Efficacy and Safety of Nefecon on Prevention of Relapse of IgA Nephropathy

Inclusion Criteria: * Diagnosed primary IgAN with biopsy verification; * Female or male participants ≥18 years of age; * Completion of ≥9 months of Nefecon 16 mg QD at the baseline visit; * Proteinuria ≥ 1g/d prior to initiation of Nefecon; * Proteinuria\<0.5 g/day (or UPCR \<0.5 g/g) at screening and randomization visit; * eGFR ≥30 ml/min/1.73m² at screening; * On stable treatment with supportive treatment (including RAASi, SGLT2i, ERA) for at least 1 month prior to the baseline visit; Exclusion Criteria: * Systemic diseases that may cause mesangial immunoglobulin A deposition, including but not limited to IgA vasculitis nephritis, systemic lupus erythematosus, dermatitis herpetiformis, ankylosing spondylitis, and others; * Type 1 or type 2 diabetes mellitus; * Presence of primary or secondary glomerulopathies (e.g., membranous nephropathy, focal segmental glomerulosclerosis, C3 glomerulopathy and others); * Active infection, severe hepatic impairment (Child-Pugh Class C), congestive heart failure, and malignant tumor within the past 5 years; * On current or planned dialysis or kidney transplantation; * Participants who have been treated with systemic glucocorticoids and immunosuppressive agents within the past 3 months, including mycophenolate mofetil, hydroxychloroquine, cyclophosphamide, azathioprine, leflunomide, calcineurin inhibitors, and Chinese traditional medicines with immunosuppressive effects (such as Tripterygium wilfordii, Sinomenium acutum, Tripterygium Glycosides Tablets, Kunxian Capsules, Kunming Shanhaitang Tablets, etc.); treatment with B-cell targeted biological agents (such as telitacicept and sibeprenlimab, etc.); complement pathway inhibitors, etc.; * Poorly controlled hypertension (resting systolic blood pressure ≥160 mmHg or diastolic blood pressure ≥100 mmHg); * Participants taking potent inhibitors of cytochrome P450 (CYP) 3A4 within the past 1 month, such as ketoconazole, itraconazole, ritonavir, indinavir, saquinavir, erythromycin, or cyclosporine; * Females who are pregnant, breastfeeding, or planning to become pregnant in the trial period. * Any other conditions that, in the investigator's judgment, make the patient ineligible for this clinical study.