Study to Evaluate NBI-921352 as Adjunctive Therapy in Subjects With SCN8A Developmental and Epileptic Encephalopathy Syndrome (SCN8A-DEE)

NCT ID: NCT04873869

Last Updated: 2025-10-16

Basic Information

• Recruitment Status: TERMINATED
• Clinical Phase: PHASE2
• Total Enrollment: 8 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-01-31
• Study Completion Date: 2023-03-17

Brief Summary

The objective of this study is to assess the efficacy, safety, and pharmacokinetics of NBI-921352 as adjunctive therapy for seizures in subjects with SCN8A Developmental and Epileptic Encephalopathy Syndrome (SCN8A-DEE).

Conditions

SCN8A Developmental and Epileptic Encephalopathy Syndrome

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

Placebo

Participants will receive matching placebo for up to 18 weeks.

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DRUG

Administered orally

NBI-921352

In the first 6 weeks participants will receive increasing doses of NBI-921352 (Titration Period) based on weight, followed by 10 weeks of treatment at their final tolerated dose (Maintenance Period) and 2 weeks of treatment with decreasing doses (Taper Period).

Group Type: EXPERIMENTAL

NBI-921352

Intervention Type: DRUG

Administered orally

Interventions

NBI-921352

Administered orally

Intervention Type: DRUG

Placebo

Administered orally

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

1. Male or female 2 to 21 years of age, inclusive.

2. Have a diagnosis of SCN8A-DEE supported by both clinical and genetic findings

3. Have on average at least 1 countable motor seizure per week and not be seizure-free for more than 20 consecutive days

4. Being treated with at least 1 other antiseizure medication (ASM), but no more than 4 ASMs

5. Have failed to achieve seizure freedom with at least 2 ASMs

6. Must be using a nocturnal alerting system or practice consistent with standards of care at the time of screening and continue to use this for the duration of the study

7. Must have an adequate rescue medication regimen per the investigator's judgment in place at the time of screening and for the duration of the study

8. Have a body weight of at least 10 kg

9. The subject's parent/caregiver is able to accurately identify seizure types, especially countable motor seizures (defined as GTCS, tonic, atonic or FOS with noticeable motor component) and is able to complete seizure diary

Exclusion Criteria

1. Have previously been enrolled in this study and received blinded treatment

2. Have participated in an interventional clinical trial < 30 days prior to screening

3. Have symptoms that would be more consistent with another epilepsy disorder such as Dravet syndrome (eg, fever-induced episodes of status epilepticus, frequent myoclonic seizures, worsening on sodium channel blockers, absence seizures with generalized spike-and-wave EEG as the sole seizure type)

4. Are currently receiving cannabinoids or medical marijuana except Epidiolex/Epidyolex, unless approved by the Sponsor

5. Are currently taking systemic steroids (excluding inhaled medication for asthma treatments and intranasal steroids for allergies). If subject has received these medications in the past, must be off these medications for at least 3 months prior to the screening visit and these drugs may not be initiated during the duration of the study. Intermittent steroids to treat nonepilepsy related diseases (such as allergies or dermatological conditions) are not exclusionary

6. Have a history of moderate or severe head trauma or other neurological disorders or systemic medical diseases that are, in the investigator's opinion, likely to affect nervous system functioning

7. Have a clinically significant medical condition or chronic disease, that in the opinion of the investigator would preclude the subject from participating in and completing the study or that could confound interpretation of study outcome

8. Have clinically significant abnormal vital signs at the screening visit as determined by the investigator

9. Have one or more clinical laboratory test values outside the reference range, based on blood samples taken at the screening visit, that are of potential risk to the subject's safety as determined by the investigator

10. Have, at the screening visit, an electrocardiogram (ECG) finding of a corrected QT interval using Fridericia's formula (QTcF) > 450 msec or presence of any significant cardiac abnormality.

• Minimum Eligible Age: 2 Years
• Maximum Eligible Age: 21 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Neurocrine Biosciences

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Clinical Development Lead

Role: STUDY_DIRECTOR

Neurocrine Biosciences

Locations

UCSF Medical Center

San Francisco, California, United States

Children's National Hospital

Washington D.C., District of Columbia, United States

University of Rochester

Rochester, New York, United States

Cook Children's Medical Center

Fort Worth, Texas, United States

Countries

United States

Provided Documents

Document Type: Study Protocol

View Document

Document Type: Statistical Analysis Plan

View Document

Other Identifiers

2020-003140-83

Identifier Type: EUDRACT_NUMBER

Identifier Source: secondary_id

NBI-921352-DEE2012

Identifier Type: -

Identifier Source: org_study_id