medwireNews: Mycophenolate mofetil (MMF) is associated with improvements in lung function compared with placebo among patients with systemic sclerosis (SSc)-associated interstitial lung disease (ILD), study results suggest.
Elizabeth Volkmann (University of California, Los Angeles, USA) and fellow researchers analyzed data from 79 participants in the placebo arm of the SLS (Scleroderma Lung Study) I trial, which compared cyclophosphamide versus placebo, and 69 patients treated with MMF in SLS II, a comparison of MMF and cyclophosphamide.
They found that patients treated with MMF had significantly higher forced vital capacity (FVC) over 2 years of follow-up compared with placebo-treated patients after adjustment for baseline disease severity.
The percentage predicted FVC rose from approximately 68% at baseline to 69% after 1 year of treatment with MMF and 75% after 2 years of treatment, compared with corresponding measurements of approximately 66%, 62%, and 67% with placebo treatment.
The benefit of MMF versus placebo was greatest in the first year of therapy and diminished over time, reports the team in Arthritis & Rheumatology.
“[I]t is plausible that lung function […] stabilized/improved in both groups after 12 months regardless of treatment,” suggest the researchers, who also speculate that the use of “potential disease modifying therapy” in the placebo arm between 1 and 2 years of follow-up – including prednisone in 12 patients and cyclophosphamide in 2 patients – may have influenced the results.
Treatment with MMF was also associated with significant improvements in dyspnea, hemoglobin-adjusted single-breath diffusing capacity for carbon monoxide (DLCO), and Modified Rodnan Skin Score compared with placebo over 2 years.
Although the researchers believe that their results “support the use of MMF for the treatment of SSc-ILD,” they stress that “there are inherent limitations in comparing participants from different trials.”
Indeed, at baseline, patients in the placebo arm of SLS I had significantly lower DLCO scores and worse dyspnea, and a greater radiographic extent of ILD, than those in the MMF arm of SLS II.
Volkmann and colleagues accounted for baseline disease severity in their analyses, but emphasize that “without a randomization process, one cannot adequately control for those ‘unknown’ variables, which may be different in the two groups and which may affect the study outcome.”
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