A Phase 3 interventional study of Pitolisant in Prader-Willi Syndrome, sponsored by Harmony Biosciences Management, Inc.. Enrolling by invitation at 1 site in United States. Open to participants aged 7 Years and older. Per ClinicalTrials.gov, last updated 2026-03-17.
Sponsored by Harmony Biosciences Management, Inc. (part of Harmony Biosciences Holdings, Inc.) · Phase 3, Interventional, and Treatment
The purpose of this study is to assess safety of pitolisant in eligible participants with Prader-Willi syndrome (PWS) who completed the End of Treatment (EOT) visit in a parent study (HBS-101-CL-002 [Open Label Extension (OLE)], HBS- 101-CL-004, or HBS-101-CL-312 OLE).
This is a Phase 3, open-label study evaluating the long-term safety of pitolisant in approximately 150 participants with Prader-Willi syndrome who have completed participation in qualifying parent studies (HBS-101-CL-002 [OLE], HBS-101-CL-004, or HBS-101-CL-312 [OLE]).
Safety assessments will be conducted every 6 months. This study is open to participants from the qualified parent studies who were enrolled at US sites only.
144 studies on the registry are indexed under Prader-Willi Syndrome; 23 are open to participants now.
This study's planned enrollment of 150 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.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Each participant must meet the following criteria to be enrolled in this study:
Completion of an EOT visit in one of the following parent studies with pitolisant: HBS-101-CL-002 (OLE), HBS-101-CL-004, or HBS-101-CL-312 (OLE).
Note: The parent study EOT visit may be completed after the participant completes screening for study HBS-101-CL-314 to allow for continuation of study drug between the 2 studies.
Exclusion Criteria:
A participant who meets any of the following criteria will be excluded from enrollment in the study:
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
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.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Child-Pugh class
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants receive pitolisant administered orally once daily in the morning upon awakening.
Drug: Pitolisant
* Pitolisant 4.45 mg tablets * Pitolisant 17.8 mg tablets
Also known as: HBS-101
Percentage of participants reporting Treatment-Emergent Adverse Events (TEAEs)
A treatment-emergent adverse event (TEAE) is any adverse event reported during treatment with study drug in this study and up to 30 days after final dose of study drug, or any worsening of a pre-existing condition reported during treatment with study drug and up to 30 days after final dose of study drug.
Time frame: From the end of the EOT visit of the parent study through 30 days after the final dose of study drug.
Plan to share: No
No publications or documents are linked to this record.
Started Aug 2025 (actual). Primary completion is estimated for Aug 2030, 60 months after the start.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
No contact was published for this record. The registry link below has the sponsor’s details.
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Studies of the drug tested here: Pitolisant
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