Open-Label Study to Evaluate Safety and Efficacy of CCX168 in Subjects With IGA Nephropathy on Stable RAAS Blockade

Key Inclusion Criteria: * Diagnosis of Immunoglobulin A nephropathy * estimated glomerular filtration rate \>60 mL/min/1.73 m2 * Proteinuria (first morning urinary protein:creatinine ratio \>1g/g creatinine) Key Exclusion Criteria: * Severe renal disease * Pregnant or nursing * Proteinuria \>8g/g creatinine or \>8g/day * Systemic manifestations of Henoch-Schonlein purpura within 2 years prior * Patients with Immunoglobulin A nephropathy deemed secondary to underlying disease * Biopsy reported severe crescentic Immunoglobulin A nephropathy * History of treatment with glucocorticoids, cyclophosphamide, azathioprine, mycophenolate mofetil, or any biologic immunomodulatory agent with 24 weeks prior * History of clinically significant cardiac conditions * History of cancer within 5 years prior * Any infection requiring antibiotic treatment that has not cleared prior to study start