Jazz Pharmaceuticals plc announced positive top-line efficacy results from the global, double-blind, placebo-controlled, randomized-withdrawal, multicenter Phase 2/3 study evaluating Xyrem (sodium oxybate) oral solution, CIII, in the treatment of cataplexy in pediatric patients with narcolepsy. Xyrem demonstrated statistically significant differences in the primary and key secondary efficacy endpoints that measured the change in the weekly number of cataplexy attacks, the Clinical Global Impression of Change scale (CGIc) for the severity of cataplexy, and the Epworth Sleepiness Scale (ESS) for children and adolescents (CHAD) score compared to placebo. The preliminary safety results were consistent with the results previously observed in Xyrem studies in adults and our Xyrem post-marketing experience.

“More than half of all narcolepsy patients report that their symptoms began as teenagers or in childhood. Although narcolepsy in children is characterized by the same symptoms as adults, pediatric narcolepsy is frequently under-recognized and under-diagnosed,” says Karen Smith, MD, PhD, global head of research and development and chief medical officer of Jazz Pharmaceuticals, in a release. “We look forward to presenting the results from this large pivotal Xyrem pediatric study in narcolepsy at the APSS meeting in June. We expect to submit a supplemental NDA to the FDA in support of the use of Xyrem in pediatric patients in the fourth quarter of 2017, subject to completion of the full data analysis.”

The EXPRESS study is a double-blind, placebo-controlled, randomized-withdrawal, multicenter study evaluating the efficacy and safety of Xyrem with an open-label pharmacokinetic evaluation and safety extension for at least one year in pediatric patients with narcolepsy with cataplexy. The study enrolled 106 patients aged 7 to 17 with narcolepsy with cataplexy. The study design included a titration period (if necessary), a Xyrem stable-dose period of two to three weeks, followed by a 1:1 randomization to either Xyrem or placebo for 2 weeks. After the completion of the double-blind, placebo-controlled treatment period, patients have the opportunity to receive Xyrem in an open-label treatment phase for at least one year. After a pre-planned interim analysis, efficacy on the primary endpoint was demonstrated. As a result, randomization to placebo was discontinued, and the study remains ongoing with open-label Xyrem treatment.