FDA Approves First Drug for Idiopathic Hypersomnia
The US Food and Drug Administration (FDA) has approved an oral solution of calcium, magnesium, potassium, and sodium oxybates (Xywav) for the treatment of idiopathic hypersomnia in adults, the company announced. It marks the second approval for Xywav. As reported, the FDA approved it last year for the treatment of cataplexy or excessive daytime sleepiness in patients as young as age 7 years with narcolepsy. This approval is the first for a treatment for idiopathic hypersomnia.

Xywav is a novel oxybate product with a unique composition of cations. It contains 92% less sodium than sodium oxybate (Xyrem) at the recommended adult dosage range of 6 to 9 g, the company noted in a news release. An estimated 37,000 people in the United States have been diagnosed with idiopathic hypersomnia, a neurologic sleep disorder characterized by chronic excessive daytime sleepiness.

Other symptoms of the disorder may include severe sleep inertia or sleep drunkenness (prolonged difficulty waking with frequent reentries into sleep, confusion, and irritability), as well as prolonged, nonrestorative nighttime sleep, cognitive impairment, and long and unrefreshing naps. The approval was based on findings from a phase 3, double-blind, multicenter, placebo-controlled, randomized withdrawal study.

Results showed "statistically significant and clinically meaningful" differences compared with placebo in change in the primary endpoint of Epworth Sleepiness Scale score and the secondary endpoints of Patient Global Impression of Change and the Idiopathic Hypersomnia Severity Scale, the company reports. The most common adverse reactions were nausea, headache, dizziness, anxiety, insomnia, decreased appetite, hyperhidrosis, vomiting, diarrhea, dry mouth, parasomnia, somnolence, fatigue, and tremor.

The novel agent can be administered once or twice nightly for the treatment of idiopathic hypersomnia in adults. "To optimize response, a patient's healthcare provider may consider prescribing a twice-nightly regimen in equally or unequally divided doses at bedtime and 2.5 to 4 hours later and gradually titrate Xywav so that a patient may receive an individualized dose and regimen based on efficacy and tolerability," the company said.