For advanced progressive primary IgA nephropathy (IgAN) no established therapy exists. We conducted a prospective, uncontrolled trial to evaluate the effect of intravenous cyclophosphamide pulse (CyP) therapy on the course of advanced progressive IgAN. Twenty-one patients (mean age 52 ± 10 years; male/female 20/1) with biopsy-proven IgAN without crescentic extracapillary proliferation and a serum creatinine of more than 2.0 mg/dl and/or an increase more than 25% in the previous 3 months were included. Patients were treated with CyP (750 mg/m² body surface area) every 4 weeks for 6 months and low dose oral prednisolone. The loss of renal function per year was significantly reduced from 16% before therapy to 4% after therapy (p < 0.001). A further increase >25% of serum creatinine after therapy was observed in 8 patients after 0.7 years (range 0.3–3.0 years), and 3 of these patients developed end-stage renal disease. Proteinuria decreased significantly during CyP therapy. A low nadir of white blood cell and platelet count was associated with a better renal outcome (p = 0.025). In conclusion, CyP therapy and low dose oral prednisolone is effective in preserving renal function in a subgroup of patients with advanced progressive IgAN.

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