LXB improves functional outcomes in patients with idiopathic hypersomnia
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LXB improved all measures of function and work productivity among patients with idiopathic hypersomnia, according to findings presented at the American Neurological Association Annual Meeting.
The treatment (calcium, magnesium, potassium and sodium oxybates; Jazz Pharmaceuticals Inc.), also referred to as lower-sodium oxybate (LXB) and Xywav, has the same active moiety at the same concentration as sodium oxybate but features 92% less sodium. The FDA approved LXB in August for adults with idiopathic hypersomnia.
“In a [prior] double-blind, placebo-controlled randomized withdrawal study in adults with idiopathic hypersomnia, LXB demonstrated clinically and statistically meaningful improvement of excessive daytime sleepiness, overall symptom severity and self-reported patient global impression of change,” Michael J. Thorpy, MD, professor of neurology at Albert Einstein College of Medicine and director of the Sleep-Wake Disorders Center in the department of neurology at Montefiore Medical Center, both in New York, said during a virtual presentation. “The objective of this study analysis was to evaluate the effects of LXB on functioning and work productivity in participants with idiopathic hypersomnia.”
Thorpy and colleagues included 154 adults aged 18 to 75 years with a primary diagnosis of idiopathic hypersomnia based on ICD-2 or ICD-3 criteria and an average nocturnal total sleep time of 7 hours or longer. Participants were treatment naive or had been taking medications, such as sodium oxybate, alerting agents or both, for their idiopathic hypersomnia symptoms. Researchers allowed concomitant alerting agents in the study.
Participants initiated LXB treatment in an open-label titration/optimization period (OLT) of 10 to 14 weeks, followed by 2 weeks of an open-label, stable-dose period (SDP). They were then randomly assigned to either placebo (n = 56) or continued LXB treatment (n = 59) during a 2-week, double-blind, randomized-withdrawal period (DBRWP).
Change in Epworth Sleepiness Scale (ESS) score from the end of the SDP to the end of the DBRWP served as the primary efficacy endpoint. The secondary endpoint was change in total score on the Functional Outcomes of Sleep Questionnaire, short version (FOSQ-10), from the end of the SDP to the end of the DBRWP. The exploratory endpoint was percent change from the end of the SDP to the end of the DBRWP in the Work Productivity and Activity Impairment Specific Health Problem (WPAI:SHP) Questionnaire, with idiopathic hypersomnia as the health problem for several measures. Thorpy and colleagues examined treatment-emergent adverse events in safety assessments.
Results showed an increase in mean FOSQ-10 score during open-label LXB treatment from 11.8 to 16.7. Participants randomly assigned to placebo exhibited worsened FOSQ-10 total scores, and those who continued LXB maintained improvement from the end of the SDP to the end of the DBRWP in the modified intent-to-treat population. Researchers noted decreases during open-label LXB treatment among the safety population in mean WPAI:SHP measures, including absenteeism (work time missed), presenteeism (impairment while working), absenteeism plus presenteeism and activity impairment. Among the modified intent-to-treat population between the end of the SDP and the end of the DBRWP, participants randomly assigned to placebo exhibited worsened WPAI:SHP measures, and those who received LXB maintained improvement. Four participants reported nine overall treatment-emergent serious adverse events, with none deemed related to the study drug. Twenty-six participants, excluding placebo, reported treatment-emergent adverse events resulting in discontinuation of the study drug across all study periods. The most common were anxiety, insomnia and nausea.
“LXB demonstrated improvement in measures of functioning and work productivity in study participants with idiopathic hypersomnia,” Thorpy said.