A Phase 3 interventional study of HBS-301 and Placebo in EDS, Cataplexy and Fatigue, sponsored by Harmony Biosciences Management, Inc.. Recruiting at 53 sites in 2 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-27.
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 treating excessive daytime sleepiness (EDS), cataplexy, sleepiness/wakefulness, and fatigue in adult participants (ages ≥18 years) with narcolepsy.
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 treating EDS, cataplexy, sleepiness/wakefulness, and fatigue in adult participants (ages ≥18 years) with narcolepsy.
Approximately 258 participants are planned for randomization into 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 Period (1 year), and 30 days of safety follow-up.
31 studies on the registry are indexed under Cataplexy; 5 are open to participants now.
This study's planned enrollment of 258 is above the median of 117 across 27 interventional studies indexed under Cataplexy.
Browse Cataplexy 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
Matching placebo tablets administered once daily in the morning upon wakening
Other: Placebo
HBS-301 tablets administered once daily in the morning upon wakening
Drug: HBS-301
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 end of Double-Blind Treatment Period (8 weeks)
Change in Weekly Rate of Cataplexy (WRC) in participants with an average WRC of ≥3 over 2 consecutive weeks at Screening
The WRC is the average number of cataplexy attacks per week.
Time frame: End of the Double-Blind Treatment Period (8 weeks)
Change in sleepiness/wakefulness measured by the Maintenance of Wakefulness Test (MWT)
The MWT consists of a series of 20-minute to 40-minute trials spaced 2 hours apart and is used to measure an individual's ability to stay awake.
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 (PROMIS-Fatigue-SF-7a)
The PROMIS-Fatigue-SF-7a is a 7-question, 5-point scale used to assess fatigue.
Time frame: Baseline to end of Double-Blind Treatment Period (8 weeks)
Change in severity of EDS as measured by the ESS
The ESS is an 8-item, 4-point rating scale.
Time frame: Baseline through Week 1 and through Week 2 of Titration Period (1 week and 2 weeks)
Onset of efficacy of HBS-301 compared with placebo in treating cataplexy measured by WRC in participants with an average WRC of ≥3 over 2 consecutive weeks during Screening
The WRC is the average number of cataplexy attacks per week.
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 Change (EDS)
The Clinical Global Impression of Change (EDS) is a 7-point scale used to measure the improvement or worsening of the participant's EDS relative to a baseline.
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: Time Frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Improvement in the 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: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in severity of cataplexy as measured by the Clinical Global Impression of Severity (Cataplexy) in participants with an average WRC of ≥3 over 2 consecutive weeks during Screening
The Clinical Global Impression of Severity (Cataplexy) is a 3-item observer-rated scale used to track cataplexy symptom changes.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in severity of cataplexy as measured by the Patient Global Impression of Severity (Cataplexy) in participants with an average WRC of ≥3 over 2 consecutive weeks during Screening
The Patient Global Impression of Severity (Cataplexy) is a participant-reported assessment that gauges the severity of cataplexy symptoms.
Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Improvement in severity of cataplexy as measured by the Patient Global Impression of Change (Cataplexy) in participants with an average WRC of ≥3 over 2 consecutive weeks during Screening
The Patient Global Impression of Change (Cataplexy) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their cataplexy symptoms.
Time frame: Baseline to the 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 to the end of Double-blind Treatment Period (8 weeks)
Change 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: Baseline to the end of the Double-blind Treatment Period (8 weeks)
Change in severity of narcolepsy symptoms as measured by the Narcolepsy Severity Scale (for participants with NT1) or Narcolepsy Severity Scale-2 (for participants with NT2)
The Narcolepsy Severity Scale is a 15-item participant-reported questionnaire that assesses the severity and consequences of narcolepsy symptoms.
Time frame: Baseline to the 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-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: Narcolepsy work productivity loss score
The Work Productivity and Activity Impairment: Narcolepsy 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 Open-label Extension)
Evaluate the pharmacokinetic concentrations of pitolisant and major identified metabolites
Pharmacokinetics is the study of how the body interacts with administered substances for the duration of exposure.
Time frame: Throughout study (16 weeks)
Plan to share: No
No publications or documents are linked to this record.
Started Jun 2026 (actual). Primary completion is estimated for Oct 2027, 16 months after the start.
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Studies of the drug tested here: HBS-301
Harmony Biosciences Management, Inc. →