Solriamfetol Improves Wakefulness and Sleepiness in Chinese Patients With Obstructive Sleep Apnea

A study published in CNS Drugs found that solriamfetol (Sunosi; Axsome Therapeutics) significantly improved objective wakefulness and reduced excessive daytime sleepiness (EDS) in Chinese patients with obstructive sleep apnea (OSA), meeting both coprimary endpoints in a 12-week phase 3 trial.¹ The trial addressed a notable gap in treatment options in China, where modafinil has been the only wake-promoting agent approved for OSA-related EDS.

The randomized, double-blind, placebo-controlled trial enrolled 204 adults across 26 sites in China with a baseline Maintenance of Wakefulness Test (MWT) sleep latency under 30 minutes and an Epworth Sleepiness Scale (ESS) score of 10 or higher, randomizing them 1:1 to flexible-dose solriamfetol (titrated up to 150 mg once daily) or placebo. Participants included those adherent, nonadherent, or not using primary OSA therapy, reflecting real-world treatment patterns in China, where a substantial share of patients with OSA go untreated or discontinue therapy early.

By week 12, mean MWT sleep latency increased to 22.9 minutes in the solriamfetol group compared with 11.5 minutes with placebo, a least-squares mean difference of 11.77 minutes (95% CI, 8.99-14.55; P < .0001), with significant separation from placebo emerging as early as week 2. The improvement held across all 5 individual MWT trials throughout the day, spanning roughly 9 hours after a single dose. Solriamfetol treatment also led to significant reductions in ESS scores relative to placebo, with a between-group difference of 1.8 points at week 12 (P = .0017). In addition, a larger share of solriamfetol-treated patients reported overall improvement on the Patient Global Impression of Change scale at week 12 (89.1% vs 77.0%; P = .0221).¹

In terms of safety, solriamfetol was generally well tolerated, with no deaths reported and a low discontinuation rate due to adverse events (AEs; 1%). The most common treatment-related AEs included upper respiratory tract infection, dizziness, hyperuricemia, hypertension, hyperlipidemia, hypertriglyceridemia, and increased blood creatine phosphokinase, most of mild to moderate severity.

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Solriamfetol produced transient increases in blood pressure and pulse rate that peaked around 4 hours post-dose and returned toward placebo levels by 10 hours, with no clinically meaningful changes in labs, ECG, or physical exam. No discontinuation symptoms or rebound hypersomnia were observed after the final dose, and no participants reported suicidal ideation or behavior on the Columbia-Suicide Severity Rating Scale.¹

The authors noted that dizziness, rather than headache, was the most frequently reported adverse event in this cohort, a divergence from prior Western trials of solriamfetol where headache predominated, which they flagged as warranting further investigation. They also observed a larger placebo response on the subjective ESS measure than seen in earlier Western trials, while the objective MWT results closely matched those of the pivotal TONES 3 study. The study authors, led by corresponding author Weifeng Mi, PhD, of Peking University Sixth Hospital, suggested this gap may reflect that Chinese participants, unlike those in earlier trials, were aware solriamfetol was already an approved drug elsewhere, potentially raising expectations and inflating the placebo effect on self-reported outcomes.¹

The study's authors concluded that solriamfetol "demonstrated robust improvement in wakefulness, reduction of excessive sleepiness, and patient-reported global improvements" in this population, with a safety profile consistent with prior placebo-controlled trials and no new safety signals identified.¹

REFERENCE
1. Cheng H, Deng L, Meng Z, et al. Efficacy and Safety of Solriamfetol on Excessive Daytime Sleepiness Associated with Obstructive Sleep Apnea in China: A Phase 3, Multicenter, Double-Blind, Placebo-Controlled Randomized Clinical Trial. CNS Drugs. 2026;40(1):83-98. doi:10.1007/s40263-025-01232-1