IL5 and asthma: The recent development of targeted asthma therapies directed at an type 2 inflammatory phenotype of severe asthma, such as anti‐interleukin (IL)‐5 therapy, anti‐IL‐4Ralpha, and CRTh2 antagonists, has benefited from investigation in populations selected based on FeNO and other measures of type 2 inflammation 27.