Obinutuzumab as Initial or Second-Line Treatment for Primary Membranous Nephropathy: A Multicenter Retrospective Study

Obinutuzumab as Initial or Second-Line Treatment for Primary Membranous Nephropathy: A Multicenter Retrospective Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Obinutuzumab as Initial or Second-Line Treatment for Primary Membranous Nephropathy: A Multicenter Retrospective Study Rong Wu, Xiaoyi Wang, Danfeng Fei, Yang Liu, Fei Han, Qilong Zhang, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9344081/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Membranous nephropathy (MN) is an autoimmune kidney disease involving B lymphocytes. Obinutuzumab is a type II, humanized anti-CD20 monoclonal antibody. Compared to rituximab, obinutuzumab has shown superior efficacy in leukemia and lymphoma. This study evaluates obinutuzumab as first or second-line treatment in MN patients. This study aims to evaluate the therapeutic effects and safety of obinutuzumab as either first-line or second-line treatment in patients with MN. Data from 34 primary MN patients (13 first-line, 21 second-line) treated with obinutuzumab and followed for ≥ 12 months were analyzed. Among the 21 second-line patients, the majority (71.4%) were refractory to prior therapy. Primary outcomes were complete remission (CR), partial remission (PR), and no response. CR was defined as urinary protein < 0.3 g/day or urinary protein-to-creatinine ratio (uPCR) < 0.3 g/g without renal function worsening. PR was defined as urinary protein 0.3–3.5 g/24h (≥ 50% baseline reduction) or uPCR 0.3–3.5 g/g (≥ 50% baseline reduction). No response meant failure to achieve CR/PR post-treatment. Over a median follow-up of 13.63 months, 94.1% achieved remission. The remission rates were 47.1% at 6 months and 79.4% at 12 months. Median uPCR decreased from 5.43 g/g to 0.53 g/g at 12 months, and serum albumin significantly improved. Renal function remained stable. All patients achieved B-cell depletion. Adverse events were mild and infrequent (25%), with no severe infusion-related reactions or deaths. Obinutuzumab represents a promising and well-tolerated therapeutic option for individuals with primary MN. The findings highlight the potential of obinutuzumab as a second-line therapy for refractory MN. membranous nephropathy Obinutuzumab anti-CD20 monoclonal antibody anti-phospholipase A2 receptor antibody chronic kidney disease Figures Figure 1 Figure 2 Figure 3 Figure 4 1. INTRODUCTION Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults, accounting for approximately 20% of primary nephrotic syndrome cases. MN is characterized by podocyte-targeted autoimmune-mediated glomerular lesions, with pathological manifestations such as subepithelial immune complex deposition, thickening of the basement membrane, and podocyte foot process effacement 1 , 2 . Without timely intervention, approximately 30%-40% of patients progress to end-stage renal disease (ESRD). Currently identified target antigens include the phospholipase A2 receptor (PLA 2 R), thrombospondin type-1 domain-containing 7A (THSD7A), neural epidermal growth factor-like 1 protein (NELL-1), and other novel antigens 1 . Studies have shown that about 70% of patients with primary MN produce anti-PLA 2 R IgG4 antibodies, leading to severe podocyte injury 3 . Currently, B-cell-targeted therapies have emerged as promising approaches for primary membranous nephropathy (PMN). Targeted monoclonal antibody therapies directed at the immune system have revolutionized the treatment of kidney-related diseases, particularly immune-mediated glomerular diseases. Rituximab is a type I chimeric anti-CD20 monoclonal antibody that targets B cells and has been used in the clinical treatment of MN 4 . Studies have reported that rituximab induces complete remission (CR) or partial remission (PR) in 35%-100% of cases 5 , 6 . Rituximab also achieves a mean reduction in 24-hour urinary protein of ≥ 50% 7 in initial treatment or refractory MN patients. Despite its clinical efficacy, 20%-40% of patients do not respond to rituximab, which may be associated with high anti-PLA 2 R antibody levels and residual tissue B cells 8 . Therefore, more optimized monoclonal antibody treatment regimens for MN are required. Obinutuzumab is a humanized type II anti-CD20 monoclonal antibody that enhances antibody-dependent cellular cytotoxicity (ADCC) and direct apoptosis through glycoengineering, achieving more thorough B-cell depletion 9 . This enhanced efficacy is attributed to the absence of a fucose residue on the oligosaccharides in the Fc region of immunoglobulin G (IgG), which significantly increases its affinity for FcγRIIIa receptors on immune effector cells 10 , 11 . Additionally, the CD20 binding epitopes of obinutuzumab and rituximab differ. These distinctions result in variations in CD20 complex formation and membrane compartmentalization. Such structural differences underlie the divergent cellular responses induced by type I (rituximab) and type II (obinutuzumab) monoclonal antibodies 12 . Obinutuzumab demonstrates superior efficacy compared to rituximab in chronic lymphocytic leukemia (CLL) and follicular lymphoma (FL). These differences may be attributed to its enhanced B-cell depletion capacity, particularly in prolonging progression-free survival (PFS) and achieving higher rates of minimal residual disease (MRD) negativity, thereby positioning it as a crucial therapeutic option for B-cell malignancies 13 – 15 . Obinutuzumab shows promising potential as an alternative to rituximab. A growing number of studies and case reports suggest obinutuzumab may serve as a more effective therapeutic option than rituximab. However, research on the efficacy and safety of obinutuzumab in treating MN remains limited. Hence, this study conducted a retrospective analysis of 34 MN patients across three centers to evaluate the efficacy and safety of obinutuzumab as first- or second-line therapy. 2. METHODS 2.1 Study Design and Patients This is a multicenter retrospective case series study. MN patients from the First Affiliated Hospital of Zhejiang University School of Medicine, Huzhou First People’s Hospital, and Anji County People’s Hospital were screened. A total of 34 patients with PMN were enrolled. Among them, 31 patients were diagnosed with MN by renal biopsy, while the remaining 3 patients presented with nephrotic syndrome and serum anti-PLA 2 R antibody titers exceeding 100 RU/mL, leading to a clinical diagnosis of PLA 2 R-associated MN. All patients received obinutuzumab treatment. The exclusion criteria were: (1) presence of viral (active hepatitis B) or bacterial infections; (2) diagnosis of any autoimmune diseases; (3) any form of malignancies. All patients underwent pre-study assessments before obinutuzumab administration, and follow-up was conducted via electronic medical records and telephone interviews. 2.2 Treatment The patients initially received a full dose of 1 g of obinutuzumab. Two weeks after the first dose, peripheral blood lymphocyte counts were analyzed, particularly CD19 + B cells. If B-cell depletion (BCD, defined as 0 CD19 + B cells/µL) was achieved, the first round of obinutuzumab treatment was concluded. If BCD was not achieved, an additional 1 g dose was administered until BCD was reached. Patients who did not achieve remission within 12 months were not further administered obinutuzumab. Prior to each infusion, patients received oral chlorpheniramine (10 mg) and acetaminophen (500 mg) or similar medications as prophylaxis for allergic reactions. In accordance with the 2021 KDIGO Guidelines, all patients without contraindications received optimal supportive care, including dietary sodium restriction, blood pressure control, and dyslipidemia management. 2.3 Outcomes Complete remission (CR) was defined as urinary protein < 0.3 g/day or urinary protein-to-creatinine ratio (uPCR) < 0.3 g/g without worsening renal function. Partial remission (PR) was defined as 0.3 g/24h ≤ urinary protein < 3.5 g/24h with a ≥ 50% reduction from baseline, or 0.3 g/g ≤ uPCR < 3.5 g/g with a ≥ 50% reduction from baseline. No response was defined as failure to achieve CR/PR after treatment. Relapse was defined as recurrence of urinary protein ≥ 3.5 g/24h or a return to < 50% reduction from baseline, uPCR ≥ 3.5 g/g, or uPCR returning to < 50% reduction from baseline. Time to first relapse-free survival was defined as the duration from the first remission to the first relapse after the initial obinutuzumab dose. 2.4 Clinical Data Collection Demographic data included gender, age at onset, and age at obinutuzumab treatment. Laboratory data included serum anti-PLA 2 R antibody levels, uPCR, serum albumin, and serum creatinine. During the follow-up, remission and relapse events, as well as medications administered before and after obinutuzumab therapy, were recorded as clinical data. For this study, the data were obtained through electronic medical record systems and serial telephone interviews. Some patients were previously treated with rituximab at a dose of 375 mg/m². A treatment course was defined as patients receiving full-dose rituximab every 1–2 weeks until BCD was achieved. Additional courses were administered if serum anti-PLA 2 R antibody titers increased significantly or peripheral CD19 + B-cell counts rebounded. Serum anti-PLA 2 R antibody titers were measured via the indirect immunofluorescence assay (minimum detectable level: 2 RU/mL). Renal biopsy PLA 2 R staining was graded as + ~ +++. Serum anti-PLA 2 R antibody levels < 5 RU/mL were defined as negative, while ≥ 5 RU/mL were defined as positive. Peripheral CD19 + B-cell counts were analyzed via flow cytometry post-obinutuzumab treatment. Off-label Obinutuzumab treatment and the protocol of retrospective outcome analyses were approved by the ethics committee of the First Affiliated Hospital of Zhejiang University School of Medicine (Approval No. 2020571), Huzhou First People’s Hospital (Approval No.2023KYLL039), and Anji County People’s Hospital (Approval No. H20240222-1). All participants provided written informed consent for Obinutuzumab infusion and retrospective analyses, in accordance with the declaration of Helsinki. 2.5 Statistical Analysis Quantitative data conforming to a normal distribution were expressed as mean ± standard deviation and compared using Student’s t-test. Skewed data were expressed as median (interquartile range, IQR) and compared using the Mann-Whitney U test. Categorical data were presented as counts and percentages and compared using the chi-square test. In this study, a P value < 0.05 was considered statistically significant. Cox proportional hazards models and log-rank tests were performed using R version 4.2.2 with the "survival", "survminer", and "ggplot2" packages. SPSS version 26.0 (IBM) was used for statistical analysis. All graphs were generated using GraphPad Prism 9, with data presented as medians except for Kaplan-Meier curves. 