Rituximab for Severe Membranous Nephropathy: A 6-Month Trial with Extended Follow-Up

Updated diagnostic and therapeutic management for membranous nephropathy

PURPOSE OF REVIEW

Pioneering contributions in membranous nephropathy over the last decade have greatly enhanced our comprehension of its pathogenesis, diagnosis, and treatments, igniting renewed interest in this entity. This review provides an updated perspective on the diagnosis and therapeutic management of membranous nephropathy.

RECENT FINDINGS

The identification of antiphospholipase A2 receptor (PLA2R) antibodies in 50-80% of membranous nephropathy patients was a key breakthrough. High or increasing PLA2R antibody levels are linked to persistent nephrotic syndrome and the need for targeted treatment. Given the high specificity of PLA2R antibodies, a kidney biopsy may not be required for pure nephrotic syndrome cases with no comorbidities. Over the years, various target antigens and associated conditions have been identified in membranous nephropathy patients, leading to a reclassification of membranous nephropathy. Treatment approaches vary based on baseline characteristics and changes in proteinuria and PLA2R titers. Rituximab has emerged as the first-line therapy for most patients without severe risk factors, with other emerging therapies under development.

SUMMARY

Advances in the diagnosis and treatment of membranous nephropathy have moved the management towards a more precision-based approach, though further studies and new therapies are needed for a comprehensive management strategy.

A novel approach to induce early remission in high-risk primary membranous nephropathy

BACKGROUND

This prospective single-arm trial with historic controls evaluated the efficacy and safety of treatment based on a combination of rituximab, intravenous cyclophosphamide and corticosteroids (RCP) administered at lower cumulative doses for the induction of early remission in primary membranous nephropathy (PMN).

METHODS

We prospectively enrolled 30 high-risk PMN patients with persistent nephrotic syndrome (NS) and elevated antibodies to the phospholipase A2 receptor who underwent RCP therapy. We compared the effectiveness of RCP with that of historic controls who received rituximab-based therapy (RTX, n = 15) or cyclosporine + corticosteroids (CSA, n = 42). The primary outcomes were complete remission (CR) and overall remission (OR) by Month 12 and the time to remission.

RESULTS

In the RCP group, the OR and CR rates by 12 months (97% and 60%) were higher than those in the RTX group (60% and 7%, P ≤ .009) and the CSA group (50% and 24%, P ≤ .003). The median time to OR [2.8 (1.6-3.9) months] was shorter compared with RTX [7.1 (3.4-17.5) months, P = .008] and CSA [7.3 (6.0-13.6) months, P < .001]. In adjusted Cox regression, hazard ratios for OR and CR attainment for RCP versus other treatments were 5.2 (95% CI 2.8-9.6) and 4.8 (95% CI 2.2-10.3), respectively. Propensity score-matched group analyses confirmed these results. One serious adverse event occurred in the RCP group in the follow-up of 56 patient-years.

CONCLUSIONS

RCP therapy is considered effective and safe for inducing early remission in high-risk PMN patients.

Comparison of Obinutuzumab and Rituximab for Treating Primary Membranous Nephropathy

Key Points

Obinutuzumab induced more remission than rituximab at 12 months in patients with primary membranous nephropathy. Obinutuzumab shared a similar safety profile as rituximab in patients with primary membranous nephropathy.

Background

This study compared the effectiveness and safety profiles of obinutuzumab and rituximab in the treatment of patients with primary membranous nephropathy (MN).

Methods

Patients with primary MN who had urine protein ≥3.5 g/24 hours and eGFR ≥30 ml/min per 1.73 m2 despite 6 months of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker and treatment with obinutuzumab or rituximab were included and matched by propensity score (ratio: 1:2) on the basis of age, sex, urine protein, eGFR, and titers of Anti-Phospholipase A2 receptor (PLA2R) antibody. The primary outcome was defined as a combination of partial or complete remission at 12 months. Logistic regression models, Kaplan–Meier curves, and absolute risk differences were used to compare the therapeutic effectiveness and safety profiles of obinutuzumab and rituximab.

Results

Sixty-three patients with primary MN were included in the study, with 21 patients receiving obinutuzumab and 42 patients receiving rituximab. At 12 months, the primary outcome was achieved in 20 of 21 patients in the obinutuzumab group and 28 of 42 patients in the rituximab group (obinutuzumab versus rituximab: 95% versus 67%; odds ratio, 10.00; 95% confidence intervals, 1.21 to 82.35; P = 0.03). Moreover, patients in the obinutuzumab group acquired more complete remission (obinutuzumab versus rituximab: 38% versus 14%; odds ratio, 3.69; 95% confidence interval, 1.08 to 12.68; P = 0.04). In PLA2R-associated primary MN subgroup analyses, patients in the obinutuzumab group sustained lower CD19 B-cell counts (CD19 B-cell counts: median [interquartile range] 0 [0–6] cells/μ l versus 20 [3–58] cells/μ l, P = 0.002) and were more prone to achieve immunological remission (defined as PLA2R antibody <2 RU/ml) at 6 months (obinutuzumab versus rituximab: 92% [12 out of 13] versus 64% [16 out of 25], P = 0.06) than rituximab. Both treatment regimens were well tolerated.

Conclusions

Our study demonstrated that obinutuzumab is associated with higher odds of clinical remission compared with rituximab at 12 months, which may be due to higher immunological remission at 6 months with a similar safety profile in patients with primary MN.

A multicenter retrospective study on comparing the efficacy and safety of the therapy of intermittent cyclophosphamide and corticosteroids versus rituximab for primary membranous nephropathy

BACKGROUND

Few clinical studies compare the long-term remission, relapse, and safety of rituximab (RTX) or a combination of intermittent intravenous infusion of cyclophosphamide (CTX) and oral corticosteroid for primary membranous nephropathy (PMN) patients.

METHODS

We collected multicenter retrospective data on PMN patients with nephrotic syndrome who received RTX or intermittent intravenous CTX with oral corticosteroids between 1 January 2019 and 31 January 2024. Patients were followed up until two years after receiving immunotherapy. The primary outcomes were a composite of complete or partial remission rates at 6, 12, and 24 months. The secondary outcomes were the relapse and safety evaluation.

RESULTS

Forty patients treated with RTX and 27 with the CTX regime were available for analysis. No significant difference in the remission rate at 6, 12, or 24 months was observed between the two groups (p > .05). Kaplan-Meier's survival analysis showed that the relapse-free cumulative survival rate of the RTX group was superior to that of the CTX group (p = .023). Compared with baseline, both the media of urine protein and serum albumin levels in the two groups showed a significant improvement at 6 months and maintained through to the second year. No significant difference in the occurrence of total side effects between the two groups (p = .160).

