Study design
This study was designed as a randomized, double-blind, placebo-controlled, multicenter bridging study in which three groups were randomly (2:2:1) treated with nalfurafine hydrochloride (5 or 2.5 μg) (Toray Industries, Inc.) or a placebo (Toray Industries, Inc.) orally after dinner once daily, as shown in detail in the Randomization Schemes in the The summary of primary endpoint.Abbreviations: FAS: full analysis set; LOCF: last-observation-carried-forward; PPS: per protocol set; LS means: least-squares means; CI: confidence interval.