Effect of Finerenone in IgA Nephropathy

Inclusion Criteria: * Kidney biopsy confirmed IgA nephropathy within 2 years, with secondary IgA nephropathy excluded; * Age ≥ 18 years; * Maximum tolerated dose of RAS inhibitors for more than 3 months, with urine albumin/creatinine ratio ≥ 500 mg/g and ≤ 3500 mg/g; V1 laboratory test showing urine albumin/creatinine ratio ≥ 500 mg/g and ≤ 3500 mg/g. After maximum tolerated dose of RAS inhibitors or ARB, V2 urine albumin/creatinine ratio ≥ 500 mg/g and ≤ 3500 mg/g; * eGFR calculated by EPI ≥ 30 ml/min/1.73 m²; * Serum potassium level ≤ 4.8 mmol/L; * SBP ≤ 150 mmHg, DBP ≤ 110 mmHg; * LVEF \> 40%; * Willing and able to provide informed consent. Exclusion Criteria: * There are clear indications for the use of immunosuppressive therapy, such as: nephrotic syndrome (urine protein greater than 3.5 g/d, blood albumin less than 30 g/L), pathological minimal change disease combined with IgA nephropathy; the proportion of crescents in kidney biopsy is ≥ 50%. * Any existing life-threatening condition with a life expectancy of less than 2 years; * Active infection, HBV infection, or active lesions (nodules, cavities, or tuberculomas); * AKI causing renal dysfunction; * Use of steroids/immunosuppressive drugs within the past 3 months; * History of malignant tumors, regardless of treatment status or evidence of local recurrence or metastasis; * Any surgical or medical condition that may significantly alter the absorption, distribution, metabolism, or excretion of the investigational drug; * History of drug or alcohol abuse within the past 12 months; * History of drug allergies or contraindications; * Previous noncompliance or unwillingness to follow the study protocol; * Any condition that may affect safety or efficacy; * History of kidney transplantation or currently receiving immunosuppressive treatment; * Pregnant or breastfeeding women; * Obese patients with a BMI \> 35.