The following article is part of conference coverage from the American Academy of Neurology (AAN) 2021 Virtual Annual Meeting. Neurology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in neurology. Check back for the latest news from the AAN 2021 Virtual Annual Meeting.

Treatment with lower-sodium oxybate (LXB) improved daytime sleepiness among patients with idiopathic hypersomnia (IH), according to results of a phase 3, placebo-controlled, double-blind, randomized clinical trial, to be presented during the American Academy of Neurology 2021 Virtual Annual Meeting, to be held April 17 to 22, 2021.

Patients (N=154) with IH were recruited for this study. They were given LXB Xywav, which has 92% less sodium than Xyrem, for a 10-14 week open-label titration and optimization stage. Following titration, patients were randomly assigned to continue on LXB or receive a placebo for 2 weeks. Study researchers assessed patients by Epworth Sleepiness Scale (ESS), Patient Global Impression of Change, and IH Severity Scale.

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Patients has a mean age of 40 (standard deviation [SD], ±14) years, 68% were women, and average baseline ESS score was 16 (SD, ±3.6 points). After the titration period, the average dose of LXB was optimized as 6.0±1.6 grams/night.

Following the titration period, significant worsening of ESS scores were observed among patients randomly assigned to switch to a placebo (least squares mean difference, -6.51; 95% CI, -7.99 to -5.03; P <.0001). Similarly, IH Severity Scale scores were poorer among the placebo recipients (estimated median difference, -12.00; 95% CI, -15.0 to -8.0; P <.0001). Patient Global Impression of Change was 88.1% among the placebo cohort and 21.4% for the treatment group (P <.0001).

The common adverse events of nausea (21.4%), headache (16.2%), dizziness (11.7%), vomiting (10.4%), and anxiety (10.4%) were reported by fewer than a quarter of study participants. Study researchers observed a total of 4 serious adverse events (syncope, rhabdomyolysis, nephrolithiasis/pyelonephritis, and non-cardiac chest pain), but determined these were not associated with the LXB treatment.

This study may have been limited by its short double-blind treatment duration.

The study authors concluded LXB significantly improved excessive daytime sleepiness, overall IH symptoms, and self-reported global change among patients with IH. Xywav therapy was associated with little risk for adverse effects.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.


Dauvilliers Y, Arnulf I, Foldvary-Schaefer N, et al. Efficacy and safety of lower-sodium oxybate in a phase 3, placebo-controlled, double-blind, randomized withdrawal study in adult participants with idiopathic hypersomnia. Presented at: American Academy of Neurology 2021 Virtual Annual Meeting; April 17-22, 2021.