Mycophenolate mofetil in idiopathic membranous nephropathy: a clinical trial with comparison to a historic control group treated with cyclophosphamide

Cyclophosphamide can decrease proteinuria and improve renal function in patients with idiopathic membranous nephropathy, but has a high risk of side effects. We studied whether mycophenolate mofetil (MMF) could be a reasonable alternative with fewer side effects.

Clinical trial with historic controls.

32 cases and 32 controls with idiopathic membranous nephropathy and renal insufficiency at multiple centers. For comparison, we selected matched historic controls treated with cyclophosphamide.

MMF, 1 g twice daily, for 12 months versus cyclophosphamide, 1.5 mg/kg/d, for 12 months. Both groups also received intermittent methylprednisolone and alternate-day prednisone.

Serum creatinine, proteinuria, and side effects during and after treatment.

Median follow-up was 23 months (range, 11 to 46 months). Median serum creatinine levels were 1.8 mg/dL (159 micromol/L) in both groups at baseline and 1.4 mg/dL (124 micromol/L) in the MMF group versus 1.3 mg/dL (115 micromol/L) in the cyclophosphamide group at 12 months (P = 0.4). Proteinuria values at baseline and 12 months were protein of 8.40 and 1.41 g/d in the MMF group versus 9.19 and 1.13 g/d in the cyclophosphamide group (P = 0.5 at 12 months), respectively. Cumulative incidences of remission of proteinuria at 12 months were 66% in the MMF group versus 72% in the cyclophosphamide group (P = 0.3). Five patients (16%) in the MMF group versus none in the cyclophosphamide group had disease that did not respond to therapy (P = 0.05). Twelve patients (38%) experienced a relapse and 9 patients (31%) were re-treated in the MMF group compared with 4 (13%) and 2 patients (6%) in the cyclophosphamide group (P < 0.01 and P = 0.024, respectively). Side effects occurred in 24 patients (75%) in the MMF group and 22 patients (69%) in the cyclophosphamide group (P = 0.6).

Nonrandomized control group, short duration of follow-up.

A 12-month course of MMF decreased proteinuria and improved renal function in the majority of patients, but did not appear as effective or better tolerated than cyclophosphamide. Long-term data and randomized controlled trials are needed to ascertain the efficacy of MMF in patients with idiopathic membranous nephropathy.