Last updated: 07/17/2024 16:53:26

Dose-Optimization, Adjunctive Treatment Study of ezogabine/retigabine immediate release in partial-onset seizures

GSK study ID
116878
See study documents
Clinicaltrials.gov ID
NCT01721317
See results summary
EudraCT ID
2012-003105-10
EU CT Number
Not applicable
Trial status
Other
Other
Overview
Eligibility
Locations
Study documents
Results summary
Plain language summaries
Additional information

Trial overview

Official title: Study PTG116878, a Dose-Optimization Study of Ezogabine/Retigabine Immediate Release Tablets versus Placebo in the Adjunctive Treatment of Subjects with Partial-Onset Seizures
Trial description: This is a Phase IV adjunctive treatment dose-optimization study evaluating the efficacy, safety, and health outcomes of ezogabine/retigabine immediate release (IR) (GW582892) compared with placebo in adult subjects with partial-onset seizures (POS). This randomized, double-blind, placebo-controlled, parallel-group, multicenter study will compare ezogabine/retigabine IR (investigator-selected daily doses of 600 milligram (mg)/day, 750 mg/day, 900 mg/day, 1050 mg/day or 1200 mg/day) with placebo. Study drug will be taken three times a day (TID) in equally or unequally divided doses.
The study design includes up to a 10-week (wk) Screening (≤2 wks)/Baseline (8 wks) Phase, a Titration Phase (2 wks), Dose-Optimization Phase (8 wks), Maintenance Phase (8 wks), and Taper/Follow-Up Phase (3 wks). The total duration of the study for each subject will be approximately 31 wks, and at minimum approximately 27 wks if subjects provide reliable 28-day retrospective seizure data.
Approximately 280 subjects will be screened with approximately 208 subjects randomly assigned to 1 of 2 treatment groups in a 2:1 ratio (ezogabine/retigabine IR, or placebo).
Subjects will be instructed to start investigational product (IP) the day after the baseline visit. During the first week of the Titration Phase, subjects will be taking 300 mg/day (100 mg TID). During the second week, subjects will be taking 450 mg/day (150 mg/day TID).
At the beginning of the Dose-Optimization Phase (3rd week of study drug) subjects will take 600 mg/day (200 mg TID) for one week. Thereafter during the Dose-Optimization Phase, subjects will continue to increase their daily dose by 150 mg per week until they have achieved their optimal tolerated dose. During this phase, the investigator may choose to have the subject stay on his/her designated dose for another week before attempting a dose increase until reaching a dose of 1200 mg/day. In addition, in the context of tolerability issues, the subject may be reduced to the preceding dose level for one week before attempting to increase the dose again at the next scheduled time point until the subject reaches optimal dose. Subjects unable to tolerate a minimum of 600 mg/day will be discontinued from the study.
The Maintenance Phase will begin at Week 10 (Visit 8) and will last 8 weeks. During the Maintenance Phase, subjects will remain on the daily TID dose achieved at the end of the Dose-Optimization Phase.
Seizure type and frequency will be monitored throughout the study via a Seizure Calendar and will be evaluated at each study visit. Subjects will be instructed to complete the daily Seizure Calendar during each phase of the study.
Primary purpose:
Treatment
Trial design:
Parallel Assignment
Masking:
Double (Participant, Investigator)
Allocation:
Randomized
Primary outcomes:

Percent change in the 28-day total partial seizure frequency (POS) from Week 0 (end of Baseline Phase) through Week 18 (end of Maintenance Phase)

Timeframe: Week 0 (end of Baseline Phase) through Week 18 (end of Maintenance Phase)

Percent change in the 28-day total partial seizure frequency (POS) within each stratum from Week 0 (end of Baseline Phase) through Week 18 (end of Maintenance Phase)

Timeframe: Week 0 (end of Baseline Phase) through Week 18 (end of Maintenance Phase)

Secondary outcomes:

Percent change in 28-day total partial seizure frequency (POS) for the indicated intervals: Maintenance Phase and the Dose-Optimization Phase + Maintenance Phase

Timeframe: Week 3 (start of Dose -Optimization Phase) to Week 18 (end of Maintenance Phase)

Number of par. experiencing >=50% reduction in 28-day total partial seizure frequency (POS) for the intervals: Double-blind period (Titration Phase + Dose-Optimization Phase + Maintenance Phase), Maintenance Phase & Dose-Optimization + Maintenance Phase

Timeframe: Week 0 (end of Baseline Phase) through Week 18 (end of Maintenance Phase)

Number of seizure free participants for the indicated intervals: Maintenance Phase and the Dose-Optimization Phase + Maintenance Phase

Timeframe: Week 3 (start of Dose-Optimization Phase) to Week 18 (end of Maintenance Phase)

Change from Baseline in the number of seizure free days for the indicated intervals: Double-blind period (Titration Phase + Dose-Optimization Phase + Maintenance Phase), Maintenance Phase and the Dose-Optimization + Maintenance Phase

