Positive topline results from a phase 3 study evaluating Xywav™ (calcium, magnesium, potassium, and sodium oxybates; Jazz Pharmaceuticals) for the treatment of idiopathic hypersomnia showed that the trial met the primary and key secondary end points.

Xywav is a novel oxybate product believed to exert its therapeutic effects through GABAB during sleep. It contains the same oxybate concentration as Xyrem (sodium oxybate; Jazz Pharmaceuticals), but with a unique composition of cations resulting in 92% less sodium.

The multicenter, double-blind, placebo-controlled phase 3 study evaluated the efficacy and safety of Xywav in adults with idiopathic hypersomnia. The study included an open-label titration period followed by a randomized withdrawal period, which included 115 patients who received either Xywav or placebo for 2 weeks. The primary end point was the change in Epworth Sleepiness Scale (ESS) score. The key secondary end points were the proportion of patients reported as worse on the Patient Global Impression of Change (PGIc) and Idiopathic Hypersomnia Severity Scale (IHSS).

Results demonstrated that patients treated with Xywav during the open-label titration period had clinically meaningful improvements in ESS. Xywav also showed clinically meaningful maintenance of efficacy for ESS, PGIc and IHSS during the randomized withdrawal period. Moreover, the placebo arm had highly statistically significant worsenings compared with Xywav for ESS (P <.0001), PGIc (P <.0001) and IHSS (P <.0001). The safety profile of Xywav was consistent with its known profile in previous studies. 

Based on these findings, the Company intends to submit a supplemental New Drug Application to the Food and Drug Administration (FDA) as early as the first quarter of 2021 for this indication.

“We are excited by these compelling results and the magnitude of improvement observed in the study, in particular for people living with idiopathic hypersomnia who currently have no approved treatment option,” said Robert Iannone, MD, MSCE, executive vice president, research and development of Jazz Pharmaceuticals.

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In July 2020, the FDA approved Xywav for the treatment of cataplexy or excessive daytime sleepiness in patients 7 years of age and older with narcolepsy.

For more information visit jazzpharma.com.


Jazz Pharmaceuticals announces positive top-line results from phase 3 study of Xywav™ (calcium, magnesium, potassium, and sodium oxybates) oral solution in adult patients with idiopathic hypersomnia. [press release]. Dublin, Ireland: Jazz Pharmaceuticals; October 8, 2020.