Management of Persistent Membranous Nephropathy

Evaluation and Treatment Approach

The American College of Nephrology recommends checking anti-PLA2R antibody status and evaluating kidney function (eGFR) to determine the next step for patients with persistent membranous nephropathy after treatment with cyclophosphamide, prednisone, and rituximab 1, 2
Evaluation of treatment resistance should include checking anti-PLA2R antibody status, a primary biomarker to guide further management, and evaluating kidney function to determine if eGFR is stable or declining 1, 3, 4

For patients with stable eGFR and present anti-PLA2R antibodies, additional rituximab (1-2 infusions of 1g each, 2 weeks apart) is recommended 2, 3
For patients with declining eGFR and present anti-PLA2R antibodies, calcineurin inhibitor therapy in combination with rituximab should be considered 2, 4
For patients with stable eGFR and absent anti-PLA2R antibodies, calcineurin inhibitor therapy with a tapering schedule may be considered 1, 2

Calcineurin inhibitor therapy should be used for 6-12 months, with caution due to high relapse rates after withdrawal, and regular monitoring of CNI levels, kidney function, and proteinuria 1, 4
Additional rituximab dosing should be similar to initial treatment (1-2 infusions of 1g each, 2 weeks apart), with monitoring of proteinuria and anti-PLA2R antibodies after 3 months 3, 4

Cumulative cyclophosphamide exposure should not exceed 36g total dose (preferably limited to 25g) due to malignancy risk, and maximum 10g for patients who wish to conceive 2, 3
Expert consultation is recommended for patients who fail to respond to both rituximab and cyclophosphamide 4

Anti-PLA2R antibodies should be checked at 3-month intervals, as immunologic remission precedes clinical remission 3, 5
Kidney function should be regularly monitored through serum creatinine and eGFR 4
Serum albumin improvement indicates therapeutic response even with persistent proteinuria 4

Defining resistance by proteinuria alone may not be accurate, as persistent proteinuria with improving serum albumin may indicate secondary FSGS rather than active MN 4
Excessive immunosuppression should be avoided, balancing efficacy against risk of infections and malignancy 2, 3
Inadequate monitoring of anti-PLA2R antibody levels can lead to premature treatment changes, as response may take time 3, 5