Efficacy of Once-Nightly Sodium Oxybate (FT218) in Narcolepsy Type 1 and Type 2: Post Hoc Analysis From the Phase 3 REST-ON Trial.

Abstract

Post hoc analyses from the phase 3 REST-ON trial evaluated efficacy of extended-release once-nightly sodium oxybate (ON-SXB; FT218) vs placebo for daytime sleepiness and disrupted nighttime sleep in narcolepsy type 1 (NT1) and 2 (NT2). Participants were stratified by narcolepsy type and randomized 1:1 to ON-SXB (4.5g, week 1; 6g, weeks 2-3; 7.5g, weeks 4-8; and 9g, weeks 9-13) or placebo. Assessments included mean sleep latency on Maintenance of Wakefulness Test (MWT) and Clinical Global Impression-Improvement (CGI-I) rating (coprimary endpoints) and sleep stage shifts, nocturnal arousals, and patient-reported sleep quality, refreshing nature of sleep, and Epworth Sleepiness Scale (ESS) score (secondary endpoints) separately in NT1 and NT2 subgroups. The modified intent-to-treat population comprised 190 participants (NT1, n=145; NT2, n=45). Significant improvements were demonstrated with ON-SXB vs placebo in sleep latency for NT1 (all doses, P<0.001) and NT2 (6 and 9g, P<0.05) subgroups. Greater proportions of participants in both subgroups had CGI-I ratings of much/very much improved with ON-SXB vs placebo. Sleep stage shifts and sleep quality significantly improved in both subgroups (all doses vs placebo, P<0.001). Significant improvements with all ON-SXB doses vs placebo in refreshing nature of sleep (P<0.001), nocturnal arousals (P<0.05), and ESS scores (P≤0.001) were reported for NT1 with directional improvements for NT2. Clinically meaningful improvements of a single ON-SXB bedtime dose were shown for daytime sleepiness and DNS in NT1 and NT2, with less power for the limited NT2 subgroup.