Despite these links between the Th17 pathway and severe Th2-low asthma, in a large double-blind, placebo-controlled phase 2 study, the anti-IL-17 RA antibody, brodalumab, overall did not meaningfully impact quality of life or lung function parameters in inadequately controlled moderate to severe asthma [15], although a post hoc analysis suggested benefit in a sub-population of patients with high bronchodilator reversibility. This evidence concerns the gene IL17A and asthma.