CONCLUSIONS

There was no difference in remission rates and safety between RTX versus intermittent intravenous CTX combined with oral corticosteroid treatment for patients with PMN within 2 years. RTX appeared to have benefits in terms of prolonging relapse-free survival.

Efficacy and safety of Mahuang Fuzi and Shenzhuo Decoction for treatment of primary membranous nephropathy: a multicenter prospective trial

BACKGROUND

This study aims to undertake a comprehensive assessment of the effectiveness and safety profile of Mahuang Fuzi and Shenzhuo Decoction (MFSD) in the management of primary membranous nephropathy (PMN), within the context of a prospective clinical investigation.

METHODS

A multicenter, open-label clinical trial was executed on patients diagnosed with PMN. These individuals were subjected to MFSD therapy for a duration of at least 24 months, with primary outcome of clinical remission rates. The Cox regression analysis was employed to discern the pertinent risk factors exerting influence on the efficacy of MFSD treatment, with scrupulous monitoring of any adverse events.

RESULTS

The study comprised 198 participants in total. Following 24 months of treatment, the remission rate was 58.6% (116/198). Among the subgroup of 130 participants subjected to a 36-month follow-up, the remission rate reached 70% (91/130). Subgroup analysis revealed that neither a history of immunosuppressive therapy (HIST) nor an age threshold of ≥60 years exhibited a statistically significant impact on the remission rate at the 24-month mark (p > .05). Multivariate Cox regression analyses elucidated HIST, nephrotic syndrome, or mass proteinuria, and a high-risk classification as noteworthy risk factors in the context of MFSD treatment. Remarkably, no fatalities resulting from side effects were documented throughout the study's duration.

CONCLUSIONS

This trial establishes the efficacy of MFSD as a treatment modality for membranous nephropathy. MFSD demonstrates a favorable side effect profile, and remission rates are consistent across patients, irrespective of HIST and age categories.

Efficacy and safety of glucocorticoid combined with cyclophosphamide therapy on membranous nephropathy: a systematic review and meta-analysis

Background

This review systematically evaluates the efficacy and safety of the combined treatment of glucocorticoids (GC) and cyclophosphamide (CTX) in patients with membranous nephropathy (MN).

Methods

As of June 2024, a comprehensive literature search was performed utilizing several reputable databases, including PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang. A meta-analysis was then carried out using Review Manager 5.4 and STATA/SE-15 software.

Results

This research evaluated a total of 22 articles involving 1,971 patients. The findings revealed that patients with MN receiving combined GC and CTX therapy had significantly higher complete remission rates (odds ratio = 1.78, p = 0.02) and total remission rates (odds ratio = 2.14, p = 0.01) when the follow-up period exceeded 12 months. Additionally, this treatment demonstrated greater efficacy in lowering serum creatinine levels compared to the control group (standardized mean difference = -0.19, p = 0.04), while its relapse rate was also lower than that of the control group (odds ratio = 0.51, p = 0.009). However, it has a high incidence of serious adverse effects (odds ratio = 2.32, p = 0.03).

Conclusion

Our systematic review highlights that the combination of GC and CTX demonstrates superior long-term effectiveness and reduced relapse rates in managing membranous nephropathy (MN). Furthermore, this drug combination is considered the optimal choice for normalizing serum creatinine levels. Data on the effectiveness and safety of glucocorticoids alone versus other drugs alone, and the treatment of secondary membranous nephropathy (SMN), are limited.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=566477, identifier CRD42024566477.

THSD7A as a Promising Biomarker for Membranous Nephrosis

Membranous nephropathy (MN) is an autoimmune disease of the kidney glomerulus and one of the leading causes of nephrotic syndrome. The disease exhibits heterogeneous outcomes with approximately 30% of cases progressing to end-stage renal disease. Traditionally, the standard approach of diagnosing MN involves performing a kidney biopsy. Nevertheless, kidney biopsy is an invasive procedure that poses risks for the patient including bleeding and pain, and bears greater costs for the health system. The clinical management of MN has steadily advanced owing to the identification of autoantibodies to the phospholipase A2 receptor (PLA2R) in 2009 and thrombospondin domain-containing 7A (THSD7A) in 2014 on the podocyte surface. At present, serum anti-PLA2R antibody detection and glomerular PLA2R antigen staining have been used for clinical diagnosis and prognosis, but the related detection of THSD7A has not been widely used in clinical practice. Here, we summarized the emerging knowledge regarding the roles THSD7A plays in MN and its clinical implications as diagnostic, prognostic, and therapeutic response as well as Methods for detecting serum THSD7A antibodies.

Efficacy and safety of Chinese herbal medicines combined with biomedicine in the treatment of idiopathic membranous nephropathy: a systematic review and network meta-analysis

Background

Chinese herbal medicines have been extensively used to treat idiopathic membranous nephropathy (IMN). However, their efficacy and safety remain uncertain. Therefore, this study employed a network meta-analysis to evaluate the efficacy and safety of various Chinese herbal medicines in combination with biomedicines for treating IMN.

Methods

A comprehensive literature search was performed across several databases, including PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), WanFang Data, VIP Database, and Chinese Biomedical Literature Database (CBM), to identify randomized controlled trials (RCTs) concerning the treatment of IMN using a combination of Chinese herbal medicines and biomedicine, up to 31 May 2024. Two researchers independently conducted the literature screening and data extraction. The quality of the included studies was assessed using the Cochrane quality review manual, and Stata 14.2 software was employed for network meta-analysis.

Results

A total of 31 RCTs involving 2195 IMN patients and 15 different Chinese herbal medicines were analyzed. The network meta-analysis revealed that QQC + BM (84.7%) was the most effective in reducing 24-hour urinary protein. For improving serum albumin, HZC + BM (86%) was the most effective. LGT + BM (77.2%) was the best for enhancing serum creatinine levels. MXC + BM demonstrated the highest effectiveness in lowering total cholesterol (89%) and triglycerides (97%). Lastly, WZC + BM (90.8%) was the most effective in reducing the incidence of adverse reactions. BM.

Conclusion

The current evidence suggests that integrating Chinese herbal medicines with biomedicine may provide significant benefits in treating IMN. Specifically, QQC + BM appears to be the most effective in reducing 24-hour urinary protein, HZC + BM seems to excel in improving serum albumin levels, MXC + BM is noted for its effectiveness in lowering triglycerides and total cholesterol, LGT + BM is optimal for reducing serum creatinine, and WZC + BM shows the lowest rate of adverse reactions. Nevertheless, due to limitations in the quantity and quality of the included studies, further validation of these conclusions is necessary.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024561028], identifier [CRD42024561028].

