Antifibrotic treatment in 18 patients with chronic Hypersensitivity Pneumonitis

Introduction: Chronic Hypersensitivity Pneumonitis (c-HP) can exhibit an IPF-like course despite immunosuppressive treatment. In this group of patients there is a need for new therapeutic approaches. Aim: To investigate the effect of antifibrotics in the clinical course of c-HP. Patients and Methods: Retrospective analysis of patients with an initial diagnosis of IPF that were subsequently diagnosed as c-HP in the context of multidisciplinary discussion (Jan2012-Dec2016). HP diagnosis was based in the absence of alternative diagnoses when at least two of the following criteria were present: Recognition of an inciting antigen, compatible HRCT pattern (mainly presence of mosaic pattern), BAL lymphocytosis>20%. Results: We enrolled in the study 96 patients with HP. From this cohort we identified 18 patients, initially diagnosed as IPF (16 males, 88,9%, median age 70 years (95% CI for the median 63 to 73.6) that had received antifibrotics for at least 12 months (10 pirfenidone and 8 nintedanib). Mean (±SE) relative changes in %FVCpred and %DLcopred over one year was -4.19±3.29 and -5.72±5.32, respectively. A decline in FVC was observed in 11 patients (in 4 patients > 10%, and in 5 patients between 5-10%). An increase in relative %FVCpred was observed in 7 patients (mean ΔFVC ± SE = 8.69±3.75). Conclusions: Antifibrotics can stabilize FVC decline in patients with c-HP. Large randomized trials are needed.