This is a Phase 3, randomized, double-blind, placebo-controlled, multicenter, global clinical study to assess the efficacy and safety of pitolisant in patients living with Prader-Willi syndrome. The primary objective of this study is to evaluate the efficacy of pitolisant in treating excessive daytime sleepiness (EDS) in patients ≥6 years of age with Prader-Willi syndrome. Secondary objectives include assessing the impact of pitolisant on: Irritable and disruptive behaviors Hyperphagia Other behavioral problems including social withdrawal, stereotypic behavior, hyperactivity/noncompliance, and inappropriate speech