Different Dosage Regimens of Rituximab in Primary Membranous Nephropathy Treatment: A Systematic Review

Primary membranous nephropathy (PMN) is one of the prevalent pathological types of adult primary nephrotic syndrome. Pathogenic autoantibodies targeting podocyte antigens such as phospholipase A2 receptor (PLA2R) lead to the disease. Patients frequently experience notable adverse effects when treated with conventional immunosuppressive therapies. Rituximab (RTX), a mouse/human monoclonal antibody, selectively depletes B cells and leads to a decrease in the antibody levels in the circulation, which helps to alleviate membranous nephropathy. Various RTX dosage regimens have been applied globally in the PMN treatment with satisfactory effects. Nevertheless, the optimal dosage of RTX has yet to be determined. This article reviews the application of different doses of RTX in the management of PMN so far.

B cell dysregulation and depletion therapy in primary membranous nephropathy: Prospects and potential challenges

B cells are crucial to the humoral immune response, originating in the bone marrow and maturing in the spleen and lymph nodes. They primarily function to protect against a wide range of infections through the secretion of antibodies. The role of B cells in primary membranous nephropathy (PMN) has gained significant attention, especially following the discovery of various autoantibodies that target podocyte antigens and the observed positive outcomes from B cell depletion therapy. Increasing evidence points to the presence of abnormal B cell subsets and functions in MN. B cells have varied roles during the different stages of disease onset, progression, and relapse. Initially, B cells facilitate self-antigen presentation, activate effector T cells, and initiate cellular immunity. Subsequently, the disruption of both central and peripheral immune tolerance results in the emergence of autoreactive B cells, with strong germinal center responses as a major source of MN autoantibodies. Additionally, critical B cell subsets, including Bregs, memory B cells, and plasma cells, play roles in the immune dysregulation observed in MN, assisting in predicting disease recurrence and guiding management strategies for MN. This review offers a detailed overview of research advancements on B cells and elucidates their pathological roles in MN.

Effects of immunosuppressive therapy on renal prognosis in primary membranous nephropathy

BACKGROUND

Immunosuppressive therapy plays a crucial role in treating membranous nephropathy, with previous studies highlighting its benefits for patients with primary membranous nephropathy (PMN). Guidelines suggest that the management of membranous nephropathy should be tailored to individual risk levels. However, there is a lack of real-world studies examining the effects of immunosuppressive therapy on renal outcomes in PMN patients. This study aimed to investigate the relationship between immunosuppressive therapy and renal prognosis in PMN patients.

METHODS

This was a real-world retrospective study including patients diagnosed with PMN in Shenzhen Second People's Hospital and Hechi People's Hospital. Univariate and multivariate Cox regression analysis and Kaplan-Meier survival analysis were used.

RESULTS

After propensity score-matching, 464 PMN patients were included and they were assigned to conservative and immunosuppressive group in a 1:1 ratio. Immunosuppressive therapy was the protective factor of renal composite outcome (HR = 0.65, p < 0.01). Separately, the effect was significant in moderate- and high-risk but not in low-risk patients. Key influencing factors including age, blood pressure, albumin and total cholesterol levels, with slight differences among patients at different risk.

CONCLUSIONS

This study demonstrates the efficacy of immunosuppressive therapy in non-low-risk PMN patients. The key factors affecting renal prognosis in patients with different risk levels are emphasized to help provide individualized treatment.

Long-Term Outcomes of Rituximab-Treated Adult Patients with Podocytopathies

Key Points

Background

Long-term outcomes of rituximab-treated adult patients with podocytopathies (either minimal change disease or FSGS) are largely unknown.

Methods

A retrospective study at 30 nephrology departments from 15 countries worldwide included rituximab-treated adults with primary podocytopathies and a minimum clinical follow-up of 36 months. The primary outcome was relapse-free survival at 36 months.

Results

One hundred eighty-three adult patients (n=64 with FSGS and n=119 with minimal change disease) with difficult-to-treat nephrotic syndrome (68% steroid-dependent/frequently relapsing, 22% steroid-resistant, 85% previously treated with two or more lines of immunosuppressive therapy) were treated with rituximab as part of a remission induction regimen. Complete or partial remission at 6 months after rituximab treatment was achieved in 82%. Eighty-three of 151 (55%) initial responders achieved long-term relapse-free survival over 3 years. Maintenance therapy with rituximab was associated with a better relapse-free survival (hazard ratio, 2.05; 95% confidence interval [CI], 1.07 to 3.91), irrespective of the dosing regimen. At 36 months, 61% of initial responders receiving maintenance therapy with rituximab achieved long-term relapse-free survival and withdrawal of all concomitant immunosuppressive medication compared with 36% of patients without maintenance treatment (odds ratio, 2.69; 95% CI, 1.27 to 5.73). Relapses per year were reduced from an annual relapse rate of 1.0 (95% CI, 1.0 to 1.7) before to 0.17 (95% CI, 0.00 to 0.24) relapses per year after rituximab initiation. Over the 36 months of follow-up, a stable course of eGFR was observed in those who initially responded with either complete or partial remission, whereas nonresponders experienced a reduction in eGFR reaching −11 (95% CI, −18 to −8) ml/min per 1.73 m2.

Conclusions

Rituximab facilitated achievement of initial and long-term response in a majority of adult patients with difficult-to-treat podocytopathies. Maintenance treatment with rituximab was further associated with long-term relapse-free survival over 3 years. Nonresponse to initial rituximab treatment was associated with poor kidney prognosis.

Epitope Spreading in Immune-Mediated Glomerulonephritis: The Expanding Target

Epitope spreading is a critical mechanism driving the progression of autoimmune glomerulonephritis. This phenomenon, where immune responses broaden from a single epitope to encompass additional targets, contributes to the complexity and severity of diseases such as membranous nephropathy (MN), lupus nephritis (LN), and ANCA-associated vasculitis (AAV). In MN, intramolecular spreading within the phospholipase A2 receptor correlates with a worse prognosis, while LN exemplifies both intra- and intermolecular spreading, exacerbating renal involvement. Similarly, ANCA reactivity in AAV highlights the destructive potential of epitope diversification. Understanding these immunological cascades reveals therapeutic opportunities-targeting early epitope spreading could curb disease progression. Despite promising insights, the clinical utility of epitope spreading as a prognostic tool remains debated. This review provides a complete overview of the current evidence, exploring the dual-edged nature of epitope spreading, the intricate immune mechanisms behind it, and its therapeutic implications. By elucidating these dynamics, we aim to pave the way for more precise, targeted interventions in autoimmune glomerular diseases.

