Ireland's Jazz Pharmaceuticals has unveiled positive results from a late-stage study assessing JZP-258 for the treatment of cataplexy and excessive daytime sleepiness (EDS) in adults with narcolepsy.
The primary endpoint of the Phase III study was the change in the weekly number of cataplexy attacks, and the key secondary endpoint was the change in the Epworth Sleepiness Scale (ESS) score with JZP-258 compared to placebo.
During the double-blind withdrawal period, there was a significant increase in median weekly number of cataplexy attacks in participants randomised to placebo compared with participants randomised to JZP-258.
As expected, initial cataplexy rates differed based on prior therapy at study entry, with participants taking sodium oxybate only or sodium oxybate and an antidepressant/anticataplectic reporting the least cataplexy at study entry.
In participants taking sodium oxybate only at study entry, cataplexy was stable with JZP-258 treatment across the open-label treatment titration and optimisation period and the stable dose period (SDP).
In those taking sodium oxybate and an antidepressant/anticataplectic at study entry, cataplexy was stable during initial titration of JZP-258, increased during taper and discontinuation of the other anticataplectic, and stabilized during SDP.
In participants taking an anticataplectic other than sodium oxybate at study entry, cataplexy decreased during initial titration of JZP-258, increased during taper and discontinuation of the other anticataplectic and stabilised during SDP, while in those treatment-naïve, cataplexy dropped consistently from week one of JZP- 258 titration through the end of SDP, the firm noted.
"It's encouraging to see these positive results from the Phase III study, as JZP-258 may represent an important and novel product candidate for people with narcolepsy" said Richard Bogan, associate clinical professor at the University of South Carolina School of Medicine, chief medical officer at SleepMed in Columbia, SC and lead investigator of this study.
"This is important for people living with narcolepsy because narcolepsy is a chronic condition that may require lifelong treatment, and is associated with increased risk of comorbid conditions, including hypertension and cardiovascular disease."