A Phase 3 interventional study of Pitolisant tablet and Placebo tablet in Prader-Willi Syndrome, sponsored by Harmony Biosciences Management, Inc.. Recruiting at 57 sites in 13 countries. Open to participants aged 6 Years and older. Per ClinicalTrials.gov, last updated 2026-08-25.
Sponsored by Harmony Biosciences Management, Inc. (part of Harmony Biosciences Holdings, Inc.) · Phase 3, Interventional, and Treatment
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
The study will consist of an up to 45-day Screening/Baseline Period, a Double-Blind Treatment Period, and an optional Open-Label Extension Period.
After completion of all Baseline assessments, patients who meet all eligibility criteria will be randomized 1:1 to receive once daily pitolisant or matching placebo. During the Double-Blind Treatment Period, in-person visits will be at Day 29, Day 57, and Day 77. Patients who do not elect to enter the Open-Label Extension Period will have follow-up visits 15 days and 30 days after the final dose of study drug.
During the optional Open-Label Extension Period, in-person visits will be at Day 113, Day 260, and Day 441. Patients will have follow-up visits 15 days and 30 days after the final dose of pitolisant.
144 studies on the registry are indexed under Prader-Willi Syndrome; 23 are open to participants now.
This study's planned enrollment of 134 is above the median of 30 across 100 interventional studies indexed under Prader-Willi Syndrome.
Browse Prader-Willi Syndrome studies →Harmony Biosciences Management, Inc. is the lead sponsor of 16 studies on the registry; 6 are open to participants now.
Of its 8 completed or terminated interventional studies of FDA-regulated products, 4 (50%) have results posted.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Pitolisant tablets administered once daily in the morning upon wakening
Drug: Pitolisant tablet
Matching placebo administered tablets once daily in the morning upon wakening
Other: Placebo tablet
Pitolisant tablets administered once daily in the morning upon wakening
Drug: Pitolisant tablet
Pitolisant tablet
Also known as: pitolisant
Placebo tablet
Also known as: placebo
Change in severity of EDS as measured by Patient-Reported Outcomes Measurement Information System Bank v1.0 - Sleep-Related Impairment (PROMIS-SRI) T-score
The PROMIS-SRI item bank consists of 13 items with a 5-point rating scale.
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Change in severity of irritable and disruptive behaviors as measured by the Aberrant Behavior Checklist-Community, Second Edition (ABC-C) Irritability domain
The ABC-C is a 58-item questionnaire, divided into 5 subscales (Irritability, Social Withdrawal, Stereotypic Behavior, Hyperactive/Noncompliance, and Inappropriate Speech).
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Change in overall severity of EDS as measured by the Caregiver Global Impression of Severity for Excessive Daytime Sleepiness (CaGI-S for EDS)
The CaGI-S for EDS is a 1-item, 5-point rating scale.
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Change in overall severity of EDS as measured by the Clinical Global Impression of Severity for Excessive Daytime Sleepiness (CGI-S for EDS)
The CGI-S for EDS is a 1-item, 5-point rating scale.
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Change in overall severity of irritable and disruptive behaviors as measured by the Caregiver Global Impression of Severity (CaGI-S) for Irritable and/or Disruptive Behaviors
The CaGI-S for Irritable and/or Disruptive Behaviors is a 1-item, 5-point rating scale.
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Change in severity of hyperphagia as measured by the Hyperphagia Questionnaire for Clinical Trials (HQ-CT), in conjunction with the Food Safe Zone Questionnaire (FSZQ)
The HQ-CT is a 9-item measure of food-related preoccupations and problems. The FSZQ is a 20-item measure of environmental controls to manage hyperphagia.
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Change in severity of EDS as measured by the Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD [parent/caregiver version]) total score
The ESS-CHAD (parent/caregiver version) is an 8-item, 4-point rating scale.
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Change in severity of other behavioral problems as measured by the Aberrant Behavior Checklist-Community, Second Edition (ABC-C) Hyperactivity/Noncompliance, Inappropriate Speech, Social Withdrawal, and Stereotypic Behavior Domains
The ABC-C is a 58-item questionnaire, divided into 5 subscales (Irritability, Social Withdrawal, Stereotypic Behavior, Hyperactive/Noncompliance, and Inappropriate Speech).
Time frame: Baseline and end of the Double Blind Treatment Period (Day 77)
Percentage of patients reporting TEAEs
A treatment-emergent adverse events is any adverse event reported after the first dose of study drug and up to 30 days after final dose of study drug, or any worsening of a pre-existing condition reported after first dose of study drug and up to 30 days after final dose of study drug.
Time frame: Baseline up to Day 441
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Studies of the drug tested here: Pitolisant
Harmony Biosciences Management, Inc. →