PubMed2026
STUDY OBJECTIVES: To evaluate the effect of daridorexant on nighttime respiratory function and sleep in adults with severe obstructive sleep apnea (OSA) without insomnia. MATERIALS AND METHODS: This randomized, double-blind, placebo-controlled, two-period, crossover trial was conducted at a single sleep center in 16 adults (≥18 years) with severe OSA without insomnia. In each period, daridorexant 50 mg or placebo was administered every evening for 5 days. Primary and secondary endpoints were the treatment differences (daridorexant-placebo) for apnea/hypopnea index (AHI) and oxygen saturation (SpO2) during total sleep time (TST), respectively, after last dosing. A mean increase in AHI ≥10 events/h and mean decrease in nocturnal SpO2 ≤-2% were the minimum changes considered to be clinically meaningful negative effects. Other endpoints included TST, latency to persistent sleep (LPS), and wake after sleep onset (WASO). RESULTS: Mean baseline AHI was 51.2 events/h (range 30.8, 82.2) and mean SpO2 during TST was 92.1% (range 88.5, 94.3). No clinically meaningful effect of daridorexant on AHI or SpO2 during TST was detected. Treatment differences were -3.7 events/h (one-sided 95% CI ≤ +4.2) and - 0.12 % (one-sided 95% CI ≥ -0.6), respectively. Compared with placebo, daridorexant increased TST by 32.5 min (90% CI: 6.9, 58.2), associated with shorter LPS (-10.3 min [90% CI: -20.6, -0.02]) and a trend towards reduced WASO (-15.2 min [-31.2, 0.9]). Four adverse events were reported (daridorexant n = 3; placebo n = 1), all of mild intensity and none related to respiratory function. CONCLUSION: Short-term treatment with daridorexant does not impair sleep-disordered breathing and may improve sleep in patients with severe OSA. CLINICAL TRIAL: ClinicalTrials.gov, https://clinicaltrials.gov/study/NCT05458193, NCT05458193. Statement of Significance Obstructive sleep apnea (OSA) is highly prevalent and associated, in 30%-50% of cases, with insomnia-related symptoms, yet the safety of insomnia medications in OSA remains unclear. Daridorexant, a dual orexin receptor antagonist for the treatment of adults with insomnia disorder, previously showed no negative effect on sleep-disordered breathing in participants with mild/moderate OSA. This randomized, double-blind, placebo-controlled, crossover trial evaluates daridorexant 50 mg (maximum therapeutic dose) in participants with severe OSA without insomnia. Repeated dosing (5 nights) did not impair nighttime respiratory function, as assessed by apnea/hypopnea index and nocturnal oxygen saturation. Moreover, improvements in sleep characteristics were observed with daridorexant, extending evidence that daridorexant 50 mg is safe and well-tolerated and may improve sleep in adults with severe OSA.