Mycophenolate mofetil in anti-neutrophil cytoplasm antibodies-associated systemic vasculitis

Mycophenolate mofetil (MMF) is an immune suppressive initially introduced for the prevention of solid organ allograft rejection that is increasingly used in autoimmune conditions, including vasculitis.

This retrospective study evaluated the efficacy and tolerability of MMF in 51 sequential patients with anti-neutrophil cytoplasm antibodies-associated systemic vasculitis (AASV) treated in a single centre between 2001 and 2004.

The mean age was 54 years and median disease duration was 36 months. A mean of 3.5 systems were involved and the previous median exposure to cyclophosphamide was 9 g. MMF was administered either as remission maintenance therapy (29/51, 56.9%) or as treatment for active disease (22/51, 43.1%). The mean duration of MMF therapy was 20 months and the mean MMF dose during the first year was 1.6 g/day. 14/29 (48.3%) of those receiving MMF for remission maintenance therapy eventually relapsed with a mean time to relapse of 14 months. Of those receiving MMF for relapsing disease, 3 failed to respond to therapy while the rest achieved remission by 3.9 months. However, 9 of these subsequently flared; mean time to disease flare was also 14 months. MMF was withdrawn in 28 patients (54.9%) because of treatment inefficacy in 21, severe adverse events in 5 and intolerance in 2. Of the 51 treated, 36 (70.6%) experienced at least 1 side effect, namely infections in 24, gastrointestinal side effects in 12 and psychological events in 6 patients.

We have observed varying efficacy of MMF in AASV, with over 50% of patients with relapsing disease achieving remission and marked falls in concomitant steroid doses. However, longer follow-up indicates a subsequent relapse rate of over 50% that may be associated with low MMF dosing.