An Updated Comprehensive Review on Diseases Associated with Nephrotic Syndromes

There have been exciting advances in our knowledge of primary glomerular diseases and nephrotic syndromes in recent years. Beyond the histological pattern from renal biopsy, more precise phenotyping of the diseases and the use of modern nephrogenetics helps to improve treatment decisions and sometimes also avoid unnecessary exposure to potentially toxic immunosuppression. New biomarkers have led to easier and more accurate diagnoses and more targeted therapeutic decisions. The treatment landscape is becoming wider with a pipeline of promising new therapeutic agents with more sophisticated approaches. This review focuses on all aspects of entities that are associated with nephrotic syndromes with updated information on recent advances in each field. This includes podocytopathies (focal segmental glomerulosclerosis and minimal-change disease), membranous nephropathy, membranoproliferative glomerulonephritis, IgA nephropathy, fibrillary glomerulonephritis, amyloidosis, and monoclonal gammopathy of renal significance in the context of the nephrotic syndrome, but also renal involvement in systemic diseases, diabetic nephropathy, and drugs that are associated with nephrotic syndromes.

Observational study of immunosuppressive treatment patterns and outcomes in primary membranous nephropathy: a multicenter retrospective analysis

BACKGROUND

We evaluated the efficacy of different immunosuppressive regimens in patients with primary membranous nephropathy in a large national cohort.

METHODS

In this registry study, 558 patients from 47 centers who were treated with at least one immunosuppressive agent and had adequate follow-up data were included. Primary outcome was defined as complete (CR) or partial remission (PR). Secondary composite outcome was at least a 50% reduction in estimated glomerular filtration (eGFR), initiation of kidney replacement therapies, development of stage 5 chronic kidney disease, or death.

RESULTS

Median age at diagnosis was 48 (IQR: 37-57) years, and 358 (64.2%) were male. Patients were followed for a median of 24 (IQR: 12-60) months. Calcineurin inhibitors (CNIs) with or without glucocorticoids were the most commonly used regimen (43.4%), followed by glucocorticoids and cyclophosphamide (GC-CYC) (39.6%), glucocorticoid monotherapy (25.8%), and rituximab (RTX) (9.1%). Overall remission rate was 66.1% (CR 26.7%, PR 39.4%), and 59 (10.6%) patients reached secondary composite outcome. Multivariate logistic regression showed that baseline eGFR (OR 1.011, 95% CI: 1.003-1.019, p = 0.007), serum albumin (OR 1.682, 95% CI: 1.269-2.231, p < 0.001), and use of RTX (OR 0.296, 95% CI: 0.157-0.557, p < 0.001) were associated with remission rates; whereas only lower baseline hemoglobin was significantly associated with secondary composite outcome (OR: 0.843, 95% CI: 0.715-0.993, p = 0.041). CYC use was significantly associated with higher remission (OR 1.534, 95% CI: 1.027-2.290, p = 0.036).

CONCLUSIONS

Higher baseline eGFR and serum albumin levels correlated with increased remission rates. Remission rates were lower in patients treated with RTX, while those on GC-CYC showed higher rates of remission. Due to the study's retrospective nature and multiple treatments used, caution is warranted in interpreting these findings.

Therapeutic targets in membranous nephropathy: plasma cells and complement

Membranous nephropathy (MN) is an antibody-mediated autoimmune disease and the most common cause of nephrotic syndrome in adults. The discovery of phospholipase A2 receptor 1 (PLA2R1) as the first target antigen in patients with MN 15 years ago has led to a paradigm shift in the pathobiological understanding of this disease. Autoantibodies against PLA2R1 as well as thrombospondin type-1 domain-containing 7A, the second identified antigen in adults, were shown to be disease-causing and act through local activation of the complement system, primarily via the classical and lectin pathways. These findings indicate that both plasma cells, the main source of antibodies and autoantibodies, as well as the complement system, the main pathogenic effector mechanism in MN, are rational and pathogenesis-based treatment targets in MN. This review summarizes pathomechanistic and clinical evidence for and against plasma cell- and complement-targeted treatments in MN.

Obinutuzumab as Initial or Second-Line Therapy in Patients With Primary Membranous Nephropathy

Introduction

B-cell lymphocytes have been demonstrated to play a key role in the pathogenesis underlying membranous nephropathy (MN). The aim of this study was to evaluate the therapeutic efficacy and safety of Obinutuzumab, a glycoengineered type II anti-CD20 monoclonal antibody in individuals with MN.

Methods

We retrospectively analyzed data from 59 consecutive patients with primary MN who provided consent to receive Obinutuzumab and were followed for at least 6 months. The primary outcomes were complete (proteinuria <0.3 g/d) or partial (proteinuria <3.5 g/d with ≥ 50% reduction) remission of proteinuria.

Results

Twenty patients received Obinutuzumab as initial therapy, and 39 patients were previously treated with at least 1 immunosuppressant (second-line therapy). Fifty patients (84.7%) achieved complete remission (CR) or partial remission (PR) of proteinuria during the median follow-up of 9.4 months. The likelihood of remission was significantly higher when Obinutuzumab was used as initial therapy than as second-line therapy after adjusting for the baseline estimated glomerular filtration rate (eGFR), 24-hour urinary protein levels, and anti-phospholipase A2 receptor (PLA2R) status (adjusted hazard ratio [HR], 4.5; 95% confidence interval [CI]: 2.1-9.5, P < 0.001). Circulating CD19+ B-cell count decreased to <5 cells/μl in all patients within 2 weeks after infusion. Serum anti-PLA2R concentrations decreased to <14 relative units (RU)/ml in 43 of 48 patients with PLA2R-related MN. After Obinutuzumab administration, a significant reduction in 24-hour urine protein and increase in serum albumin were observed. No serious adverse events were observed.

Conclusion

Obinutuzumab may represent a promising and well-tolerated therapeutic option for individuals with primary MN. The potential of Obinutuzumab was highlighted as an initial therapy for primary MN.

Prospective study of the effect of rituximab on kidney function in membranous nephropathy

Background

Patients with membranous nephropathy (MN) and poor kidney function or active disease despite previous immunosuppression are underrepresented in clinical trials. It is unknown how effective rituximab is in this population.

