Gossamer Bio, Inc., a clinical-stage biopharmaceutical company, focuses on developing and commercializing seralutinib for the treatment of pulmonary arterial hypertension (PAH) in the United States. The company is developing GB002, an inhaled, small molecule, platelet-derived growth factor receptor, or PDGFR, colony-stimulatin factor 1 receptor and c-KIT inhibitor, which is in Phase 3 clinical trial for the treatment of PAH. It has license agreements with Pulmokine, Inc. to develop and commercialize GB002 and related backup compounds.