Clinical trial NCT04912856: An Open-Label Extension of the Study XEN496 (Ezogabine) in Children With KCNQ2-DEE
Official title: An Open-Label Extension of the Study XEN496 in Children With KCNQ2 Developmental and Epileptic Encephalopathy
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: PHASE3
Conditions: Epilepsy
Epilepsy in Children
Epilepsy; Seizure
Disease
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Epileptic Syndromes
Keywords: XEN496
Ezogabine
Retigabine
Encephalopathy
Seizure
KCNQ2
EPIK
Lead sponsor: Xenon Pharmaceuticals Inc.
Sponsor class: INDUSTRY
First posted: 2021-06-03
Enrollment: 8
Sex: ALL
Minimum age (years): 1
Maximum age (years): 6
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: SEQUENTIAL
Primary purpose: TREATMENT

Brief summary: To assess the long-term safety and tolerability of XEN496 in pediatric subjects with KCNQ2 developmental and epileptic encephalopathy (KCNQ2-DEE) who had participated in the primary study (XPF-009-301).

Detailed description: This is an open-label, long-term extension study of XEN496 for the treatment of seizures in subjects with KCNQ2-DEE, that will be open to eligible subjects who participated in the primary study, XPF-009-301. The primary objective is to assess the long-term safety of XEN496. A double-blind transition/titration period will be used to maintain blinding to the treatment allocation in the primary study (XPF-009-301). After completion of the blinded transition/titration period, subjects will receive the open label study drug at their optimal dose for approximately 35 months.

Eligibility criteria: Inclusion Criteria:

* Subject completed participation in the primary study, XPF-009-301. A subject who withdraws from the primary study due to meeting protocol-specified worsening criteria will be considered as having completed participation in the primary study.
* The caregiver is willing and able to be compliant with diary completion, visit schedule, and study drug administration.
* Subject's caregiver achieved a minimum of 85% compliance with daily diary completion during both baseline and the double-blind period of the primary study.

Exclusion Criteria:

* Any adverse event(s) or serious adverse event(s) during the primary study XPF-009-301, which in the opinion of the investigator and sponsor's medical monitor, would preclude the subject's entry into the OLE study.
* A clinically significant condition or illness, or symptoms other than those resulting from KCNQ2-DEE, present at screening/baseline that, in the opinion of the investigator, would pose a risk to the subject if s/he were to enter the study.
* Any conditions that were specified as exclusion criteria in the primary study, XPF-009-301.
* It is anticipated that the subject will require treatment with at least 1 of the disallowed medications during the study.
* Any change in cardiac rhythm or atrioventricular conduction in the primary study that, in the investigator's opinion, is a significant risk to subject safety.

Primary outcomes:
measure: Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs) Related to Intervention
timeFrame: From Screening/Baseline through to 4 weeks post last dose
Secondary outcomes:
Other outcomes:
Locations:
city: Philadelphia
country: United States
facility: Children's Hospital of Philadelphia
state: Pennsylvania
city: Tacoma
country: United States
facility: MultiCare Health System - Mary Bridge Pediatrics - Tacoma
state: Washington
city: Sydney
country: Australia
facility: Sydney Children's Hospital
state: New South Wales
city: Edegem
country: Belgium
facility: Universitair Ziekenhuis Antwerpen - Dienst Kinderneurologie
state: Antwerpen
Study officials:
affiliation: Xenon Pharmaceuticals Inc.
name: Study Director
role: STUDY_DIRECTOR
References: