Is mycophenolate mofetil an effective alternative in azathioprine-intolerant patients with chronic active Crohn's disease?

OBJECTIVES: Up to 50% of patients with Crohn's disease (CD) develop steroid -dependent or refractory disease requiring immunosuppression. Azathioprine (AZA) is usually used for this purpose but must be withdrawn in up to 10% o f patients because of adverse events. Mycophenolate mofetil (MMF) is of pro ven efficacy and safety in transplantation and in some autoimmune disorders . The aim of the present study was to investigate the effect of MMF, especi ally in AZA-intolerant patients with chronic active CD, in comparison to a matched control group treated with AZA. METHODS: In a retrospective study, 15 patients treated with MMF and 30 rand omly chosen, matched patients treated with AZA for chronic active CD were c ompared over a period of I yr. Intolerance to AZA was the indication for MM F. Crohn's Disease Activity Index (CDAI), steroid demand, extraintestinal m anifestations, and hematological and biochemical parameters were assessed a t the start of therapy and 1, 2, 3, 6, 9, and 12 months thereafter. RESULTS: All patients who completed the 12 months of treatment (77% AZA, 60 % MMF) achieved omission. Under MMF, the cumulative prednisolone dose could be reduced by 1 g in the first half year, whereas, under AZA, this reducti on was possible only in the second half year. MMF patients had almost twice as many flare-ups (80% vs 47%). Adverse events prompted the withdrawal of AZA in five patients (17%) and of MMF in three (20%). CONCLUSIONS: Both drugs are effective in inducing remission. AZA seems to b e more effective in maintaining remission. The onset of therapeutic effect is delayed less under MMF. Both drugs have steroid sparing potential, which is delayed under AZA. It seems that AZA still is the immunouppressant of c hoice in chronic active CD, but MMF is a reasonable alternative in patients who do not tolerate AZA. (C) 2001 by Am. Cell. of Gastroenterology.