TD139 (also known as GB0139), a small-molecule inhibitor of Galectin-3 in phase 1/2 clinical trials for idiopathic pulmonary fibrosis (IPF) (NCT02257177) and COVID-19 pneumonitis (NCT04473053), exhibits high affinity for the carbohydrate recognition domain of Galectin-3, preferentially targeting extracellular Galectin-3, due to its limited cell permeability (19–21). Here, LGALS3 is linked to pulmonary fibrosis.