Abstract: FR-PO1275
When Tumor Control Is Not Enough: Rituximab for Persistent Malignancy-Associated Membranous Nephropathy
Session Information
- Onconephrology: Diagnostic Dilemmas, Therapy-Related Toxicities, and Clinical Cases
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1600 Onconephrology
Authors
- Yao, Jie, SingHealth Group, Singapore, Singapore
- Loh, Alwin Hwai Liang, Singapore General Hospital, Singapore, Singapore
- Tan, Hui Zhuan, Singapore General Hospital, Singapore, Singapore
Introduction
Membranous nephropathy occurring with active malignancy (mMN) is often presumed paraneoplastic and managed with treatment of the underlying tumor. However, in palliative settings, tumor control may be uncertain, and mMN may persist, with significant associated complications and morbidity. We present a case of mMN that achieved remission with Rituximab (RTX) administered concurrently with peptide receptor radionuclide therapy (PRRT) and Octreotide.
Case Description
A 61-year-old Chinese woman developed NS on the background of relapsed ovarian stromal carcinoid tumor. She was commenced on PRRT/Octreotide and was referred after 7 months of treatment for persistent NS (sCr 64µmol/L; sAlb 19G/L; 24hUTP 17g/day) despite an improvement in serum Chromogranin A (sCgA) levels. ANA was positive (1:640), while anti-dsDNA, anti-PLA2R antibody, and sPEP/sIFX were unremarkable. Kidney biopsy confirmed MN, with negative glomerular PLA2R staining. THSD7A and NELL-1 staining were unavailable. Given persistent NS and limited response with tumor-directed therapy, Rituximab (RTX) 1g was initiated concurrently following multidisciplinary discussion, and careful risk assessment in view of low-grade PRRT-related cytopenias. Patient was closely monitored, and a second RTX dose was deferred but ultimately not required due to continued improvement in serum albumin and overall clinical status. No infectious complications occurred. Near complete remission of mMN (sCr 75 µmol/L; sAlb 42G/L; uPCR 0.67g/g) was achieved at 11 months, together with continued decline in sCgA levels and radiological regression. PRRT was completed, and the patient remains on Octreotide.
Discussion
While mMN is often presumed paraneoplastic, a causal relationship cannot be proven in this case although strongly suspected given the temporal association with tumor recurrence. Persistent NS despite tumor-directed therapy suggests some patients may require kidney-directed treatment, either due to continued antigenic stimulation that cannot be fully eradicated in the palliative setting or a non-malignancy-driven process. Reliance on tumor control alone may be insufficient, as NS may not remit. In this case, RTX given in a stepwise, response-guided manner, was safely co-administered with PRRT without interrupting oncologic therapy. Further studies are needed to define which patients with mMN may benefit from concurrent kidney-directed treatment.