Background: In progressive IgA nephropathy (IgAN), cyclophosphamide or steroids have been used to reduce the loss of renal function, but disease progression may occur after the end of treatment. The value of mycophenolic acid (MPA) maintenance therapy following initial immunosuppression in progressive IgAN is largely unknown.
Methods: In a prospective single-center trial, 20 patients with advanced IgAN (median glomerular filtration rate [GFR], 22 ml/min) and disease progression after cyclophosphamide pulse (CyP; n=18) or steroid pulse therapy (n=2) were treated with MPA for a median of 27 months. MPA dosages (initially mycophenolate mofetil 500 mg twice daily) were adjusted according to predose plasma concentrations (target concentrations 1.5 to 4 microg/mL). The course of renal function was assessed by linear regression of glomerular filtration rates.
Results: Median loss of renal function per month was significantly reduced from -0.8 ml/min to -0.03 ml/min per month after 6 months, to -0.05 ml/min per month after 12 months, and to -0.12 ml/min per month at the end of the study after median 27 months (p<0.05). An improved or stable GFR was observed in 16 of 20 patients during the first 12 months, and sustained in 10 patients during 24 months of follow-up. Proteinuria decreased significantly from 1.1 g/L to 0.4 g/L during MPA treatment (p=0.018).
Conclusion: Our results indicate that MPA may be beneficial to slow down the loss of renal function in patients with progressive IgAN after previous immunosuppressive treatment.