A Phase 2 Study to Evaluate the Safety and Efficacy of Pitolisant in Patients With Prader-Willi Syndrome, Followed by an Open Label Extension

Inclusion criteria

• ✓. Is able to provide voluntary, written informed consent (patient or parent\[s\]/legal guardian\[s\]) and, where applicable, voluntary, written assent (patient, as appropriate).
• ✓. Has a diagnosis of PWS confirmed by genetic testing and/or patient medical records. Genetic testing will be provided by the Sponsor, if not confirmed based on the review of the patient's medical records.
• ✓. Male or female patients ages 6 to 65 years at the time of enrollment.
• ✓. Demonstrates adequate sleep duration via patient sleep diary during Screening, defined as at least 8 hours of sleep per night for patients ages 6 to \<12 years, at least 7 hours for patients ages 12 to \<18 years, or at least 6 hours for patients ages ≥18 years, based on the mean number of hours from up to 14 nights (at least 7 nights must be recorded for evaluation).
• ✓. Has EDS as determined by Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD) (parent/caregiver version) score of ≥12.
• ✓. If taking hormone treatments (including growth hormone, testosterone, and estrogen supplements) and/or allowed chronic concomitant medication or supplements, patient must be on a stable dose of these medications for 3 months prior to randomization and for the duration of the Double-Blind Treatment Phase of the study; a 10% variability in hormone dose is allowed.
• ✓. If taking a wake-promoting treatment that could affect EDS (including stimulants, modafinil, and armodafinil), must be on a stable dose for at least 28 days prior to Screening and remain on a stable dose during the Double-Blind Treatment Phase of the study (dose adjustments will be permitted in the OLE Phase) or agree to wash out of treatment for 5 half-lives or 14 days, whichever is longer.
• ✓. If taking a chronically administered sedating medication for management of behavioral manifestations (e.g., hypnotics, benzodiazepines, antipsychotics, alpha agonists, anticholinergics, and antidepressants) must be on a stable dose for at least 28 days prior to Screening and remain on a stable dose during the Double-Blind Treatment Phase of the study (dose adjustments will be permitted in the OLE Phase) or agree to wash out of treatment for 5 half-lives or 14 days, whichever is longer.