Methods

This prospective, multi-centre, single-arm, real-world study of patients with active MN [urine protein-creatinine ratio (uPCR) >350 mg/mmol and serum albumin <30 g/L, or a fall in estimated glomerular filtration rate (eGFR) of at least 20% or more over at least 3 months] evaluated rituximab in those with contraindications to calcineurin inhibitors and cytotoxic therapy. The primary outcome was change in rate of eGFR decline before and after rituximab. Complete or partial remission were defined as uPCR <30 mg/mmol or uPCR <350 mg/mmol with a ≥50% fall from baseline, respectively.

Results

A total of 180 patients [median age 59 years, interquartile range (IQR) 48-68] received rituximab and were followed up for a median duration of 17 months. Seventy-seven percent had prior immunosuppression. Median eGFR and uPCR at baseline were 49.2 mL/min/1.73 m2 (IQR 34.4-80.6) and 766 mg/mmol (IQR 487-1057), respectively. The annual rate of decline of eGFR fell from 13.9 to 1.7 mL/min/1.73 m2/year following rituximab (Z score = 2.48, P < .0066). At 18 months 12% and 42% of patients were in complete or partial remission, respectively. Rituximab was well tolerated; patient survival was 95.6% at 2 years and in patients in whom eGFR was available, kidney survival was 93% at 2 years.

Conclusion

Rituximab significantly reduced the rate of eGFR decline in active MN including those who had received prior immunosuppression or with poor baseline kidney function.

Membranous Nephropathy: Updates on Management

Membranous nephropathy is a major etiology of nephrotic syndrome in adults and less frequently in children. Circulating antibodies to intrinsic podocyte antigens, such as M-type phospholipase A2 receptor, or to extrinsic proteins accumulate beneath the podocyte to cause damage via complement activation and/or other mechanisms. The availability of clinical testing for autoantibodies to M-type phospholipase A2 receptor has allowed noninvasive diagnosis of this form of membranous nephropathy and a means to monitor immunologic activity to guide immunosuppressive therapy. Treatment of membranous nephropathy includes optimal supportive care with renin-angiotensin-system blockers, lipid-lowering agents, diuretics, lifestyle changes, and additional immunosuppressive therapy in patients with an increased risk of progression to kidney failure. Rituximab has been recognized as a first-line immunosuppressive therapy for most membranous nephropathy patients with an increased risk of progressive disease, except those with life-threatening nephrotic syndrome or rapidly deteriorating kidney function from membranous nephropathy. This article discusses the major and minor antigens described in membranous nephropathy, the natural history of the disease, and guidelines for clinical management and immunosuppressive treatment.

Membranous nephropathy: pathogenesis and treatments

Membranous nephropathy (MN), an autoimmune disease, can manifest at any age and is among the most common causes of nephrotic syndrome in adults. In 80% of cases, the specific etiology of MN remains unknown, while the remaining cases are linked to drug use or underlying conditions like systemic lupus erythematosus, hepatitis B virus, or malignancy. Although about one-third of patients may achieve spontaneous complete or partial remission with conservative management, another third face an elevated risk of disease progression, potentially leading to end-stage renal disease within 10 years. The identification of phospholipase A2 receptor as the primary target antigen in MN has brought about a significant shift in disease management and monitoring. This review explores recent advancements in the pathophysiology of MN, encompassing pathogenesis, clinical presentations, diagnostic criteria, treatment options, and prognosis, with a focus on emerging developments in pathogenesis and therapeutic strategies aimed at halting disease progression. By synthesizing the latest research findings and clinical insights, this review seeks to contribute to the ongoing efforts to enhance our understanding and management of this challenging autoimmune disorder.

Ten tips on immunosuppression in primary membranous nephropathy

Membranous nephropathy (MN) management poses challenges, particularly in selecting appropriate immunosuppressive treatments (IST) and monitoring disease progression and complications. This article highlights 10 key tips for the management of primary MN based on current evidence and clinical experience. First, we advise against prescribing IST to patients without nephrotic syndrome (NS), emphasizing the need for close monitoring of disease progression. Second, we recommend initiating IST in patients with persistent NS or declining kidney function. Third, we suggest prescribing rituximab (RTX) or RTX combined with calcineurin inhibitors in medium-risk patients. Fourth, we propose cyclophosphamide-based immunosuppression for high-risk patients. Fifth, we discourage the use of glucocorticoid monotherapy or mycophenolate mofetil as initial treatments. Sixth, we underscore the importance of preventing infectious complications in patients receiving IST. Seventh, we emphasize the need for personalized monitoring of IST by closely measuring kidney function, proteinuria, serum albumin and anti-M-type phospholipase A2 receptor levels. Eighth, we recommend a stepwise approach in the treatment of resistant disease. Ninth, we advise adjusting treatment for relapses based on individual risk profiles. Finally, we caution about the potential recurrence of MN after kidney transplantation and suggest appropriate monitoring and treatment strategies for post-transplantation MN. These tips provide comprehensive guidance for clinicians managing MN, aiming to optimize patient outcomes and minimize complications.

Optimized rituximab regimen versus recommended regimen for idiopathic membranous nephropathy: A single-center retrospective cohort study

BACKGROUND

Rituximab (RTX) has become the first-line treatment for idiopathic membranous nephropathy (IMN). Compared with conventional therapy, rituximab therapy has a more favorable safety profile. However, the recommended RTX dose as a flux may have its limitations. The aim of this study was to investigate the clinical efficacy and safety of three regimens, including a cyclic corticosteroid-cyclophosphamide regimen and two different doses of RTX regimens, for the treatment of IMN.

METHODS

We recruited 58 patients with IMN confirmed by renal biopsy. 20 patients were treated with a cycle regimen, 22 patients were received RTX with 500 mg per week, totaling a dose of 2000 mg (optimized RTX group), and 16 patients received RTX with 1000 mg at day 1 and day 15 (recommended RTX group). Treatment responses, including complete remission (CR) and partial remission (PR), and outcome adverse events such as steroid diabetes, infections and a drop in white blood cell count, were compared among the three groups after 9 months of follow-up.

RESULTS

At 9-month follow-up, the composite remission rates (CR + PR) were 90 %, 72.7 %, and 75 % for the cycle regimen group, optimized RTX group, and recommended RTX group, respectively, with CR of 35 %, 22.7 %, and 25 %, respectively. There was no statistical difference between the three groups on CR and composite remission. Kaplan-Meier survival analyses showed no significant differences in cumulative CR rates and cumulative composite remission rates among the three groups (P = 0.632, P = 0.258). The cycle regimen group had a higher risk of steroid diabetes (35 %). Compared with the recommended RTX regimen, the optimized regimen reduced the incidence of adverse events of infection (9.1 % vs. 37.5 %, P = 0.049), especially in patients older than 60 years of age (P = 0.026). A lower anti-PLA2R at baseline may be associated with a higher risk of infection (P = 0.043).

