Long-Term Safety Study of Retigabine Immediate Release (IR) as Adjunctive Therapy in the Treatment of Adults With Partial-Onset Seizures (POS)

NCT ID: NCT01336621

Last Updated: 2020-03-11

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE3
• Total Enrollment: 98 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2011-02-21
• Study Completion Date: 2017-09-13

Brief Summary

The purpose of this Phase III study is to assess the long-term safety, tolerability and efficacy of flexibly dosed retigabine Immediate Release (IR) as adjunctive therapy in adult subjects with partial-onset seizures. In addition, those subjects who successfully completed 20 weeks of adjunctive treatment with retigabine IR in the parent study, RGB113905, and who were thought to have benefitted from treatment will be provided continued access to retigabine IR.

Detailed Description

RTG113413 is an open-label, multicentre extension study of RGB113905. This study will enroll adult subjects with partial-onset seizures (POS) who successfully completed 20 weeks of adjunctive treatment with retigabine IR (4-weeks Titration Phase and 16-weeks Flexible Dose Evaluation Phase) in the parent study, RGB113905 and who were thought to have benefitted from the treatment.

The Screening Visit (Visit 1) will be performed on the same day as the final visit of the parent study (Visit 7/Week 20). Subjects entering the extension study will initially receive the same dose of retigabine IR and concurrent antiepileptic drug (AED) as they were receiving on the final visit of the parent study. After the first week of the extension study, the subject's retigabine dose can be adjusted based on efficacy and tolerability. The overall daily dose of retigabine IR must be maintained between 300 mg/day (minimum) and 1200 mg/day (maximum). In addition, the dose and the number of concurrent AEDs can be adjusted to meet the individual needs of the subject. Retigabine IR monotherapy is not permitted. If concurrent AED therapy is removed, the subject must be withdrawn from the study.

Subjects in this study will be eligible to receive retigabine IR treatment until one of the following criteria have been met: 1) regulatory approval and commercial availability of retigabine IR or 2) retigabine IR is not approved by the regulatory authorities or 3) the study is terminated by the sponsor for reasons including, but not limited to, safety issues or 4) subject is withdrawn or withdraws consent or 5) subject has received retigabine IR treatment for a total of 3 years and options i-iv have not been met. After the Screening Visit, subjects will be required to attend 4 further clinic visits at Weeks 13, 26, 39, and 52 in the first year of the study and a total of 3 clinic visits at approximately 4-monthly intervals during each of the second and third year of study. Upon completion or early withdrawal, subjects will begin a 3-week taper period and then return for a follow-up visit.

Conditions

Epilepsy

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Retigabine IR

Open label flexible dose between 300 mg/day (Minimum) and 1200 mg/day (maximum).

Group Type: EXPERIMENTAL

Retigabine IR

Intervention Type: DRUG

Flexible dose between 300 mg/day (minimum) and 1200 mg/day (maximum)

Interventions

Retigabine IR

Flexible dose between 300 mg/day (minimum) and 1200 mg/day (maximum)

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

• The subject has successfully completed the 20-weeks (4-weeks Titration and 16-weeks of Flexible Dose Evaluation Phases) of treatment with retigabine IR as adjunctive therapy to one of the pre-specified AEDs in the parent study RGB113905.
• The investigator and the subject, or caregiver, if applicable, should consider it beneficial for the subject to receive continued retigabine IR therapy.
• The subject is able and willing to maintain an accurate and complete daily written Seizure Calendar or has a caregiver who is able and willing to maintain an accurate and complete daily written Seizure Calendar for the entire duration of the study.
• The subject has given written informed consent, or has a legally authorized representative who has given written informed consent, prior to the performance of any study assessments.
• A female subject is eligible to enter and participate in the study if she is of non-childbearing potential (i.e., physiologically incapable of becoming pregnant, including any female who is pre- menarcheal or post menopausal).
• A female subject is eligible to enter and participate in the study if she is child-bearing potential and has a negative pregnancy test at Screening, and agrees to use one of the contraceptive methods listed in Appendix 3 of the protocol.
• A female subject is eligible to enter and participate in the study if she not pregnant or lactating or planning to become pregnant during the study.
• French subjects only: In France, a subject will be eligible for inclusion in this study only if either affiliated to or a beneficiary of a social security category.

Exclusion Criteria

• Has met any of the withdrawal criteria in the previous RGB113905 study or has clinically significant abnormal clinical laboratory or ECG findings not resolved prior to entry to the open-label extension study.
• Is suffering from acute or progressive neurological disease, severe psychiatric disease, or severe mental abnormalities that are likely to interfere with the study objectives.
• Has 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.
• Has any abnormality on 12-lead ECG at Screening which is clinically significant in the opinion of the investigator, or has QTc (either QTcB Bazett's correction or QTcF Fridericia's correction) >500 msec or >530 msec for subjects with Bundle Branch Block or an increase in QTc of >60 msec from Baseline in the parent study.
• Is unwilling or inability to follow the study procedures or reporting of AEs.
• Is planning on following a ketogenic diet or planning surgery or implantation of a Vagus Nerve Stimulator (VNS) to control seizures during the study. Note: Subjects who already have a VNS implanted which is functional may be permitted to enter the study.
• Has active suicidal plan/intent or has had active suicidal thoughts in the past 6 months. Has history of suicide attempt in the last 2 years or more than 1 lifetime suicide attempt.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

GlaxoSmithKline

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

GSK Clinical Trials

Role: STUDY_DIRECTOR

GlaxoSmithKline

Locations

GSK Investigational Site

Ghent, , Belgium

GSK Investigational Site

Plovdiv, , Bulgaria

GSK Investigational Site

Sofia, , Bulgaria

GSK Investigational Site

Sofia, , Bulgaria

GSK Investigational Site

Limoges, , France

GSK Investigational Site

Strasbourg, , France

GSK Investigational Site

Bielefeld, North Rhine-Westphalia, Germany

GSK Investigational Site

Foggia, Apulia, Italy

GSK Investigational Site

Bologna, Emilia-Romagna, Italy

GSK Investigational Site

Rome, Lazio, Italy

GSK Investigational Site

Rome, Lazio, Italy

GSK Investigational Site

Genoa, Liguria, Italy

GSK Investigational Site

Torrette Di Ancona, The Marches, Italy

GSK Investigational Site

Pisa, Tuscany, Italy

GSK Investigational Site

Heemstede, , Netherlands

GSK Investigational Site

Warsaw, , Poland

GSK Investigational Site

Belgorod, , Russia

GSK Investigational Site

Kazan', , Russia

GSK Investigational Site

Krasnodar, , Russia

GSK Investigational Site

Moscow, , Russia

GSK Investigational Site

Moscow, , Russia

GSK Investigational Site

Saint Petersburg, , Russia

GSK Investigational Site

Samara, , Russia

GSK Investigational Site

Smolensk, , Russia

GSK Investigational Site

Bangkok, , Thailand

GSK Investigational Site

Khon Kaen, , Thailand

GSK Investigational Site

Dnipro, , Ukraine

GSK Investigational Site

Luhansk, , Ukraine

GSK Investigational Site

Odesa, , Ukraine

GSK Investigational Site

Oleksandrivka Village, Odesa, , Ukraine

GSK Investigational Site

Poltava, , Ukraine

Countries

Belgium; Bulgaria; France; Germany; Italy; Netherlands; Poland; Russia; Thailand; Ukraine

Other Identifiers

2010-022777-34

Identifier Type: EUDRACT_NUMBER

Identifier Source: secondary_id

113413

Identifier Type: -

Identifier Source: org_study_id