Randomized polysomnography study of gabapentin enacarbil in subjects with restless legs syndrome.

We assessed the efficacy and tolerability of gabapentin enacarbil in the treatment of moderate to severe primary restless legs syndrome and associated sleep disturbance. This was a multicenter, randomized, double-blind, placebo-controlled, 2-period crossover polysomnography study of gabapentin enacarbil 1200 mg or placebo taken once daily. Subjects were randomized 1:1 to a sequence of gabapentin enacarbil:placebo or placebo:gabapentin enacarbil, receiving each treatment for 4 weeks. The primary end point was the mean change from baseline at weeks 4 and 10 (4/10) last observation carried forward in wake time during sleep. The key secondary end point was the mean change from baseline at weeks 4/10 last observation carried forward in periodic limb movements associated with arousal per hour of sleep. Tolerability assessments included adverse events. One hundred thirty-six subjects were randomized (gabapentin enacarbil:placebo, 67; placebo:gabapentin enacarbil, 69), and 114 (gabapentin enacarbil:placebo, 53; placebo:gabapentin enacarbil, 61) completed the study. Gabapentin enacarbil 1200 mg significantly reduced wake time during sleep (mean change from baseline [adjusted mean treatment difference]: -26.0 minutes; P < .0001) and periodic limb movements associated with arousal per hour of sleep (adjusted mean treatment difference: -3.1 periodic limb movements with arousal/hour; P = .002) compared with placebo at weeks 4/10 last observation carried forward. The most commonly reported adverse events were dizziness (gabapentin enacarbil 20%, placebo 2%) and somnolence (gabapentin enacarbil 13%, placebo 2%). Gabapentin enacarbil 1200 mg once daily significantly reduces restless legs syndrome-associated sleep disturbance and periodic limb movements associated with arousal per hour of sleep and is generally well tolerated in adults with moderate to severe primary restless legs syndrome.