336 Effect of Lemborexant Versus Placebo and Zolpidem on REM Sleep by Quarter Night Intervals in Older Adults with Insomnia Disorder

Abstract Introduction Effects of the dual orexin receptor antagonist lemborexant (LEM) on sleep architecture in adults ≥55y with insomnia disorder were assessed in Study E2006-G000-304 (Study 304; SUNRISE-1; NCT02783729). These post hoc analyses of Study 304 examined the acute effect of LEM on REM pressure (REM latency [REM-L] and REM by quarter of the night [QoN]). Methods This study was a 1mo, randomized, double-blind, placebo- and active-controlled (zolpidem tartrate extended-release 6.25mg [ZOL]) study of LEM (5mg, LEM5; 10mg, LEM10). Subjects received placebo (n=208), ZOL (n=263), LEM5 (n=266), or LEM10 (n=269). Two nights of PSGs were recorded at baseline, first 2 (N1/2), and last 2 (N29/30) treatment nights. Results Baseline REM-L (minutes) was similar across treatments (98.4–101.4). Significant decreases from baseline in REM-L were observed for LEM5 (−42.6 [53.9]) and LEM10 (−49.6[52.9]) vs placebo (−6.9[54.5]) and ZOL (0.2[54.2]) on N1/2 (all P<0.0001). No difference was observed for ZOL vs placebo. Baseline REM (minutes) for each QoN was similar across treatments. In Q1, mean(SD) REM (minutes) on N1/2 was 16.5(9.7), 19.7(10.5), 10.3(8.2), and 8.5(7.6) for LEM5, LEM10, placebo, and ZOL, respectively. The difference was significant for LEM5 and LEM10 vs placebo and ZOL (all P<0.0001), and ZOL vs placebo (P<0.05). In Q2, mean(SD) REM on N1/2 was 19.2(9.4), 21.6(10.0), 17.9(8.9), and 17.2(9.3) for LEM5, LEM10, placebo, and ZOL, respectively. The difference was significant for LEM10 vs placebo (P<0.0001) and for LEM5 and LEM10 vs ZOL (P<0.01, P<0.0001, respectively). No difference was observed for ZOL vs placebo. In Q3, mean(SD) REM on N1/2 was 23.3(10.3), 25.9(9.7), 20.8(9.4), and 22.8(9.9) for LEM5, LEM10, placebo, and ZOL, respectively. The difference was significant for LEM5, LEM10, and ZOL vs placebo (P<0.01, P<0.0001, P<0.05, respectively) and LEM10 vs ZOL (P<0.001). In Q4, mean (SD) REM on N1/2 was 23.8(9.4), 26.1(11.0), 21.6(10.9), and 22.5(10.1) for LEM5, LEM10, placebo, and ZOL, respectively. The differences were significant for LEM5 and LEM10 vs placebo (P<0.05, P<0.0001, respectively), and for LEM10 vs ZOL (P<0.0001). Generally, similar findings were noted at N29/30; these data will be reported. Conclusion LEM, but not ZOL, acutely increases REM pressure as evidenced by REM latency and REM duration per quarter. Support (if any) Eisai Inc.