3. RESULTS 3.1 Patient Characteristics and Therapy This retrospective study included 34 patients with primary MN from the First Affiliated Hospital of Zhejiang University School of Medicine, Huzhou First People’s Hospital and Anji County People’s Hospital, as shown in Fig. 1. A total of 31 patients underwent renal biopsy, confirming the diagnosis of MN. In addition, 3 patients showed high serum anti-PLA 2 R antibody titers (> 500 RU/mL in 2, 198.34 RU/mL in 1) in the presence of nephrotic syndrome, which provided a clinical diagnosis of MN. PLA 2 R staining was positive in 22 of 23 (95.7%) tested renal tissues. Based on serum anti-PLA 2 R antibody levels and renal PLA 2 R staining, 32 (88.9%) patients were assigned to the PLA 2 R-associated subgroup, while 2 patients were assigned to the non-PLA 2 R-associated subgroup (serum anti-PLA 2 R < 2 RU/mL, negative histology). Regarding prior immunosuppressive therapy (IST), 21 (61.8%) patients had received at least one IST and were classified as the second-line treatment subgroup. In contrast, the remaining 13 (38.2%) patients receiving obinutuzumab as initial therapy were classified as the initial treatment subgroup. IST included glucocorticoids, calcineurin inhibitors, rituximab, cyclophosphamide, triptolide, and mycophenolate mofetil. Of the 21 patients receiving obinutuzumab as second-line therapy, 15 patients were classified as refractory to prior immunosuppression, while 6 patients had relapsing disease. To minimize confounding effects from prior IST and reduce over-immunosuppression risks such as infections, the second-line treatment subgroup patients discontinued prednisone or mycophenolate mofetil at least 1 month before initiating obinutuzumab and alkylating agents at least 6 months before. In terms of prior rituximab use, 15 (44.1%) patients had received rituximab, with a median dose of 1.8 (1.44–2.59) g. Among them, 2 patients switched to obinutuzumab due to infusion reactions, while 13 patients switched due to unsatisfactory or unsustained responses. Detailed demographics and clinical features are shown in Table 1. Table 1 Baseline demographic and clinical characteristics of the 34 patients with PMN Demographics Overall Cohort (N = 34) Initial Treatment (N = 13) Second-line Treatment(N = 21) Ethnicity All Han Chinese Age (y) at obinutuzumab, median(IQR) 50.77(43.16–52.45) 53.09(42.23–56.25) 51.75(44.45–53.17) Disease history Age (y) at disease onset, mean ± SD 49.08 ± 10.26 47.6 ± 12.34 47.91 ± 10.69 Duration of disease,mo,median(IQR) 13.63(12.81–20.80) 11.9(8.28–16.47) 13.67(13.07–16.97) Time since last immunosuppressivetherapy,mo, median(IQR) 4.47(2.23–5.87) non-nephrotic syndrome,n(%) 8(23.5%) 2(15.3%) 6(28.6%) Laboratory values before obinutuzumab Urine protein creatinine ratio,g/g,median(IQR) 3.75(3.34–7.17) 6.71(2.83–8.43) 3.69(1.86–6.74) Serum albumin,g/L,mean ± SD 27.21 ± 7.23 25.12 ± 5.72 28.7 ± 7.93 Serum creatinine,µmol/L,mean ± SD 88.66 ± 32.95 81.19 ± 23.81 94 ± 37.83 Serum anti-PLA2R antibody titer at the commencement of obinutuzumab,RU/mL,median(IQR) 10.32(17.19-113.82) 27.09(2-67.01) 9.08(1.98–19.13) Serum anti-PLA2R antibody titer(> 150RU/mL),n(%) 8(23.6%) 5(38.5%) 3(14.3%) Kidney bioposy(stage) I 3(8.8%) 2(15.3%) 1(4.8%) II 23(67.67%) 10(77%) 13(61.9%) III 5(14.7%) 1(7.7%) 4(19%) Previous therapy Rituximab,n(%) 15(41.7%) 15(71.4%) Cyclophosphamide,n(%) 12(33.3%) 12(57.1%) Mycophenolate,n(%) 3(8.3%) 3(14.3%) CNI(tacrolimus or cyclosporine),n(%) 13(36.1%) 13(61.9%) ACEI/ARB,n(%) 20(55.6%) 5(38.5%) 15(71.4%) Abbreviation:ARB,angiotensin II receptor blocker;ACEI,angiotensin-converting Enzyme Inhibitor;CNI,calcineurin inhibitor;IQR,interquartile range;SD,standard deviation, non-nephrotic syndrome,proteinuria 30g/L. 3.2 Primary Outcome Over a median follow-up of 13.63 (12.81–20.80) months, the median obinutuzumab dose was 2 (1.76–2.24) g. Among the 34 patients, 6 patients received 1 dose, 21 patients received 2 doses, 6 patients received 3 doses, and 1 patient received 4 doses. By the end of follow-up, 21 (61.8%) patients achieved PR, and 11 (32.4%) patients achieved CR. However, 2 patients failed to achieve remission during follow-up. Moreover, 1 patient showed a decline in serum anti-PLA 2 R antibody levels from 572 RU/mL to 152 RU/mL at 3 months, but treatment regimen modification precluded further assessment of potential obinutuzumab response. The other patient who failed to achieve remission during follow-up maintained uPCR < 3.5 g/g without achieving a 50% reduction from baseline. Remission rates were 47.1% (16/34) at 6 months and 79.4% (27/34) at 12 months. Among the 13 patients who received obinutuzumab as first-line therapy, 11 (84.6%) patients achieved remission. Among these, 6 (46.2%) patients achieved PR, and 5 (38.5%) patients achieved CR. In the 21 second-line treatment patients, all achieved remission. Among these, 15 (71.4%) patients achieved PR, and 6 (28.6%) patients achieved CR. The primary outcomes comparing subgroups with and without prior immunosuppressive therapy are presented in Table 2. Among the 15 patients previously treated with rituximab, all achieved clinical remission. Among these, 10 (66.7%) patients achieved PR, and 5 (33.3%) patients achieved CR. A total of 19 patients had no history of previous rituximab use, with 17 (89.5%) patients achieving remission. Among these, 11 (57.9%) patients achieved PR, and 6 (31.6%) patients achieved CR. Outcomes in terms of prior rituximab use are detailed in Table 3. Table S1 displays the outcomes between the PLA 2 R-associated treatment subgroup and the non-PLA2R-associated treatment subgroup. Among the 32 patients who achieved remission during the follow-up period, the median time to first remission (PR or CR) was 6.63 (5.28–8.73) months. A total of 11 patients achieved CR, with a median time to CR of 6.70 (4.42–9.53) months. Only 1 patient experienced relapse 9 months after achieving PR, who achieved PR again after an additional dose of obinutuzumab; the other patients remained in remission by the end of follow-up. Over a median follow-up of 13.63 (12.81–20.80) months, the mean relapse-free survival time was 5.88 ± 4.53 months. The primary outcomes are detailed in Table 4. 3.3 Secondary Outcome: uPCR, Serum Albumin, and Creatinine At 6 and 12 months after the initial dose of obinutuzumab, the uPCR decreased from a median baseline of 5.43 (3.74–6.49) g/g to 1.2 (0.89–2.82) g/g and 0.53 (0.35–1.81) g/g, respectively. Serum albumin increased from a median baseline of 25.5 (23-33.2) g/L to 40.6 (37.9–41.9) g/L and 43.9 (41.7–46.2) g/L, respectively. The reductions in uPCR at both 6 and 12 months post-initial dose were statistically significant compared to baseline ( p = 0.0024 and p = 0.0009, respectively). Similarly, the increases in serum albumin at both time points were statistically significant (both p < 0.001). Throughout the follow-up period, serum creatinine levels remained stable in all patients, indicating preserved renal function following obinutuzumab treatment. The Kaplan-Meier curve and detailed trend changes in patients are shown in Fig. 2. No significant difference in remission rates was observed between the initial treatment group and the second-line treatment group during the follow-up period ( p = 0.8). However, the first-line treatment group exhibited a trend of higher remission rates within 12 months of follow-up compared to the second-line treatment group. As the follow-up duration increased, the remission rates between the two groups converged. Additionally, no significant differences in uPCR, serum albumin, and serum creatinine levels were observed between the two groups. The detailed results are displayed in Fig. 3. No significant difference in remission rates was observed between the previous rituximab treatment group and the group without previous rituximab treatment during the follow-up period ( p = 0.8). However, a trend was observed indicating that patients who had not received rituximab exhibited higher remission rates within 12 months of follow-up compared to those with prior rituximab exposure. Additionally, no significant differences in uPCR, serum albumin, and serum creatinine levels were found between the two groups. The detailed results are shown in Fig. 4. No significant difference in remission rates was observed between the PLA 2 R-associated group and non-PLA 2 R-associated group during the follow-up period ( p = 0.6). Additionally, no significant differences in uPCR, serum albumin, and serum creatinine levels were found between the two groups. Detailed results are displayed in Figure S1. 3.4 Serum Anti-PLA2R Antibodies Based on serum PLA 2 R antibody titers and renal tissue PLA 2 R staining, 32 patients were diagnosed with PLA 2 R-associated membranous nephropathy. Among them, only 18 had serum anti-PLA 2 R antibody levels > 5 RU/mL at the initiation of obinutuzumab therapy. Of these 18 patients, 11 had previously received immunosuppressive treatment. The changes in serum anti-PLA 2 R antibody levels are presented in Table S2. 3.5 Lymphocyte Subsets Following obinutuzumab treatment, significant alterations in lymphocyte subsets were observed. Notably, both CD19 + B-cell counts (108 [71.42–177.58] vs. 0.0 [-0.04–0.39]; p < 0.001) and total B-lymphocyte counts (2390.89 ± 845.50 vs. 1385.61 ± 575.12; p 0.05). Detailed data are presented in Table 5. 3.6 Combination Therapy Following obinutuzumab treatment, 30 (88.2%) patients successfully discontinued all immunosuppressive medications during follow-up. One patient continued tacrolimus for 8 months with gradual tapering, achieving complete withdrawal after retreatment with obinutuzumab. Another patient with suboptimal response to obinutuzumab received cyclophosphamide and prednisone but failed to achieve remission by the end of follow-up. Moreover, one patient developed fever after the first obinutuzumab infusion and was switched to tacrolimus maintenance until follow-up completion. Another patient contracted COVID-19 four months after the final obinutuzumab dose and was managed with methylprednisolone (tapered to discontinuation). 3.7 Safety During the follow-up period, no severe treatment-related adverse events were observed either during or after obinutuzumab therapy. Adverse events occurred in 9(25%) patients, including pulmonary infections (n = 3), pruritus (n = 2), low-grade fever (n = 1), chills with high fever (n = 1), and nausea and vomiting with high fever (n = 1). Refer to Table 6 for details. 