A study to evaluate efficacy and safety of telitacicept in the treatment of patients with primary IgA nephropathy at high risk of progression.

IgA nephropathy is a glomerulonephritis characterized by pathological IgA deposition in the mesangial region. Its clinical and pathological manifestations are diverse and heterogeneous. Its pathogenesis has not yet been fully clarified, and there is currently no unified treatment plan. As a recombinant human B lymphocyte stimulator receptor-antibody fusion protein, telitacicept has become a new therapeutic target. The results of the Phase II clinical trial of this drug for IgA nephropathy have already been published. It is one of the key pioneering clinical studies in the field of IgA nephropathy treatment. The study showed that telitacicept can effectively reduce patients' proteinuria and reduce the risk of disease progression. Based on the above research results, the investigators plan to conduct a multicenter, randomized, controlled clinical study to evaluate the efficacy and safety of telitacicept in the treatment of primary IgA nephropathy patients with a high risk of progression.

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.