Improvement in sleep latency with extended-release once-nightly sodium oxybate for the treatment of adults with narcolepsy: Analysis from the phase 3 REST-ON clinical trial.

Background: In the REST-ON clinical trial (NCT02720744), mean sleep latency on the Maintenance of Wakefulness Test (MWT) was significantly improved with extended-release once-nightly sodium oxybate (ON-SXB) vs placebo ( < 0.001) in participants with narcolepsy. This post hoc analysis assessed response to treatment and improvement in excessive daytime sleepiness.

Methods: Participants with narcolepsy aged ≥16 years were randomized 1:1 to receive ON-SXB (4.5 g, week 1; 6 g, weeks 2-3; 7.5 g, weeks 3-8; and 9 g, weeks 9-13) or placebo. Mean sleep latency on the MWT was measured across 5 trials of ≤30 min each. Post hoc assessments included percentage of participants whose sleep latency improved ≥5, ≥10, ≥15, and ≥20 min and with a mean sleep latency of 30 min.

Results: Significantly more participants receiving ON-SXB vs placebo experienced increased mean sleep latency ≥5 min (all doses  < 0.001), ≥10 min (all doses  < 0.001), ≥15 min (6 and 7.5 g,  < 0.001; 9 g,  < 0.01), and ≥20 min (6 g,  < 0.01; 7.5 g,  < 0.001; 9 g,  < 0.05). More participants receiving ON-SXB had mean sleep latency of 30 min vs placebo (6 g, 5.7 % vs 0 %, respectively [ < 0.05]; 7.5 g, 10.5 % vs 1.3 % [ < 0.05]; 9 g, 13.2 % vs 5.1 % [ = 0.143]).

Conclusions: Significantly more participants who received ON-SXB experienced increased mean sleep latency ≥5 to ≥20 min; at the 2 highest doses, >10 % remained awake for the entirety of the MWT. ON-SXB offers a once-at-bedtime treatment option for adults with narcolepsy.