A Phase 3 Efficacy and Safety Study of HBS-301 in Participants With Narcolepsy
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
2 other identifiers
interventional
258
1 country
14
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 excessive daytime sleepiness (EDS), cataplexy, sleepiness/wakefulness, and fatigue in adult participants (ages ≥18 years) with narcolepsy.
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 Jun 2026
14 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
June 4, 2026
CompletedFirst Submitted
Initial submission to the registry
June 22, 2026
CompletedFirst Posted
Study publicly available on registry
June 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
November 1, 2027
June 30, 2026
June 1, 2026
1.3 years
June 22, 2026
June 25, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
Change in severity of EDS as measured by the Epworth Sleepiness Scale (ESS)
The ESS is an 8-item, 4-point rating scale.
Baseline to end of Double-Blind Treatment Period (8 weeks)
Secondary Outcomes (19)
Change in Weekly Rate of Cataplexy (WRC) in participants with an average WRC of ≥3 over 2 consecutive weeks at Screening
End of the Double-Blind Treatment Period (8 weeks)
Change in sleepiness/wakefulness measured by the Maintenance of Wakefulness Test (MWT)
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)
Baseline to end of Double-Blind Treatment Period (8 weeks)
Change in severity of EDS as measured by the ESS
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
Baseline through Week 1 and Week 2 of the Titration Period (1 week and 2 weeks)
- +14 more secondary outcomes
Study Arms (3)
Double-Blind Treatment Period HBS-301
EXPERIMENTALHBS-301 tablets administered once daily in the morning upon wakening
Double-blind Treatment Period Placebo
PLACEBO COMPARATORMatching placebo tablets administered once daily in the morning upon wakening
Open-Label Extension Period HBS-301
EXPERIMENTALHBS-301 tablets administered once daily in the morning upon wakening
Interventions
Eligibility Criteria
You may qualify if:
- 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.
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, 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).
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (14)
Phoenix Medical Group, PC
Peoria, Arizona, 85381, United States
Santa Monica Clinical Trials
Los Angeles, California, 90025, United States
Alpine Clinical Research Center, Inc
Boulder, Colorado, 80301, United States
PharmaDev Clinical Research Institute, LLC
Miami, Florida, 33176, United States
Central Florida Pediatric Sleep Disorders Institute
Winter Park, Florida, 32789, United States
Neurotrials Research Inc
Atlanta, Georgia, 30328, United States
Sleep Practitioners, LLC
Macon, Georgia, 31210, United States
Intrepid Research, LLC
Cincinnati, Ohio, 45245, United States
Respiratory Specialists
Wyomissing, Pennsylvania, 19610, United States
Lowcountry Lung and Critical Care PA
Charleston, South Carolina, 29406, United States
Bogan Sleep Consultants, LLC
Columbia, South Carolina, 29201, United States
Southwest Family Medicine
Dallas, Texas, 75235, United States
Sleep Therapy & Research Center
San Antonio, Texas, 78229, United States
Sleep and Performance Research Center
Spokane, Washington, 99202, 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
June 22, 2026
First Posted
June 30, 2026
Study Start
June 4, 2026
Primary Completion (Estimated)
October 1, 2027
Study Completion (Estimated)
November 1, 2027
Last Updated
June 30, 2026
Record last verified: 2026-06
Data Sharing
- IPD Sharing
- Will not share