An Open-Label Extension of the Study XEN496 (Ezogabine) in Children With KCNQ2-DEE

NCT ID: NCT04912856

Last Updated: 2025-02-14

Basic Information

• Recruitment Status: TERMINATED
• Clinical Phase: PHASE3
• Total Enrollment: 8 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2021-08-17
• Study Completion Date: 2023-11-17

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.

Conditions

Epilepsy; Epilepsy in Children; Epilepsy; Seizure; Disease; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Epileptic Syndromes

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: SEQUENTIAL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: QUADRUPLE

Study Groups

Group 1: XEN496 only

24-day blinded transition/titration period. Subjects who received XEN496 in the preceding study will continue to receive XEN496 at the same dose, in a blinded manner, without any further titration. To maintain the blinded aspect of the study, placebo will be dispensed to all subjects during the transition/titration period to ensure the total number of capsules are consistent across all subjects.

Subjects who discontinue will be required to taper off study drug over a period of up to 15 days

Group Type: EXPERIMENTAL

XEN496

Intervention Type: DRUG

XEN496 sprinkle capsules. Parents / caregivers will be instructed to sprinkle and mix the contents of the capsules into soft foods or liquids and feed it to the child.

Group 2: Placebo to XEN496

24-day blinded transition/titration period. Subjects who were allocated to placebo in the preceding study, will be titrated to a tolerated dose up to a maximum dose of 21 mg/kg/day, with a maximum daily dose of 672 mg/day. To maintain the blinded aspect of the study, placebo will be dispensed to all subjects during the transition/titration period to ensure the total number of capsules are consistent across all subjects

Subjects who discontinue or complete the study treatment will be required to taper off study drug over a period of up to 15 days.

Group Type: EXPERIMENTAL

XEN496

Intervention Type: DRUG

XEN496 sprinkle capsules. Parents / caregivers will be instructed to sprinkle and mix the contents of the capsules into soft foods or liquids and feed it to the child.

Interventions

XEN496

XEN496 sprinkle capsules. Parents / caregivers will be instructed to sprinkle and mix the contents of the capsules into soft foods or liquids and feed it to the child.

Intervention Type: DRUG

Other Intervention Names

ezogabine; retigabine

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.
• 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.

• Minimum Eligible Age: 1 Month
• Maximum Eligible Age: 6 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Xenon Pharmaceuticals Inc.

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Study Director

Role: STUDY_DIRECTOR

Xenon Pharmaceuticals Inc.

Locations

Children's Hospital of Philadelphia

Philadelphia, Pennsylvania, United States

MultiCare Health System - Mary Bridge Pediatrics - Tacoma

Tacoma, Washington, United States

Sydney Children's Hospital

Sydney, New South Wales, Australia

Universitair Ziekenhuis Antwerpen - Dienst Kinderneurologie

Edegem, Antwerpen, Belgium

Countries

United States; Australia; Belgium

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan: Study Protocol

View Document

Document Type: Statistical Analysis Plan: Statistical Analysis Plan

View Document

Related Links

https://clinicaltrials.gov/ct2/show/NCT04639310

XPF-009-301 Study (EPIK)

Other Identifiers

2020-003447-28

Identifier Type: EUDRACT_NUMBER

Identifier Source: secondary_id

XPF-009-302

Identifier Type: -

Identifier Source: org_study_id