Recurrence of progressive skin involvement following discontinuation or dose reduction of Mycophenolate Mofetil treatment in patients with diffuse Systemic Sclerosis.

BACKGROUND: Rapidly progressive diffuse cutaneous Systemic Sclerosis (rp-dcSSc) is associated with severe internal organ involvement and high mortality. Mycophenolate Mofetil (MMF) has been shown to halt the progression of rp-dcSSc cutaneous and pulmonary involvement in observational and randomized controlled trials, respectively. However, optimal MMF therapy duration has not been established. Here, we describe the clinical evolution of rp-dcSSc patients successfully treated with MMF following MMF therapy discontinuation or dose reduction. METHODS: Twenty-five patients with recent-onset (< 24 mo) rp-dcSSc received MMF as the only SSc disease-modifying therapy. Following MMF discontinuation or dose reduction to or below 1000 mg/day after an average of two years, the Modified Rodnan skin score (mRSS) and Pulmonary function tests (PFT) were serially evaluated for additional 5 years. MMF therapy was re-instituted if the mRSS increased by greater than 20% or if restrictive lung disease developed. RESULTS: From nineteen patients serially evaluated following MMF discontinuation or dose reduction, five patients (26.3%) developed recurrence of rapid skin involvement with an average of 35.9% increase in mRSS from 7.8 to 10.6 points requiring MMF re-institution. Two of these patients also presented worsening respiratory symptoms and reduction of lung volumes in PFTs. Following MMF resumption, mRSS returned to baseline or stabilized and PFTs improved or stabilized. All these patients were maintained on high dose long term MMF treatment. CONCLUSION: Recurrence of severe skin involvement occurred in 26.3% of patients with rp-dcSSc following MMF discontinuation or dose reduction, requiring prompt MMF therapy resumption. These findings confirm the therapeutic benefit of MMF in rp-dcSSc and suggest that MMF treatment should be maintained for longer than 2 years.