0645 Comparison of Demographics and Baseline Narcolepsy Symptoms Between Participants with NT1 and NT2 from REST-ON

Abstract Introduction Narcolepsy is classified into 2 subtypes: narcolepsy type 1 (NT1; with cataplexy) and 2 (NT2; without cataplexy). Limited data are available regarding subtype differences in clinical characteristics and disease severity. In the phase 3 REST-ON trial, once-nightly sodium oxybate (ON-SXB; LUMRYZ™) demonstrated significant improvement in the 3 coprimary endpoints of change from baseline in mean sleep latency on the Maintenance of Wakefulness test (MWT), Clinical Global Impression of Improvement rating, and weekly cataplexy episodes (all P< 0.001) in patients with NT1 and NT2. This post hoc analysis compared baseline characteristics between participants with NT1 and NT2. Methods REST-ON (NCT02720744) participants were ≥16 years of age with NT1 or NT2, excessive daytime sleepiness, and cataplexy (NT1 only). Use of alerting agents was permitted. Randomization (1:1 to ON-SXB or placebo) was stratified by narcolepsy type; the trial population was oversampled for NT1. Baseline characteristics were compared between narcolepsy types. Results The safety population included 212 participants (NT1, n=162; NT2, n=50). At baseline, demographic characteristics of participants with NT1 vs NT2 were: mean (SD) age, 32.1 (11.1) vs 28.3 (10.0) years, respectively; sex, 72.8% vs 52.0% female; body mass index, 28.9 (7.5) vs 25.7 (5.6) kg/m2; and use of concurrent alerting agents, 59.2% vs 68.0%. Mean (SD) baseline clinical characteristics in participants with NT1 vs NT2 were: mean sleep latency (MWT), 4.9 (2.9) vs 4.9 (2.9) minutes; Clinical Global Impression rating (CGI-Severity), 5.2 (1.1) vs 4.7 (1.1); ESS scores, 17.6 (4.0) vs 15.4 (3.2); number of sleep stage shifts to lighter stage of sleep or wake measured by polysomnography (PSG), 61.5 (22.2) vs 55.8 (23.5); number of nocturnal arousals by PSG, 81.5 (42.4) vs 73.2 (35.9); sleep quality (visual analog scale [VAS; 1 = did not sleep and 100 = slept very well]), 54.5 (22.0) vs 55.8 (20.8); and refreshing nature of sleep (VAS; 1 = not refreshed and 100 = refreshed), 49.9 (22.6) vs 42.6 (21.6). Conclusion Limited data are available comparing NT1 and NT2 populations; these data indicate a similar level of disease severity at baseline. Support (if any) Avadel Pharmaceuticals