2 patients developed coronavirus-induced viral pneumonia 4 months after completing the final dose of obinutuzumab treatment, and 1 patient developed coronavirus-induced viral pneumonia 8 months after receiving the subsequent dose of obinutuzumab. All 3 patients were hospitalized and successfully treated. In addition, 2 patients developed pruritus during initial obinutuzumab infusions, with recurrence during subsequent administrations. Neither patient presented with an associated rash. Furthermore, 1 patient developed fever during initial obinutuzumab infusion. Notably, this patient had previously discontinued rituximab therapy due to similar febrile reactions. Based on safety considerations, the treatment regimen was switched to tacrolimus. Moreover, 1 patient developed chills and fever (peak temperature 38.8℃) during the first obinutuzumab infusion, which resolved after intravenous administration of 5mg dexamethasone. The final infusion was completed without recurrence of similar symptoms. Notably, 2 patients experienced nausea, vomiting, and fever during their first obinutuzumab infusion. Symptoms improved with symptomatic treatment, and neither patient experienced recurrence during subsequent infusions, including the final dose. No anaphylactic shock, sepsis, malignancy, or mortality was observed in any patient. 4. DISCUSSION As a multicenter retrospective study, this research investigated the efficacy of obinutuzumab as a second-line therapy for refractory MN (resistant to glucocorticoids + cyclophosphamide and/or calcineurin inhibitors, and/or rituximab). Additionally, these patients were compared with those receiving obinuzumab as first-line therapy for primary MN. In our study, 94.1% (32 of 34) of MN patients achieved either partial or complete remission after obinutuzumab treatment. This suggests that obinutuzumab demonstrates favorable efficacy in the treatment of MN. In the present study, the composite remission rate (including both PR and CR) in the initial treatment group was 84.6% (11 of 13). This finding aligns closely with an earlier case series of 12 primary MN patients treated with obinutuzumab as first-line therapy, which reported a comparable composite remission rate of 83.3% 16 . A more recent and larger study by Sun et al. further supports this, reporting a 12-month remission rate of 87.2% in initial treatment patients receiving obinutuzumab 17 . The consistency across these studies, including ours, strongly reinforces the high efficacy and reliability of obinutuzumab as an initial treatment regimen for MN. Many case reports have demonstrated the favorable efficacy of obinutuzumab in refractory membranous nephropathy. Sethi et al. reported that 85.7% of 11 refractory patients (7 of whom had prior rituximab therapy and 7 had received glucocorticoids plus either tacrolimus or cyclophosphamide) achieved remission after two doses of obinutuzumab 18 . Furthermore, a recent international multicenter study by Teisseyre et al. specifically investigated patients with anti-rituximab antibodies, a known mechanism of resistance. Their findings strongly support the use of alternative anti-CD20 therapies, demonstrating that obinutuzumab and ofatumumab were significantly more effective than rituximab in inducing clinical remission at both 6 months and 12 months in this challenging patient population 19 . In our study, 100% of patients (21/21) in the second-line treatment group achieved remission following obinutuzumab therapy. Notably, 3 patients (14.2%) had previously received triple immunosuppressive therapy (cyclophosphamide plus glucocorticoids, calcineurin inhibitors, and rituximab), while 12 patients (57.1%) had been treated with two immunosuppressants. Another study demonstrated that 82.1% of 39 patients with prior immunosuppressive treatment achieved remission after obinutuzumab therapy 17 . In the present study, the second-line treatment group demonstrated composite remission rates of 42.9% (9/21) at 6 months and 81% (17/21) at 12 months post-obinutuzumab. These results were significantly superior to the 35.5% (6-month) and 37% (12-month) remission rates observed with rituximab in refractory MN patients reported by Xu et al 9 . The superior B-cell depletion observed with obinutuzumab in our study (100% of patients), consistent with the findings of Teisseyre et al, likely underpins its enhanced clinical efficacy, particularly in neutralizing the negative impact of anti-rituximab antibodies 19 . In our study, 85.7% (12/14) of patients with detectable serum PLA 2 R antibodies achieved immunological remission. Stratified by treatment line, the immunological remission rates were 60% (3/5) in the initial therapy group and 88.9% (8/9) in the second-line therapy group. These findings suggest that obinutuzumab holds significant therapeutic potential for managing complex, refractory MN. In our study, the median time to remission was 5.55 months in the first-line treatment group compared to 7.76 months in the second-line group. These results imply that obinutuzumab induces remission more rapidly when used as initial therapy for MN compared to salvage treatment. In the second-line treatment group, 71.4% (15/21) of patients had previously received but responded inadequately to rituximab therapy. Among these rituximab-refractory patients, the composite remission rates were 33.3% (5/15) at 6 months and 93.3% (14/15) at 12 months following obinutuzumab treatment. When compared to the landmark MENTOR trial's 24-month follow-up of 65 MN patients receiving rituximab, the 6-month and 12-month composite remission rates were 35% and 60%, respectively 20 . Notably, in our study, rituximab-refractory patients achieved significantly higher 12-month remission rates (93.3%) compared to the rituximab-treated cohort in MENTOR. These preliminary findings suggest that obinutuzumab not only serves as an effective salvage therapy but may also offer a more potent initial B-cell depletion strategy, warranting future head-to-head comparisons with rituximab. Obinutuzumab is a humanized type II anti-CD20 monoclonal antibody that binds to a distinct CD20 epitope with higher affinity for FCγRIII compared to type I anti-CD20 antibodies like rituximab 21 . Multiple studies have demonstrated that obinutuzumab exhibits significantly enhanced antibody-dependent cellular cytotoxicity (ADCC) and direct cell death induction compared to rituximab. An in vitro study investigating lymphokine-activated killer (LAK) cells combined with rituximab or obinutuzumab in follicular lymphoma (FL) demonstrated that both anti-CD20 antibodies enhanced ADCC activity against CRL-1596 (CD20+) cells, with obinutuzumab showing superior potency (42% vs. 32% ADCC enhancement, respectively) 22 . Ofatumumab is another CD20-targeted therapy. A case series of 17 male MN patients with stage 1–3 chronic kidney disease (CKD) reported that 7 of 10 rituximab-resistant patients (70%) and 3 of 7 rituximab-intolerant patients (42.9%) achieved composite remission 23 . However, clinical evidence supporting ofatumumab for MN remains limited, necessitating further studies to validate its therapeutic potential. Furthermore, obinutuzumab treatment significantly improved serum albumin levels while maintaining stable renal function. In the present study, obinutuzumab demonstrated a favorable safety profile, with no reported severe adverse events. Notably, obinutuzumab demonstrated excellent tolerability in patients who had previously experienced severe infusion reactions to rituximab. This improved safety profile likely reflects its humanized structure, which reduces immunogenicity and subsequent immune-mediated reactions. Large-scale clinical trials are currently being conducted to further evaluate the efficacy and safety of obinutuzumab in MN (NCT04629248, NCT05050214), with preliminary results anticipated by mid-2025. Our study has several strengths and limitations. The primary strength lies in its evaluation of obinutuzumab as initial therapy—a rare approach in current literature. Although this represents one of the largest available cohorts comparing refractory MN patients (n = 21) to obinutuzumab-naïve cases (n = 13), it still remains relatively modest from the perspective of an ideal study cohort. The multicenter design across three cities further reduces single-center bias. Limitations include inherent retrospective data constraints, including its retrospective nature and the lack of a control group for direct comparative efficacy analysis. Furthermore, the median follow-up duration of approximately 14 months is insufficient to evaluate long-term outcomes such as sustained remission, relapse rates over time, and long-term renal survival. Immunoglobulin monitoring was omitted due to insurance restrictions, while incomplete B-cell/anti-PLA 2 R antibody data were due to patient reluctance over testing costs. The high response rates observed may be partially influenced by the disease characteristics of our cohort. The median anti-PLA2R antibody titer at baseline was relatively low, and a portion of patients did not present with full nephrotic syndrome, suggesting a population with potentially lower overall disease activity. This may limit the generalizability of our efficacy results to all MN patients, particularly those with highly active, severe disease. Declarations Ethics approval and consent to participate The study was approved by the Ethics Committees of the First Affiliated Hospital of Zhejiang University School of Medicine (Approval No. 2020571), Huzhou First People’s Hospital (Approval No. 2022KYLL047), and Anji County People’s Hospital (Approval No. H20240222-1), and written informed consent was obtained from all participants prior to sample collection, in accordance with the declaration of Helsinki. Data Availability Statement The data that support the findings of this study are available from the corresponding author, Huayan Zhu, upon reasonable request. Author's Contribution RW conceived the study and drafted the manuscript. JZ, ZZ and YL performed data collection. FH, HL and ZS performed statistical analysis. QZ and JZ performed data curation and visualization. XW and DF acquired funding and administered the project. HZ supervised research and finalized the manuscript. Funding Declaration This work was supported by National Science and Technology Major Project (2023ZD0509802), Huzhou Municipal Science and Technology Bureau Project (2022GYB33). Conflict of interest The authors declare that they have no competing interests. References Sethi S, Fervenza FC. Membranous nephropathy-diagnosis and identification of target antigens. Nephrol Dial Transpl 2023;39(4). Hoxha E, Reinhard L, Stahl RAK. Membranous nephropathy: new pathogenic mechanisms and their clinical implications. Nat Rev Nephrol 2022;18(7). Avasare R, Andeen N, Beck L. Novel Antigens and Clinical Updates in Membranous Nephropathy. Annu Rev Med 2023;75(0). Kaegi C, Wuest B, Schreiner J, et al. Systematic Review of Safety and Efficacy of Rituximab in Treating Immune-Mediated Disorders. Front Immunol. 2019;10:0. Allinovi M, Teisseyre M, Accinno M et al. Anti-Rituximab Antibodies Occurrence and Clinical Outcomes in Patients With Primary Membranous Nephropathy. Kidney Int Rep 2025;10(8). Teisseyre M, Cremoni M, Boyer-Suavet S, et al. Advances in the Management of Primary Membranous Nephropathy and Rituximab-Refractory Membranous Nephropathy. Front Immunol. 