Inclusion Criteria:
* Male or female, between 18 and 75 years age;
* Biopsy confirmed diagnosis of primary IgA nephropathy or IgA Vasculitis-Associated Nephritis;
* Persistent proteinuria, defined as: two separate measurements (with an interval of ≥ 4 weeks) of 24-hour urinary protein excretion (24hUTP) ≥ 0.5 g/day, or urine protein-to-creatinine ratio (UPCR) ≥ 0.44 g/g;
* Estimated glomerular filtration rate (eGFR) (CKD-EPI) ≥ 30 ml/min per 1.73m\^2;
* Have received the angiotensin converting enzyme Inhibitors(ACEI) / angiotensin receptor blocker(ARB) standard treatment for 4 weeks prior to randomization;
* Intending to receive or having received Nefecon or telitacicept treatment for ≤ 2 weeks at the time of screening.
Exclusion Criteria:
* Secondary IgA nephropathy (excluding IgA vasculitis) caused by ankylosing spondylitis, systemic lupus erythematosus, viral hepatitis, liver cirrhosis, etc.;
* With a known history or clinical evidence of concurrent renal diseases other than IgA nephropathy;
* Treating with systemic corticosteroids or immunosuppressants including cyclophosphamide, azathioprine, mycophenolate mofetil, tacrolimus, cyclosporine, rituximab, etc. within 3 months prior to randomizing;
* Have initiated or had a dose adjustment of leflunomide, tripterygium wilfordii or hydroxychloroquine within 3 months prior to randomizing;
* Active tuberculosis or latent carrier without treatment;
* Herpes zoster infected patients or patients with positive HIV antibody, positive HCV antibody or HBV infection (According to the HBV screening test, a) the HBsAg-positive; b) HBsAg-negative and HBcAb-positive, the HBV-DNA should be tested to determine the situation: the HBV-DNA positive subjects should be excluded, while the HBV-DNA negative subjects can participated in.)
* Suffering from following gastrointestinal diseases: gastric ulcer bleeding within the past 6 months, active inflammatory bowel disease, a history of major gastrointestinal surgery (e.g., gastrectomy, gastroenterostomy, or bowel resection), or pancreatic injury/pancreatitis within the past 6 months;
* A confirmed history of osteoporosis or osteonecrosis of the femoral head;
* Type 1 or type 2 diabetes with poor glycemic control (HbA1c \> 8%);
* Body mass index (BMI) \< 18.5 kg/m².;
* Systolic blood pressure (SBP) \> 180 mmHg or diastolic blood pressure (DBP) \> 110 mmHg;
* Decreased lymphocyte count (absolute value \< 1.1 × 10⁹/L) or decreased immunoglobulin G (IgG \< 6 g/L).
* Hepatic dysfunction, meeting any of the following: a) Child-Pugh Class C liver dysfunction; b) ALT or AST \> 2 × upper limit of normal (ULN), or total bilirubin \> 2 × ULN at screening; c) history of hepatic encephalopathy, esophageal varices, or portosystemic shunt surgery;
* Evidence of urinary tract obstruction or dysuria.
* A history of solid organ transplantation, hematopoietic stem cell/cell/bone marrow transplantation, or kidney transplantation.
* Pregnancy, lactation, female participants with childbearing plans during the trial or within 6 months of its completion, and male participants planning to conceive or donate sperm during the trial or within 3 months of its completion;
* With a history of malignant tumors within the past 5 years (excluding cutaneous squamous cell carcinoma or basal cell carcinoma);
* Allergy to human-derived biologics;
* Nephrotoxic drugs is unavoidable during the study period;
* Not suitable for the study judged by investigator.
