A multicenter, randomized, open-label, comparative, phase IV study to evaluate the efficacy and safety of combined treatment with mycophenolate mofetil and corticosteroids in advanced immunoglobulin A nephropathy

Background: It remains unclear whether immunosuppressive agents are effective in patients with immunoglobulin A nephropathy (IgAN). We investigated the efficacy of a mycophenolate mofetil (MMF) and corticosteroid combination therapy in patients with advanced IgAN. Methods: We conducted a multicenter, randomized, placebo-controlled, parallel-group study of 48 weeks administration of MMF and corticosteroids in biopsy-proven advanced IgAN patients with estimated glomerular filtration rate (eGFR) of 20–50 mL/min/1.73 m² and urine protein-to-creatinine ratio (UPCR) of >0.75 g/day. The primary outcome was complete (UPCR < 0.3 g/day) or partial (>50% reduction of UPCR compared to baseline) remission at 48 weeks. Results: Among the 48 randomized patients, the percentage that achieved complete or partial remission was greater in the combination therapy group than in the control group (4.2% vs. 0% and 29.1% vs. 5.0%, respectively). Compared with the combination therapy group, eGFR in the control group decreased significantly from week 36 onward, resulting in a final adjusted mean change of –4.39 ± 1.22 mL/min/1.73 m² (p = 0.002). The adjusted mean changes after 48 weeks were 0.62 ± 1.30 and –5.11 ± 1.30 mL/min/1.73 m² (p = 0.005) in the treatment and control groups, respectively. The UPCR was significantly different between the two groups; the adjusted mean difference was –0.47 ± 0.17 mg/mgCr and 0.07 ± 0.17 mg/mgCr in the treatment and control group, respectively (p = 0.04). Overall adverse events did not differ between the groups. Conclusion: In advanced IgAN patients with a high risk for disease progression, combined MMF and corticosteroid therapy appears to be beneficial in reducing proteinuria and preserving renal function.