Previous attempts with other IL-13-targeted agents have produced mixed results: lebrikizumab, for instance, failed to show consistent benefit in both all-comers and serum periostin- or eosinophil-high subgroups during Phase III trials [188], whereas dupilumab, targeting both IL-4 and IL-13, demonstrated efficacy in a broad severe asthma population as well as in those with elevated blood eosinophils in a Phase IIb trial [189]. The gene discussed is IL4; the disease is asthma.