2022;13:0. Dahan K, Debiec H, Plaisier E et al. Rituximab for Severe Membranous Nephropathy: A 6-Month Trial with Extended Follow-Up. J Am Soc Nephrol 2016;28(1). Hudson R, Rawlings C, Mon SY, Jefferis J, John GT. Treatment resistant M-type phospholipase A2 receptor associated membranous nephropathy responds to obinutuzumab: a report of two cases. BMC Nephrol 2022;23(1). Xu M, Wang Y, Wu M et al. Obinutuzumab versus rituximab for the treatment of refractory primary membranous nephropathy. Nephrol Dial Transpl 2024;40(5). Shadman M. Diagnosis and Treatment of Chronic Lymphocytic Leukemia: A Review. JAMA 2023;329(11). Abeles I, Palma C, Meednu N, Payne AS, Looney RJ, Anolik JH. B Cell-Directed Therapy in Autoimmunity. Annu Rev Immunol 2023;42(1). Freeman CL, Sehn LH. A tale of two antibodies: obinutuzumab versus rituximab. Br J Haematol 2018;182(1). Hampel PJ, Parikh SA. Chronic lymphocytic leukemia treatment algorithm 2022. Blood Cancer J 2022;12(11). Hallek M, Chronic Lymphocytic L. 2025 Update on the Epidemiology, Pathogenesis, Diagnosis, and Therapy. Am J Hematol 2025;100(3). Kaegi C, Wuest B, Crowley C, Boyman O. Systematic Review of Safety and Efficacy of Second- and Third-Generation CD20-Targeting Biologics in Treating Immune-Mediated Disorders. Front Immunol 2022;12(0). Hao J, Wang J, Zhou P, Xu R, Chen X. Obinutuzumab in untreated primary membranous nephropathy: An observational case series. Nephrol (Carlton). 2024;29(11). Su X, Wu B, Tie X et al. Obinutuzumab as Initial or Second-Line Therapy in Patients With Primary Membranous Nephropathy. Kidney Int Rep 2024;9(8). Sethi S, Kumar S, Lim K, Jordan SC. Obinutuzumab is Effective for the Treatment of Refractory Membranous Nephropathy. Kidney Int Rep 2020;5(9). Teisseyre M, Allinovi M, Audard V et al. Obinutuzumab and Ofatumumab are More Effective Than Rituximab in the Treatment of Membranous Nephropathy Patients With Anti-Rituximab Antibodies. Kidney Int Rep 2025(3):753–61. Fervenza FC, Appel GB, Barbour SJ et al. Rituximab or Cyclosporine in the Treatment of Membranous Nephropathy. N Engl J Med 2019;381(1). Fischer K, Al-Sawaf O, Bahlo J et al. Venetoclax and Obinutuzumab in Patients with CLL and Coexisting Conditions. N Engl J Med 2019;380(23). García-Muñoz R, López-Díaz-de-Cerio A, Feliu J et al. Follicular lymphoma: in vitro effects of combining lymphokine-activated killer (LAK) cell-induced cytotoxicity and rituximab- and obinutuzumab-dependent cellular cytotoxicity (ADCC) activity. Immunol Res 2015;64(2). Allinovi M, Teisseyre M, Accinno M et al. Anti-Rituximab Antibodies Occurrence and Clinical Outcomes in Patients With Primary Membranous Nephropathy. Kidney Int Rep 2025;10(8). Table 2 To 6 Table 2 and 6 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files SupplementFigure1.tif Figure S1.(A) Probability of achieving remission (PR or CR) in the PLA2R-associated treatment group and the non-PLA2R-associated treatment group following obinutuzumab administration (PLA2R-associated treatment group n=30). (B-D) Changes in urinary uPCR, serum. SupplementTable1.pdf SupplementTable2.pdf Table2To6.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 05 May, 2026 Reviews received at journal 26 Apr, 2026 Reviewers agreed at journal 21 Apr, 2026 Reviewers agreed at journal 20 Apr, 2026 Reviewers invited by journal 19 Apr, 2026 Editor invited by journal 13 Apr, 2026 Editor assigned by journal 10 Apr, 2026 Submission checks completed at journal 10 Apr, 2026 First submitted to journal 07 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9344081","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":629744504,"identity":"c0080a8d-82a3-42d0-ac2a-36d8dec85a75","order_by":0,"name":"Rong Wu","email":"","orcid":"","institution":"First Affiliated Hospital of Huzhou University","correspondingAuthor":false,"prefix":"","firstName":"Rong","middleName":"","lastName":"Wu","suffix":""},{"id":629744505,"identity":"7b6aa302-df82-49da-9295-5b9ef4d3a766","order_by":1,"name":"Xiaoyi Wang","email":"","orcid":"","institution":"First Affiliated Hospital of Huzhou University","correspondingAuthor":false,"prefix":"","firstName":"Xiaoyi","middleName":"","lastName":"Wang","suffix":""},{"id":629744506,"identity":"5fba7d6f-38c1-4194-ac52-4a0eef7db4f2","order_by":2,"name":"Danfeng Fei","email":"","orcid":"","institution":"First Affiliated Hospital of Huzhou University","correspondingAuthor":false,"prefix":"","firstName":"Danfeng","middleName":"","lastName":"Fei","suffix":""},{"id":629744507,"identity":"8e366a87-7c2d-4e02-8b27-9fe7c587410f","order_by":3,"name":"Yang Liu","email":"","orcid":"","institution":"First Affiliated Hospital of Huzhou University","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"Liu","suffix":""},{"id":629744508,"identity":"1bd07cd2-cf38-4a73-a9d7-03c5810e1e92","order_by":4,"name":"Fei Han","email":"","orcid":"","institution":"Zhejiang University School of 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Zhu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyklEQVRIiWNgGAWjYBACef6G9M8/frDx8LM3EKnFcMaBZ8yMPXwykj0HiLXmQOIzZgY2ORuDGwlE6mBsOJz2uIDHjEdy5uONNxhqbKIJamFnbks3nmGRxsMvnVZswXAsLbeBsC1nEiR4eI7xSM7OMZMA2klYC8OB/A8SPGz/eQxuniFaS0KaNA8bG4/BDR4itQADOdlwZg8bj2QP0C8JxPgFGJWJDz78YLPnZz+88caHGhsiHIYEDCQSSFEO0UKqjlEwCkbBKBgZAADOND8RPvUM6wAAAABJRU5ErkJggg==","orcid":"","institution":"First Affiliated Hospital of Huzhou University","correspondingAuthor":true,"prefix":"","firstName":"Huayan","middleName":"","lastName":"Zhu","suffix":""}],"badges":[],"createdAt":"2026-04-07 11:12:43","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9344081/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9344081/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107918333,"identity":"133879fc-dbad-4a1d-94ab-0cc1f0f0f287","added_by":"auto","created_at":"2026-04-27 14:27:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1333939,"visible":true,"origin":"","legend":"\u003cp\u003eStudy flow diagram.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/4c747b38b5ac1ccd6c8857d3.png"},{"id":107918322,"identity":"0f6617d7-7d0e-419a-9c8a-67c7b40be53a","added_by":"auto","created_at":"2026-04-27 14:27:43","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":7165204,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Probability of achieving remission (PR or CR) in all patients following obinutuzumab administration (n=13). (B-D) Changes in urinary uPCR, serum albumin, and serum creatinine levels in all patients after obinutuzumab treatment.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/90968948a6cd8c5eb438656d.png"},{"id":107918337,"identity":"0bed3982-f54f-43e0-852b-5b3e4a92bbee","added_by":"auto","created_at":"2026-04-27 14:27:49","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":9683371,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Probability of achieving remission (PR or CR) in the initial therapy group and second-line therapy group following obinutuzumab administration (first-line therapy group, n=34). (B-D) Changes in urinary uPCR, serum albumin, and serum creatinine levels in the initial therapy group and second-line therapy group after obinutuzumab treatment.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/0911a515fff17b1209186ebd.png"},{"id":107918334,"identity":"7c5b6e7e-f885-4315-a6c6-b856a4434b1b","added_by":"auto","created_at":"2026-04-27 14:27:49","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":8673088,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Probability of achieving remission (PR or CR) in the previous rituximab treatment group and the group without previous rituximab treatment following obinutuzumab administration (rituximabtreatment group, n=15). (B-D) Changes in urinary uPCR, serum albumin, and serum creatinine levels in the previous rituximab treatment group and the group without previous rituximab treatment after obinutuzumab treatment.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/52454c1f3ca9b8751bebffba.png"},{"id":108490726,"identity":"c5278760-ec6a-4048-8658-31cdf980e633","added_by":"auto","created_at":"2026-05-05 09:47:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":25736008,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/4d5d6ce2-22ca-499d-bbf2-9d1a92b7399b.pdf"},{"id":107918323,"identity":"9fe340e2-7603-4004-a060-d872915f3081","added_by":"auto","created_at":"2026-04-27 14:27:43","extension":"tif","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":2830148,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure S1.\u003c/strong\u003e(A) Probability of achieving remission (PR or CR) in the PLA2R-associated treatment group and the non-PLA2R-associated treatment group\u003c/p\u003e\n\u003cp\u003efollowing obinutuzumab administration (PLA2R-associated treatment group n=30). (B-D) Changes in urinary uPCR, serum.\u003c/p\u003e","description":"","filename":"SupplementFigure1.tif","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/9f3f882e6dafcd8e9bcf6980.tif"},{"id":107918324,"identity":"344944ef-7855-4773-a3ff-6e96d1e77ac9","added_by":"auto","created_at":"2026-04-27 14:27:43","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":58695,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementTable1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/fc1157f4e9e8d1f93e307947.pdf"},{"id":107918331,"identity":"eda97ea0-8b6d-4377-bf6a-f59471749c7c","added_by":"auto","created_at":"2026-04-27 14:27:49","extension":"pdf","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":98785,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementTable2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/de16096ae6d05f04589cea40.pdf"},{"id":107918325,"identity":"4b90394a-bb51-4dc5-98ed-5b1e839ef4ef","added_by":"auto","created_at":"2026-04-27 14:27:43","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":23585,"visible":true,"origin":"","legend":"","description":"","filename":"Table2To6.docx","url":"https://assets-eu.researchsquare.com/files/rs-9344081/v1/8cb03d001636fbec7a5bc3dd.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Obinutuzumab as Initial or Second-Line Treatment for Primary Membranous Nephropathy: A Multicenter Retrospective Study","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eMembranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults, accounting for approximately 20% of primary nephrotic syndrome cases. MN is characterized by podocyte-targeted autoimmune-mediated glomerular lesions, with pathological manifestations such as subepithelial immune complex deposition, thickening of the basement membrane, and podocyte foot process effacement\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Without timely intervention, approximately 30%-40% of patients progress to end-stage renal disease (ESRD). Currently identified target antigens include the phospholipase A2 receptor (PLA\u003csub\u003e2\u003c/sub\u003eR), thrombospondin type-1 domain-containing 7A (THSD7A), neural epidermal growth factor-like 1 protein (NELL-1), and other novel antigens\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. Studies have shown that about 70% of patients with primary MN produce anti-PLA\u003csub\u003e2\u003c/sub\u003eR IgG4 antibodies, leading to severe podocyte injury\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Currently, B-cell-targeted therapies have emerged as promising approaches for primary membranous nephropathy (PMN).