A Phase I/II Open-label, Single-arm, Multicenter Clinical Study to Evaluate the Safety and Efficacy of FKC289 in Subjects With Relapsed/Refractory Membranous Nephropathy

Inclusion Criteria: 1. Voluntarily signed the informed consent form (ICF); 2. Aged between 18-70 years old (inclusive); 3. Histologically confirmed diagnosis of primary membranous nephropathy by renal biopsy obtained within the past 2 years.; 4. Relapsed or refractory disease; 5. Anti-PLA2R antibody \> 50 RU/mL; 6. 24-hour urine protein \> 3.5 g at screening; 7. No active systemic infection (e.g., infectious pneumonia, pulmonary tuberculosis) within 2 weeks prior to leukapheresis; 8. Adequate bone marrow and major organ function (including hepatic, renal, cardiac, and pulmonary); Exclusion Criteria: 1. Secondary membranous nephropathy or patients with a prior diagnosis of other renal diseases; 2. Presence of any clinically significant cardiovascular disease within 6 months prior to screening; 3. Clinically significant central nervous system (CNS) disease or pathological abnormality; 4. History of solid organ transplantation (e.g., heart, lung, kidney, liver); 5. Presence of complete intestinal obstruction; 6. Moderate to severe pleural effusion or ascites that is difficult to control with conventional treatment and requires continuous catheter drainage;