Rituximab Versus Mycophenolate in the Treatment of Recalcitrant Connective Tissue Disease–Associated Interstitial Lung Disease

Abstract

Objective Interstitial lung disease (ILD) is a major cause of morbidity and mortality in connective tissue diseases (CTDs). We aimed to assess the effect of rituximab ± mycophenolate mofetil (MMF) compared with MMF on pulmonary function and prednisone dosage in patients with CTD‐related ILD (CTD‐ILD). Methods This retrospective study included 83 patients from Stanford and Centre Hospitalier de l’Universite de Montreal. Fifteen patients received rituximab ± MMF (rituximab group), and 68 patients received MMF only (control group). Results Median ILD duration at the start of treatment was longer in the rituximab group at 47 months (range: 4‐170) versus 6.5 months (range: 0‐164) in controls. Forced vital capacity (FVC) decreased by 3.0% (range: 11%‐21%) after treatment in the rituximab group, whereas it increased by 2.0% (range: 14%‐25%) in the control group (p = 0.025). Diffusing capacity of carbon monoxide (DLCO) decreased by 3.0% (range: 10%‐12%) after treatment in the rituximab group, whereas it increased by 4.5% (range: 30%‐36%) in the control group (p = 0.046). Mixed model analysis controlling for ILD duration, baseline DLCO, systemic sclerosis, pulmonary hypertension, and prednisone use showed no significant difference in FVC or DLCO between groups at 6 months or 1 year. The average daily prednisone dose score decreased after treatment in the rituximab group, whereas it remained unchanged in the control group (p = 0.017). Conclusion Rituximab ± MMF did not significantly change pulmonary function compared with MMF alone, but it did result in a relative decrease in average daily prednisone dose in a population with recalcitrant CTD‐ILD.