A Study to Evaluate the Respiratory Safety of Lemborexant in Adult and Elderly Participants With Moderate to Severe Obstructive Sleep Apnea, and in Adult and Elderly Participants With Moderate to Severe Chronic Obstructive Pulmonary Disease

The primary purpose of the study is to determine whether lemborexant increases the apnea hypopnea index (AHI) on Day 8 of treatment in adult and elderly participants (adults greater than or equal to \[\>=\] 45 to less than \[\<\] 65 years; elderly \>=65 to 90 years) with moderate to severe obstructive sleep apnea (OSA) compared with placebo, and using pulse oximetry determine whether lemborexant decreases the peripheral oxygen saturation (SpO2) during total sleep time (TST) on Day 8 of treatment in adult and elderly participants (adults \>=45 to \<65 years; elderly \>=65 to 90 years) with moderate to severe chronic obstructive pulmonary disease (COPD) compared with placebo.