Twelve-month azathioprine as maintenance therapy in early diffuse systemic sclerosis patients treated for 1-year with low dose cyclophosphamide pulse therapy.

Objective. To investigate the role of azathioprine in maintaining improvement after 1-year low-dose IV pulse CYC therapy in patients with early diffuse Systemic Sclerosis (dcSSc). Methods. Thirteen patients with early dcSSc who had completed a year of treatment with low-dose IV pulse CYC underwent AZA treatment (100 mglday) in a prospective 1-year study. Modified Rodnan skin score (mRss), Health Assessment Questionnaire-Disability Index (HAQ-DI), forced vital capacity (FVC), and diffusing lung capacity for CO (DLCO) were assessed as outcome measures. In addition, the nine organ/ system Medsger et al. severity scores and the European Scleroderma Study Group (ESSG) activity index were evaluated. Results. The improvement from a year of CYC therapy was maintained by AZA treatment. No outcome measures deteriorated (mRss 8.23 ±2.9 vs. 6.38 ± 3.4; HAQ-DI 0.38 ± 0.4 vs. 0.32 ± 0.3; FVC 89.5 ± 13.2 vs. 89.4 ± 15.9; DLCO 73.6 ± 14.4 vs. 75.0 ± 19.5), nor were there any increases in any organ/ system severity scores or ESSG activity index detected. Conclusion. This study suggests a role of AZA in maintaining the improvement induced by low dose pulse CYC in early dcSSc, making it possible a short duration of treatment at a low cumulative dose of the drug. These results, however, await confirmation in controlled studies.