POSTN and asthma: Two large phase 3 clinical trials, STRATOS 1 and STRATOS 2, explored the use of periostin and DPP-4 as biomarkers of IL-13-driven inflammatory patterns in patients aged 12–75 years with severe uncontrolled asthma treated with tralokinumab (300 mg s.c. every 2 weeks for 52 weeks) or placebo (Panettieri et al., 2018).