Identifying Predictors Of Response To Mepolizumab In CRSwNP

Patients will receive Mepolizumab 100mg SC once every 4 weeks for 48 weeks (twelve injections, no placebo) at the hospital. The IMP will be administered following clinic procedures and blood collection. Patients will be monitored at the study site for at least 30 minutes after injections for signs of hypersensitivity reaction. Subcutaneous injection sites should be alternated among the 4 quadrants of the abdomen (avoiding navel and waist areas) or the upper arms. Background therapy will be assured with mometasone furoate nasal spray (200µg BID) daily throughout the study.