The FDA has approved a new treatment for idiopathic hypersomnia (IH), an uncommon sleep disorder that causes constant, excessive daytime sleepiness. The new therapy, called Xywav, is a combination of calcium, magnesium, potassium, and sodium oxybates and is administered orally. Xywav is to be the first FDA-approved treatment for IH, although it was approved for narcolepsy in 2002 under the name Xyrem.
“A novel indication for Xywav is significant as the FDA has never granted an approval for idiopathic hypersomnia,” said Eric Bastings, M.D., deputy director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research. “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.”
Effectiveness of Xywav
In a double-blind placebo-controlled randomized-withdrawal study of 154 adults, Xywav was found to be superior to a placebo. Patients who were given Xywav and then switched to an inert replacement reported worsened sleepiness than patients who remained on Xywav.
Several adverse effects of the drug were reported in the study, however, which included nausea (21.4%), headache (16.2%), dizziness (11.7%), anxiety (10.4%) and vomiting (10.4%).
These adverse effects may be partially attributed to the active component of Xywav, gamma-hydroxybutyrate — better known as GHB. GHB is a Schedule I Controlled Substance due to its psychoactive effects and high potential for abuse. At low doses, the drug produces euphoria, relaxation and increased sex drive, but higher doses induce hallucinations and loss of consciousness. These effects have given it notoriety as a “date rape” drug.
Due to the above, Xywav must be prescribed and dispensed under a Risk Evaluation and Mitigation Strategy (REMS) program. This means it can only be prescribed by a doctor participating in Xywav’s REMS program and dispensed only by a REMS-certified pharmacy. Xywav will not be available in retail pharmacies, according to the FDA. The drug will also come with a printed warning on its packaging for “central nervous system depression and abuse and misuse.”
Despite its risks, Xywav, if taken as prescribed, has the potential to improve the quality of life of millions of IH sufferers across the United States.