Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs) related to intervention |
Safety and tolerability of XEN496 as assessed by incidence and severity of AEs and SAEs |
From Screening/Baseline through to 4 weeks post last dose |
|
Secondary |
Change in monthly countable motor seizure frequency |
Comparing the first 15 weeks of XEN496 treatment in the OLE study to the seizure frequency reported during treatment in the preceding primary study, XPF-009-301, among only those subjects who were randomized to the placebo arm in the primary study, XPF-009-301 |
Screening/Baseline to first 15 weeks (up to Visit 10) |
|
Secondary |
Change from pre-randomization baseline in the previous study over time based on response categories (<25%, 25 to <50%, 50 to <75%, 75 to <100%, 100%), based on estimated seizure frequency every 3 months during the OLE period |
Caregivers will be instructed on how to complete the diary and will be asked to record information daily in the diary. Information on the number and type of countable motor seizures will be collected daily. |
Every three months from screening/baseline through to study completion, up to 162 weeks |
|
Secondary |
Percent change from baseline in countable motor seizure frequency, relative to pre-randomization baseline of the primary study, XPF-009-301, assessed over time every 3 months during the OLE |
Caregivers will be instructed on how to complete the diary and will be asked to record information daily in the diary. Information on the number and type of countable motor seizures will be collected daily. |
Every three months from screening/baseline through to study completion, up to 162 weeks |
|
Secondary |
Percent change from baseline in countable motor seizure frequency, relative to pre-randomization baseline of the primary study, XPF-009-301, every 3 months based on combined data from both primary and OLE studies, by treatment group in the primary study |
Caregivers will be instructed on how to complete the diary and will be asked to record information daily in the diary. Information on the number and type of countable motor seizures will be collected daily. |
Every three months from screening/baseline through to study completion, up to 162 weeks |
|
Secondary |
Change over time in Caregiver Global Impression of Severity (CaGI-S) scores for the subject's overall condition and for seizures. |
CaGI-S scale is Caregiver-reported assessment of the severity of the subject's seizures and overall condition over the previous 7 days. Responses to the CaGI-S questionnaire are to be rated on a 5 item Likert scale ranging from none to very severe. |
Study days: 1, 24, 67, 109, 182, 273, 364, 455, 546, 637, 728, 819, 910, 1001 and 1092 |
|
Secondary |
Change over time in Caregiver Global Impression of Change (CaGI-C) scores for the subject |
CaGI-C scale is a caregiver-reported assessment for the subject's overall condition and for seizures. Responses to the CaGI-C questionnaire are to be rated on a 7 item Likert scale ranging from very much improved to very much worse. |
Study days: 24, 67, 109, 182, 273, 364, 455, 546, 637, 728, 819, 910, 1001 and 1092 |
|
Secondary |
Change over time in neurocognitive development based on the Bayley Scales of Infant and Toddler Development III (BSID-III) |
The BSID-III is designed to identify young children with development delays, and assesses developmental function across 5 domains: cognition; language (expressive and receptive); motor (fine and gross motor functioning); social-emotional, and adaptive behavior. |
Study days: 1, 109, 364, 728 and 1092 |
|
Secondary |
Change over time in adaptive behavior based on the Adaptive Behavior Assessment System, Third Edition (ABAS-3) |
On a 4-point response scale, raters indicate whether, and how frequently, the individual performs each activity. The ABAS-3 assesses up to 11 skill areas: communication, community use, functional academics, health and safety, home or school living, leisure, motor, self-care, self-direction, social, and work. |
Study days: 1, 109, 182, 364, 546, 728, 910 and 1092 |
|
Secondary |
Change over time in the Investigator's Clinical Global Impression of Change scale (CGI-C) scores for the subject's seizures and overall condition |
The CGI-C consists of single items relating to each concept and is scored by the investigator using a 7-point Likert scale ranging from 1 to 7, anchored at 1 = "Very much improved" and 7 = "Very much worse". |
Study days: 67, 109, 182, 364, 546, 728, 910 and 1092 |
|
Secondary |
Use of rescue medication |
Caregivers will be instructed on how to complete the diary and will be asked to record information daily in the diary. Information on the number and type of rescue medications will be collected daily. |
From screening/baseline through to study completion, up to 162 weeks |
|
Secondary |
Use of all concomitant medications including treatments used for seizure control |
Caregivers will be instructed on how to complete the diary and will be asked to record information daily in the diary. Information on the number and type of concomitant medications will be collected daily. |
From screening/baseline through to 162 weeks |
|
Secondary |
Change in the Pediatric Quality of Life Inventory scale in subjects with KCNQ2-DEE |
A modular instrument designed to measure health-related quality of life in both healthy and chronically ill children. The scales include parent-reported measures of the child's physical functioning, physical symptoms, emotional functioning, social functioning, and cognitive functioning |
Study days: 1, 67, 109, 182, 546, 728, 910 and 1092 |
|
Secondary |
Change in Pediatric Quality of Life Inventory, Family Impact scale in subjects with KCNQ2-DEE |
To evaluate the impact of pediatric chronic health conditions on parents and the family including measures of parent self-reported physical, emotional, social and cognitive function, communication and worry, in addition to family daily activities and family relationships |
Study days: 1, 67, 109, 182, 546, 728, 910 and 1092 |
|
Secondary |
Plasma concentrations of ezogabine and N-acetyl metabolite of ezogabine (NAMR) |
Blood samples will be taken at predefined visit dates to analyze the plasma concentrations. |
Study days: 1, 16, 32, 67, 109, 182, 546, 728, 910 and 1092 |
|