A Phase 3 Open-Label Study to Investigate bexicaserin (LP352) in Children and Adults with Developmental and Epileptic Encephalopathy

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Longboard Pharmaceuticals Inc.

Participant type

Pediatric, Patients

Age range

0-17 years, 18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Nervous System Diseases [C10]

Trial duration

10 Oct 2025 → ongoing

Decision date (initial)

2025-06-17

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

Yes

Funding sources

Longboard Pharmaceuticals, Inc

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Safety, Efficacy, Others

To evaluate the safety and tolerability of bexicaserin (LP352) in DEE

Secondary objectives 1

1. To evaluate the efficacy of bexicaserin (LP352) in DEE

Conditions and MedDRA coding

Developmental and Epileptic Encephalopathies (DEEs)

Regulatory references

Scientific advice from competent authorities

Food And Drug Administration, European Medicines Agency

EMA paediatric investigation plan (PIP)

EMEA-003288-PIP01-22

Plan to share IPD

No

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 5

1. 1. The participant has satisfactorily completed Study LP352-301 or LP352-302 Visit 8, and who, in the opinion of the investigator, may benefit from continued LP352 administration.
2. 2. Diagnosis of DEE that includes DS, LGS, or DEE Other (as defined and evaluated in Study LP352-301 or LP352-302).
3. 3. Has at least one reliable and consistent parent, legal guardian, or caregiver during the study.
4. 4. 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 must provide informed consent and the participant will need to assent (as per local regulations) before participation in the study.
5. 5. 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.

Exclusion criteria 4

1. 1. Using exclusionary medications defined in protocol LP352-303
2. 2. Current use of any cannabis product or cannabidiol that is not in oral solution/capsule/tablet form, not obtained from a government-approved dispensary, or containing ≥50% THC.
3. 3. 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.
4. 4. Is unable or unwilling to comply with any of the study requirements or timelines.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 7

1. 1. Incidence and severity of TEAEs, including SAEs and AEs leading to discontinuation
2. 2. Changes in safety laboratory parameters
3. 3. Physical examination findings
4. 4. Vital signs
5. 5. ECGs, and growth parameters (height and weight)
6. 6. Changes in suicidality or depression as rated by C-SSRS and PHQ-9 responses
7. 7. Changes in puberty development as rated by Tanner Staging

Secondary endpoints 4

1. 1. Frequency percent change in countable motor seizures during Treatment (28-day average) compared to Baseline (28-day average) as assessed by seizure eDiary
2. 2. 50% responder rate (the percentage of participants with a ≥50% reduction in countable motor seizures) during Treatment (28-day average) compared to Baseline (28-day average) as assessed by seizure eDiary
3. 3. Frequency percent change in countable motor seizures during Maintenance (28-day average) compared to Baseline (28-day average) as assessed by seizure eDiary
4. 4. 50% responder rate (the percentage of participants with a ≥50% reduction in countable motor seizures) during Maintenance (28-day average) compared to Baseline (28-day average) as assessed by seizure eDiary

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Placebo 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Longboard Pharmaceuticals Inc.

Sponsor organisation

Longboard Pharmaceuticals Inc.

Address

4275 Executive Square Suite 950

City

La Jolla

Postcode

92037-9208

Country

United States

Scientific contact point

Organisation

Longboard Pharmaceuticals Inc.

Contact name

Global Regulatory Lead

Public contact point

Organisation

Longboard Pharmaceuticals Inc.

Contact name

Global Regulatory Lead

Third parties 10

Locations

8 EU/EEA countries · 40 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 102 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

4 submissions — initial application plus substantial / non-substantial modifications