International Rhinologic Society Rhinology 0300-0729 2026 06 01 Mepolizumab improves outcomes in patients with CRSwNP with one or more prior nasal polyp surgeries EN J.K. Han Department of Otolaryngology Head and Neck Surgery, Old Dominion University, Norfolk, VA, USA J. Mullol Department of Otorhinolaryngology, Hospital Clínic Barcelona, FRCB-IDIBAPS, University of Barcelona, CIBERES, Barcelona, Catalonia, Spain M. Wagenmann Department of Otorhinolaryngology, Düsseldorf University Hospital, Düsseldorf, Germany L. Walrave Global Medical, Specialty Care, GSK, Wavre, Belgium L. Zhang Respiratory Biostatistics, GSK, Collegeville, PA, USA A.R. Sousa Clinical Sciences, Respiratory, GSK, London, UK P. Howarth Global Medical, Specialty Care, GSK, London, UK C. Hopkins ENT Department, Guy’s and St Thomas’s NHS Foundation, London, UK Journal Article 3468 10.4193/Rhin25.599 BACKGROUND: Patients with chronic rhinosinusitis with nasal polyps (CRSwNP) often undergo multiple nasal surgeries. The Phase III SYNAPSE study (GSK ID:205687; NCT0308579) demonstrated that mepolizumab reduces the need for repeat surgery. We explored whether outcomes differed based on the number of prior surgeries. METHODOLOGY: This post hoc analysis of SYNAPSE stratified patients by history of 1 or >1 prior surgery. Patients were randomised to receive mepolizumab or placebo every 4 weeks, alongside standard of care, for 52 weeks. Outcomes included change from baseline in endoscopic nasal polyp (NP) score, visual analogue scale (VAS) scores for nasal obstruction, loss of smell and overall symptoms, Sino-Nasal Outcome Test-22 (SNOT-22), and time to repeat surgery and/or oral corticosteroid (OCS) use. RESULTS: 189 patients had 1 prior surgery (108 mepolizumab; 81 placebo) and 218 had >1 prior surgery (98; 120). In both subgroups, mepolizumab significantly improved mean changes versus placebo in NP, nasal obstruction, loss of smell VAS, overall symptom VAS, and SNOT-22. Significant reductions in risk of repeat surgery and requiring OCS were observed with mepolizumab versus placebo in patients with 1 prior surgery. CONCLUSIONS: Mepolizumab improves outcomes in patients with CRSwNP with one or multiple prior surgeries; however, may offer greater benefit when initiated after a single surgery.