Vol. 6, Issue 1, Part A (2024)

Introduction: Rituximab is recommended as the first-line therapy for PLA2R-associated membranous nephropathy in patients at moderate to high risk of progressive loss of kidney function, due to its superior long-term efficacy and improved safety profile. This study aims to assess the use of rituximab for treating PLA2R-associated membranous nephropathy at a tertiary hospital centre.
Methods: A retrospective study was conducted on patients diagnosed with PLA2R-associated membranous nephropathy who underwent their first rituximab administration between 2017 and 2022 at Coimbra Hospital and University Centre. The study assessed the occurrence of immune and clinical remission, relapse, response predictors, and adverse events.
Results: Eleven patients were included, with a mean follow-up time post-rituximab of 36.9±23.1 months. Rituximab was the first immunosuppressive therapy for only 3 patients. Additional immunosuppressive therapies were required for 7 (63.6%) patients. No response was observed in 2 patients (18.2%). Immune remission was achieved in 9 patients (81.8%), at mean time of 3.8±1.4 months. Among them, 5 (55.6%) patients achieved complete remission, 2 (22.2%) experienced partial remission, and 2 (22.2%) maintained nephrotic proteinuria. Immune remission consistently preceded clinical remission. Immune relapses occurred in 5 (45.5%) patients, at a mean time of 20.6±13.7 months. Four patients (36.4%) remained free of relapses throughout the entire follow-up period, with a mean time of 22.8±10.0 months. Patients with lower serum albumin were more likely to experience non-response or relapse (T(9) = 2.51, p= 0.03). Patients with anti-PLA2R exceeding 150 RU/mL exhibited no response or relapsed. 
Within the 6 months following rituximab, 4 patients experienced adverse events.
Discussion: Rituximab demonstrated both efficacy and safety in PLA2R-associated membranous nephropathy. Monitoring disease progression through anti-PLA2R titres may guide clinical decisions. Patients with lower serum albumin levels, higher anti-PLA2R titres (>150 RU/mL) and no proteinuria response, demand closer surveillance.