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NCT Number: NCT07500090

A Phase 3 Efficacy and Safety Study of HBS-301 in Participants With Idiopathic Hypersomnia (IH)

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).

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Key information

Conditions

Idiopathic Hypersomnia Disorders of Excessive Somnolence Dyssomnias Fatigue Mental Disorders 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

Sleep Disorders Center of Alabama, Birmingham, Alabama, United States

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About this study

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.

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 IH per the International Classification of Sleep Disorders, Third Edition (ICSD-3) or Text Revision (ICSD-3-TR) criteria with confirmatory polysomnogram (PSG) with multiple sleep latency test (MSLT; and if applicable, a 24-hour PSG report or an actigraphy report with sleep log) on file that led to the diagnosis and was completed within the last 10 years.
  • Has EDS.
  • Has moderate to very severe symptoms of IH.
  • 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 use of any treatment that could affect daytime sleepiness (including but not limited to stimulants, modafinil, and armodafinil) used on an as-needed basis 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.
  • Has a history of moderate or severe hepatic impairment.
  • Has a body surface area (BSA)-corrected estimated glomerular filtration rate (eGFR) <60 mL/min.
  • Has a known history of long QT syndrome or any significant history of a serious abnormality of the electrocardiogram (ECG).

Treatment and study plan

HBS-301 tablet

Drug

HBS-301 tablet

Other names: pitolisant delayed-release

Placebo

Drug

Placebo tablet

Primary outcomes

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

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

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

Secondary outcomes

  1. Change in severity of IH symptoms as measured by the Idiopathic Hypersomnia Severity Scale (IHSS)

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

    The IHSS is a 14-item questionnaire designed to measure IH symptoms.

  2. Change in sleep inertia as measured by the Sleep Inertia Questionnaire (SIQ)

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

    The SIQ is a 22-item questionnaire that measures aspects of night and day sleep symptoms and the sleep inertia related to each.

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

    Time frame: Baseline to the end of the 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 Epworth Sleepiness Scale

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

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

  5. Change in severity of IH symptoms as measured by the IHSS

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

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

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

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

    The Clinical Global Impression of Severity (EDS) is a 5-item observer-rated scale that gauges the severity of a participant's EDS symptoms.

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

    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 severity of EDS as measured by the Patient Global Impression of Change (EDS)

    Time frame: 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 IH symptoms as measured by the Clinical Global Impression of Severity (IH)

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

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

  10. Change in severity of IH symptoms as measured by the Patient Global Impression of Severity (IH)

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

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

  11. Improvement in severity of IH symptoms as measured by the Patient Global Impression of Change (IH)

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

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

  12. Change in severity of sleep inertia as measured by the Patient Global Impression of Severity (Sleep Inertia)

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

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

  13. Improvement in severity of sleep inertia as measured by the Patient Global Impression of Change (Sleep Inertia)

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

    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.

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

    Time frame: Baseline of the end of the 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.

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

    Time frame: 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.

  16. 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.

  17. Change in health-related quality of life as measured by the Short Form Health Survey-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.

  18. Change in work productivity as measured by the Work Productivity and Activity Impairment: Idiopathic Hypersomnia Work Productivity loss score

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

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

  19. Incidence of treatment-emergent adverse events

    Time frame: Throughout study (16 months including OLE)

    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.

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 Idiopathic Hypersomnia (IH) Followed by an Open-label Extension

Important dates

Study start
2026
Primary completion
2027
Study completion
2028
First posted
Mar 30, 2026
Registry last updated
Jul 2, 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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