Jazz's Xyrem Follow-On Drug Succeeds in Phase III Study

Jazz Pharmaceuticals plc JAZZ announced positive top-line data from a phase III study evaluating its sleep disorder candidate, JZP-258. Data showed that treatment with the candidate achieved clinically meaningful maintenance of efficacy in adult patients suffering from cataplexy and excessive daytime sleepiness (“EDS”) with narcolepsy.

JZP-258 is an oxybate product candidate with 92% less sodium content than its marketed product Xyrem (sodium oxybate). Xyrem is currently approved for narcolepsy with cataplexy and EDS.

Jazz’s shares have increased 10.1% so far this year compared with the industry’s rise of 15.2%.


The phase III study evaluated JZP-258 for change in weekly cataplexy attacks compared to a placebo in adult patients with narcolepsy as its primary endpoint. It was mainly initiated to reduce sodium intake in narcolepsy patients associated with Xyrem. Data from the study demonstrated highly statistically significant differences in the number of cataplexy attacks as well as in the key secondary endpoint of change in Epworth Sleepiness Scale (ESS) score for JZP-258 versus placebo. The candidate has a safety profile similar to Xyrem.

Detailed data from the study will be presented at an upcoming medical meeting. Top-line data from the phase III study along with interim data from an ongoing 24-week open-label safety study will form the basis for the new drug application (“NDA”) for JZP-258.

Xyrem generates significant revenues for Jazz with sales from the drug expected to cross $1.5 billion in 2019. Earlier this month, the FDA approved Sunosi (solriamfetol) as a treatment to improve wakefulness and reduce EDS. Potential approval to JZP-258 will boost Jazz’s sleep disorder portfolio further.

Moreover, JZP-258 is likely to expand the patient population for Jazz as it will include patients ineligible for Xyrem as they are at risk for high sodium intake-related consequences, including hypertension and other cardiovascular diseases. The highest approved dose of Xyrem of 9 grams per night contains 1,640 mg of sodium, which is almost 70% of the recommended daily sodium intake for a healthy adult per an article published on FDA’s website.

The generic version of Xyrem is set to hit the market starting 2023. The low sodium content of JZP-258 and a similar safety profile is likely to largely offset the decline in Xyrem sales once generic versions enter the market.

A few other pharma companies are also developing treatment for narcolepsy, which includes Avadel Pharmaceuticals AVDL. Approved drugs for narcolepsy include Teva Pharma’s TEVA Provigil and Novartis’ NVS Ritalin-SR.

Jazz Pharmaceuticals PLC Price


Jazz Pharmaceuticals PLC Price | Jazz Pharmaceuticals PLC Quote

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Jazz currently has Zacks Rank #3 (Hold).

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