The study was a 12-week randomized, double-blind, placebo-controlled, multicenter phase 3 trial in Chinese patients with obstructive sleep apnea and excessive daytime sleepiness (OSA-EDS). Participants were randomized 1:1 to a daily dose of 150 mg solriamfetol or placebo in the morning. Coprimary endpoints were changes in sleep latency during the maintenance of vigilance test and in Epworth sleepiness scale scores from baseline to week 12. Polysomnography (PSG) survey parameters included total sleep time (TST), wakefulness after sleep onset (WASO), sleep stages (N1, N2, N3), apnea-hypopnea index (AHI), mean and minimum oxygen saturation (SaO2). At weeks 2, 5, and 12, there were no significant differences between groups in TST, WASO, N2 sleep, and AHI (P > 0.05). Significant changes appeared only in N1 at week 2 (P = 0.0022) and in N3 at week 5 (P = 0.0212). No clinically significant or consistent changes in PSG parameters were observed compared to placebo, indicating that morning administration of solriamfetol does not have a significant effect on nighttime sleep quality.