International Rhinologic Society Rhinology 0300-0729 2026 03 23 Improving sleep in severe CRSwNP: an RCT on the effect of mepolizumab and FESS on OSA, sleep disturbances and quality of life EN A.S. Homøe Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark E.K. Kiaer Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark K. Aanæs Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark J. Tidemandsen Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark P. Jennum Department of Clinical Neurophysiology, Copenhagen University Hospital (Rigshospitalet), Glostrup, Denmark V. BackerDepartment of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark Journal Article 3362 10.4193/Rhin25.228 BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) often leads to poor sleep quality and fatigue. Many patients with CRSwNP are also at risk for obstructive sleep apnea (OSA). This study examined how mepolizumab and/or endoscopic sinus surgery (FESS) affect sleep quality and OSA in patients with severe uncontrolled CRSwNP. METHODS: In a randomised trial with 58 patients, participants received mepolizumab alone or combined with FESS. Sleep quality was measured using FOSQ-10 and ESS, and OSA severity via AHI from home sleep apnea tests. RESULTS: At baseline, 70% of participants had OSA (AHI ≥ 5), with 34.6% having moderate-to-severe OSA. After six months, there were significant improvements in sleep quality (SNOT-22, FOSQ-10, ESS) in both groups but no significant change in objective OSA measures (AHI, ODI). Patients with OSA showed a reduction in severity, however non-significant. There were no severe adverse events (SAE) during the follow-up. CONCLUSIONS: Mepolizumab, with or without FESS, improved subjective sleep quality and reduced fatigue but did not significantly affect OSA severity. This suggests that while treatment eases sleep-related symptoms, it may not resolve underlying OSA, particularly in more severe cases.