0459 Effects of Lemborexant on Sleep Architecture in Chinese, Korean, and American/European Participants with Insomnia

Abstract Introduction It is important to understand whether there are differences in sleep architecture depending on the race of the patient. The lemborexant (LEM) clinical program provided information based on polysomnography (PSG) studies conducted in North America, Europe, China and South Korea. Methods E2006-G000-304 (Study 304; NCT02783729), E2006-J086-311 (Study 311; NCT04549168), and E2006-J082-204 (Study 204; NCT05594589) were 1-month, multicenter, randomized, double-blind, placebo (PBO)-controlled, parallel group studies evaluating the efficacy and safety of LEM in adults with insomnia disorder. Study 304 enrolled participants (≥55y) of any race. Study 311 participants were ≥18y and exclusively Chinese. Study 204 participants were 19–80y and exclusively South Korean. In Studies 304 and 311, pairs of PSGs were conducted during a single-blind PBO run-in (baseline), after the first 2 doses of LEM or PBO, and after the last 2 doses (end of 1-month). In Study 204, one PSG was conducted during a single-blind PBO run-in (baseline) and after the last dose (end of 1-month). All 3 studies included LEM 10mg (LEM10) and PBO; Studies 304 and 204 also included LEM 5mg (LEM5), and Study 304 included zolpidem (LEM5 and zolpidem are not reported here). Analyses of sleep architecture parameters included change from baseline in total sleep time (TST), rapid eye movement (REM) sleep, REM latency, total non-REM (NREM) sleep, and stages N1–N3 sleep. Results Populations for the current analyses comprised 477 participants (PBO, n=208; LEM10, n=269), 193 participants (PBO, n=100; LEM10, n=93), and 39 participants (PBO, n=13; LEM10, n=26) for Studies 304, 311, and 204, respectively. In all studies, after 1 month, LEM10 treatment elicited larger increases (improvements) from baseline in TST, REM, NREM total, and stages N1 and N2 and decreases from baseline in REM latency compared with PBO. Stage N3 sleep was not different following treatment with LEM10 versus PBO. In the 3 studies, LEM was well tolerated, with most treatment-emergent adverse events being mild or moderate in severity. Conclusion Consistent findings of sleep architecture improvements from these 3 studies support the use of LEM in patients with insomnia, regardless of race. Support (if any) Eisai Inc.