Gimsilumab (development code MOR-087, GSK-3196165) is an investigational, fully human monoclonal antibody developed for the treatment of inflammatory and fibrotic diseases, most notably idiopathic pulmonary fibrosis (IPF) and rheumatoid arthritis (RA). It functions as a targeted inhibitor of granulocyte-macrophage colony-stimulating factor (GM-CSF). By binding with high affinity to GM-CSF in the circulation, gimsilumab neutralizes this cytokine, preventing it from interacting with its receptor on myeloid cells (macrophages, neutrophils, eosinophils). This blockade aims to suppress the GM-CSF-mediated signaling that drives the activation, proliferation, and survival of pro-inflammatory and pro-fibrotic myeloid cells, thereby reducing inflammation and tissue scarring.