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NCT Number: NCT07675135

A Phase 3 Efficacy and Safety Study of HBS-301 in Participants 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 excessive daytime sleepiness (EDS), cataplexy, sleepiness/wakefulness, and fatigue in adult participants (ages ≥18 years) with narcolepsy.

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Key information

Conditions

EDS Cataplexy Disorders of Excessive Somnolence Dyssomnias Fatigue Mental Disorders Narcolepsy Nervous System Diseases Pathological Conditions, Signs and Symptoms Signs and Symptoms Sleep Disorders, Intrinsic Sleep Wake Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Phoenix Medical Group, PC, Peoria, Arizona, United States

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About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Has a current documented diagnosis of NT1 or NT2 per the International Classification of Sleep Disorders, Third Edition (ICSD-3) or the ICSD-3 Text Revision (ICSD-3-TR) within the last 10 years.
  • Has EDS.
  • If taking a permitted chronic concomitant medication or supplement, including nonprohibited antidepressants or wake-promoting agents, must be on a stable dose for at least 3 months prior to Screening and agree to continue at that stable dose for the Double-blind Treatment Period of the study. As needed (PRN) use of any treatment that could affect daytime sleepiness (including but not limited to oxybates, stimulants, modafinil, and armodafinil) is not permitted.

Exclusion criteria

  • Has hypersomnia due to another medical disorder.
  • Has a history of pitolisant use within 5 half-lives prior to Screening.
  • Has a primary diagnosis of psychiatric illness, including depression, that is not well controlled (i.e., symptoms and medications have not been stable for at least 3 months prior to Screening).
  • Has any history of bipolar disorder or psychosis
  • Has acute or chronic liver disease or a history of moderate or severe hepatic impairment.
  • Has a body surface area-corrected estimated glomerular filtration rate (eGFR) <60 mL/min.
  • Has a known history of long QT syndrome or serious abnormality of the electrocardiogram (ECG).

Treatment and study plan

HBS-301

Drug

HBS-301 tablet

Other names: pitolisant delayed-release

Placebo

Other

Placebo tablet

Primary outcomes

  1. Change in severity of EDS as measured by the Epworth Sleepiness Scale (ESS)

    Time frame: Baseline to end of Double-Blind Treatment Period (8 weeks)

    The ESS is an 8-item, 4-point rating scale.

Secondary outcomes

  1. Change in Weekly Rate of Cataplexy (WRC) in participants with an average WRC of ≥3 over 2 consecutive weeks at Screening

    Time frame: End of the Double-Blind Treatment Period (8 weeks)

    The WRC is the average number of cataplexy attacks per week.

  2. Change in sleepiness/wakefulness measured by the Maintenance of Wakefulness Test (MWT)

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    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.

  3. Change in fatigue as measured by the Patient-Reported Outcomes Measurement Information System Fatigue Short Form 7a (PROMIS-Fatigue-SF-7a)

    Time frame: Baseline to end of Double-Blind Treatment Period (8 weeks)

    The PROMIS-Fatigue-SF-7a is a 7-question, 5-point scale used to assess fatigue.

  4. Change in severity of EDS as measured by the ESS

    Time frame: Baseline through Week 1 and through Week 2 of Titration Period (1 week and 2 weeks)

    The ESS is an 8-item, 4-point rating scale.

  5. 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

    Time frame: Baseline through Week 1 and Week 2 of the Titration Period (1 week and 2 weeks)

    The WRC is the average number of cataplexy attacks per week.

  6. Change in severity of EDS as measured by the Clinical Global Impression of Change (EDS)

    Time frame: Baseline to end of Double-blind Treatment Period (8 weeks)

    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.

  7. Change in severity of EDS as measured by the Patient Global Impression of Severity (EDS)

    Time frame: Time Frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Patient Global Impression of Severity (EDS) is a participant-reported assessment that gauges the severity of a participant's EDS symptoms.

  8. Improvement in the severity of EDS as measured by the Patient Global Impression of Change (EDS)

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Patient Global Impression of Change (EDS) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their EDS symptoms.

  9. 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

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Clinical Global Impression of Severity (Cataplexy) is a 3-item observer-rated scale used to track cataplexy symptom changes.

  10. 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

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Patient Global Impression of Severity (Cataplexy) is a participant-reported assessment that gauges the severity of cataplexy symptoms.

  11. 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

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Patient Global Impression of Change (Cataplexy) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their cataplexy symptoms.

  12. Change in severity of fatigue as measured by the Patient Global Impression of Severity (Fatigue)

    Time frame: Baseline to the end of Double-blind Treatment Period (8 weeks)

    The Patient Global Impression of Severity (Fatigue) is a participant-reported assessment that gauges the severity of a participant's fatigue symptoms.

  13. Change in severity of fatigue as measured by the Patient Global Impression of Change (Fatigue)

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Patient Global Impression of Change (Fatigue) is a participant-reported outcome used to evaluate the effectiveness of a treatment on their fatigue symptoms.

  14. 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)

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Narcolepsy Severity Scale is a 15-item participant-reported questionnaire that assesses the severity and consequences of narcolepsy symptoms.

  15. Change in cognitive complaints as measured by the British Columbia Cognitive Complaints Inventory

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The British Columbia Cognitive Complaints Inventory is a participant-reported, 6-item, 4-point scale that assesses perceived cognitive difficulties.

  16. Change in health-related quality of life as measured by the Short Form-36 physical and mental component summaries

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Short Form-36 includes 36 questions across 8 health domains to measure a participant's functional health and well-being.

  17. Change in work productivity as measured by the Work Productivity and Activity Impairment: Narcolepsy work productivity loss score

    Time frame: Baseline to the end of the Double-blind Treatment Period (8 weeks)

    The Work Productivity and Activity Impairment: Narcolepsy questionnaire is a 6-item scale used to measure impairments over 7 days.

  18. Incidence of treatment-emergent adverse events

    Time frame: Throughout study (16 months, including Open-label Extension)

    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.

  19. Evaluate the pharmacokinetic concentrations of pitolisant and major identified metabolites

    Time frame: Throughout study (16 weeks)

    Pharmacokinetics is the study of how the body interacts with administered substances for the duration of exposure.

Study contacts

Contact information is provided by the study sponsor or research team.

Katie Wilmsen

CONTACT

[email protected]

443-309-5556

Michelle Manuel

CONTACT

[email protected]

847-903-4610

Sponsors and collaborators

Lead sponsor

Harmony Biosciences Management, Inc.

Industry

Registry information

Official study title

A Phase 3, Randomized, Double-blind, Placebo-Controlled, Efficacy and Safety Study of HBS-301 in Participants With Narcolepsy Followed by an Open-label Extension

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jun 30, 2026
Registry last updated
Jun 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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