Background: Interstitial lung disease (ILD) is a frequent manifestation of connective tissue disease (CTD), especially systemic sclerosis (SSc), polymyositis-dermatomyositis, and rheumatoid arthritis. ILD related to CTDs heralds a poor prognosis and is associated with high mortality and 60% of patients have evidence of ILD. Cyclophosphamide (CYC) is extensively used in SSc ILD with moderate initial response but a poor long-term outcome, and is associated with significant toxicity.
Results: Mycophenolate mofetil (MMF) was administered to 10 patients with autoimmune-related ILD: 4 with SSc, 3 with rheumatoid arthritis, 2 with polymyositis, and 1 with systemic lupus erythematosus and Sjögren syndrome. Five patients received remote CYC infusion. Ten patients had improvement in alveolitis, symptoms (cough, dyspnea, and chest discomfort), perceived quality of life and activity levels. Four of 5 patients discontinued oxygen. Two of 8 repeat high-resolution computed tomography improved, 6 stabilized, none worsened. Pulmonary function testing in 1 of 9 patients showed worsening, 3 with improvement and 5 stabilized. Serial echocardiograms revealed no new pulmonary arterial hypertension and no worsening of preexisting pulmonary arterial hypertension. Very importantly, averaged prednisone dose decreased from 58 to 1.4 mg without worsening.
Conclusion: MMF is safe, well tolerated, and allows reduction or discontinuation of prednisone without worsening of symptoms or objective progression of disease. MMF is less toxic and its targeted antifibrotic properties make it a potentially more effective agent than CYC that may supplant it as a first-line agent or provide sensible post-CYC maintenance or synergistic strategy in the treatment of CTD-ILD.