A Study of Lemborexant in Chinese Participants With Insomnia Disorder

Inclusion Criteria

Participants must meet all of the following criteria to be included in this study:

• Chinese male or female, age 18 years or older, at the time of informed consent (in Taiwan only participants with age 20 years or older are eligible)
• Meets the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for Insomnia Disorder, as follows:
• Complains of dissatisfaction with night time sleep, in the form of difficulty staying asleep and/or awakening earlier in the morning than desired despite adequate opportunity for sleep
• Frequency of complaint greater than or equal to (>=) 3 times per week
• Duration of complaint >=3 months
• Associated with complaint of daytime impairment
• At Screening: History of sSOL >=30 minutes on at least 3 nights per week in the previous 4 weeks and/or sWASO >=60 minutes on at least 3 nights per week in the previous 4 weeks
• At Screening: Reports regular time spent in bed, either sleeping or trying to sleep, between 7 and 9 hours
• At second Screening Visit (Visit 2a) and Run-in Visit (Visit 3a): Sleep diary confirms regular bedtime, defined as the time the participant attempts to sleep, between 21:00 and 01:00 on at least 5 of the final 7 nights and regular waketime, defined as the time the participant gets out of bed for the day, between 05:00 and 10:00 on at least 5 of the final 7 nights
• At Screening and Baseline: ISI score >=15
• Confirmation of current insomnia symptoms, as determined from responses on the sleep diary on the 7 most recent mornings before the first PSG during Screening Period (Visit 2a) and Run-in visit (Visit 3a), such that sSOL >=30 minutes on at least 3 of the 7 nights and/or sWASO >=60 minutes on at least 3 of the 7 nights
• At the second Screening Visit (Visit 2a) and the Run-in visit (Visit 3a): Confirmation of sufficient duration of time spent in bed, as determined from responses on the sleep diary on the 7 most recent mornings before the Visit, such that there are no more than 2 nights with time spent in bed duration less than ( ) 10 hours
• During the Run-in Period, objective (PSG) evidence of insomnia as follows:
• LPS average >=30 minutes on the 2 consecutive Baseline PSGs, with neither night =60 minutes on the two consecutive Baseline PSGs, with neither night 450 millisecond [ms]) as demonstrated by a repeated electrocardiogram. A history of risk factors for torsade de pointes (for example, heart failure, hypokalemia, family history of long QT Syndrome) or the use of concomitant medications that prolonged the QTcF interval
• Any suicidal ideation with intent with or without a plan at Screening or within 6 months of Screening
• Any suicidal behavior in the past 10 years
• Evidence of clinically significant disease (for example, cardiac; respiratory including chronic obstructive pulmonary disease, acute and/or severe respiratory depression; gastrointestinal; moderate and severe hepatic impairment; renal including severe renal impairment; neurological including myasthenia gravis; psychiatric disease; or malignancy within the past 5 years other than adequately treated basal cell carcinoma) or chronic pain that in the opinion of the investigator(s) could affect the participant's safety or interfere with the study assessments. Participants for whom a sedating drug would be contraindicated for safety reasons because of the participant's occupation or activities are also excluded
• Hypersensitivity to lemborexant or to their excipients
• Scheduled for surgery during the study
• Known to be human immunodeficiency virus positive
• Active viral hepatitis (B or C) as demonstrated by positive serology
• History of drug or alcohol dependency or abuse within approximately the last 2 years
• A current diagnosis of sleep-related breathing disorder including obstructive sleep apnea (with or without continuous positive airway pressure treatment), periodic limb movement disorder, restless legs syndrome, circadia