Prevalence and Predictors of Response to Antifibrotics in Long-Term Survivors with Idiopathic Pulmonary Fibrosis.

Purpose: The natural history of IPF remains unpredictable despite antifibrotic treatment. In addition, some patients discontinue treatment due to the occurrence of adverse events. To date, no data exist on either the effect of long-term treatment or predictors of treatment response. In the present study, we aim to evaluate the functional trajectory of IPF patients treated with antifibrotics for at least three years and to establish predictors of treatment response.

Methods: This multicenter study enrolled long-term survivors IPF patients provided they had stopped treatment for no longer than one month during at least three-year study period. Based on the absolute decline of FVC%predicted (pred.) observed during the 3-year treatment and normalized per year, patients were defined as progressors (≥ 5%) or non-progressors (< 5%).

Results: We identify 172 IPF patients who completed three years of antifibrotic treatment with no interruption. The 27% of these IPF patients progressed despite complete adherence to treatment. Progressors were more likely to be non-smokers compared to non-progressors, with higher occurrence of diarrhea and with a more preserved lung function at diagnosis. FVC %pred. and liters at diagnosis, a greater FVC decline in the 1-st year of follow up, being non-smokers, and complaining of diarrhea over treatment are independent predictors of progression.

Conclusion: Almost one third of IPF patients adherent to three years of antifibrotics experience progression. A functional decline at first year of treatment despite preserved lung function at diagnosis, non-smoking status, and occurrence of diarrhea over treatment are independent predictors of disease progression.