Positive results from phase III trial of JZP 258 for the treatment of cataplexy and excessive daytime sleepiness

Jazz Pharmaceuticals plc announced positive top-line results from the global, double-blind, placebo-controlled, randomized-withdrawal, multicenter Phase III study evaluating the efficacy and safety of JZP 258 for the treatment of cataplexy and excessive daytime sleepiness (EDS) in adult patients with narcolepsy. JZP 258 is a novel oxybate product candidate with a unique composition of cations resulting in 92% less sodium than Xyrem (sodium oxybate).

The Phase III study demonstrated highly statistically significant differences in the primary endpoint that measured the change in the weekly number of cataplexy attacks and the key secondary endpoint of change in Epworth Sleepiness Scale (ESS) score with JZP 258 compared to placebo. In this study, patients were randomized to either continue JZP 258 or to receive placebo. Patients randomized to JZP 258 showed clinically meaningful maintenance of efficacy for both cataplexy and EDS, while a statistically significant worsening for both cataplexy and ESS endpoints was observed in the placebo group compared with JZP 258. The safety profile of JZP 258 is consistent with sodium oxybate. The most commonly reported treatment-emergent adverse events that occurred in greater than 5% of patients who received JZP 258 were headache, nausea, dizziness, cataplexy, nasopharyngitis, decreased appetite, influenza, diarrhea and vomiting. Two patients experienced serious adverse events (SAEs) that were considered by the investigator to be treatment related.

Jazz will submit the Phase III study data for presentation at an upcoming medical meeting. Data from the completed Phase III study and interim data from the ongoing 24-week open-label, safety study will be included in the planned submission of a New Drug Application (NDA) to the FDA.