NAsal Polyps: Inflammatory & Molecular Phenotyping of Responders to Benralizumab

Background and rationale: Phase III-b study. Population and patient selection criteria: Adult patients with Chronic Rhinosinusitis with Nasal Polyps (allergic and non-allergic) requiring at least 1000 mg oral prednisone over the previous twelve months to control symptoms of rhinosinusitis, and with: * Nasal polyps score (Meltzer et al.) ≥ 5 * Symptoms VAS scores (for nasal obstruction, hyposmia, post-nasal drip, sneezing, rhinorrea; 0-10 for each symptom) \> 24 Sample size: 20 subjects. Study design and study duration: This is a pilot, prospective, double-blind placebo-controlled (DBPC) phase III-b trial with Benralizumab 30 mg administered subcutaneously every 4 weeks for the first 3 doses and then every 8 weeks, for a treatment-period of 16 weeks (followed up at 32 and 52 weeks) in patients with chronic rhinosinusinusitis with nasal polyps (CRSwNP). Description of study treatment/product/intervention: Benralizumab, 30 mg subcutaneously every 4 week for the first 3 doses, and then every 8 weeks. Objectives: * Primary objective: To assess the clinical efficacy of Benralizumab on CRSwNP at week 24 (vs baseline) after the beginning of treatment, and to correlate the presence of baseline biomarkers with nasal polyp (NP) score improvement, in order to identify any possible predictive biomarker of response to Benralizumab. * Secondary objective: In the follow up phase we will monitor all the biomarkers at 32 and 52 weeks , this monitoring will ascertain if any of those will predict relapse of nasal polyps and consequently when Benralizumab treatment has to be reinstalled. * Safety objective: To evaluate the safety and tolerability of Benralizumab in patients with CRSwNP Statistical methods, data analysis: Descriptive analysis of all collected variables at all time-points will be performed. Patients will be classified into "responders" and "non responders", for primary endopoint variable. Continuous variables will be evaluated with the normality test of Kolmogoro