\u003c/p\u003e \u003cp\u003eTargeted monoclonal antibody therapies directed at the immune system have revolutionized the treatment of kidney-related diseases, particularly immune-mediated glomerular diseases. Rituximab is a type I chimeric anti-CD20 monoclonal antibody that targets B cells and has been used in the clinical treatment of MN\u003csup\u003e4\u003c/sup\u003e. Studies have reported that rituximab induces complete remission (CR) or partial remission (PR) in 35%-100% of cases\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. Rituximab also achieves a mean reduction in 24-hour urinary protein of \u0026ge;\u0026thinsp;50%\u003csup\u003e7\u003c/sup\u003e in initial treatment or refractory MN patients. Despite its clinical efficacy, 20%-40% of patients do not respond to rituximab, which may be associated with high anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody levels and residual tissue B cells\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Therefore, more optimized monoclonal antibody treatment regimens for MN are required.\u003c/p\u003e \u003cp\u003eObinutuzumab is a humanized type II anti-CD20 monoclonal antibody that enhances antibody-dependent cellular cytotoxicity (ADCC) and direct apoptosis through glycoengineering, achieving more thorough B-cell depletion\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. This enhanced efficacy is attributed to the absence of a fucose residue on the oligosaccharides in the Fc region of immunoglobulin G (IgG), which significantly increases its affinity for FcγRIIIa receptors on immune effector cells\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. Additionally, the CD20 binding epitopes of obinutuzumab and rituximab differ. These distinctions result in variations in CD20 complex formation and membrane compartmentalization. Such structural differences underlie the divergent cellular responses induced by type I (rituximab) and type II (obinutuzumab) monoclonal antibodies\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Obinutuzumab demonstrates superior efficacy compared to rituximab in chronic lymphocytic leukemia (CLL) and follicular lymphoma (FL). These differences may be attributed to its enhanced B-cell depletion capacity, particularly in prolonging progression-free survival (PFS) and achieving higher rates of minimal residual disease (MRD) negativity, thereby positioning it as a crucial therapeutic option for B-cell malignancies\u003csup\u003e\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Obinutuzumab shows promising potential as an alternative to rituximab.\u003c/p\u003e \u003cp\u003eA growing number of studies and case reports suggest obinutuzumab may serve as a more effective therapeutic option than rituximab. However, research on the efficacy and safety of obinutuzumab in treating MN remains limited. Hence, this study conducted a retrospective analysis of 34 MN patients across three centers to evaluate the efficacy and safety of obinutuzumab as first- or second-line therapy.\u003c/p\u003e"},{"header":"2. METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study Design and Patients\u003c/h2\u003e \u003cp\u003eThis is a multicenter retrospective case series study. MN patients from the First Affiliated Hospital of Zhejiang University School of Medicine, Huzhou First People\u0026rsquo;s Hospital, and Anji County People\u0026rsquo;s Hospital were screened. A total of 34 patients with PMN were enrolled. Among them, 31 patients were diagnosed with MN by renal biopsy, while the remaining 3 patients presented with nephrotic syndrome and serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody titers exceeding 100 RU/mL, leading to a clinical diagnosis of PLA\u003csub\u003e2\u003c/sub\u003eR-associated MN. All patients received obinutuzumab treatment. The exclusion criteria were: (1) presence of viral (active hepatitis B) or bacterial infections; (2) diagnosis of any autoimmune diseases; (3) any form of malignancies. All patients underwent pre-study assessments before obinutuzumab administration, and follow-up was conducted via electronic medical records and telephone interviews.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Treatment\u003c/h2\u003e \u003cp\u003eThe patients initially received a full dose of 1 g of obinutuzumab. Two weeks after the first dose, peripheral blood lymphocyte counts were analyzed, particularly CD19\u003csup\u003e+\u003c/sup\u003e B cells. If B-cell depletion (BCD, defined as 0 CD19\u003csup\u003e+\u003c/sup\u003e B cells/\u0026micro;L) was achieved, the first round of obinutuzumab treatment was concluded. If BCD was not achieved, an additional 1 g dose was administered until BCD was reached. Patients who did not achieve remission within 12 months were not further administered obinutuzumab. Prior to each infusion, patients received oral chlorpheniramine (10 mg) and acetaminophen (500 mg) or similar medications as prophylaxis for allergic reactions. In accordance with the 2021 KDIGO Guidelines, all patients without contraindications received optimal supportive care, including dietary sodium restriction, blood pressure control, and dyslipidemia management.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Outcomes\u003c/h2\u003e \u003cp\u003eComplete remission (CR) was defined as urinary protein\u0026thinsp;\u0026lt;\u0026thinsp;0.3 g/day or urinary protein-to-creatinine ratio (uPCR)\u0026thinsp;\u0026lt;\u0026thinsp;0.3 g/g without worsening renal function. Partial remission (PR) was defined as 0.3 g/24h\u0026thinsp;\u0026le;\u0026thinsp;urinary protein\u0026thinsp;\u0026lt;\u0026thinsp;3.5 g/24h with a\u0026thinsp;\u0026ge;\u0026thinsp;50% reduction from baseline, or 0.3 g/g\u0026thinsp;\u0026le;\u0026thinsp;uPCR\u0026thinsp;\u0026lt;\u0026thinsp;3.5 g/g with a\u0026thinsp;\u0026ge;\u0026thinsp;50% reduction from baseline. No response was defined as failure to achieve CR/PR after treatment. Relapse was defined as recurrence of urinary protein\u0026thinsp;\u0026ge;\u0026thinsp;3.5 g/24h or a return to \u0026lt;\u0026thinsp;50% reduction from baseline, uPCR\u0026thinsp;\u0026ge;\u0026thinsp;3.5 g/g, or uPCR returning to \u0026lt;\u0026thinsp;50% reduction from baseline. Time to first relapse-free survival was defined as the duration from the first remission to the first relapse after the initial obinutuzumab dose.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Clinical Data Collection\u003c/h2\u003e \u003cp\u003eDemographic data included gender, age at onset, and age at obinutuzumab treatment. Laboratory data included serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody levels, uPCR, serum albumin, and serum creatinine. During the follow-up, remission and relapse events, as well as medications administered before and after obinutuzumab therapy, were recorded as clinical data. For this study, the data were obtained through electronic medical record systems and serial telephone interviews.\u003c/p\u003e \u003cp\u003eSome patients were previously treated with rituximab at a dose of 375 mg/m\u0026sup2;. A treatment course was defined as patients receiving full-dose rituximab every 1\u0026ndash;2 weeks until BCD was achieved. Additional courses were administered if serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody titers increased significantly or peripheral CD19\u003csup\u003e+\u003c/sup\u003e B-cell counts rebounded. Serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody titers were measured via the indirect immunofluorescence assay (minimum detectable level: 2 RU/mL). Renal biopsy PLA\u003csub\u003e2\u003c/sub\u003eR staining was graded as + ~ +++. Serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody levels\u0026thinsp;\u0026lt;\u0026thinsp;5 RU/mL were defined as negative, while\u0026thinsp;\u0026ge;\u0026thinsp;5 RU/mL were defined as positive. Peripheral CD19\u003csup\u003e+\u003c/sup\u003e B-cell counts were analyzed via flow cytometry post-obinutuzumab treatment.\u003c/p\u003e \u003cp\u003e Off-label Obinutuzumab treatment and the protocol of retrospective outcome analyses were approved by the ethics committee of the First Affiliated Hospital of Zhejiang University School of Medicine (Approval No. 2020571), Huzhou First People\u0026rsquo;s Hospital (Approval No.2023KYLL039), and Anji County People\u0026rsquo;s Hospital (Approval No. H20240222-1). All participants provided written informed consent for Obinutuzumab infusion and retrospective analyses, in accordance with the declaration of Helsinki.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Statistical Analysis\u003c/h2\u003e \u003cp\u003eQuantitative data conforming to a normal distribution were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation and compared using Student\u0026rsquo;s t-test. Skewed data were expressed as median (interquartile range, IQR) and compared using the Mann-Whitney U test. Categorical data were presented as counts and percentages and compared using the chi-square test. In this study, a P value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. Cox proportional hazards models and log-rank tests were performed using R version 4.2.2 with the \"survival\", \"survminer\", and \"ggplot2\" packages. SPSS version 26.0 (IBM) was used for statistical analysis. All graphs were generated using GraphPad Prism 9, with data presented as medians except for Kaplan-Meier curves.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. RESULTS","content":"\u003ch2\u003e3.1 Patient Characteristics and Therapy\u003c/h2\u003e\n\u003cp\u003eThis retrospective study included 34 patients with primary MN from the First Affiliated Hospital of Zhejiang University School of Medicine, Huzhou First People’s Hospital and Anji County People’s Hospital, as shown in Fig. 1. A total of 31 patients underwent renal biopsy, confirming the diagnosis of MN. In addition, 3 patients showed high serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody titers (\u0026gt; 500 RU/mL in 2, 198.34 RU/mL in 1) in the presence of nephrotic syndrome, which provided a clinical diagnosis of MN. PLA\u003csub\u003e2\u003c/sub\u003eR staining was positive in 22 of 23 (95.7%) tested renal tissues. Based on serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody levels and renal PLA\u003csub\u003e2\u003c/sub\u003eR staining, 32 (88.9%) patients were assigned to the PLA\u003csub\u003e2\u003c/sub\u003eR-associated subgroup, while 2 patients were assigned to the non-PLA\u003csub\u003e2\u003c/sub\u003eR-associated subgroup (serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR \u0026lt; 2 RU/mL, negative histology).