Efficacy and Safety of Telitacicept in IgAN

Inclusion Criteria: 1. 18-70 years old, male or female 2. Primary IgA nephropathy confirmed by renal biopsy. 3. Urine protein ≥ 0.75g/24h or 24-hour urine protein creatinine ratio (PCR) ≥ 0.6 g/g. 4. eGFR ≥ 25 ml/min/1.73 m2 calculated using the CKD-EPI formula. 5. Received treatment with ACEI/ARB for 12 weeks before randomization, and the drug dose (within the maximum tolerated range) was stable within 4 weeks before randomization. 6. Use of SGLT2, MRA, hydroxychloroquine, and etc. remained unchanged. 7. Voluntarily participated in this study and signed the informed consent form. Exclusion Criteria: 1. Patients with abnormal laboratory indicators (see study protocol for details). 2. Secondary IgA nephropathy such as Henoch-Schonlein purpura, SLE, cirrhosis, etc. 3. Use of systemic glucocorticoids/immunosuppressants within 3 months (such as cyclophosphamide, azathioprine, mycophenolate mofetil, leflunomide, tacrolimus, cyclosporine, tripterygium wilfordii, etc.). 4. Use of biological agents within 6 months (rituximab, etc.). 5. Active infection, such as active tuberculosis, active hepatitis, hepatitis C, herpes zoster, HIV, etc. According to the results of the five hepatitis B test: patients with positive HBsAg should be excluded; patients with negative HBsAg but positive HBcAb, regardless of whether HBsAb is positive or negative, need to test HBV-DNA to determine their situation: if HBV-DNA is positive, the patient needs to be excluded; if HBV-DNA is negative, the patient can participate in the trial. 6. COVID-19 infection within 2 weeks before randomization. 7. Live vaccine within 4 weeks before randomization. 8. History of malignant tumor within five years. 9. Uncontrolled hypertension (systolic blood pressure\>140mmHg or diastolic blood pressure\>90mmHg). 10. Poorly controlled diabetes (glycosylated hemoglobin\>8%). 11. Pregnant women and breastfeeding women. 12. Participating in other clinical trials at the same time. 13. Surgery, chemotherapy, radiotherapy and other treatments are planned during the study. 14. Other reasons judged by researchers as unsuitable for inclusion in the study.