Dose-Response and Pharmacokinetics of Gabapentin Enacarbil (GEn [XP13512 / GSK1838262]) in Restless Legs Syndrome (XP081)
This was a multicenter, randomized, double blind, placebo controlled, parallel group study, comparing 4 doses of GEn (XP13512) with placebo given once daily to subjects with RLS. Eligible subjects were randomized in equal numbers into 1 of 5 treatment groups (GEn 600 mg, 1200 mg, 1800 mg, or 2400 mg or placebo) for 12 weeks of treatment. The objective of the study was to generate the data necessary to determine the gabapentin exposure produced by 4 dose levels of GEn (600 mg, 1200 mg, 1800 mg, and 2400 mg) or placebo, and the corresponding relief of symptoms in subjects with Restless Legs Syndrome (RLS). Data from this study will be utilized as part of a larger pharmacokinetic (PK) pharmacodynamic (PD) analysis of data from several studies (XP084/RXP111495) that are part of the GEn RLS clinical development program. Safety and tolerability were also assessed.
Restless Legs Syndrome
Drug: GEn (XP13512/GSK1838262)
Drug: placebo comparator
|Study Design:||Allocation: Randomized
Endpoint Classification: Pharmacokinetics Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
|Official Title:||A Randomized, Double-Blind, Placebo-Controlled, Dose-Response Study to Assess the Efficacy, Safety, and Pharmacokinetics of XP13512 (GSK1838262) in Patients With Restless Legs Syndrome|
- Mean Css, Max and Css, Min [ Time Frame: Weeks 4 and 12 ] [ Designated as safety issue: No ]Css, max is defined as the maximum or "peak" concentration of a drug observed after multiple administration, at steady state. Css, max is one of the parameters of particular use in estimating the bioavailability of drugs, by measuring the total amount of drug absorbed. Css, min is defined as the minimum concentration of a drug observed after its administration, in steady state. ng, nanograms; PK, pharmacokinetic; W, week; BLQ, below limit of quantitation.
- Mean Tmax and T1/2 [ Time Frame: Weeks 4 and 12 ] [ Designated as safety issue: No ]Tmax is defined as the time to the maximum or "peak" concentration of a drug observed after multiple administration. T1/2 is defined as the time to when half of the total amount of a particular substance is eliminated from the body.
- Mean AUCss [ Time Frame: Weeks 4 and 12 ] [ Designated as safety issue: No ]The area under the plot of plasma concentration of drug against time after drug administration is defined as the area under the curve (AUC). The AUCss is the area under the curve during the steady-state period. The AUCss is of particular use in estimating the bioavailability of drugs, by measuring the extent of absorption. AUCss used concentration data from 0 to 24 hours at steady-state for Weeks 4 and 12.
|Study Start Date:||January 2007|
|Study Completion Date:||January 2008|
|Primary Completion Date:||January 2008 (Final data collection date for primary outcome measure)|
|Experimental: GEn (XP13512/GSK1838262) 600 mg||Drug: GEn (XP13512/GSK1838262)|
|Experimental: GEn (XP13512/GSK1838262) 1200 mg||Drug: GEn (XP13512/GSK1838262)|
|Experimental: GEn (XP13512/GSK1838262) 1800 mg||Drug: GEn (XP13512/GSK1838262)|
|Experimental: GEn (XP13512/GSK1838262) 2400 mg||Drug: GEn (XP13512/GSK1838262)|
|Placebo Comparator: Placebo||Drug: placebo comparator|