Mepolizumab in chronic rhinosinusitis with severe nasal polyposis: Real-life Spanish cohort study

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a type 2 inflammation-driven condition that causes nasal blockage, olfactory loss, and diminished quality of life. Standard therapies often result in recurrence in severe cases. Mepolizumab, a monoclonal antibody targeting interleukin-5 (IL-5), has demonstrated efficacy in improving clinical symptoms and patient-reported outcomes in phase 3 trials and real-world studies. To assess the real-life efficacy and safety of mepolizumab in patients with CRSwNP, both with and without comorbid asthma, over a 12-month period, focusing on nasal symptoms, polyp size, and olfactory function. A multicentric, prospective observational study was conducted in three hospitals in Catalonia, Spain, involving 28 adult patients with severe CRSwNP treated with mepolizumab (100&#x202f;mg subcutaneously every 4 weeks). Assessments were performed at baseline, 6, and 12 months. Outcomes included Nasal Polyp Score (NPS), Sinonasal Outcome Test-22 (SNOT-22), visual analogue scales (VAS) for symptoms and smell, and the 48- complete version of the Sniffin' Sticks Smell Test. Blood eosinophil counts and adverse events were also recorded. Significant improvements were observed in NPS, SNOT-22, and symptom VAS at both 6 and 12 months (P&#x202f;<&#x202f;.05). Olfactory function improved significantly at 12 months, while subjective olfactory VAS did not. Blood eosinophils decreased sharply. Patients with asthma and AERD showed greater clinical benefit. No serious adverse events occurred. Mepolizumab appears safe and effective for severe CRSwNP, offering substantial clinical and endoscopic improvement. Olfactory gains at one year suggest prolonged treatment may be necessary for sensory recovery.