Maintenance of Effectiveness of Pirfenidone in Elderly Patients with Progressive Functional Impairment: A Real-World Retrospective Study in IPF

Background/Objectives: In clinical trials designed to evaluate efficacy and safety of pirfenidone in patients with idiopathic pulmonary fibrosis (IPF), inclusion criteria were age ≤ 80 years, FVC ≥ 50%pred and DLco ≥ 35%pred. The outcomes in patients progressing beyond these criteria are not yet fully investigated. This study aims to evaluate the effectiveness of pirfenidone in patients who, during treatment, progress beyond the criteria adopted in clinical trials. Methods: This observational retrospective single-centre study included patients younger than 81 years and with mild-to-moderate IPF who had initiated pirfenidone from December 2011 to October 2023. We compared the monthly decline in absolute FVC and %DLco before and after the progression beyond one or more inclusion criteria used in clinical trials. Results: A total of 174 patients were included in the study, with a mean follow-up of 39.2 months (SD ± 29.7 months, range 2–152 months). Seventy-six of them remained within all criteria (control group), 72 passed one criterion, 25 two criteria and 1 all criteria. There was no difference in the trend of FVC and %DLco between the control group and the groups that passed one or two criteria. The intra-individual trend after passing one criterion was similar to that shown before, for both FVC and %DLco. The intra-individual trend also appeared to be preserved when analyzing a small group of patients who had passed any two criteria. Conclusions: Neither attaining advanced age nor the development of severe functional impairment appeared to limit the effectiveness of pirfenidone.