Effect of Mycophenolate Mofetil on Pulmonary Function in Scleroderma-Associated Interstitial Lung Disease

We sought to determine the effectiveness of mycophenolate mofetil (MMF) in scleroderma- associated interstitial lung disease (SSc-ILD). We retrospectively identified patients who met criteria for systemic sclerosis, had evidence of SSc-ILD on chest CT, received > 1 g/d of MMF for ≥ 6 months, and had pulmonary function data available. Vital capacity (VC) and diffusion capacity of the lung for carbon monoxide (Dlco) at treatment onset were compared with VC and Dlco values 12 months before and 12 months after treatment onset. Twelve-month values were imputed from regression lines generated using all VC and Dlco measurements made in the 24-month period either prior to or following treatment onset. Among 13 patients who met inclusion criteria, MMF was associated with a significant improvement in VC (mean, + 159 mL; confidence interval [CI], + 30 to + 289 mL; and + 4% of the predicted normal value; CI, + 2 to + 7%) after 12 months of treatment. In contrast, patients had a significant decrease in VC (mean, – 239 mL; CI, – 477 to – 0.5 mL; and − 5% of the predicted normal value; CI, – 11 to − 0.3%) in the 12 months prior to MMF treatment. Dlco did not change significantly during MMF treatment (mean, + 1% of the predicted normal value; CI, – 2 to + 5%) but decreased significantly in the 12 months prior to treatment (mean, – 5% of the predicted normal value; CI, − 10 to − 1%). These retrospective data suggest MMF improves VC in patients with SSc-ILD.