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

Harmony Biosciences Management, Inc.

Status and phase: Enrolling; Phase 3

Conditions: Idiopathic Hypersomnia

Treatments: Drug: HBS-301 tablet; Drug: Placebo

Study type: Interventional

Funder types: Industry

Identifiers

NCT07500090

2025-523822-42-00 (EU Trial (CTIS) Number)

HBS-301-CL-302

Details and patient eligibility

About

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.

Full description

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 IH symptoms, including EDS, sleep inertia, and fatigue in adult participants (ages ≥18 years) with IH.

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.

Enrollment: 248 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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, 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.

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 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).

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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248 participants in 3 patient groups, including a placebo group

Double-Blind Treatment Period HBS-301

Experimental group

Description:

HBS-301 tablets administered once daily in the morning upon wakening at least 1 hour before meals

Treatment:

Drug: HBS-301 tablet

Double-blind Treatment Period Placebo

Placebo Comparator group

Description:

Matching placebo tablets administered once daily in the morning upon wakening at least 1 hour before meals

Treatment:

Drug: Placebo

Open-label Extension Period HBS-301

Experimental group

Description:

HBS-301 tablets administered once daily in the morning upon wakening at least 1 hour before meals

Treatment:

Drug: HBS-301 tablet