Mycophenolate therapy in interstitial pneumonia with autoimmune features: a cohort study

International experts recently characterized interstitial pneumonia with autoimmune features (IPAF) as a provisional diagnosis for patients with interstitial lung disease who have characteristics of autoimmune disease but do not meet criteria for a specific autoimmune disease. We describe clinical characteristics of IPAF patients and examine responses to mycophenolate as a therapy for IPAF. This retrospective cohort included adult patients meeting European Respiratory Society/American Thoracic Society classification criteria for IPAF. Sociodemographic, clinical, and pulmonary function test data were abstracted for patients with and without mycophenolate treatment and followed longitudinally from interstitial lung disease diagnosis for change in pulmonary function test results. We identified 52 patients who met criteria for IPAF. Of 52 IPAF patients, 24 did not receive mycophenolate and 28 did, with median time to mycophenolate treatment 22 months. Changes in FVC% and percentage predicted lung diffusion capacity for carbon monoxide (D %) between the mycophenolate-treated and untreated groups were not significantly different (FVC% change =0.08, D % change =0.17). However, there was a trend toward more rapid baseline decline of both FVC% and D % in the mycophenolate-treated cohort before vs after mycophenolate therapy. The slope of both FVC% and D % values improved after onset of mycophenolate exposure for the treated group, although this finding was not statistically significant. Patients with IPAF might benefit from mycophenolate therapy. Larger prospective clinical trials are needed to evaluate the efficacy of mycophenolate for patients who meet criteria for IPAF.