\u003c/p\u003e\n\u003cp\u003eRegarding prior immunosuppressive therapy (IST), 21 (61.8%) patients had received at least one IST and were classified as the second-line treatment subgroup. In contrast, the remaining 13 (38.2%) patients receiving obinutuzumab as initial therapy were classified as the initial treatment subgroup. IST included glucocorticoids, calcineurin inhibitors, rituximab, cyclophosphamide, triptolide, and mycophenolate mofetil. Of the 21 patients receiving obinutuzumab as second-line therapy, 15 patients were classified as refractory to prior immunosuppression, while 6 patients had relapsing disease. To minimize confounding effects from prior IST and reduce over-immunosuppression risks such as infections, the second-line treatment subgroup patients discontinued prednisone or mycophenolate mofetil at least 1 month before initiating obinutuzumab and alkylating agents at least 6 months before.\u003c/p\u003e\n\u003cp\u003eIn terms of prior rituximab use, 15 (44.1%) patients had received rituximab, with a median dose of 1.8 (1.44–2.59) g. Among them, 2 patients switched to obinutuzumab due to infusion reactions, while 13 patients switched due to unsatisfactory or unsustained responses. Detailed demographics and clinical features are shown in Table 1.\u003c/p\u003e\n\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003eTable 1\u0026nbsp;\u003cp\u003eBaseline demographic and clinical characteristics of the 34 patients with PMN\u003c/p\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth colname=\"c1\"\u003e\n \u003cp\u003eDemographics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth colname=\"c2\"\u003e\n \u003cp\u003eOverall Cohort (N = 34)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth colname=\"c3\"\u003e\n \u003cp\u003eInitial Treatment (N = 13)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth colname=\"c4\"\u003e\n \u003cp\u003eSecond-line Treatment(N = 21)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eEthnicity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003eAll Han Chinese\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eAge (y) at obinutuzumab, median(IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e50.77(43.16–52.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e53.09(42.23–56.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e51.75(44.45–53.17)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eDisease history\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eAge (y) at disease onset, mean ± SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e49.08 ± 10.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e47.6 ± 12.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e47.91 ± 10.69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eDuration of disease,mo,median(IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e13.63(12.81–20.80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e11.9(8.28–16.47)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e13.67(13.07–16.97)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eTime since last immunosuppressivetherapy,mo, median(IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e4.47(2.23–5.87)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003enon-nephrotic syndrome,n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e8(23.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e2(15.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e6(28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eLaboratory values before obinutuzumab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eUrine protein creatinine ratio,g/g,median(IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e3.75(3.34–7.17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e6.71(2.83–8.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e3.69(1.86–6.74)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eSerum albumin,g/L,mean ± SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e27.21 ± 7.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e25.12 ± 5.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e28.7 ± 7.93\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eSerum creatinine,µmol/L,mean ± SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e88.66 ± 32.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e81.19 ± 23.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e94 ± 37.83\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eSerum anti-PLA2R antibody titer at the commencement of obinutuzumab,RU/mL,median(IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e10.32(17.19-113.82)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e27.09(2-67.01)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e9.08(1.98–19.13)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eSerum anti-PLA2R antibody titer(\u0026gt; 150RU/mL),n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e8(23.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e5(38.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e3(14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eKidney bioposy(stage)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e3(8.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e2(15.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e1(4.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eII\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e23(67.67%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e10(77%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e13(61.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eIII\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e5(14.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e1(7.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e4(19%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003ePrevious therapy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eRituximab,n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e15(41.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e15(71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eCyclophosphamide,n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e12(33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e12(57.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eMycophenolate,n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e3(8.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e3(14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eCNI(tacrolimus or cyclosporine),n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e13(36.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e13(61.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colname=\"c1\"\u003e\n \u003cp\u003eACEI/ARB,n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c2\"\u003e\n \u003cp\u003e20(55.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c3\"\u003e\n \u003cp\u003e5(38.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colname=\"c4\"\u003e\n \u003cp\u003e15(71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003eAbbreviation:ARB,angiotensin II receptor blocker;ACEI,angiotensin-converting Enzyme Inhibitor;CNI,calcineurin inhibitor;IQR,interquartile range;SD,standard deviation, non-nephrotic syndrome,proteinuria \u0026lt; 3.5g/day and/or serum albumin \u0026gt; 30g/L.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003ch2\u003e3.2 Primary Outcome\u003c/h2\u003e\n\u003cp\u003eOver a median follow-up of 13.63 (12.81–20.80) months, the median obinutuzumab dose was 2 (1.76–2.24) g. Among the 34 patients, 6 patients received 1 dose, 21 patients received 2 doses, 6 patients received 3 doses, and 1 patient received 4 doses. By the end of follow-up, 21 (61.8%) patients achieved PR, and 11 (32.4%) patients achieved CR. However, 2 patients failed to achieve remission during follow-up. Moreover, 1 patient showed a decline in serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody levels from 572 RU/mL to 152 RU/mL at 3 months, but treatment regimen modification precluded further assessment of potential obinutuzumab response. The other patient who failed to achieve remission during follow-up maintained uPCR \u0026lt; 3.5 g/g without achieving a 50% reduction from baseline. Remission rates were 47.1% (16/34) at 6 months and 79.4% (27/34) at 12 months.\u003c/p\u003e\n\u003cp\u003eAmong the 13 patients who received obinutuzumab as first-line therapy, 11 (84.6%) patients achieved remission. Among these, 6 (46.2%) patients achieved PR, and 5 (38.5%) patients achieved CR. In the 21 second-line treatment patients, all achieved remission. Among these, 15 (71.4%) patients achieved PR, and 6 (28.6%) patients achieved CR. The primary outcomes comparing subgroups with and without prior immunosuppressive therapy are presented in Table 2.\u003c/p\u003e\n\u003cp\u003eAmong the 15 patients previously treated with rituximab, all achieved clinical remission. Among these, 10 (66.7%) patients achieved PR, and 5 (33.3%) patients achieved CR. A total of 19 patients had no history of previous rituximab use, with 17 (89.5%) patients achieving remission. Among these, 11 (57.9%) patients achieved PR, and 6 (31.6%) patients achieved CR. Outcomes in terms of prior rituximab use are detailed in Table 3.\u003c/p\u003e\n\u003cp\u003eTable S1 displays the outcomes between the PLA\u003csub\u003e2\u003c/sub\u003eR-associated treatment subgroup and the non-PLA2R-associated treatment subgroup. Among the 32 patients who achieved remission during the follow-up period, the median time to first remission (PR or CR) was 6.63 (5.28–8.73) months. A total of 11 patients achieved CR, with a median time to CR of 6.70 (4.42–9.53) months. Only 1 patient experienced relapse 9 months after achieving PR, who achieved PR again after an additional dose of obinutuzumab; the other patients remained in remission by the end of follow-up. Over a median follow-up of 13.63 (12.81–20.80) months, the mean relapse-free survival time was 5.88 ± 4.53 months. The primary outcomes are detailed in Table 4.\u003c/p\u003e\n\u003ch2\u003e3.3 Secondary Outcome: uPCR, Serum Albumin, and Creatinine\u003c/h2\u003e\n\u003cp\u003eAt 6 and 12 months after the initial dose of obinutuzumab, the uPCR decreased from a median baseline of 5.43 (3.74–6.49) g/g to 1.2 (0.89–2.82) g/g and 0.53 (0.35–1.81) g/g, respectively. Serum albumin increased from a median baseline of 25.5 (23-33.2) g/L to 40.6 (37.9–41.9) g/L and 43.9 (41.7–46.2) g/L, respectively.