Timeframe: Week 0 (end of Baseline Phase) to Week 18 (end of Maintenance Phase)

Percent change from Baseline in functional status (epilepsy-related worry and activity limitation) and productivity (missed work or school) to the end of the Dose-Optimization Phase and the end of the Maintenance Phase

Timeframe: Week 3 (start of Dose -Optimization Phase) to Week 18 (end of Maintenance Phase)

Incidence of new seizure types in participants without a history of these seizure types

Timeframe: Week 0 (end of Baseline Phase) to Week 21 (end of Taper Phase)

Number of participants at each dose during the Maintenance Phase and average maintenance dose over all participants

Timeframe: Week 11 (start of Maintenance Phase) to Week 18 (end of Maintenance Phase)

Number of participants with early study discontinuation

Timeframe: Week 0 (end of Baseline Phase) to Week 21 (end of Taper Phase)

Change from Baseline in body weight

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 2 (end of Titration Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in systolic blood pressure (SBP) and diastolic blood pressure (DBP)

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 2 (end of Titration Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in heart rate

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 2 (end of Titration Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in the QT interval using Bazett’s correction (QTcB) and QT interval using Fridericia’s correction (QTcF)

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 2 (end of Titration Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in the percentage of basophils, eosinophils, lymphocytes, monocytes, neutrophils, segmented neutrophils and red blood cell (RBC) distribution width

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in the basophils, eosinophils, lymphocytes, monocytes, neutrophils, segmented neutrophils, white blood cell (WBC) count and platelet count

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in hemoglobin and mean corpuscle hemoglobin concentration

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in hematocrit

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in red blood cell (RBC) count

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in mean corpuscle hemoglobin

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in albumin and total protein

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase, lactate dehydrogenase and gamma glutamyltransferase (GGT)

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in direct bilirubin, indirect bilirubin, total bilirubin, uric acid and creatinine

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in calcium, chloride, potassium, sodium, glucose, magnesium, phosphorus inorganic, bicarbonate and urea/blood urea nitrogen (BUN)

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in BUN/Creatinine ratio

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in creatinine clearance

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in urine specific gravity (USG)

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in urine potential of hydrogen (pH)

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Number of participants for the indicated urinalysis parameters tested by dipstick

Timeframe: Screening, Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase), Week 18 (end of Maintenance Phase) and Week 21 (end of Taper Phase)

Change from Baseline in post-void residual (PVR) urinary bladder ultrasound volume

Timeframe: Week 0 (end of Baseline Phase), Week 10 (end of Dose-Optimization Phase) and Week 18 (end of Maintenance Phase)

Number of participants with the indicated assessment events of suicidal behavior, suicidal ideation or non-suicidal self injurious behavior via the Columbia Suicide Severity Rating Scale (C-SSRS)

Timeframe: Week 0 (end of Baseline Phase), Week 2 (end of Titration Phase), Week 4, Week 6 and Week 8

Interventions:
  • Drug: Ezogabine/Retigabine IR
  • Drug: Placebo
    • Enrollment:
    6
    Primary completion date:
    2013-20-06
    Observational study model:
    Not applicable
    Time perspective:
    Not applicable
    Clinical publications:
    Not applicable
    Medical condition
    Seizures
    Product
    retigabine
    Collaborators
    Bausch Health Americas, Inc.
    Study date(s)
    December 2012 to June 2013
    Type
    Interventional
    Phase
    4

