Swathi Nayak Ammunje
1 
, Shankar Prasad Nagaraju
1 , Dharshan Rangaswamy
1 , Ravindra Prabhu Attur
1 , Indu Ramachandra Rao
1 , Mohan Varadanayakanahalli Bhojaraja
1 , Srinivas Vinayak Shenoy
1 , Shriya Narendra Shet Shirodkar
1 , Priya Rani
1 , Sindhura Lakshmi Koulmane Laxminarayana
2* 1 Department of Nephrology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
2 Department of Pathology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
Abstract
Primary membranous nephropathy (pMN) is characterized by thickening of the glomerular capillary wall and a variable course of disease. Rituximab, an anti-CD20 monoclonal antibody (mAb), has been shown to have therapeutic effects; however, optimal dosing regimens and monitoring practices remain uncertain. To assess the usefulness of rituximab level monitoring in pMN and determine the factors associated with variations in treatment effects. A literature review was conducted on studies comparing rituximab pharmacokinetics, monitoring methods, and clinical outcomes in pMN. Information on drug clearance, urinary loss, inactivation by antibodies, and Fc receptor polymorphisms were reviewed. Our review showed, ELISA is the most commonly employed method for rituximab quantification. However, uncertainty remains due to the large inter-patient variability. Drug availability is affected by urinary loss, internalization by B cells, anti-drug antibodies, and Fc receptor polymorphisms. Regular monitoring has been shown to reduce under- and over-treatment, favoring individualized therapies. Therefore, monitoring rituximab levels may facilitate precision-based treatment in pMN. Additionally, standardized protocols are needed for directing dosing, maintenance, and monitoring practices.
Implication for health policy/practice/research/medical education:
Serial rituximab level monitoring in primary membranous nephropathy can facilitate precision-based, individualized treatment by detecting patients at risk for sub-therapeutic drug exposure due to phenomena such as urinary drug loss, anti-drug antibodies, or Fc receptor polymorphisms. The integration of standardized monitoring protocols for rituximab into clinical guidelines can minimize the risk of under-or over-treatment, maximize resource utilization, and enhance patient outcomes. Subsequent research and medical education should aim to confirm monitoring strategies in patient subgroups, incorporate pharmacokinetic evaluation into the practice of multiple disciplines, and establish evidence-based dosing algorithms for rituximab in patients with primary membranous nephropathy.
Please cite this paper as: Nayak Ammunje S, Nagaraju SP, Rangaswamy D, Prabhu Attur R, Rao IR, Bhojaraja MV, Shenoy SV, Shet Shirodkar SN, Rani P, Koulmane Laxminarayana SL. Monitoring rituximab levels in primary membranous nephropathy; is it necessary for finding the perfect dose for lasting remission. J Nephropathol. 2026;15(4):e27683. DOI: 10.34172/jnp.27683.