A Study of Telitacicept for Injection (RC18) in Subjects With IgA Nephropathy

Inclusion Criteria: 1. IgA nephropathy confirmed by pathological biopsy; 2. Male or female aged ≥ 18 years old; 3. Average 24-hour urine total protein ≥ 0.75 g/24 h 4. Estimated GFR (using the CKD-EPI formula) \> 30 mL/min per 1.73 m\^2; 5. Stabilized AEI/ARB medications, diuretics, or other antihypertensive therapy. Exclusion Criteria: 1. Patients with clinically significant abnormal laboratory tests at screening; 2. Evidence of rapid eGFR decrease \> 15 ml/min during screening; 3. Renal or other organ transplantation prior to, or expected during, the study; 4. Patients with secondary IgA nephropathy; 5. Patients with nephrotic syndrome, crescentic nephritis minimal change nephropathy with IgA deposition, or other pathological or clinical types of renal diseases that may confound the study data interpretation; 6. Patients with history of any severe unstable cardiovascular and cerebrovascular events within 12 weeks prior to screening; 7. Immunocompromised individuals.