Gann PH, Deaton RJ, McMahon N, et al. - Researchers performed a substudy of a double-blind, placebo-controlled phase 2 trial, to investigate if epithelial-mesenchymal transition (EMT) biomarkers modulation by RPC4046 (anti‒IL-13 monoclonal antibody) could be seen in biopsies from adults suffering from active eosinophilic esophagitis. This study involved 69 patients who were randomized to weekly subcutaneous RPC4046 180 mg (n = 19), 360 mg (n = 26), or placebo (n = 24). Experts collected baseline and week-16 esophageal biopsies from these patients. The endpoints were alteration from baseline to week 16 in percentage vimentin-positive epithelial cells (primary), total e-cadherin, and vimentin:e-cadherin ratio per cell (average of 47,000 cells/biopsy examined). In this patient population, a significant decrease in EMT markers was brought about by RPC4046, with greater impacts seen at 360 mg. The hypothesis that pharmacologic IL-13 inhibition causes amelioration of both inflammatory and remodeling pathways, as well as could potentially decrease the risk of fibrostenotic complications, is supported by these findings combined with the results for eosinophil density and clinical endpoints from the main trial.