 41 participants
- Where
- 28 sitesin 2 countries
- Study dates
- 8 Nov 2022to 20 Dec 2024
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 65 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Male or non-pregnant, non-lactating female, age 12 to 65 years who have satisfactorily completed study LP352-201
- Diagnosis of Dravet syndrome, Lennox-Gastaut syndrome, or other developmental and epileptic encephalopathy
- The patient/parent/caregiver is able and willing to attend study visits, complete the diary and take study drug as instructed
Who cannot join
- Had an SAE in Study LP352-201 that was definitely, probably, or possibly related to exposure to study drug
- Current or past history of cardiovascular or cerebrovascular disease, such as cardiac valvulopathy, myocardial infarction, stroke, pulmonary arterial hypertension or abnormal blood pressure
- Has glaucoma, renal impairment, liver disease or any other medical condition that would affect study participation or pose a risk to the subject
- Current or recent history of moderate or severe depression, anorexia nervosa, bulimia or at risk of suicidal behavior
- Currently taking anorectic agents, monoamine oxidase inhibitors; serotonin agonists or antagonists including fenfluramine, atomoxetine, vortioxetine, or other medications for weight loss
- Positive test result on the drug screen, except tetrahydrocannabinol (THC) for patients taking prescribed cannabidiol
Trial locations and contacts
28 sites in 2 countries.
28 sites in 2 countries
United States25 sites
Child Neurology Consultants of Austin
Austin, Texas, 78757
Austin Epilepsy Care Center
Austin, Texas, 78758
Mid-Atlantic Epilepsy and Sleep Center
Bethesda, Maryland, 20817
OnSite Clinical Solutions LLC
Charlotte, North Carolina, 98277
Northwestern University Feinberg School of Medicine
Chicago, Illinois, 60611
University Hospitals Cleveland Medical Center
Cleveland, Ohio, 44106
Rancho Los Amigos National Rehabilitation Center (RLANRC)
Downey, California, 90242
Spectrum Health
Grand Rapids, Michigan, 49503
Northwest Florida Clinical Research Group
Gulf Breeze, Florida, 32561
Boston Children's Health Physicians LLP
Hawthorne, New York, 10532
Hawaii Pacific Neuroscience
Honolulu, Hawaii, 96817
Arkansas Children's Hospital
Little Rock, Arkansas, 72202
University of Miami
Miami, Florida, 33136
Northwell Health
New York, New York, 10075
Advent Health Orlando
Orlando, Florida, 32803
Research Institute of Orlando
Orlando, Florida, 32806
Providence Neurological Specialties-East
Portland, Oregon, 97213
University of Washington Valley Medical Center
Renton, Washington, 98055
Mayo Clinic
Rochester, Minnesota, 55905
University of Utah
Salt Lake City, Utah, 84132
University of California San Francisco
San Francisco, California, 94158
Washington University School of Medicine
St Louis, Missouri, 63110
Northeast Regional Epilepsy Group
Staten Island, New York, 10305
University of South Florida
Tampa, Florida, 33606
Wake Forest University School of Medicine
Winston-Salem, North Carolina, 27157
Australia3 sites
Austin Health
Heidelberg, Victoria, 3084
Alfred Health
Melbourne, Victoria, 3004
Queensland Children's Hospital
South Brisbane, Queensland, 4101
About this study
Official title: A Phase 2, Multicenter, Open-label, Long-term Safety Study of LP352 in Subjects With Developmental and Epileptic Encephalopathy Who Completed Study LP352-201 and Are Candidates for Continuous Treatment for Up to 52 Weeks
The objective of this study is to assess the long-term safety, tolerability, and efficacy of adjunctive therapy of LP352 in subjects with developmental and epileptic encephalopathies who completed participation in Study LP352-201.
Read the detailed description
This Phase 2, multicenter, open-label, multiple-dose extension clinical study is designed to evaluate long-term safety of LP352 in subjects with developmental and epileptic encephalopathy who completed Study LP352-201.
The study consists of a Screening Period (Day -1) and a 50-week open-label Treatment Period that includes a 15-day Up-titration Period (during which time subjects will titrate up to their highest tolerated doses) and an open-label Maintenance Period (48 weeks). The Treatment Period will be followed by a Down-titration/Taper Period (up to 15 days) and Follow-up Period (14 days after completion of down-titration). The starting dose of up-titration will be 6 mg TID. The target final maintenance doses are 6 mg TID, 9 mg TID, and 12 mg TID after a 15-day up-titration period, if tolerated.
