Mycophenolate mofetil and azathioprine in chronic hypersensitivity pneumonitis

Abstract

Background: The pharmacologic management of chronic hypersensitivity pneumonitis (cHP) has traditionally included oral corticosteroids, but the morbidity associated with prednisone has driven the search for alternative approaches to therapy. Aims: To describe the impact of treatment with mycophenolate mofetil (MMF) or azathioprine (AZA) on longitudinal lung function in patients with cHP. Methods: We retrospectively identified patients from three ILD centers with a diagnosis of cHP treated with either MMF or AZA. Longitudinal change in lung function before and after treatment initiation was analyzed using linear mixed effect modeling adjusting for age, gender, and prednisone use. Results: Sixty-five patients were included; 48 were treated with MMF and 17 with AZA. Median follow-up after treatment initiation was 11 months. Prior to treatment initiation, there was a decline in both mean forced vital capacity (FVC) and mean diffusion capacity of the lung for carbon monoxide (DLCO) % predicted over time (Figure). Treatment with MMF or AZA showed no significant impact on FVC decline (improvement of 0.4% over pre-treatment rate of decline (p=0.57)) but a significant improvement in DLCO of 4% (p Conclusions: In a multicenter cohort of patients with cHP, treatment with MMF or AZA was associated with improvement in DLCO, but no significant impact on FVC. Prospective trials are needed to further investigate the clinical effectiveness of MMF and AZA for cHP.