Study objective: To investigate the potential anti-proteinuric efficacy of aliskiren, a novel direct renin inhibitor (DRI), in addition to angiotensin receptor blocker (ARB) in immunoglobulin A nephropathy (IgAN) patients at risk of developing progressive renal failure.

This will be an open-label pilot study in which IgAN patients with persistent proteinuria despite maximum dose of ARB treatment will be assigned to receive Aliskiren. There is the optional addition of other anti-hypertensive agents to achieve an optimal target blood pressure of <130/80 mmHg.

Inclusion Criteria:

• Male or female 18 - 70 years of age
• Histologic diagnosis of IgA nephropathy
• Proteinuria > 1 g/day or UPC > 1 mg/mg or 113 mg/mmol at least twice
• Receiving treatment with the maximum dose of ARB for at least 3 months
• Patients who are willing to give written, informed consent

Exclusion Criteria:

• eGFR < 15 ml/min/1.73 sq.m
• UPC >5000 mg/g or 570 mg/mmol, or <500 mg/g or 57 mg/mmol
• Serum K+ > 5.2 mmol/L
• Presence of bilateral renal artery stenosis
• Presence of diabetes mellitus
• Renal histology showing pathologies other than IgAN
• Known allergy to ARB or DRI
• Patients on ARB/ACEi combination within 12 weeks of randomization
• Concurrent treatment with corticosteroids, Nsaid, or immunosuppressant
• Patients with connective tissue disease or obstructive uropathy
• Patients with malignancy or conditions severely limiting life expectancy
• Female who are pregnant or intending to conceive
• Female of child-bearing age unwilling to practice contraception
• Patients who are unable to give informed consent
• Patients simultaneously participating in another study