- Being tested
- LP352, bexicaserin
- Keywords
- CDKL5 deficiency disorder, developmental and epileptic encephalopathy, Dravet Syndrome, epilepsy, Lennox-Gastaut Syndrome, treatment resistant epilepsy, tuberous sclerosis complex
- Medical subject headings
- Epilepsies, Myoclonic, Lennox Gastaut Syndrome, CDKL5 deficiency disorder, Epilepsy, Tuberous Sclerosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LP352, bexicaserinDrug
LP352 6 mg, 9 mg or 12 mg administered three times daily, orally or through G-tube
| Study group | Role | What they receive |
|---|---|---|
| LP352, bexicaserin | Experimental | Subjects will be titrated up to highest tolerated dose of LP352 during a 15-day period, followed by a 48-week maintenance period and a 15-day taper/down titration period. Receives: Drug: LP352, bexicaserin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Treatment-emergent Adverse Events
Incidence and severity of treatment-emergent adverse events, including serious adverse events and adverse events leading to study discontinuation and clinically significant changes in vital signs, physical examination endpoints, clinical safety laboratory values and ECGs
Measured: Baseline up to Week 52
Columbia-Suicide Severity Rating Scale (C-SSRS) Response
Type of Suicidal Ideation, Intensity (1 - 5, with 5 being most severe), Suicidal Behavior
Measured: Baseline up to Week 52
Patient Health Questionnaire-9 Total Score and Question 9 Score
Severity Rating Scale: 0 - 27; higher scores indicate greater severity of depressive disorder
Measured: Baseline up to Week 52
Secondary outcomes (8)
Percent Change from Baseline in Observed Countable Motor Seizure Frequency During the Treatment Period
Baseline Used for Seizure Frequency = Baseline from Study LP352-201 and Baseline from Study LP352-202
Measured: Baseline to Week 50
Proportion of Subjects with > 50% Reduction in Total Seizures During the Treatment Period
Measured: Baseline to Week 50
Percent Reduction in Individual Seizure Type During the Treatment Period
Measured: Baseline to Week 50
Proportion of Subjects Requiring Rescue Medication During the Treatment Period
Measured: Baseline to Week 50
Percent Change from Baseline in the Number of Episodes of Status Epilepticus During the Treatment Period
Measured: Baseline to Week 50
Percent of Subjects with Countable Motor Seizure-free Days During the Treatment Period
Measured: Baseline to Week 50
Percentage Change from Baseline in Non-motor and Difficult to Count Seizures
Measured: Baseline to Week 50
LGS: Percentage Change from Baseline in the Frequency of Observed Drop Seizures Over the Treatment Period
Measured: Baseline to Week 50
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Nov 2022
- Study start8 Nov 2022
- Primary completion20 Dec 2024
- Study completion20 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Developmental and Epileptic EncephalopathyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 41 participants (actual)
Sponsor and investigators
- Lead sponsor
- Longboard Pharmaceuticals
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Dennis J Dlugos, MD, Principal investigator, Children's Hospital of Philadelphia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05626634
- Sponsor's protocol ID
- LP352-202
- Status last verified
- Dec 2025
- First submitted
- 15 Nov 2022
- Last updated
- 3 Dec 2025
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2, Multicenter, Open-label, Long-term Safety Study of LP352 in Subjects With Developmental and Epileptic Encephalopathy Who Completed Study LP352-201 and Are Candidates for Continuous Treatment for Up to 52 Weeks
- ClinicalTrials.gov ID
- NCT05626634
- Acronym / sponsor ID
- LP352-202
- Keywords
- CDKL5 deficiency disorder, developmental and epileptic encephalopathy, Dravet Syndrome, epilepsy, Lennox-Gastaut Syndrome, treatment resistant epilepsy, tuberous sclerosis complex
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 41 participants (actual)
- Lead sponsor
- Longboard PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- 8 Nov 2022 (actual)
- Primary completion
- 20 Dec 2024 (actual)
- Study completion
- 20 Dec 2024 (actual)
- First posted
- 25 Nov 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The objective of this study is to assess the long-term safety, tolerability, and efficacy of adjunctive therapy of LP352 in subjects with developmental and epileptic encephalopathies who completed participation in Study LP352-201.
