Yoshikawa T, Otsuka M, Chiba H, et al. - By performing a retrospective inquiry among patients with idiopathic pulmonary fibrosis (IPF) who were started on pirfenidone or nintedanib (anti-fibrotic drugs) between January 2014 and June 2018, researchers intended to clarify if therapeutic results of these anti-fibrotic drugs in this patient population are reflected by serum surfactant protein (SP)-A, SP-D, and Krebs von den Lungen-6 (KL-6). Two groups were defined: progression group including patients with ≥ 10% drop in forced vital capacity or ≥ 15% drop in diffusing capacity of the lung for carbon monoxide from baseline to 6 months; and the stable group including the other patients. A significant reduction in changes in SP-A and KL-6 from baseline to 3 and 6 months was noted in the stable group vs the progression group. Findings revealed that the outcomes of anti-fibrotic drug treatment in IPF patients were reflected by alterations in serum SP-A. The potential of serum SP-A was suggested as a biomarker of therapeutic results of anti-fibrotic drugs.