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TerminatedNCT05493293Updated Apr 12, 2024

Extension Study to Evaluate the Safety and Tolerability of NBI-921352 When Used With Anti-seizure Medications in Adults With Focal Onset Seizures

A Phase 2 interventional study of NBI-921352 in Focal Onset Seizure and Focal Onset Epilepsy, sponsored by Neurocrine Biosciences. Terminated at 26 sites in 7 countries. Open to participants aged 18 Years to 67 Years. Per ClinicalTrials.gov, last updated 2024-04-12.

Sponsored by Neurocrine Biosciences · Phase 2, Interventional, and Treatment

Why this study was terminated
The long-term extension study was terminated because the parent study NBI-921352-FOS2021 (NCT05159908) failed to meet its primary endpoint.
Phase
Phase 2
Study type
Interventional
Enrollment
82
Allocation
Not applicable
Ages
18 Years to 67 Years
Sex
All
01

Study summary

This Phase 2, prospective, interventional, active extension study was designed to evaluate the long-term safety and tolerability of NBI-921352 as adjunctive therapy in adult participants with focal onset seizures who completed 11 weeks of treatment in randomized, double-blind, placebo-controlled Study NBI-921352-FOS2021. Eligible participants may enroll directly following the completion of the Week 11 study visit of Study NBI-921352-FOS2021 or after a gap following completion of that study.

02

Conditions studied

  • Focal Onset Seizure
  • Focal Onset Epilepsy

Keywords

  • epilepsy
  • focal seizure
  • sodium channel
  • voltage-gated
  • alpha subunit
  • Nav1.6 inhibitor
  • antiseizure medicine
  • ASM
  • antiepileptic drug
  • AED
  • partial seizure
  • partial onset epilepsy
03

In context

Seizures

896 studies on the registry are indexed under Seizures; 145 are open to participants now.

This study's enrollment of 82 is above the median of 62 across 621 interventional studies indexed under Seizures.

Browse Seizures studies →

Lead sponsor

Neurocrine Biosciences is the lead sponsor of 86 studies on the registry; 16 are open to participants now.

Of its 35 completed or terminated interventional studies of FDA-regulated products, 23 (66%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 67 Years
Sexes eligible
All
Accepts healthy volunteers
No

Eligibility criteria

Key Inclusion Criteria:

  • Provided informed consent.
  • Completed 11 weeks of treatment in Study NBI-921352-FOS2021.
  • Stable treatment with at least 1 but not more than 4 antiseizure medicines.

Key Exclusion Criteria:

  • Have developed any other disorder for which the treatment takes priority over the treatment of focal onset seizure or is likely to interfere with study treatment or impair treatment compliance.
05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
82 participants (actual)

Study arms

  • Experimental
    NBI-921352 Treatment

    Treatment for up to 107 weeks.

    Drug: NBI-921352

Interventions

06

What researchers measure

Primary outcomes

  1. The occurrence of serious treatment-emergent adverse events (TEAEs)

    Time frame: Through Week 111

07

Study locations

26 sites
  • Neurocrine Clinical Site
    Fitzroy, 3065, Australia
  • Neurocrine Clinical Site
    Heidelberg, 3084, Australia
  • Neurocrine Clinical Site
    Melbourne, 3004, Australia
  • Neurocrine Clinical Site
    Brussels, 1070, Belgium
  • Neurocrine Clinical Site
    Ghent, 9000, Belgium
  • Neurocrine Clinical Site
    Leuven, 3000, Belgium
  • Neurocrine Clinical Site
    Brno, 65691, Czechia
  • Neurocrine Clinical Site
    Ostrava, 708 52, Czechia
  • Neurocrine Clinical Site
    Prague, 15006, Czechia
  • Neurocrine Clinical Site
    Prague, 16000, Czechia
  • Neurocrine Clinical Site
    Prague, 18600, Czechia
  • Neurocrine Clinical Site
    Rychnov nad Kněžnou, 51601, Czechia
  • Neurocrine Clinical Site
    Bron, 69677, France
  • Neurocrine Clinical Site
    Lille, 59037, France
  • Neurocrine Clinical Site
    Rennes, 35000, France
  • Neurocrine Clinical Site
    Toulouse, 31059, France
  • Neurocrine Clinical Site
    Budapest, 1145, Hungary
  • Neurocrine Clinical Site
    Budapest, 40320, Hungary
  • Neurocrine Clinical Site
    Pécs, 7623, Hungary
  • Neurocrine Clinical Site
    Bologna, 40139, Italy
  • Neurocrine Clinical Site
    Milan, 20133, Italy
  • Neurocrine Clinical Site
    Pavia, 27100, Italy
  • Neurocrine Clinical Site
    Barcelona, 8035, Spain
  • Neurocrine Clinical Site
    Madrid, 28034, Spain
  • Neurocrine Clinical Site
    Madrid, 28040, Spain
  • Neurocrine Clinical Site
    Valencia, 46026, Spain
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Apr 12, 2024, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05493293
Responsible party
Sponsor
First posted
Aug 9, 2022
Start date
Nov 9, 2022
Primary completion
Mar 11, 2024
Completion
Mar 11, 2024
Last update
Apr 12, 2024

Study contacts

Clinical Development Lead
study director · Neurocrine Biosciences

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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