In the murine bleomycin-induced model of lung fibrosis, GSK3008348 engages αvβ6 integrins, inhibits the activation of TGFβ with a prolonged duration of action, and reduces lung fibrotic end points including collagen deposition and serum C3M levels, a clinically relevant marker of IPF disease progression. Here, TGFB1 is linked to idiopathic pulmonary fibrosis.