Effects of Mycophenolate Mofetil Combined with Corticosteroids for Induction Therapy of Microscopic Polyangiitis

<i>Aims:</i> We prospectively compared the effects of oral mycophenolate mofetil (MMF) or intravenous cyclophosphamide (IVC) combined with corticosteroids for induction therapy of microscopic polyangiitis (MPA) with renal involvement over a follow-up period of 6 months. <i>Methods:</i> 41 MPA patients were randomly assigned to either the open-label MMF group or the IVC group. Patients in the MMF group (n = 19) received oral MMF 1.0 g/day (1.5 g/day for patients with a body weight >70 kg) and patients in the IVC group (n = 22) received IVC in monthly pulses of 1.0 g per pulse (0.8 g per pulse for patients with a body weight <50 kg). Both groups received intravenous methylprednisolone 360–500 mg/day for 3 days, followed by oral prednisone 0.6–0.8 mg/kg/day and gradual tapering. <i>Results:</i> There was no significant difference of estimated glomerular filtration rate (eGFR) level between the IVC and MMF groups at baseline. At 6 months, the eGFR level increased significantly in both groups, but there was no significant difference between the two. Three patients in the IVC group and 1 in the MMF group received maintenance dialysis within 6 months (p = 0.36). The remission rate was 63.6% in the IVC group and 78.9% in the MMF group (p = 0.23). <i>Conclusion:</i> MMF is effective for inducing remission in Chinese MPA patients and may represent an alternative therapy to monthly impulses of IVC.