    Participation criteria

    Sex
    Female & Male
    Age
    18+ years
    Accepts healthy volunteers
    Yes
    • A male or female of 18 years of age or above capable of giving written informed consent
    • Have a confident diagnosis of epilepsy for >=6 months with partial-onset seizures (POS), i.e., simple or complex POS with or without secondary generalization (classified according to the International League Against Epilepsy (ILAE) Guidelines, prior to the Screening Visit
    • Have generalized epilepsy (e.g. Lennox-Gastaut, Juvenile Myoclonic epilepsy, Absence, etc.) or non-epileptic seizures.
    • Have had innumerable seizures within the 12-month period prior to the Screening Visit where the individual seizures cannot be counted.
    Inclusion and exclusion criteria
    Inclusion criteria:
    • A male or female of 18 years of age or above capable of giving written informed consent
    • Have a confident diagnosis of epilepsy for >=6 months with partial-onset seizures (POS), i.e., simple or complex POS with or without secondary generalization (classified according to the International League Against Epilepsy (ILAE) Guidelines, prior to the Screening Visit
    • Currently receiving monotherapy treatment with an antiepileptic drug (AED) at a stable dose for at least 28 days prior to the screening visit (Visit 1). If the subject is taking a barbiturate (e.g., phenobarbital), the dose must be stable for ≥3 months prior to the Screening Visit. Note: Subjects who have received previous adjunctive treatment but are currently taking one AED are eligible for enrolment.
    • Investigator-confirmed partial seizure frequency rate of ≥3 partial seizures per 28 days over the 8 weeks preceding the screening visit and must not have been seizure-free for ≥ 21 consecutive days.
    • Female of non-child bearing potential, or female of child-bearing potential willing to use protocol-specified methods of contraception to prevent pregnancy during the study.
    • Capable to comply with dosing of study drug, background AED, all study procedures and to maintain an accurate and complete daily written Seizure Calendar and Functional Status Diary
    Exclusion criteria:
    • Have generalized epilepsy (e.g. Lennox-Gastaut, Juvenile Myoclonic epilepsy, Absence, etc.) or non-epileptic seizures.
    • Have had innumerable seizures within the 12-month period prior to the Screening Visit where the individual seizures cannot be counted.
    • Have had status epilepticus within 12 months prior to screening
    • Have a history of pseudo seizures, non-epileptic events or any other type of psychogenic seizures that could be confused with seizures.
    • Have been treated with felbamate or vigabatrin within the 6 months prior to Screening. If a subject has been previously treated with vigabatrin >6 months prior to Screening, a visual perimetry test performed within 6 months prior to Screening must show normal visual fields or no worsening of recognized visual field abnormalities as compared with prior to vigabatrin treatment
    • Benzodiazepines used in any manner other than acute usage as defined in this protocol will be considered concurrent AED usage and will not be permitted -- Are using Central Nervous System (CNS)-active medication (other than concomitant AED therapy), unless the subject has been stabilized on such medication for at least 1 month prior to the Screening Visit.
    • Are using herbal treatments with CNS activity within at least 1 month prior to the Screening Visit
    • Have received ezogabine/retigabine in a previous study or have taken POTIGA or TROBALT.
    • Are currently following or planning to follow the ketogenic diet
    • Have an active Vagus Nerve Stimulator (VNS) to control seizures
    • Are planning surgery to control seizures during the study
    • Have impaired renal function as judged by a creatinine clearance of <50 mL/min
    • Have a history of urinary retention or risk factors for urinary retention that in the investigator’s judgment could potentially affect subject safety.
    • Have an average corrected QT interval (QTc), using Bazett’s QT correction (QTcB), ≥450msec or ≥480msec for subjects with bundle branch block at the time of the Screening Visit
    • Liver function tests: alanine aminotransferase (ALT) is ≥2 times the upper limit of normal (ULN); alkaline phosphatase and bilirubin are >1.5 × ULN (isolated bilirubin >1.5 × ULN is acceptable if bilirubin is fractionated and direct bilirubin is <35%).
    • Are suffering from acute or progressive neurological disease, severe psychiatric disease, or severe mental abnormalities that are likely to interfere with the objectives of the study
    • Have a history of malignancy within the past 2 years; with the exception of basal cell carcinoma
    • Have unstable liver disease [chronic stable hepatitis B and C are acceptable if subject otherwise meets entry criteria; chronic stable Hepatitis B to be excluded if significant immunosuppressive agents administered due to risk of hepatitis B reactivation]
    • Have any medical condition that, in the investigator’s judgment, is considered to be clinically significant and could potentially affect subject safety or study outcome, including but not limited to: clinically significant cardiac, renal, hepatic condition, or a condition that affects the absorption, distribution, metabolism or excretion of drugs
    • Have an active suicidal plan/intent or have had active suicidal thoughts in the past 6 months. Have history of suicide attempt in the last 2 years or more than 1 lifetime suicide attempt.
    • Have a history of substance abuse (alcohol or drugs) or substance dependence within 12 months prior to screening
    • Have a known hypersensitivity to any components of the study medication
    • Have taken an investigational drug, or used an investigational device, within the previous 30 days prior to screening or plans to take an investigational drug anytime during the study.

    Trial location(s)

    Location
    Status
    Contact us
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    Location
    GSK Investigational Site
    Arlington, Texas, United States, 76017
    Status
    Study Complete
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    Location
    GSK Investigational Site
    Athens, Greece, 10676
    Status
    Study Complete
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    Location
    GSK Investigational Site
    Bethesda, Maryland, United States, 20817
    Status
    Study Complete
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    Location
    GSK Investigational Site
    Colorado Springs, Colorado, United States, 80907
    Status
    Study Complete
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    Location
    GSK Investigational Site
    Fresno, California, United States, 93710
    Status
    Study Complete
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    Location
    GSK Investigational Site
    Golden Valley, Minnesota, United States, 55422
    Status
    Study Complete
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    Showing 1 - 6 of 11 Results

    Study documents

    Protocol
    Available language(s): English
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    Clinical study report
    Available language(s): English
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    Scientific result summary
    Available language(s): English
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    If you wish to request for full study report, please contact - [email protected]

    Results overview

    Results posted on ClinicalTrials.gov

    Recruitment status
    Other
    Actual primary completion date
    2013-20-06
    Actual study completion date
    2013-20-06

    Plain language summaries

    Plain language summaries of clinical trial results for Phase 2-4 clinical trials that were initiated on or after January 2022 will be posted by GSK within one year following study completion.

    Additional information about the trial

    Additional information
    Not applicable
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