2020 Volume 37 Issue 2 Pages 180-186
We evaluated the efficacy and safety of gabapentin enacarbil 600 mg/day for patients with restless legs syndrome in a multicentre, randomized, double–blind, placebo–controlled, parallel–group, post–marketing clinical study conducted in Japan from March 2017 to June 2018. The primary endpoint was mean change in International Restless Legs Syndrome Rating Scale (IRLS) score from baseline to the end of the treatment period (Week 12) ; secondary endpoints included mean change in IRLS score through the 12–week treatment period. Of 375 randomized patients (189 gabapentin enacarbil ; 186 placebo), 346 completed the treatment period. The difference (gabapentin enacarbil vs placebo) in the change in IRLS score was not statistically significant (adjusted mean difference : −1.2 ; 95% CI : −2.6 to 0.2 ; p＝0.088) ; however, changes in IRLS score at all time points were greater with gabapentin enacarbil than with placebo. Adverse events in ≥10% of patients that were more frequent in the gabapentin enacarbil arm were somnolence, nasopharyngitis, and dizziness. In a post–hoc analysis of data combined with a Japanese phase II/III study, the difference in the change in IRLS score was significant (adjusted mean difference : −1.7 ; 95% CI : −2.8 to −0.6 ; p＝0.002). These results suggest the clinical efficacy of gabapentin enacarbil 600 mg/day in Japanese patients with restless legs syndrome.
