Factors that may predict a good response to anti-IL5/IL5R biologics are defined as follows: (a) higher blood eosinophil count (strongly predictive), (b) more frequent severe exacerbations during the previous year (strongly predictive), (c) adult-onset asthma, (d) nasal polyposis, and e) maintenance with OCS at baseline. The gene discussed is IL5RA; the disease is Nasal polyposis.