Failure of interleukin 13 blockade in ulcerative colitis

Contrary to a decade ago, clinical devel-opment in ulcerative colitis (UC) has become highly active with multiple prom-ising innovative assets currently in early and late phase clinical studies. The anti-integrin α4β7 monoclonal antibody vedo-lizumab has been leading this wave, and has received marketing authorisation by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) based on an excellent effi-cacy and safety record. One of the targets that had raised high hopes several years ago was interleukin 13 (IL-13), together with IL-4 and IL-5 the signature cytokine of a T helper 2 (Th2) immune response. As such, its blockade was hypothesised as a brilliant therapeutic strategy in diseases such as allergic asthma and UC. However, in this issue of Gut, results from a trial with anrukinzumab in active UC are reported,1 which, together with results of a trial with tralokinumab reported in the January issue,2 crush enthusiasm for anti-IL-13 blockade as a therapeutic strategy in UC. Anrukinzumab is a humanised IgG1 antibody, which binds IL-13 and inhibits IL-13’s binding to the IL-4Rα chain, par