Background: Aliskiren is a relatively new oral direct renin inhibitor (DRI) that has been increasingly used for the treatment of diabetic nephropathy and hypertension. Its potential efficacy in nondiabetic chronic kidney diseases that are driven by renin-angiotensin system activation remains to be explored.
Methods: From a teaching and regional hospital in Hong Kong between July 2009 and March 2010, patients with biopsy-proven immunoglobulin A nephropathy (IgAN) in whom the ratio of protein to creatinine, as measured in early morning urine samples, remained >113 mg/mmol (1000 mg/g), despite receiving the maximum recommended dose of losartan (100 mg daily) were recruited to receive additional DRI treatment. They were followed prospectively for 12 months with changes in proteinuria as the main outcome measure.
Results: Twenty-five consecutive patients were enrolled. Treatment with aliskiren for 12 months reduced the mean urinary protein-to-creatinine ratio by 26.3% (95% confidence interval, 20.1-43.6; P = 0.001 versus baseline), with a reduction of ≥ 50% in 24% of patients. There were significant reductions in plasma renin activity (P < 0.0001) and serum interleukin-6 (P < 0.05) and transforming growth factor-β (P = 0.01) levels, compared with baseline. Two patients (8%) developed mild allergic reactions and six (24%) had transient hyperkalemia (K >5.5 mmol/L) during the study.
Conclusion: Aliskiren confers an antiproteinuric effect in IgAN patients with significant residual proteinuria, despite receiving the recommended renoprotective treatment. Further prospective randomized trials are warranted to examine its long-term renoprotective potential. This trial is registered with the ClinicalTrials.gov number NCT00922311.