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Meta-Analysis Plan for Pooled Data for Studies VRX-RET-E22-303 and VRX-RET-E22-304

This study has been completed.
Information provided by (Responsible Party):
GlaxoSmithKline Identifier:
First received: October 20, 2011
Last updated: October 25, 2012
Last verified: October 2012
The objective of this meta-analysis is to provide data on long-term safety and efficacy following the recent positive Committee for Medicinal Products for Human Use (CHMP) opinion for retigabine using pooled data from ongoing open-label extension (OLE) Studies VRX-RET-E22-303 and VRX-RET-E22-304.

Condition Intervention
Epilepsy, Partial
Drug: retigabine/ezogabine

Study Type: Observational
Study Design: Time Perspective: Prospective
Official Title: Meta-Analysis of VRX-RET-E22-303 and VRX-RET-E22-304: Two Multicenter, Open-Label, Long-Term, Safety, Tolerability and Efficacy Studies of Retigabine in Adult Epilepsy Patients With Partial-onset Seizures (Extensions of Studies VRX-RET-E22-301 and VRX-RET-E22-302)

Resource links provided by NLM:

Further study details as provided by GlaxoSmithKline:

Primary Outcome Measures:
  • Incidence of Adverse Events [ Time Frame: during open-label drug exposure up to database cutoff (max 40 months) ]
    Adverse events were the primary means to assess safety.

Secondary Outcome Measures:
  • Time to Discontinuation [ Time Frame: during open-label extension up to date of discontinuation; subjects who continue in the study are censored at database cutoff (max 40 months) ]
    Time to discontinuation in number of days since first dose in open-label extension until subject discontinues

  • The number and percent of subjects exposed to study drug [ Time Frame: for at least 3, 6, 12, 18, 24 and 32 months ]
    The number and percent of subjects exposed to study drug

  • Listing of abnormal liver function test results and liver adverse events [ Time Frame: during open-label drug exposure up to database cutoff (max 40 months) ]
    Abnormal lab results if reported as adverse events or values of alkaline phosphatase, alanine transaminase, aspartate transaminase [>3, >5, >10xupper limit of normal (ULN)] or total bilirubin (>1.5, >2, >4xULN); treatment emergent adverse events related to liver function test abnormalities

  • Observed values and change from baseline summaries for American Urological Association symptom index scores, Post-Void Residual bladder ultrasound, Vital Signs and Weight [ Time Frame: baseline (parent study) and at 1, 3, 12, 24 and 36 months ]
    Univariate statistics summarizing the observed values and change from baseline, using parent study baseline value

  • Percent change from baseline in seizure frequency [ Time Frame: entire open-label extension period up to database cutoff (max 40 months) ]
    Percent change from baseline in 28-day total partial seizure frequency, using parent study baseline value.

  • Number and percent of responders [ Time Frame: entire open-label extension period up to database cutoff (max 40 months) ]
    Number and percent of responders (defined as subjects with >=50% reduction from baseline in 28-day total partial seizure frequency) using parent study baseline value

  • Number and percent of seizure free subjects [ Time Frame: during open-label drug exposure up to database cutoff (max 40 months) ]
    Percent of subjects seizure free for any 6 continuous months or longer for subjects treated for at least 6, 12 and 24 months; percent of seizure free subjects for any 12 continuous months or longer for subjects treated for at least 12 and 24 months

  • Proportion of subjects retained in the study [ Time Frame: at 3, 6, 12, 24 and 32 months after exposure to first dose in open-label extension study. ]
    Length of time subjects retained in OLE as summarized by proportion of subjects remaining in both studies at given timepoints.

  • Mean of average dose [ Time Frame: entire open-label drug extension period up to database cutoff (max 40 months) ]
    Mean average dose for all subjects combined and by modal dose category [the range of doses (<=750 mg/day, >750 to 1050 mg/day, >1050 mg/day) taken most frequently].

Enrollment: 1
Study Start Date: August 2011
Study Completion Date: August 2011
Primary Completion Date: August 2011 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
retigabine/ezogabine; dose range up to 1200 mg/day
Drug: retigabine/ezogabine
dose range up to 1200 mg/day
Other Name: Trobalt

Detailed Description:
Data from the October 2009 data-cut of ongoing Studies VRX-RET-E22-303 (Study 303) and VRX-RET-E22-304 (Study 304) will be pooled, summarized, and published with the goal of providing updated long-term safety and efficacy information for subjects and prescribers following the recent positive CHMP opinion for retigabine for adjunctive use in patients with partial seizures. Studies 303 and 304 are the open-label extensions of two Phase 3 studies (VRX-RET-E22-301 and VRX-RET-E22-302), respectively. Studies 301 and 302 were randomized, double-blind, placebo-controlled, parallel-group, multicenter studies of 600 mg and 900 mg per day (Study 302) and 1200 mg per day (Study 301). All subjects who wished to enter the OLE studies and, in the opinion of the investigator, were expected to benefit from participation in the OLEs, entered a 6-week (Study 301) or 4-week (Study 302) transition phase in which their dose of retigabine was titrated to or maintained at 400 mg TID (Study 301) or 300 mg TID (Study 302). Upon completion of the Transition phase, subjects enrolled into the extension studies. Once enrolled in the OLE, doses could be adjusted within the range of 600 mg to 1200 mg per day. Treatment in Studies 303 and 304 is planned to continue until regulatory approval and commercialization of retigabine or until the program is discontinued.

Ages Eligible for Study:   18 Years to 75 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Adult patients with partial onset seizures who have successfully completed the transition phase of VRX-RET-E22-301 and VRX-RET-E22-302.
This is meta-analysis therefore Inclusion/Exclusion criteria are not applicable.
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Please refer to this study by its identifier: NCT01457989

Sponsors and Collaborators
Study Director: GSK Clinical Trials GlaxoSmithKline
  More Information

Responsible Party: GlaxoSmithKline Identifier: NCT01457989     History of Changes
Other Study ID Numbers: 115476
Study First Received: October 20, 2011
Last Updated: October 25, 2012

Keywords provided by GlaxoSmithKline:
retention rate
responder rate
seizure freedom
discontinuation rate
safety assessment
reduction in seizure frequency

Additional relevant MeSH terms:
Epilepsies, Partial
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action processed this record on May 24, 2017