CONCLUSIONS

The efficiency of low-dose and long-course of RTX regiment is not inferior to the recommended treatment regimen, and this regimen can effectively reduce the incidence of infection in patients with IMN. Moreover, we recommend a low-dose, long course of RTX treatment for the elderly.

Dosing optimization of rituximab for primary membranous nephropathy by population pharmacokinetic and pharmacodynamic study

Primary membranous nephropathy (PMN) is the most common cause for adult nephrotic syndrome. Rituximab has demonstrated promising clinical efficacy by random controlled trials and the off-label use is widely adopted in PMN. However, the standard dosage is borrowed from B cell lymphoma treatment with far more antigens and is oversaturated for PMN treatment, accompanied with additional safety risk and unnecessary medical cost. More than 15% serious adverse events were observed under standard dosage and low dose therapies were explored recently. Dose optimization by clinical trials is extremely time- and cost-consuming and can be significantly accelerated with the aid of model-informed drug development. Here, we aim to establish the first population pharmacokinetic and pharmacodynamic (PPK/PD) model for rituximab in PMN to guide its dosage optimization. Rituximab pharmacokinetic and pharmacodynamic data from 41 PMN patients in a retrospective study under a newly proposed monthly mini-dose were used to construct quantitative dose-exposure-response relationship via mechanistic target-mediated drug disposition (TMDD) model followed by regression between the reduction of anti-PLA2R titer and time after the treatment. The final model, validated by goodness-of-fit plots, visual predictive checks and bootstrap, was used to recommend the optimized dosing regimen by simulations. The model was well validated for PK/PD prediction. The systemic clearance and half-life are 0.54 L/h and 14.7 days, respectively. Simulation of a novel regimen (6 monthly doses of 100 mg) indicated the comparable ability and superior duration time of CD20+ B cell depletion compared with standard dosage, while the cumulative dosage and safety risk was significantly decreased. We established the first PPK/PD model and provide evidence to support the dosage optimization based on monthly mini-dose. Our study can also efficiently accelerate dosage optimization of novel anti-CD20 antibodies in PMN and other indications.

Primary membranous nephropathy in the Italian region of Emilia Romagna: results of a multicenter study with extended follow-up

BACKGROUND

Since primary membranous nephropathy is a heterogeneous disease with variable outcomes and multiple possible therapeutic approaches, all 13 Nephrology Units of the Italian region Emilia Romagna decided to analyze their experience in the management of this challenging glomerular disease.

METHODS

We retrospectively studied 205 consecutive adult patients affected by biopsy-proven primary membranous nephropathy, recruited from January 2010 through December 2017. The primary outcome was patient and renal survival. The secondary outcome was the rate of complete remission and partial remission of proteinuria. Relapse incidence, treatment patterns and adverse events were also assessed.

RESULTS

Median (IQR) follow-up was 36 (24-60) months. Overall patient and renal survival were 87.4% after 5 years. At the end of follow-up, 83 patients (40%) had complete remission and 72 patients (35%) had partial remission. Among responders, less than a quarter (23%) relapsed. Most patients (83%) underwent immunosuppressive therapy within 6 months of biopsy. A cyclic regimen of corticosteroid and cytotoxic agents was the most commonly used treatment schedule (63%), followed by rituximab (28%). Multivariable analysis showed that the cyclic regimen significantly correlates with complete remission (odds ratio 0.26; 95% CI 0.08-0.79) when compared to rituximab (p < 0.05).

CONCLUSIONS

In our large study, both short- and long-term outcomes were positive and consistent with those published in the literature. Our data suggest that the use of immunosuppressive therapy within the first 6 months after biopsy appears to be a winning strategy, and that the cyclic regimen also warrants a prominent role in primary membranous nephropathy treatment, since definitive proof of rituximab superiority is lacking.

An Updated Review of Membranous Nephropathy

Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults. The discovery of phospholipase A2 receptor (PLA2R) as a target antigen has led to a paradigm shift in the understanding and management of MN. At present, serum PLA2R antibodies are used for diagnosis, prognostication, and guiding treatment. Now, with the discovery of more than 20 novel target antigens, antigen mapping is almost complete. The clinical association of certain antigens provides clues for clinicians, such as the association of nerve epidermal growth factor-like 1 with malignancies and indigenous medicines. Serum antibodies are detected for most target antigens, except exostosin 1 and 2 and transforming growth factor-beta receptor 3, but their clinical utility is yet to be defined. Genome-wide association studies and studies investigating environmental factors, such as air pollution, shed more light on the underpinnings of MN. The standard therapy of MN diversified from cyclical cyclophosphamide and steroids to include rituximab and calcineurin inhibitors over the past decades. Here, we provide a cutting-edge review of MN, focusing on genetics, immune system and environmental factors, novel target antigens and their clinical characteristics, and currently available and emerging novel therapies in MN.

Practice patterns of rituximab for primary membranous nephropathy 2021 in Japan: a web-based survey of board-certified nephrologists

BACKGROUND

Although rituximab (RTX) is recommended by kidney disease improving global outcomes as one of the standard therapies for primary membranous nephropathy (pMN), given the constraint of insurance coverage, it is not clear how the drug is used in Japan.

METHODS

This cross-sectional study was conducted via a web-based survey between November and December 2021. The participants were certified nephrologists and recruited through convenience sampling. Experience with RTX for pMN was compared to experience with RTX for minimal change nephrotic syndrome (MCNS). Reasons for withholding RTX for pMN, even when it is indicated, were also investigated. Furthermore, the proportion difference in RTX experience was analyzed.

RESULTS

Responses from 380 nephrologists across 278 facilities were analyzed. RTX was used for pMN by 83 (21.8%), which was less than the 181 (47.6%) who had used RTX for MCNS (ratio of proportions: 0.46). RTX use for pMN was more frequent in facilities performing 41-80 and 81 or more kidney biopsies annually (vs. none) and by physicians with experience in anti-PLA2R antibody measurement. RTX administration for pMN was covered by insurance for 56 (67.5%), was facility-paid for 10 (12.0%), and was copaid by patients for 6 (7.2%). The most common reason for withholding RTX for pMN was difficulty in ensuring financing (146, 79.3%).

CONCLUSIONS

RTX use for pMN is less common than for MCNS but not infrequent. Treatment with RTX was more frequent in biopsy-intensive facilities, and it was fully paid by the facility or patient in one-fifth of cases.

