July 22, 2020
The U.S. FDA has approved Xywav™ (calcium/magnesium/potassium/sodium oxybate) oral solution, manufactured by Jazz Pharmaceuticals, to treat cataplexy (sudden, brief loss of voluntary muscle tone) or excessive daytime sleepiness (EDS) in patients at least seven years old who have been diagnosed with narcolepsy. Xywav is a central nervous system (CNS) depressant and classified as a Schedule III controlled substance.
Narcolepsy is a neurological disorder that affects an estimated 1 in 2,000 people in the United States. Symptoms typically manifest during childhood or adolescence, and include cataplexy, EDS, disruptions of nighttime sleep, sleep-related hallucinations, and sleep paralysis. The exact symptoms vary from person to person, though all individuals with narcolepsy experience EDS. EDS is defined as an inability to stay awake and alert during the day, leading to drowsiness and unplanned lapses into sleep.
In a clinical study, Xywav delivered statistically significant improvements in Epworth Sleepiness Scale scores and weekly number of cataplexy attacks compared to placebo. In addition, it has a unique formulation that contains 92% less sodium compared to other products containing sodium oxybate, one of its active pharmaceutical ingredients and a current standard of care for cataplexy and EDS. This can help patients better align their daily sodium intake with current dietary guidelines for heart health.
Recommended initial dosing for adults is 4.5g of Xywav per day, divided into two doses. The first is taken at bedtime, and the second 2.5–4 hours later. Daily dosing is then titrated up in increments of 1.5g each week based on patient response. The recommended maintenance dose range is 6g to 9g each night, split into two doses. Some patients may experience an improved response with unequal doses at bedtime and 2.5–4 hours later. In pediatric patients, the recommended starting dosage, titration regimen, and maximum total nightly dosage are based on body weight.
A black box warning cautions that Xywav, like other CNS depressants, carries a risk of misuse and abuse and can cause respiratory depression. As a result, the drug is only available through a Risk Evaluation and Mitigation Strategy (REMS) program.
Jazz Pharmaceuticals expects to launch Xywav by the end of 2020. Pricing information is not yet available.