A Phase 3 Efficacy and Safety Study of HBS-301 in Participants With Idiopathic Hypersomnia (IH)
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
2 other identifiers
interventional
248
1 country
12
Brief Summary
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 idiopathic hypersomnia (IH) symptoms, including excessive daytime sleepiness (EDS), sleep inertia, and fatigue in adult participants (ages ≥18 years) with idiopathic hypersomnia (IH). The primary objective of this study is to evaluate the efficacy of HBS-301 compared with placebo in treating IH symptoms. Secondary objectives include evaluating the efficacy of HBS-301 compared with placebo in treating EDS, sleep inertia, and fatigue.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P50-P75 for phase_3
Started Mar 2026
Typical duration for phase_3
12 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
Study Start
First participant enrolled
March 16, 2026
CompletedFirst Submitted
Initial submission to the registry
March 21, 2026
CompletedFirst Posted
Study publicly available on registry
March 30, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
October 1, 2027
ExpectedStudy Completion
Last participant's last visit for all outcomes
October 1, 2028
March 30, 2026
March 1, 2026
1.5 years
March 21, 2026
March 25, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
To evaluate the efficacy of HBS-301 compared with placebo in treating IH symptoms
Change in severity of IH symptoms as measured by the Idiopathic Hypersomnia Severity Scale
Baseline to the end of the Double-blind Treatment Period (8 weeks)
Secondary Outcomes (16)
To evaluate the efficacy of HBS-301 compared with placebo in treating EDS
Baseline to the end of the Double-blind Treatment Period (8 weeks)
To evaluate the efficacy of HBS-301 compared with placebo in treating sleep inertia
Baseline to the end of the Double-blind Treatment Period (8 weeks)
To evaluate the efficacy of HBS-301 compared with placebo on fatigue
Baseline to the end of the Double-blind Treatment Period (8 weeks)
To evaluate the onset of efficacy of HBS-301 compared with placebo in treating EDS
Baseline through Week 1 and Week 2 of the Titration Period (1 week and 2 weeks)
To evaluate the onset of efficacy of HBS-301 compared to placebo in treating IH symptoms
Baseline through Week 1 and Week 2 of the Titration Period (1 week and 2 weeks)
- +11 more secondary outcomes
Study Arms (3)
Double-Blind Treatment Period HBS-301
EXPERIMENTALHBS-301 tablets administered once daily in the morning upon wakening at least 1 hour before meals
Double-blind Treatment Period Placebo
PLACEBO COMPARATORMatching placebo tablets administered once daily in the morning upon wakening at least 1 hour before meals
Open-label Extension Period HBS-301
EXPERIMENTALHBS-301 tablets administered once daily in the morning upon wakening at least 1 hour before meals
Interventions
HBS-301 tablet
Eligibility Criteria
You may qualify if:
- 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, an actigraphy report with sleep log on file that led to the diagnosis and was completed within the last 10 years.
- Has moderate to very severe symptoms of IH.
- If taking a permitted chronic concomitant medication or supplement, including nonprohibited antidepressants, 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. 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.
- For participants being treated for obstructive sleep apnea (OSA) or other hypoventilatory conditions, must be compliant with their medical device or oral appliance as determined by the Investigator. Participants must maintain OSA treatment compliance throughout the study.
You may not qualify if:
- 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 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).
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (12)
Santa Monica Clinical Trials
Santa Monica, California, 90404, United States
PharmDev Research Institute, LLC
Miami, Florida, 33176, United States
Central Florida Pediatric Sleep Disorders Institute (Florida Pediatric Research Institute, LLC)
Winter Park, Florida, 32789, United States
NeuroTrials Research Inc.
Atlanta, Georgia, 30328, United States
Phillip Nowlin
Stockbridge, Georgia, 30281, United States
St. Luke's Hospital, Sleep Medicine and Research Center
Chesterfield, Missouri, 63017, United States
Clinical Research of Gastonia
Gastonia, North Carolina, 28054, United States
Stern Research Partners, LLC
Huntersville, North Carolina, 28078, United States
David Kudrow, MD
Morrisville, North Carolina, 27560, United States
Respiratory Specialists
Wyomissing, Pennsylvania, 19610, United States
K2 Medical Research
Nashville, Tennessee, 37204, United States
West Virginia University
Morgantown, West Virginia, 26506, United States
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
David Seiden, MD
Harmony Biosciences Management, Inc.
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 3
- Allocation
- RANDOMIZED
- Masking
- TRIPLE
- Who Masked
- PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
March 21, 2026
First Posted
March 30, 2026
Study Start
March 16, 2026
Primary Completion (Estimated)
October 1, 2027
Study Completion (Estimated)
October 1, 2028
Last Updated
March 30, 2026
Record last verified: 2026-03
Data Sharing
- IPD Sharing
- Will not share