Detailed description
This Phase 2, multicenter, open-label, multiple-dose extension clinical study is designed to evaluate long-term safety of LP352 in subjects with developmental and epileptic encephalopathy who completed Study LP352-201.
The study consists of a Screening Period (Day -1) and a 50-week open-label Treatment Period that includes a 15-day Up-titration Period (during which time subjects will titrate up to their highest tolerated doses) and an open-label Maintenance Period (48 weeks). The Treatment Period will be followed by a Down-titration/Taper Period (up to 15 days) and Follow-up Period (14 days after completion of down-titration). The starting dose of up-titration will be 6 mg TID. The target final maintenance doses are 6 mg TID, 9 mg TID, and 12 mg TID after a 15-day up-titration period, if tolerated.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| LP352, bexicaserin | Experimental | Drug: LP352, bexicaserinSubjects will be titrated up to highest tolerated dose of LP352 during a 15-day period, followed by a 48-week maintenance period and a 15-day taper/down titration period. |
Who may qualify
- Ages
- 12 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (3 listed)
- Male or non-pregnant, non-lactating female, age 12 to 65 years who have satisfactorily completed study LP352-201
- Diagnosis of Dravet syndrome, Lennox-Gastaut syndrome, or other developmental and epileptic encephalopathy
- The patient/parent/caregiver is able and willing to attend study visits, complete the diary and take study drug as instructed
Key exclusion criteria (6 listed)
- Had an SAE in Study LP352-201 that was definitely, probably, or possibly related to exposure to study drug
- Current or past history of cardiovascular or cerebrovascular disease, such as cardiac valvulopathy, myocardial infarction, stroke, pulmonary arterial hypertension or abnormal blood pressure
- Has glaucoma, renal impairment, liver disease or any other medical condition that would affect study participation or pose a risk to the subject
- Current or recent history of moderate or severe depression, anorexia nervosa, bulimia or at risk of suicidal behavior
- Currently taking anorectic agents, monoamine oxidase inhibitors; serotonin agonists or antagonists including fenfluramine, atomoxetine, vortioxetine, or other medications for weight loss
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| LP352, bexicaserinLP352 6 mg, 9 mg or 12 mg administered three times daily, orally or through G-tube | Drug | LP352, bexicaserin |
Primary outcome
Treatment-emergent Adverse Events
Time frame: Baseline up to Week 52
Incidence and severity of treatment-emergent adverse events, including serious adverse events and adverse events leading to study discontinuation and clinically significant changes in vital signs, physical examination endpoints, clinical safety laboratory values and ECGs
Columbia-Suicide Severity Rating Scale (C-SSRS) Response
Time frame: Baseline up to Week 52
Type of Suicidal Ideation, Intensity (1 - 5, with 5 being most severe), Suicidal Behavior
Patient Health Questionnaire-9 Total Score and Question 9 Score
Time frame: Baseline up to Week 52
Severity Rating Scale: 0 - 27; higher scores indicate greater severity of depressive disorder
8 secondary outcomes
Percent Change from Baseline in Observed Countable Motor Seizure Frequency During the Treatment Period
Time frame: Baseline to Week 50
Proportion of Subjects with > 50% Reduction in Total Seizures During the Treatment Period
Time frame: Baseline to Week 50
Percent Reduction in Individual Seizure Type During the Treatment Period
Time frame: Baseline to Week 50
Proportion of Subjects Requiring Rescue Medication During the Treatment Period
Time frame: Baseline to Week 50
Percent Change from Baseline in the Number of Episodes of Status Epilepticus During the Treatment Period
Time frame: Baseline to Week 50
Percent of Subjects with Countable Motor Seizure-free Days During the Treatment Period
Time frame: Baseline to Week 50
Percentage Change from Baseline in Non-motor and Difficult to Count Seizures
Time frame: Baseline to Week 50
LGS: Percentage Change from Baseline in the Frequency of Observed Drop Seizures Over the Treatment Period
Time frame: Baseline to Week 50
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Dec 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Dennis J Dlugos, MD principal investigator
Children's Hospital of Philadelphia
28 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing LP352, bexicaserin in people with Developmental and Epileptic Encephalopathy and Dravet Syndrome, run by Longboard Pharmaceuticals at 28 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 28 sites in United States, Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Treatment-emergent Adverse Events (time frame: Baseline up to Week 52). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Dec 2025.