A Study of Pitolisant in Patients With Prader-Willi Syndrome

Prader-Willi Syndrome (PWS) is a genetic condition that affects growth, metabolism, and behavior. This study tests a medicine called pitolisant to see if it helps with daytime sleepiness and behavior problems in people with PWS who are 6 years or older. Daytime sleepiness means feeling very tired during the day. The study will also look at other problems like irritability, excessive eating (called hyperphagia), and behavior issues like being too active or not following instructions.

The study has three parts: a screening period up to 45 days, a treatment period, and an optional extension period. During the treatment period, participants will visit the study center three times over 77 days. If they join the extension period, there will be three more visits, ending at Day 441.

• Visits are required at specific days during the study.
• Participants will be randomly assigned to receive either pitolisant or a placebo, which is a look-alike pill with no active ingredients.
• Participants cannot have uncontrolled sleep apnea or be part of another study recently.