[Corrected 7/23/20, 10:13 am. See below.] Jazz Pharmaceuticals has received FDA approval for a narcolepsy drug that it has developed as a lower-sodium successor to its biggest moneymaker, a treatment that was first approved in 2002 to reduce attacks of muscle weakness associated with the disease.
That drug, sodium oxybate (Xyrem), was first OK’d to reduce the incidence of cataplexy, as such episodes are called; later, its use was expanded to excessive daytime sleepiness (EDS), the hallmark symptom of the chronic condition.
The new Jazz (NASDAQ: JAZZ) drug, Xywav, combines sodium oxybates with calcium, magnesium, and potassium, a compound that delivers about 1,000 to 1,500 mg, or 92 percent, less sodium per night compared to the recommended dose of Xyrem. The daily recommended dosage for both drugs, which act as sedatives, is designed to be taken nightly across two doses—one at bedtime and another two and a half hours to four hours later.
Before Tuesday, when the FDA granted approval of Xyway, sodium oxybate was the only approved treatment for narcolepsy patients with both cataplexy and EDS. In the first quarter of this year its sales earned the Dublin, Ireland-based company $408 million—77 percent of its total net product revenue. [An earlier version of this story mistakenly identified the day of approval as Wednesday.]
Narcolepsy, a chronic sleep disorder for which there is no cure, is characterized by overwhelming daytime drowsiness and sudden attacks of sleep. People with the condition may suddenly enter deep sleep, skipping over the transitional phase of slowed brain waves known as non-rapid eye movement sleep. The condition is estimated to affect 135,000 to 200,000 people in the US, although misdiagnosis is common, according to the National Institutes of Health.
The Jazz sleepiness drugs are both controlled by the Drug Enforcement Agency (DEA) because of their potential for misuse and abuse. The active ingredient, sodium oxybate, is a form of gamma hydroxybutyric, a street drug popularly associated with sexual assault. Xywav, like Xyrem, carries a black box warning on its label flagging the risks associated with depressing the central nervous system and the drug’s potential for abuse and misuse. The regulatory approval comes with a requirement that Jazz offer a program that informs physicians and patients about the drug’s risks.
Clinicians often prescribe stimulants to treat EDS and antidepressants to counter cataplexy before or instead of prescribing Xyrem. And Harmony Biosciences pitolisant (Wakix) received FDA approval last year to treat EDS, introducing to the market the only narcolepsy medication not classified as a controlled substance by the DEA.
FDA approval of Xywav was based on the results of a study that enrolled 201 patients and measured statistically significant differences in the weekly number of cataplexy attacks and scores measuring sleepiness experienced by patients compared to those who received a placebo. The most common side effects were headache, nausea, dizziness, decreased appetite, unwanted sleep behaviors, diarrhea, excessive sweating, anxiety, and vomiting.
Jazz hopes prescribers will recommend its newly approved drug to patients given the relationship between too much dietary sodium and an increased risk of high blood pressure, heart disease, and stroke.
The company plans to launch Xywav by year’s end. Shares in Jazz rose 4.5 percent on Wednesday to $110.26 apiece.
Avadel Pharmaceuticals (NASDAQ: AVDL), another Dublin-based company, is developing a formulation of sodium oxybate designed to be taken once rather than twice per night. The company reported in April that the drug candidate, FT218, reduced cataplexy attacks and daytime sleepiness and improved patients’ overall functioning as compared to a placebo in a Phase 3 study.
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