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

June 30, 2026 updated by: Harmony Biosciences Management, Inc.

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

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).

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

248

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35213
        • Recruiting
        • Sleep Disorders Center of Alabama
        • Contact:
    • California
      • Redwood City, California, United States, 94063
        • Recruiting
        • Stanford Center for Sleep Medicine
        • Principal Investigator:
          • Oliver Sum-Ping, MD
      • Santa Monica, California, United States, 90404
        • Recruiting
        • Santa Monica Clinical Trials
        • Principal Investigator:
          • Daniel Norman, MD
        • Contact:
          • Jualynda Smith
    • Colorado
      • Boulder, Colorado, United States, 80301
        • Recruiting
        • Alpine Clinical Research Center, Inc.
        • Contact:
    • Florida
      • Miami, Florida, United States, 33176
        • Recruiting
        • PharmDev Research Institute, LLC
        • Principal Investigator:
          • Edward Mezerhane, MD
        • Contact:
          • Lisbet Machado Cordova, APRN
      • Winter Park, Florida, United States, 32789
        • Recruiting
        • Central Florida Pediatric Sleep Disorders Institute (Florida Pediatric Research Institute, LLC)
        • Contact:
          • Akinyemi Ajayi, MD
    • Georgia
      • Atlanta, Georgia, United States, 30328
        • Recruiting
        • NeuroTrials Research Inc.
        • Contact:
          • Dennis Lacey, MD
        • Contact:
          • Melody
        • Principal Investigator:
          • Dennis Lacey, MD
      • Macon, Georgia, United States, 31210
      • Stockbridge, Georgia, United States, 30281
        • Recruiting
        • Phillip Nowlin
        • Contact:
          • Phillip Nowlin, MD
    • Michigan
      • Southfield, Michigan, United States, 48975
        • Recruiting
        • Revive Research Institute
        • Principal Investigator:
          • Syed Muhammad Talib Rizvi Raza, MD
    • Missouri
      • Chesterfield, Missouri, United States, 63017
        • Recruiting
        • St. Luke's Hospital, Sleep Medicine and Research Center
        • Principal Investigator:
          • Michael McLeland, PhD
        • Contact:
          • Michael McLeland, PhD
    • North Carolina
      • Gastonia, North Carolina, United States, 28054
        • Recruiting
        • Clinical Research of Gastonia
        • Contact:
        • Contact:
        • Principal Investigator:
          • Anup Banerjee, MD
      • Huntersville, North Carolina, United States, 28078
        • Recruiting
        • Stern Research Partners, LLC
        • Principal Investigator:
          • Thomas Stern, MD
        • Contact:
      • Morrisville, North Carolina, United States, 27560
        • Recruiting
        • David Kudrow, MD
        • Contact:
          • David Kudrow, MD
    • Pennsylvania
      • West Chester, Pennsylvania, United States, 19380
        • Recruiting
        • Suburban Research Associates
        • Principal Investigator:
          • Omer Abdullah, MD
      • Wyomissing, Pennsylvania, United States, 19610
        • Recruiting
        • Respiratory Specialists
        • Principal Investigator:
          • Alec Platt, MD
        • Contact:
          • Alex Platt, MD
    • South Carolina
      • Charleston, South Carolina, United States, 29406
        • Recruiting
        • Lowcountry Lung and Critical Care, PA
        • Contact:
      • Columbia, South Carolina, United States, 29201
    • Tennessee
      • Nashville, Tennessee, United States, 37204
        • Recruiting
        • K2 Medical Research
        • Contact:
          • Auchaia Farley, PA
        • Principal Investigator:
          • Joshua Lennon, MD
    • Texas
      • Dallas, Texas, United States, 75235
        • Recruiting
        • Southwest Family Medicine Associates
        • Contact:
      • San Antonio, Texas, United States, 78240
        • Recruiting
        • HAS Research
        • Principal Investigator:
          • Hernan A Salazar, DO
    • West Virginia
      • Morgantown, West Virginia, United States, 26506

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Double-Blind Treatment Period HBS-301
HBS-301 tablets administered once daily in the morning upon wakening
Drug: HBS-301 tablet
HBS-301 tablet
Other Names:
  • pitolisant delayed-release
Placebo Comparator: Double-blind Treatment Period Placebo
Matching placebo tablets administered once daily in the morning upon wakening
Drug: Placebo
Placebo tablet
Experimental: Open-label Extension Period HBS-301
HBS-301 tablets administered once daily in the morning upon wakening
Drug: HBS-301 tablet
HBS-301 tablet
Other Names:
  • pitolisant delayed-release

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Baseline to the end of the Double-blind Treatment Period (8 weeks)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
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)
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.
Baseline to the end of the Double-blind Treatment Period (8 weeks)
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.
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
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.
Baseline to the end of the Double-blind Treatment Period (8 weeks)
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.
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
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.
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)
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.
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)
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.
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)
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.
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)
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.
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)
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.
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)
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.
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)
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.
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)
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.
End of the Double-blind Treatment Period (8 weeks)
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.
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)
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.
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
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.
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
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.
Baseline to the end of the Double-blind Treatment Period (8 weeks)
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.
Throughout study (16 months including OLE)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Harmony Biosciences Management, Inc.

Investigators

  • Study Director: David Seiden, MD, Harmony Biosciences Management, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 16, 2026

Primary Completion (Estimated)

October 1, 2027

Study Completion (Estimated)

October 1, 2028

Study Registration Dates

First Submitted

March 21, 2026

First Submitted That Met QC Criteria

March 25, 2026

First Posted (Actual)

March 30, 2026

Study Record Updates

Last Update Posted (Actual)

July 2, 2026

Last Update Submitted That Met QC Criteria

June 30, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HBS-301-CL-302
  • 2025-523822-42-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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