Objective: Cyclophosphamide is considered the treatment of choice for interstitial lung disease (ILD) secondary to systemic sclerosis (SSc), albeit having a minimal effect. Although controlled evidence does not exist, mycophenolate is used increasingly in clinical practice as an alternative. We aimed to compare the long-term efficacy of these drugs.
Methods: Patients from our SSc cohort who received mycophenolate for over 1 year for progressive ILD were 1:1 matched for age, gender, and baseline forced vital capacity (FVC ±3 %) with cyclophosphamide-treated patients. Changes in FVC, total lung capacity (TLC), diffusion capacity for carbon monoxide (DLCO), and high-resolution computed tomography (HRCT) scans were compared between groups. Changes in pulmonary function tests (PFTs) over at least 1 year in six unmatched control patients, who had denied mycophenolate or cyclophosphamide, also were examined.
Results: FVC, TLC, and DLCO did not change significantly in either mycophenolate (from 79.0 ± 12.5 to 80.2 ± 8.1 to 81.2 ± 11.4, from 71.5 ± 16.1 to 74.3 ± 10.8 to 71.8 ± 13.0, from 56.8 ± 12.0 to 55.2 ± 9.9 to 50.6 ± 8.5, respectively) or cyclophosphamide group (from 77.3 ± 12.5 to 79.7 ± 10.3 to 82.5 ± 12.9, from 64.7 ± 14.9 to 68.6 ± 16.0 to 66.1 ± 15.5, from 53.1 ± 14.3 to 56.4 ± 13.5 to 56.3 ± 6.7, respectively), after 1 or 2 years of treatment. PFTs also remained stable in the control group. In either the mycophenolate or cyclophosphamide groups, six patients remained stable, three improved, and one deteriorated according to the definitions of the American Thoracic Society. However, and despite the fact that patients in the cyclophosphamide group had more extended ILD at baseline, a deterioration of lung HRCT findings at 2 years was noticed after mycophenolate (from 10.0 ± 8.9 to 12.7 ± 8.2, p = 0.039) but not after cyclophosphamide.
Conclusions: Although these results derive from patients selected for receiving at least 1 year of treatment and therefore they do not represent an intention-to-treat cohort, an eagerness to replace cyclophosphamide by mycophenolate in SSc-associated ILD treatment is not supported.