Study Considerations for Efficacy, Safety of JZP-258 for Idiopathic Hypersomnia

young man sleeping
male lying on pillow and sleeping in morning
In order to assess the efficacy and safety of JZP-258, a lower sodium alternative product to sodium oxybate, study authors designed a double-blind, placebo-controlled, randomized withdrawal, multicenter study with an open-label safety extension.

The following article is a part of conference coverage from Psych Congress 2020 Virtual Experience, held virtually from September 10 to 13, 2020. The team at Psychiatry Advisor will be reporting on the latest news and research conducted by leading experts in psychiatry. Check back for more from the Psych Congress 2020.


At present, there are no treatments approved by the US Food and Drug Administration (FDA) for idiopathic hypersomnia, a central disorder of hypersomnolence characterized by excessive daytime sleepiness. A clinical trial is currently underway to determine the effectiveness of a novel oxybate candidate, JZP-258, according to a presentation at Psych Congress 2020, held virtually from September 10 to 13, 2020.

While there are currently no well-controlled clinical trials that inform evidence-based treatment of idiopathic hypersomnia with pharmacotherapies, sodium oxybate, an FDA-approved treatment for excessive daytime sleepiness in patients ≥7 years of age with narcolepsy, has demonstrated effectiveness in the treatment of idiopathic hypersomnia in a retrospective chart review.

Inclusion criteria of the 154-member study with participants aged 18 to 75 years were: a primary diagnosis of idiopathic hypersomnia according to International Classification of Sleep Disorders, Second Edition (ICSD-2) or ICSD-3 criteria; an Epworth Sleepiness Scale (ESS) score ≥11 at screening and at baseline for participants not taking sodium oxybate; and an average total nightly sleep time ≥7 hours per participant. In addition, participants treated with wake-promoting agents must have been on the same regimen for ≥2 months prior to screening and remain on the same dose throughout duration of the study.

Treatment is initiated at ≤2.25 g twice nightly, ≤3.0 g once nightly, or an established sodium oxybate regimen if participants are utilizing the treatment at study entry. Ultimately the treatment is titrated to an optimal regimen of a total nightly dose ≤9 g.

The trial has been designed to enable individualized dosing to optimize treatment and dosing without regard to food and allows for once- or twice-nightly dosing at treatment initiation based on the clinical presentation of each individual patient, and once-, twice-, or thrice-nightly dosing throughout treatment to optimize efficacy, tolerability, and sleep duration. 

Efficacy measures include change in ESS score, Patient Global Impression of Change, Idiopathic Hypersomnia Severity Scale, and assessments of sleep inertia and duration. Safety of participants is being monitored throughout the study, and assessments and analyses are ongoing.

Disclosure: This study is supported by Jazz Pharmaceuticals, Inc. Several of the authors are full-time employees of Jazz Pharmaceuticals.

Visit Psychiatry Advisor’s meetings section for complete coverage of Psych Congress 2020.



Chandler P, Profant J, Chen D, et al. Challenges and considerations in design of a placebo-controlled, double-blind, randomized-withdrawal study evaluating the efficacy and safety of JZP-258 for the treatment of idiopathic hypersomnia. Presented at: Psych Congress 2020 Virtual Experience; September 10-13, 2020. Poster 118.