Ofatumumab in Rituximab-Resistant and Rituximab-Intolerant Patients With Primary Membranous Nephropathy: A Case Series

RATIONALE & OBJECTIVE

Rituximab is the first-choice therapy for patients with primary membranous nephropathy (MN) and nephrotic syndrome. However, approximately 30% of patients are treatment-resistant or become treatment-intolerant with hypersensitivity reactions upon repeated drug exposures. We aimed to assess whether ofatumumab, a fully human second-generation anti-CD20 antibody, could be a valuable alternative to rituximab in this population.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

7 rituximab-intolerant and 10 rituximab-resistant patients with MN who consented to receive ofatumumab (50-300mg, single intravenous infusion) and were followed at the nephrology unit of Azienda Socio-Sanitaria Territoriale Papa Giovanni XXIII (Bergamo, Italy) between September 2015 and January 2019.

FINDINGS

Over a median (IQR) follow-up of 5.0 (3.0-9.8) months, all 7 rituximab-intolerant and 3 of the 10 rituximab-resistant patients exhibited complete (proteinuria<0.3g/d) or partial (proteinuria<3.5g/d with≥50% reduction vs baseline) remission of nephrotic syndrome. Circulating B cells were similarly depleted in all patients by 1 week, and serum anti-phospholipase A2 receptor antibody concentrations decreased to<2.7 relative units/mL in 3 of 4 rituximab-intolerant and 4 of 8 rituximab-resistant patients with phospholipase A2 receptor-related disease. Ofatumumab significantly reduced 24-hour urinary protein and immunoglobulin G excretion and increased serum albumin and immunoglobulin G levels. These effects were greater in rituximab-intolerant than in rituximab-resistant patients. Measured glomerular filtration rate significantly increased by an average of 13.4% at 24 months compared with baseline (P=0.036) among all patients in the series. There were 14 nonserious infusion-related adverse events in 9 patients that recovered with temporary infusion interruption.

LIMITATIONS

Retrospective design, limited number of patients.

CONCLUSIONS

Ofatumumab may represent an effective and safe treatment for rituximab-intolerant cases of MN. Larger prospective studies will be needed to validate these preliminary findings and explore the effectiveness of other second-generation anti-CD20 antibodies in this clinical setting.

PLAIN-LANGUAGE SUMMARY

Primary membranous nephropathy (MN) is one of the most frequent causes of nephrotic syndrome (NS) in adults. In this case series, we explored the efficacy of ofatumumab, a fully human second-generation anti-CD20 antibody, in 17 patients with MN and NS who were intolerant or unresponsive to rituximab. All 7 rituximab-intolerant patients exhibited complete or partial clinical remission, compared with only 3 of the 10 rituximab-resistant patients. Autoantibody levels decreased in all patients with phospholipase A2 receptor-related disease. Ofatumumab achieved a significant reduction in urinary protein and immunoglobulin G excretion while increasing serum albumin and immunoglobulin G levels. Ofatumumab may be a promising option for patients with MN who are rituximab-intolerant. Further investigations are warranted to validate these preliminary findings.

Membranous nephropathy treatment standard

Membranous nephropathy (MN) is characterized by deposition of immune complexes leading to thickening of glomerular basement membranes. Over time, the understanding of MN has evolved, with the identification of specific autoantibodies against novel podocyte antigens and the unraveling of intricate pathogenic pathways. Although the anti-CD20 monoclonal antibody rituximab is favored as part of the initial therapy in MN, a subgroup of MN patients may be resistant to rituximab necessitating the use of alternative agents such as cytotoxic therapies. In addition, newer agents such as novel anti-CD20 monoclonal antibodies, therapies targeting the CD38-positive plasma cells and anti-complement therapy are being studied in patients who are resistant to traditional treatment strategies. This manuscript furnishes a review of the novel developments in the pathophysiology of MN including the identification of target antigens and current treatment standards for MN, concentrating on evidenced-based interventions designed to attain remission and to prevent disease progression.

Comparison of the efficacy of steroid-free versus classic steroid-containing regimens in primary membranous nephropathy

Objective: To compare the efficacy of a steroid-free regimen with steroid-based treatment in managing primary membranous nephropathy (PMN) and investigate the potential benefits of steroid-free regimens in PMN therapy. Methods: This was a single-centre prospective cohort study. A total of 81 patients were divided into two groups according to their medication regimen: a rituximab (RTX)/tacrolimus (TAC) group (low-dose RTX combined with low-dose TAC group, without steroids, n = 31) and a prednisone (P)/TAC group (P combined with TAC group, n = 61). The changes in 24-h urine protein quantification, levels of blood albumin, blood creatinine, total cholesterol, triglyceride and fasting blood glucose as well as anti-phospholipase A2 receptor antibody titres were observed in both groups before treatment and after 1, 3, 6 and 12 months of treatment. Clinical remission (complete and partial remission), serological remission and recurrence were assessed in both groups after treatment, and the occurrence of adverse reactions was observed. Results: 1) Before treatment, there was no significant difference in baseline values between the two groups (p > 0.05). 2) After 12 months of treatment, the 24-h proteinuria and total cholesterol levels in the RTX/TAC group were significantly lower than those in the P/TAC group (p < 0.05). 3) After 6 months of treatment, the clinical remission rate of the RTX/TAC group was significantly higher than that of the P/TAC group (p < 0.05). After 12 months of treatment, the clinical remission rate of the RTX/TAC group was significantly higher than that of the P/TAC group (p < 0.05). (4) After 3, 6 and 12 months of treatment, serological remission rates in the RTX/TAC group were significantly higher than those in the P/TAC group (p < 0.05). During treatment, the anti-PLA2R antibody titres in the RTX/TAC group remained lower than those in the P/TAC group (p < 0.05). Conclusion: The low-dose RTX combined with low-dose TAC steroid-free regimen induces serological remission in patients with PMN earlier than the classic regimen of P combined with TAC, and there was no significant difference in adverse effects between the two groups. Besides, the long-term clinical remission effect of low-dose RTX combined with low-dose TAC is better than that of P combined with TAC.

