Personalized Medicine for Membranous Nephropathy

Inclusion Criteria: * Age 18 years or more * Anti-PLA2R1 activity detected by ELISA or Euroimmune Immunofluorescence Assay * Nephrotic syndrome defined by proteinuria \> 3.5 g/24h (or UPCR \> 3.5 g/g) and serum albumin \< 30 g/L at diagnosis * eGFR (CKD-EPI) \> 30 ml/min/1,73 m2 at diagnosis * Symptomatic treatment according to KDIGO guidelines: maximal tolerated dose of NIAT : Non Immunosuppressive Antiproteinuric Treatment (angiotensin-converting enzyme inhibitor and/or angiotensin 2 receptor blockers, diuretics and statins) * Medical insurance * Signed informed consent * Having understood and accepted the need for long-term medical follow-up * Woman of child-bearing age must be using an effective method of contraception Exclusion Criteria: * Secondary Membranous Nephropathy: Membranous Nephropathy related to cancer, infectious, systemic lupus erythematosis, drug * Anti-PLA2R1 antibodies not confirmed by central analysis (in this case the patient will be replaced) * Pregnancy or breastfeeding * Immunosuppressive treatment in the 3 last months * Cancer under treatment * Patient with complicated nephrotic syndrome that would require early immunosuppressive treatment (thrombosis, acute renal failure…) * Patients with active, severe infections or active hepatitis B * Hypersensitivity to the active substance or to murine proteins, or to any of the other excipients * Patients in a severely immunocompromised state * Severe heart failure (New York Heart Association Class IV) or severe, uncontrolled cardiac disease * Patients unable to give an informed consent