The lysophosphatidic acid (LPA) axis is identified as a therapeutic target for IPF.<h4>Objective</h4>This study aims to assess BI 1819479, an LPA pathway inhibitor, in patients with IPF (ClinicalTrials.gov Identifier: NCT06335303).<h4>Methods</h4>In this placebo-controlled, phase II trial, patients will be randomised (2:1:1:1) to receive one of three oral doses of BI 1819479 or placebo, stratified by nintedanib/pirfenidone use. Here, LPA is linked to idiopathic pulmonary fibrosis.