INTRODUCTION: The insomnia severity index (ISI) is a self-report instrument that evaluates perception of insomnia severity. In Study 303 (SUNRISE-2), lemborexant (LEM) showed greater reduction from baseline in ISI total score versus placebo (PBO) at 6mo. Here we report on ISI items related to worry/distress about subjects’ insomnia and interference of insomnia with daily function.
METHODS: Study 303 was a 12-month, double-blind, phase 3 study; subjects were randomized to PBO or LEM (5mg, [LEM5]; 10mg, [LEM10]) for the first 6mo. ISI items were rated on a 5-point Likert scale: 0 (no problem) to 4 (very severe problem). Least squares mean (LSM) treatment differences (TD) were calculated using MMRM model adjusted for relevant factors at 6mo.
RESULTS: For ISI item “worried/distressed with sleep,” mean[SD] baseline scores were similar for PBO (2.9[0.7]; n=312), LEM5 (3.0[0.7]; n=312), and LEM10 (2.9[0.8]; n=311). Mean[SD] scores at 6mo (PBO, 1.6[1.0]; LEM5, 1.3[1.1]; LEM10, 1.3[1.0]) demonstrated decreases from baseline across all groups. The LSM[SE] TD in change from baseline (CFB) was significantly greater for LEM5 (−0.3[0.1], P=0.001) and LEM10 (−0.3[0.1], P < 0.01) versus PBO.
For ISI item “interference with daily functioning,” mean[SD] baseline scores were similar for PBO (2.6[0.8]; n=312), LEM5 (2.7[0.7]; n=312), and LEM10 (2.6[0.8]; n=311). Mean[SD] scores at 6mo (PBO, 1.5[1.0]; LEM5, 1.2[1.0]; LEM10, 1.2[1.0]) demonstrated decreases from baseline. The LSM[SE] TD in CFB was significantly greater for both LEM5 (−0.4[0.1], P < 0.0001) and LEM10 (−0.3[0.1]), P=0.0001) versus PBO.
CONCLUSIONS: LEM treatment may reduce worry/distress about a patient’s insomnia condition and interference of insomnia with daily function.