A Phase 3 Efficacy and Safety Study of HBS-301 in Participants With Narcolepsy

Inclusion Criteria: * 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. 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 (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).