Effect of Antifibrotic Therapies in Patients with Interstitial Pneumonia with Autoimmune Features

Interstitial pneumonia with autoimmune features (IPAF) is a new terminology for a special group of patients characterized by idiopathic interstitial pneumonia who have a clinical feature of underlying connective tissue disease not meeting the current criteria for CTD-s. The aim of this study was to evaluate real-world clinical characteristics and response to antifibrotic treatment. We identified 44 (8,6%) patients affected by fibrosing lung disease and positive autoantibodies out of 512 patients discussed between January 2017 and June 2019 at the ILD MDD at our university center. Pulmonary symptoms, lung function with CO diffusion, therapy and adverse events were analyzed longitudinally in patients with at least 6 months’ follow-up (N=26). IPAF patients (42% men, mean age 67 ± 14 years) were divided into two subgroups according to antifibrotic treatment. Patients of Group 1 received antifibrotic treatment (N=11), had decreased lung function (forced vital capacity; FVC 75.5 ± 16.8 %pred) at baseline compared to Group 2 (N=15; FVC 86.2 ± 22.2%pred; p=0.19). No differences between groups were identified regarding clinical parameters and radiological pattern. Three of Group 1 patients were treated with pirfenidone and 8 patients with nintedanib. Majority of Group 2 (80%) received steroid therapy in the observation period. The most common adverse events in Group 1 were gastrointestinal symptoms (36%) and elevated liver enzymes (18%). FVC decline >10% affected 9% of Group 1, while 27 % of Group 2 (p=0.0009). Our real word data confirmed that IPAF is associated with significant FVC decline in a high proportion of patients and was significantly reduced when antifibrotic treatment was initiated.