Efficacy and Safety in Chinese Patients with Immunoglobulin a Nephropathy (IgAN) Who Have Completed Study Nef-301

Inclusion Criteria: 1. Patients that completed study Nef-301. 2. On a stable dose of RAS inhibitor therapy (ACEIs and/or ARBs) at the maximum allowed dose or maximum tolerated dose according to the 2012 Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. 3. Willing and able to provide written informed consent. 4. Urine protein to creatinine ratio (UPCR) equal to or more than 0.5 g/gram or Average proteinuria equal or more than 0.75 g/day. 5. eGFR equal to or more than 30 mL/min per 1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. Exclusion Criteria: 1. Systemic diseases that may cause mesangial Immunoglobulin A (IgA) deposition. 2. Patients who have undergone a kidney transplant. 3. Patients with presence of other glomerulopathies and/or nephrotic syndrome. 4. Patients with acute, chronic, or latent infectious disease including hepatitis, tuberculosis (TB), human immunodeficiency virus (HIV), and chronic urinary tract infections. 5. Patients with liver cirrhosis, as assessed by the Investigator. 6. Patients with a diagnosis of type 1 or type 2 diabetes mellitus which is poorly controlled. 7. Patients with history of unstable angina, class III or IV congestive heart failure, and/or clinically significant arrhythmia, as judged by the Investigator. 8. Patients with unacceptable blood pressure control defined as a blood pressure consistently above national guidelines for proteinuric renal disease, as assessed by the Investigator. 9. Patients with diagnosed malignancy within the past 5 years.