Background: Scleroderma lung disease (ILD-SSc) is treated mainly with cyclophosphamide (CYC). The effectiveness of CYC was judged after 12–24 months in most reports.
Objectives: To analyze the effect of monthly intravenous CYC on pulmonary function tests including forced vital capacity (FVC) and diffusing lung capacity (DLCO), as well as Rodnan skin score (mRSS), during long-term follow-up.
Methods: We retrospectively collected the data on 26 ILD-SSc patients who began CYC treatments before 2007. Changes in FVC, DLCO and mRSS before treatment, and at 1, 4 and 7 years after completion of at least six monthly intravenous CYC treatments for ILD-SSc were analyzed.
Results: Mean cumulative CYC dose was 8.91 ± 3.25 G. More than 30% reduction in FVC (0%, 8%, and 31% of patients), DLCO (15%, 23%, 31%), and mRSS (31%, 54%, 62%) at years 1, 4 and 7 was registered. During the years 0–4 and 4–7, annual changes in FVC, DLCO and mRSS were 3.2 vs. 0.42% (P < 0.040), 4.6 vs. 0.89% (P < 0.001), and 1.8 vs. 0.2 (P = 0.002). The greatest annual FVC and DLCO reduction over the first 4 years correlated with mortality (P = 0.022). There were no differences in the main variables regarding doses of CYC (< 6 G and > 6 G).
Conclusions: In patients with ILD-SSc, CYC stabilized the reduction of FVC during treatment, but this effect was not persistent. The vascular characteristic of ILD-SSc (DLCO) was not affected by CYC treatment. CYC rapidly improved the mRSS. This effect could be achieved with at least 6 G of CYC. Higher rates of annual reduction in FVC and DLCO in the first 4 years indicate the narrow window of opportunity and raise the question regarding ongoing immunosuppression following CYC infusions.