Tacrolimus Decreases Albuminuria in Patients with IgA Nephropathy and Normal Blood Pressure: A Double-Blind Randomized Controlled Trial of Efficacy of Tacrolimus on IgA Nephropathy

BACKGROUND: Treatment remains uncertain for IgA nephropathy patients with mild to moderate proteinuria, for whom anti-hypertensive medication or the RAS blocker is not applicable due to low blood pressure. TRIAL DESIGN: A double blinded randomized trial. METHODS: The anti-proteinuric effect of tacrolimus was explored for 40 biopsy-proven mild IgA nephropathies for 16 weeks. We randomly assigned patients either to receive tacrolimus or placebo with stratification by using a renin angiotensin system blocker. The primary outcome was the percentage change of final UACR compared to the baseline value (pcUACR). RESULTS: The mean value of pcUACR at 12-week and 16-week visits (primary outcome) was decreased more in the Tac group compared to the control group (–52.0±26.4 vs –17.3±29.3%, p = 0.001). At each visit, pcUACR was also decreased more in the Tac group compared to the control group. In the Tac group, the pcUACRs were –60.2±28.2%, –62.2±33.9%, –48.5±29.8%, and –55.5±24.0%, and, in the control group, –6.8±32.2%, –2.5±35.9%, –12.7±34.2%, and –21.9±30.6%, at 4-week, 8-week, 12-week, and 16-week visits, respectively. The pre-defined secondary outcomes were better in the Tac group compared to the control group. The frequency of decrease in pcUACR and percentage change of UPCR (pcUPCR) ≥50% at 16 weeks were 65.0% (13/20) and 55.0% (11/20)in the Tac group, and 25.0% (5/20) and 15.0% (3/20), in the control group, respectively (p = 0.025 for pcUACR and p = 0.019 for pcUPCR). However, tacrolimus wasn't effective with a dose of 0.05 mg/kg/day in patients taking ARB. The adverse events were tolerable. CONCLUSION: Tacrolimus effectively reduced proteinuria in IgA nephropathy with normal blood pressure. This suggested that tacrolimus could be an alternative to corticosteroid and RAS blocker for IgA nephropathy patients who cannot endure anti-hypertensive medication. TRIAL REGISTRATION: Clinicaltrial.gov NCT1224028