A Phase 3 interventional study of HBS-301 tablet and Placebo in Idiopathic Hypersomnia, sponsored by Harmony Biosciences Management, Inc.. Recruiting at 42 sites in 2 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-14.
Sponsored by Harmony Biosciences Management, Inc. (part of Harmony Biosciences Holdings, Inc.) · Phase 3, Interventional, and Treatment
This is a Phase 3, multicenter, randomized, double-blind, parallel-group, placebo-controlled clinical study to assess the efficacy and safety of HBS-301 in adult participants (ages ≥18 years) with idiopathic hypersomnia (IH).
Approximately 248 participants are planned for randomization in the study. The study will consist of a Screening/Baseline Period (up to 28 days), a Double-blind Treatment Period (8 weeks), an optional Open-label Extension (OLE) Period (1 year), and 30 days of safety follow-up.
52 studies on the registry are indexed under Idiopathic Hypersomnia; 23 are open to participants now.
This study's planned enrollment of 248 is above the median of 82 across 40 interventional studies indexed under Idiopathic Hypersomnia.
Browse Idiopathic Hypersomnia 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.
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.
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.
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.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
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.
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.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HBS-301 tablets administered once daily in the morning upon wakening
Drug: HBS-301 tablet
Matching placebo tablets administered once daily in the morning upon wakening
Drug: Placebo
HBS-301 tablets administered once daily in the morning upon wakening
Drug: HBS-301 tablet
HBS-301 tablet
Also known as: pitolisant delayed-release
Placebo tablet
Change in severity of EDS as measured by the Epworth Sleepiness Scale (ESS)
The ESS is an 8-item, 4-point rating scale.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in severity of IH symptoms as measured by the Idiopathic Hypersomnia Severity Scale (IHSS)
The IHSS is a 14-item questionnaire designed to measure IH symptoms.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in sleep inertia as measured by the Sleep Inertia Questionnaire (SIQ)
The SIQ is a 22-item questionnaire that measures aspects of night and day sleep symptoms and the sleep inertia related to each.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in fatigue as measured by the Patient-Reported Outcomes Measurement Information System Fatigue Short Form 7a
The PROMIS-Fatigue-SF-7a is a 7-question, 5-point scale used to assess fatigue.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in severity of EDS as measured by the Epworth Sleepiness Scale
The ESS is an 8-item, 4-point rating scale.
Time frame: Baseline through Week 1 and Week 2 of the Titration Period (1 week and 2 weeks)
Change in severity of IH symptoms as measured by the IHSS
The ESS is an 8-item, 4-point rating scale.
Time frame: Baseline through Week 1 and Week 2 of the Titration Period (1 week and 2 weeks)
Change in severity of EDS as measured by the Clinical Global Impression of Severity (EDS)
The Clinical Global Impression of Severity (EDS) is a 5-item observer-rated scale that gauges the severity of a participant's EDS symptoms.
Time frame: Baseline to end of Double-blind Treatment Period (8 weeks)
Change in severity of EDS as measured by the Patient Global Impression of Severity (EDS)
The Patient Global Impression of Severity (EDS) is a participant-reported assessment that gauges the severity of a participant's EDS symptoms.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Improvement in severity of EDS as measured by the Patient Global Impression of Change (EDS)
The Patient Global Impression of Change (EDS) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their EDS symptoms.
Time frame: End of the Double-blind Treatment Period (8 weeks)
Change in severity of IH symptoms as measured by the Clinical Global Impression of Severity (IH)
The Clinical Global Impression of Severity (IH) is a 3-item observer-rated scale used to track IH symptom changes.
Time frame: Baseline to end of Double-blind Treatment Period (8 weeks)
Change in severity of IH symptoms as measured by the Patient Global Impression of Severity (IH)
The Patient Global Impression of Severity (IH) is a participant-reported assessment that gauges the severity of a participant's IH symptoms.
Time frame: Baseline to end of Double-blind Treatment Period (8 weeks)
Improvement in severity of IH symptoms as measured by the Patient Global Impression of Change (IH)
The Patient Global Impression of Change (IH) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their IH symptoms.
Time frame: Baseline to end of Double-blind Treatment Period (8 weeks)
Change in severity of sleep inertia as measured by the Patient Global Impression of Severity (Sleep Inertia)
The Patient Global Impression of Severity (Sleep Inertia) is a participant-reported assessment that gauges the severity of a participant's sleep inertia symptoms.
Time frame: Baseline to end of Double-blind Treatment Period (8 weeks)
Improvement in severity of sleep inertia as measured by the Patient Global Impression of Change (Sleep Inertia)
The Patient Global Impression of Change (Sleep Inertia) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their sleep inertia symptoms.
Time frame: End of the Double-blind Treatment Period (8 weeks)
Change in severity of fatigue as measured by the Patient Global Impression of Severity (Fatigue)
The Patient Global Impression of Severity (Fatigue) is a participant-reported assessment that gauges the severity of a participant's fatigue symptoms.
Time frame: Baseline of the end of the Double-blind Treatment Period (8 weeks)
Improvement in severity of fatigue as measured by the Patient Global Impression of Change (Fatigue)
The Patient Global Impression of Change (Fatigue) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their fatigue symptoms.
Time frame: End of the Double-blind Treatment Period (8 weeks)
Change in cognitive complaints as measured by the British Columbia Cognitive Complaints Inventory
The British Columbia Cognitive Complaints Inventory is a participant-reported, 6-item, 4-point scale that assesses perceived cognitive difficulties.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in health-related quality of life as measured by the Short Form Health Survey-36 physical and mental component summaries
The Short Form-36 includes 36 questions across 8 health domains to measure a participant's functional health and well-being.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in work productivity as measured by the Work Productivity and Activity Impairment: Idiopathic Hypersomnia Work Productivity loss score
The Work Productivity and Activity Impairment: Idiopathic Hypersomnia questionnaire is a 6-item scale used to measure impairments over 7 days.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Incidence of treatment-emergent adverse events
A treatment-emergent adverse event 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: Throughout study (16 months including OLE)
Plan to share: No
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Studies of the drug tested here: HBS-301
Harmony Biosciences Management, Inc. →