Patient population
Adult patients (>18 years) diagnosed with eCRS who had undergone endoscopic sinus surgery and whose upper airway disease was not controlled with long term continuous oral corticosteroids were eligible for participation. Exclusion criteria included patients previously treated with mepolizumab, mepolizumab hypersensitivity, established immunodeficiency, cystic fibrosis, pregnancy, lactation and hypereosinophilic syndromes.
Patients were recruited to receive 100mg subcutaneous mepolizumab (GlaxoSmithKline, UK) at four-weekly intervals for 24 weeks. Demographic characteristics, including age, gender, asthma status, atopy, smoking status, date of previous surgery, and use of intranasal and systemic corticosteroid medication, were recorded. Asthma status was determined by either a 15 percent change in forced expiratory volume in 1 second on spirometry with challenge testing or β-agonist use, or current use of regular inhaled bronchodilator or corticosteroid therapy. Atopy was determined by an spIgE automated immunoassay (ImmunoCAPVR, Thermo Fisher Scientific, Massachusetts, United States). Concentration of any allergen group >0.35 kUA/L was classed as a positive result. The grass mix consisted of Lolium perenne , Phleum pratense ,Poa pratensis (Kentucky blue), Sorghum halepense(Johnson), Paspalum notatum (Bahia) and Cynodon dactylon(Bermuda). The dust mite mix contained Dermatophagoides pteronyssinus , Dermatophagoides farina and Blatella germanica (German cockroach). The mould mix comprised Penicillium chrysogenum , Cladosporium herbarum , Aspergillus fumigatusand Alternaria alternata . The animal epithelium mix includedFelis domesticus (Cat), Equus caballus (Horse), Bos Taurus (Cow) and Canis familiaris (Dog). Smoking status was defined by having smoked within the last 12 months. Medication name and dosage were recorded at screening and reviewed at each treatment visit. All trial participants were precluded from changing medication in the four weeks prior to commencement of mepolizumab treatment.