\u003c/p\u003e\n\u003cp\u003eThe reductions in uPCR at both 6 and 12 months post-initial dose were statistically significant compared to baseline (\u003cem\u003ep\u003c/em\u003e = 0.0024 and \u003cem\u003ep\u003c/em\u003e = 0.0009, respectively). Similarly, the increases in serum albumin at both time points were statistically significant (both \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). Throughout the follow-up period, serum creatinine levels remained stable in all patients, indicating preserved renal function following obinutuzumab treatment. The Kaplan-Meier curve and detailed trend changes in patients are shown in Fig. 2.\u003c/p\u003e\n\u003cp\u003eNo significant difference in remission rates was observed between the initial treatment group and the second-line treatment group during the follow-up period (\u003cem\u003ep\u003c/em\u003e = 0.8). However, the first-line treatment group exhibited a trend of higher remission rates within 12 months of follow-up compared to the second-line treatment group. As the follow-up duration increased, the remission rates between the two groups converged. Additionally, no significant differences in uPCR, serum albumin, and serum creatinine levels were observed between the two groups. The detailed results are displayed in Fig. 3.\u003c/p\u003e\n\u003cp\u003eNo significant difference in remission rates was observed between the previous rituximab treatment group and the group without previous rituximab treatment during the follow-up period (\u003cem\u003ep\u003c/em\u003e = 0.8). However, a trend was observed indicating that patients who had not received rituximab exhibited higher remission rates within 12 months of follow-up compared to those with prior rituximab exposure. Additionally, no significant differences in uPCR, serum albumin, and serum creatinine levels were found between the two groups. The detailed results are shown in Fig. 4.\u003c/p\u003e\n\u003cp\u003eNo significant difference in remission rates was observed between the PLA\u003csub\u003e2\u003c/sub\u003eR-associated group and non-PLA\u003csub\u003e2\u003c/sub\u003eR-associated group during the follow-up period (\u003cem\u003ep\u003c/em\u003e = 0.6). Additionally, no significant differences in uPCR, serum albumin, and serum creatinine levels were found between the two groups. Detailed results are displayed in Figure S1.\u003c/p\u003e\n\u003ch2\u003e3.4 Serum Anti-PLA2R Antibodies\u003c/h2\u003e\n\u003cp\u003eBased on serum PLA\u003csub\u003e2\u003c/sub\u003eR antibody titers and renal tissue PLA\u003csub\u003e2\u003c/sub\u003eR staining, 32 patients were diagnosed with PLA\u003csub\u003e2\u003c/sub\u003eR-associated membranous nephropathy. Among them, only 18 had serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody levels \u0026gt; 5 RU/mL at the initiation of obinutuzumab therapy. Of these 18 patients, 11 had previously received immunosuppressive treatment. The changes in serum anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody levels are presented in Table S2.\u003c/p\u003e\n\u003ch2\u003e3.5 Lymphocyte Subsets\u003c/h2\u003e\n\u003cp\u003eFollowing obinutuzumab treatment, significant alterations in lymphocyte subsets were observed. Notably, both CD19\u003csup\u003e+\u003c/sup\u003e B-cell counts (108 [71.42–177.58] vs. 0.0 [-0.04–0.39]; p \u0026lt; 0.001) and total B-lymphocyte counts (2390.89 ± 845.50 vs. 1385.61 ± 575.12; p \u0026lt; 0.001) were markedly reduced. In contrast, no significant differences were observed in total T-lymphocyte counts, CD4\u003csup\u003e+\u003c/sup\u003e or CD8\u003csup\u003e+\u003c/sup\u003e T-cell counts, the CD4\u003csup\u003e+\u003c/sup\u003e/CD8\u003csup\u003e+\u003c/sup\u003e ratio, or NK-cell counts (all p \u0026gt; 0.05). Detailed data are presented in Table 5.\u003c/p\u003e\n\u003ch2\u003e3.6 Combination Therapy\u003c/h2\u003e\n\u003cp\u003eFollowing obinutuzumab treatment, 30 (88.2%) patients successfully discontinued all immunosuppressive medications during follow-up. One patient continued tacrolimus for 8 months with gradual tapering, achieving complete withdrawal after retreatment with obinutuzumab. Another patient with suboptimal response to obinutuzumab received cyclophosphamide and prednisone but failed to achieve remission by the end of follow-up. Moreover, one patient developed fever after the first obinutuzumab infusion and was switched to tacrolimus maintenance until follow-up completion. Another patient contracted COVID-19 four months after the final obinutuzumab dose and was managed with methylprednisolone (tapered to discontinuation).\u003c/p\u003e\n\u003ch2\u003e3.7 Safety\u003c/h2\u003e\n\u003cp\u003eDuring the follow-up period, no severe treatment-related adverse events were observed either during or after obinutuzumab therapy. Adverse events occurred in 9(25%) patients, including pulmonary infections (n = 3), pruritus (n = 2), low-grade fever (n = 1), chills with high fever (n = 1), and nausea and vomiting with high fever (n = 1). Refer to Table 6 for details. 2 patients developed coronavirus-induced viral pneumonia 4 months after completing the final dose of obinutuzumab treatment, and 1 patient developed coronavirus-induced viral pneumonia 8 months after receiving the subsequent dose of obinutuzumab. All 3 patients were hospitalized and successfully treated. In addition, 2 patients developed pruritus during initial obinutuzumab infusions, with recurrence during subsequent administrations. Neither patient presented with an associated rash. Furthermore, 1 patient developed fever during initial obinutuzumab infusion. Notably, this patient had previously discontinued rituximab therapy due to similar febrile reactions. Based on safety considerations, the treatment regimen was switched to tacrolimus. Moreover, 1 patient developed chills and fever (peak temperature 38.8℃) during the first obinutuzumab infusion, which resolved after intravenous administration of 5mg dexamethasone. The final infusion was completed without recurrence of similar symptoms. Notably, 2 patients experienced nausea, vomiting, and fever during their first obinutuzumab infusion. Symptoms improved with symptomatic treatment, and neither patient experienced recurrence during subsequent infusions, including the final dose. No anaphylactic shock, sepsis, malignancy, or mortality was observed in any patient.\u003c/p\u003e"},{"header":"4. DISCUSSION","content":"\u003cp\u003eAs a multicenter retrospective study, this research investigated the efficacy of obinutuzumab as a second-line therapy for refractory MN (resistant to glucocorticoids\u0026thinsp;+\u0026thinsp;cyclophosphamide and/or calcineurin inhibitors, and/or rituximab). Additionally, these patients were compared with those receiving obinuzumab as first-line therapy for primary MN. In our study, 94.1% (32 of 34) of MN patients achieved either partial or complete remission after obinutuzumab treatment. This suggests that obinutuzumab demonstrates favorable efficacy in the treatment of MN.\u003c/p\u003e \u003cp\u003eIn the present study, the composite remission rate (including both PR and CR) in the initial treatment group was 84.6% (11 of 13). This finding aligns closely with an earlier case series of 12 primary MN patients treated with obinutuzumab as first-line therapy, which reported a comparable composite remission rate of 83.3%\u003csup\u003e16\u003c/sup\u003e. A more recent and larger study by Sun et al. further supports this, reporting a 12-month remission rate of 87.2% in initial treatment patients receiving obinutuzumab\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. The consistency across these studies, including ours, strongly reinforces the high efficacy and reliability of obinutuzumab as an initial treatment regimen for MN.\u003c/p\u003e \u003cp\u003eMany case reports have demonstrated the favorable efficacy of obinutuzumab in refractory membranous nephropathy. Sethi et al. reported that 85.7% of 11 refractory patients (7 of whom had prior rituximab therapy and 7 had received glucocorticoids plus either tacrolimus or cyclophosphamide) achieved remission after two doses of obinutuzumab\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Furthermore, a recent international multicenter study by Teisseyre et al. specifically investigated patients with anti-rituximab antibodies, a known mechanism of resistance. Their findings strongly support the use of alternative anti-CD20 therapies, demonstrating that obinutuzumab and ofatumumab were significantly more effective than rituximab in inducing clinical remission at both 6 months and 12 months in this challenging patient population\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. In our study, 100% of patients (21/21) in the second-line treatment group achieved remission following obinutuzumab therapy. Notably, 3 patients (14.2%) had previously received triple immunosuppressive therapy (cyclophosphamide plus glucocorticoids, calcineurin inhibitors, and rituximab), while 12 patients (57.1%) had been treated with two immunosuppressants. Another study demonstrated that 82.1% of 39 patients with prior immunosuppressive treatment achieved remission after obinutuzumab therapy\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. In the present study, the second-line treatment group demonstrated composite remission rates of 42.9% (9/21) at 6 months and 81% (17/21) at 12 months post-obinutuzumab. These results were significantly superior to the 35.5% (6-month) and 37% (12-month) remission rates observed with rituximab in refractory MN patients reported by Xu et al\u003csup\u003e9\u003c/sup\u003e. The superior B-cell depletion observed with obinutuzumab in our study (100% of patients), consistent with the findings of Teisseyre et al, likely underpins its enhanced clinical efficacy, particularly in neutralizing the negative impact of anti-rituximab antibodies\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. In our study, 85.7% (12/14) of patients with detectable serum PLA\u003csub\u003e2\u003c/sub\u003eR antibodies achieved immunological remission. Stratified by treatment line, the immunological remission rates were 60% (3/5) in the initial therapy group and 88.9% (8/9) in the second-line therapy group. These findings suggest that obinutuzumab holds significant therapeutic potential for managing complex, refractory MN.\u003c/p\u003e \u003cp\u003eIn our study, the median time to remission was 5.55 months in the first-line treatment group compared to 7.76 months in the second-line group. These results imply that obinutuzumab induces remission more rapidly when used as initial therapy for MN compared to salvage treatment.\u003c/p\u003e \u003cp\u003eIn the second-line treatment group, 71.4% (15/21) of patients had previously received but responded inadequately to rituximab therapy. Among these rituximab-refractory patients, the composite remission rates were 33.3% (5/15) at 6 months and 93.3% (14/15) at 12 months following obinutuzumab treatment.