First Drug OK’d for Idiopathic Hypersomnia

A calcium, magnesium, potassium, and sodium oxybate oral solution (Xywav) gained a new indication and became the first drug approved to treat adult idiopathic hypersomnia, the FDA said Thursday.

“A novel indication for Xywav is significant as the FDA has never granted an approval for idiopathic hypersomnia,” Eric Bastings, MD, deputy director of the Office of Neuroscience at FDA’s Center for Drug Evaluation and Research, said in a statement. “Idiopathic hypersomnia is a life-long condition, and the approval of Xywav will be instrumental in providing treatment for symptoms such as excessive sleepiness and difficulty waking, and in effectively managing this debilitating disorder.”

Idiopathic hypersomnia is characterized by excessive daytime sleepiness, prolonged nighttime sleep, and sleep inertia. It is associated with decreased health-related quality of life, impairment in social and work functioning, and increased motor vehicle accidents. An estimated 37,000 people in the U.S. have been diagnosed with the disorder.

The drug was first approved in 2020 for both cataplexy and excessive daytime sleepiness in people 7 years and older living with narcolepsy. The Xywav formulation has 92% less sodium than sodium oxybate (Xyrem), which was approved in 2002.

The effectiveness of the lower sodium oxybate drug in idiopathic hypersomnia was evaluated in a phase III, placebo-controlled, double-blind, randomized withdrawal study. The trial showed that patients randomized to switch from the drug to placebo experienced worsening on measures of sleepiness and idiopathic hypersomnia symptoms, compared with patients who continued treatment.

In the clinical trial, the most common adverse events as a result of the treatment observed included nausea (21.4%), headache (16.2%), dizziness (11.7%), anxiety (10.4%), and vomiting (10.4%).

Xywav carries a boxed warning as a central nervous system (CNS) depressant and for its abuse and misuse potential. Because of these risks, the drug is available only through a Risk Evaluation and Mitigation Strategies (REMS).

Taking Xywav with CNS depressants including opioids, benzodiazepines, sedating antidepressants, antipsychotics, sedating anti-epileptic medicines, general anesthetics, muscle relaxants, alcohol, or street drugs, may cause respiratory depression, hypotension, drowsiness, syncope, and death, drugmaker Jazz Pharmaceuticals warned.

The active ingredient in the drug is a form of gamma hydroxybutyrate (GHB), a Schedule I controlled substance, according to the FDA. Abuse or misuse of illegal GHB alone or with other drugs that cause changes in consciousness has caused serious side effects including seizures, respiratory depression, drowsiness, coma, and death. FDA-approved GHB products, however, are Schedule III substances under the Controlled Substances Act.

The drug should be available to patients with idiopathic hypersomnia later this year following REMS implementation, the drugmaker said.