Treatment for Primary Membranous Nephropathy with Worsening ACR and Proteinuria

Initial Assessment and Management

The American Journal of Kidney Diseases recommends a 6-month course of alternating monthly cycles of oral and intravenous corticosteroids with oral cyclophosphamide as the initial immunosuppressive therapy for primary membranous nephropathy (PMN) with worsening albumin-to-creatinine ratio (ACR) and proteinuria 1
Target systolic blood pressure <120 mmHg using standardized office BP measurement 3
Restrict dietary sodium to <2.0 g/day to enhance antiproteinuric effects 4

Immunosuppressive therapy should be initiated when urinary protein excretion persistently exceeds 4 g/day AND remains at >50% of baseline value despite 6 months of conservative therapy 1
Immunosuppressive therapy should be initiated in the presence of severe, disabling, or life-threatening symptoms related to nephrotic syndrome 1
Immunosuppressive therapy should be initiated when serum creatinine has risen by ≥30% within 6-12 months (but eGFR remains >30 ml/min/1.73m²) 1

First-line immunosuppressive therapy: 6-month course of alternating monthly cycles of oral and IV corticosteroids with oral cyclophosphamide (modified Ponticelli regimen) 1
Cyclophosphamide is preferred over chlorambucil due to better safety profile 1
Adjust cyclophosphamide dose according to patient age and eGFR to minimize toxicity 1

Monitor patients for at least 6 months following completion of immunosuppressive therapy before considering treatment failure 1
Perform repeat kidney biopsy only if patient has rapidly deteriorating kidney function (doubling of serum creatinine over 1-2 months) in the absence of massive proteinuria (≥15 g/day) 1
Monitor labs frequently when on ACE inhibitor or ARB therapy, including serum creatinine, potassium levels, and proteinuria 4

For patients not responding to initial therapy, consider intensifying dietary sodium restriction 4
Consider using mineralocorticoid receptor antagonists in refractory cases (monitor for hyperkalemia) 4
Use potassium-wasting diuretics and/or potassium-binding agents to manage hyperkalemia when using RAS blockers 2

Do not use immunosuppressive therapy in patients with serum creatinine persistently ≥3.5 mg/dl (or eGFR ≤30 ml/min/1.73m²) AND reduced kidney size on ultrasound OR those with severe/life-threatening infections 1
Do not stop ACE inhibitor or ARB with modest and stable increase in serum creatinine (up to 30%) unless kidney function continues to worsen or refractory hyperkalemia develops 3