\u003c/p\u003e \u003cp\u003eWhen compared to the landmark MENTOR trial's 24-month follow-up of 65 MN patients receiving rituximab, the 6-month and 12-month composite remission rates were 35% and 60%, respectively\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. Notably, in our study, rituximab-refractory patients achieved significantly higher 12-month remission rates (93.3%) compared to the rituximab-treated cohort in MENTOR. These preliminary findings suggest that obinutuzumab not only serves as an effective salvage therapy but may also offer a more potent initial B-cell depletion strategy, warranting future head-to-head comparisons with rituximab. Obinutuzumab is a humanized type II anti-CD20 monoclonal antibody that binds to a distinct CD20 epitope with higher affinity for FCγRIII compared to type I anti-CD20 antibodies like rituximab\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Multiple studies have demonstrated that obinutuzumab exhibits significantly enhanced antibody-dependent cellular cytotoxicity (ADCC) and direct cell death induction compared to rituximab. An in vitro study investigating lymphokine-activated killer (LAK) cells combined with rituximab or obinutuzumab in follicular lymphoma (FL) demonstrated that both anti-CD20 antibodies enhanced ADCC activity against CRL-1596 (CD20+) cells, with obinutuzumab showing superior potency (42% vs. 32% ADCC enhancement, respectively)\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Ofatumumab is another CD20-targeted therapy. A case series of 17 male MN patients with stage 1\u0026ndash;3 chronic kidney disease (CKD) reported that 7 of 10 rituximab-resistant patients (70%) and 3 of 7 rituximab-intolerant patients (42.9%) achieved composite remission\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. However, clinical evidence supporting ofatumumab for MN remains limited, necessitating further studies to validate its therapeutic potential. Furthermore, obinutuzumab treatment significantly improved serum albumin levels while maintaining stable renal function. In the present study, obinutuzumab demonstrated a favorable safety profile, with no reported severe adverse events. Notably, obinutuzumab demonstrated excellent tolerability in patients who had previously experienced severe infusion reactions to rituximab. This improved safety profile likely reflects its humanized structure, which reduces immunogenicity and subsequent immune-mediated reactions. Large-scale clinical trials are currently being conducted to further evaluate the efficacy and safety of obinutuzumab in MN (NCT04629248, NCT05050214), with preliminary results anticipated by mid-2025.\u003c/p\u003e \u003cp\u003eOur study has several strengths and limitations. The primary strength lies in its evaluation of obinutuzumab as initial therapy\u0026mdash;a rare approach in current literature. Although this represents one of the largest available cohorts comparing refractory MN patients (n\u0026thinsp;=\u0026thinsp;21) to obinutuzumab-na\u0026iuml;ve cases (n\u0026thinsp;=\u0026thinsp;13), it still remains relatively modest from the perspective of an ideal study cohort. The multicenter design across three cities further reduces single-center bias. Limitations include inherent retrospective data constraints, including its retrospective nature and the lack of a control group for direct comparative efficacy analysis. Furthermore, the median follow-up duration of approximately 14 months is insufficient to evaluate long-term outcomes such as sustained remission, relapse rates over time, and long-term renal survival. Immunoglobulin monitoring was omitted due to insurance restrictions, while incomplete B-cell/anti-PLA\u003csub\u003e2\u003c/sub\u003eR antibody data were due to patient reluctance over testing costs. The high response rates observed may be partially influenced by the disease characteristics of our cohort. The median anti-PLA2R antibody titer at baseline was relatively low, and a portion of patients did not present with full nephrotic syndrome, suggesting a population with potentially lower overall disease activity. This may limit the generalizability of our efficacy results to all MN patients, particularly those with highly active, severe disease.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was approved by the Ethics Committees of the First Affiliated Hospital of Zhejiang University School of Medicine (Approval No. 2020571), Huzhou First People\u0026rsquo;s Hospital (Approval No. 2022KYLL047), and Anji County People\u0026rsquo;s Hospital (Approval No. H20240222-1), and written informed consent was obtained from all participants prior to sample collection, in accordance with the declaration of Helsinki.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author, Huayan Zhu, upon reasonable request. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor\u0026apos;s Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRW conceived the study and drafted the manuscript. JZ, ZZ and YL performed data collection. FH, HL and ZS performed statistical analysis. QZ and JZ performed data curation and visualization. XW and DF acquired funding and administered the project. HZ supervised research and finalized the manuscript.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFunding Declaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by National Science and Technology Major Project (2023ZD0509802), Huzhou Municipal Science and Technology Bureau Project (2022GYB33).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSethi S, Fervenza FC. Membranous nephropathy-diagnosis and identification of target antigens. 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Kidney Int Rep 2025(3):753\u0026ndash;61.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFervenza FC, Appel GB, Barbour SJ et al. Rituximab or Cyclosporine in the Treatment of Membranous Nephropathy. N Engl J Med 2019;381(1).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFischer K, Al-Sawaf O, Bahlo J et al. Venetoclax and Obinutuzumab in Patients with CLL and Coexisting Conditions. N Engl J Med 2019;380(23).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGarc\u0026iacute;a-Mu\u0026ntilde;oz R, L\u0026oacute;pez-D\u0026iacute;az-de-Cerio A, Feliu J et al. Follicular lymphoma: in vitro effects of combining lymphokine-activated killer (LAK) cell-induced cytotoxicity and rituximab- and obinutuzumab-dependent cellular cytotoxicity (ADCC) activity. Immunol Res 2015;64(2).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAllinovi M, Teisseyre M, Accinno M et al. Anti-Rituximab Antibodies Occurrence and Clinical Outcomes in Patients With Primary Membranous Nephropathy. Kidney Int Rep 2025;10(8).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Table 2 To 6","content":"\u003cp\u003eTable 2 and 6 are available in the Supplementary Files section.\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bnep","sideBox":"Learn more about [BMC Nephrology](http://bmcnephrol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bnep/default.aspx","title":"BMC Nephrology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"membranous nephropathy, Obinutuzumab, anti-CD20 monoclonal antibody, anti-phospholipase A2 receptor antibody, chronic kidney disease","lastPublishedDoi":"10.21203/rs.3.rs-9344081/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9344081/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMembranous nephropathy (MN) is an autoimmune kidney disease involving B lymphocytes. Obinutuzumab is a type II, humanized anti-CD20 monoclonal antibody. Compared to rituximab, obinutuzumab has shown superior efficacy in leukemia and lymphoma. This study evaluates obinutuzumab as first or second-line treatment in MN patients. This study aims to evaluate the therapeutic effects and safety of obinutuzumab as either first-line or second-line treatment in patients with MN. Data from 34 primary MN patients (13 first-line, 21 second-line) treated with obinutuzumab and followed for \u0026ge;\u0026thinsp;12 months were analyzed. Among the 21 second-line patients, the majority (71.4%) were refractory to prior therapy. Primary outcomes were complete remission (CR), partial remission (PR), and no response. CR was defined as urinary protein\u0026thinsp;\u0026lt;\u0026thinsp;0.3 g/day or urinary protein-to-creatinine ratio (uPCR)\u0026thinsp;\u0026lt;\u0026thinsp;0.3 g/g without renal function worsening. PR was defined as urinary protein 0.3\u0026ndash;3.5 g/24h (\u0026ge;\u0026thinsp;50% baseline reduction) or uPCR 0.3\u0026ndash;3.5 g/g (\u0026ge;\u0026thinsp;50% baseline reduction). No response meant failure to achieve CR/PR post-treatment. Over a median follow-up of 13.63 months, 94.1% achieved remission. The remission rates were 47.1% at 6 months and 79.4% at 12 months. Median uPCR decreased from 5.43 g/g to 0.53 g/g at 12 months, and serum albumin significantly improved. Renal function remained stable. All patients achieved B-cell depletion. Adverse events were mild and infrequent (25%), with no severe infusion-related reactions or deaths. Obinutuzumab represents a promising and well-tolerated therapeutic option for individuals with primary MN. The findings highlight the potential of obinutuzumab as a second-line therapy for refractory MN.\u003c/p\u003e","manuscriptTitle":"Obinutuzumab as Initial or Second-Line Treatment for Primary Membranous Nephropathy: A Multicenter Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-27 14:27:26","doi":"10.21203/rs.3.rs-9344081/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"279275782380827058438951514407577718312","date":"2026-05-05T21:54:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-26T12:55:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"157851253043884201985016413304295798699","date":"2026-04-22T03:11:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"298988134491396249951030561140414886183","date":"2026-04-20T06:56:12+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-19T22:04:01+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-04-13T05:55:40+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-10T13:46:34+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-10T13:45:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Nephrology","date":"2026-04-07T11:04:24+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bnep","sideBox":"Learn more about [BMC Nephrology](http://bmcnephrol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bnep/default.aspx","title":"BMC Nephrology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f6830265-919d-4893-86fc-cb01dee3fec0","owner":[],"postedDate":"April 27th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"279275782380827058438951514407577718312","date":"2026-05-05T21:54:36+00:00","index":32,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-27T14:27:27+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-27 14:27:26","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9344081","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9344081","identity":"rs-9344081","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}