Targeted therapy in glomerular diseases

Targeted therapy has emerged as a more precise approach to treat glomerular diseases, focusing on specific molecular or cellular processes that contribute to disease development or progression. This approach complements or replaces traditional immunosuppressive therapy, optimizes supportive care, and provides a more personalized treatment strategy. In this review, we summarize the evolving understanding of pathogenic mechanisms in immune-mediated glomerular diseases and the developing targeted therapies based on these mechanisms. We begin by discussing pan-B-cell depletion, anti-CD20 rituximab, and targeting B-cell survival signaling through the BAFF/APRIL pathway. We also exam specific plasma cell depletion with anti-CD38 antibody. We then shift our focus to complement activation in glomerular diseases, which is involved in antibody-mediated glomerular diseases, such as IgA nephropathy, membranous nephropathy, ANCA-associated vasculitis, and lupus nephritis. Non-antibody-mediated complement activation occurs in glomerular diseases, including C3 glomerulopathy, complement-mediated atypical hemolytic uremic syndrome, and focal segmental glomerulosclerosis. We discuss specific inhibition of terminal, lectin, and alternative pathways in different glomerular diseases. Finally, we summarize current clinical trials targeting the final pathways of various glomerular diseases, including kidney fibrosis. We conclude that targeted therapy based on individualized pathogenesis should be the future of treating glomerular diseases.

Novel Antigens and Clinical Updates in Membranous Nephropathy

Membranous nephropathy (MN), an autoimmune kidney disease and leading cause of nephrotic syndrome, leads to kidney failure in up to one-third of affected individuals. Most MN cases are due to an autoimmune reaction against the phospholipase A2 receptor (PLA2R) located on kidney podocytes. Serum PLA2R antibody quantification is now part of routine clinical practice because antibody titers correlate with disease activity and treatment response. Recent advances in target antigen detection have led to the discovery of more than 20 other podocyte antigens, yet the clinical impact of additional antigen detection remains unknown and is under active investigation. Here we review recent findings and hypothesize how current research will inform future care of patients with MN.

Comparative pharmacoeconomic analysis of rituximab and traditional tacrolimus regimens in membranous nephropathy in China

Background: Rituximab (RTX) is a monoclonal antibody that selectively targets CD20 and is frequently used in the treatment of membranous nephropathy (MN). Analysis of the therapeutic efficacy and safety of RTX in treating MN in practice and a comparative pharmacoeconomic analysis of the RTX and traditional tacrolimus (TAC) regimens can provide valuable insights to aid decision-making by the government and relevant medical insurance departments. Methods: We conducted a statistical analysis of medical records from patients diagnosed with MN who underwent RTX treatment between 1 January 2019 and 1 January 2023. The TAC data were obtained from the clinical literature. The efficacy rates and incidence of adverse effects (AEs) were calculated to compare the efficacy and safety of RTX and TAC. Based on the patient's disease status, we developed a Markov model to compare the total cost, remission rate, and incremental cost-effectiveness ratio (ICER) of the two regimens. Both univariate and probability sensitivity analyses were performed to validate the stability of the developed model. Results: The RTX group enrolled 53 patients with MN, and the 12-month overall efficacy rate was not significantly different from that of the TAC group with 35 patients (86.79% vs. 71.4%, p = 0.0131); however, the relapse rate was significantly lower in the RTX group (3.77% vs. 22.8%, p = 0.016). The RTX group demonstrated no severe AEs (SAEs), while the TAC group demonstrated six cases of SAEs, including 4 cases of severe pneumonia, 1 case of lung abscess and 1 case of interstitial lung disease, accounting for 7.89% of traditional tacrolimus-treated patients. The baseline analysis results revealed that over a 5-year post-treatment period, RTX increased quality-adjusted life years (QALYs) by 0.058 and costs by ¥7,341. Assuming three times the 2022 domestic gross domestic product as the willingness-to-pay (WTP) threshold per QALY, the ICER of RTX compared to TAC was ¥124,631.14/QALY, which is less than the WTP threshold of ¥257,094/QALY, indicating that RTX treatment is approximately two times more cost-effective compared to TAC. Conclusion: The current analysis indicates that despite the expensive unit price of RTX, it remains a cost-effective treatment option for MN compared to TAC.

Effect of rituximab in patients with PLA2R-associated membranous nephropathy and malignancy

INTRODUCTION

Phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN) is a common cause of nephrotic syndrome in nondiabetic adults who are also within the common age group for malignancy. How to treat patients with PLA2R-associated MN and malignancy effectively and safely still requires careful consideration. The aim of our study was to examine the outcomes and safety of rituximab (RTX) in these patients.

METHODS

Retrospective analysis of clinical data was performed on 15 patients with PLA2R-associated MN and malignancy. Patients were followed every 1-3 months for a minimum of 24 months. Clinical data were collected, including CD19+ B cells, anti-PLA2R antibodies, 24-hour urinary protein, serum albumin, and serum creatinine. The percentage of patients who achieved clinical remission and immunological remission was also measured.

RESULTS

Among these 15 patients, 14 patients with solid tumors received treatment for malignant diseases with complete resection. One patient received chemotherapy for chronic myeloid leukemia, and achieved complete remission 36 months before the diagnosis of MN. There were 6 (40.00 %) patients who achieved complete remission and 14 (93.33 %) patients who achieved complete or partial remission at the last visit after RTX treatment. At the last visit, patients were clinically improved, as evidenced by significant improvements in anti-PLA2R antibody titer [2.00 (2.00, 2.00) vs 35.25 (11.18, 91.58) RU/ml, P = 0.002], 24-hour urine protein [0.39 (0.11, 2.28) vs 9.22 (4.47, 14.73) g/d, P = 0.001], and serum albumin [38.15 (34.80, 43.20) vs 23.70 (18.70, 25.70) g/L, P = 0.001]. During the follow-up, the renal function of those patients remained stable. Recurrence of malignant tumors or the occurrence of new tumor events were not observed.

CONCLUSION

In this single-center retrospective study with a small sample size, RTX therapy might be an effective and safe treatment in patients with PLA2R-associated MN and malignancy.

Optimization of Rituximab Therapy in Adult Patients With PLA2R1-Associated Membranous Nephropathy With Artificial Intelligence

Introduction

Rituximab is a first-line treatment for membranous nephropathy. Nephrotic syndrome limits rituximab exposure due to urinary drug loss. Rituximab underdosing (serum level <2 μg/ml at month-3) is a risk factor for treatment failure. We developed a machine learning algorithm to predict the risk of underdosing based on patients' characteristics at rituximab infusion. We investigated the relationship between the predicted risk of underdosing and the cumulative dose of rituximab required to achieve remission.

Methods

Rituximab concentrations were measured at month-3 in 92 sera from adult patients with primary membranous nephropathy, split into a training (75%) and a testing set (25%). A forward-backward machine-learning procedure determined the best combination of variables to predict rituximab underdosing in the training data set, which was tested in the test set. The performances were evaluated for accuracy, sensitivity, and specificity in 10-fold cross-validation training and test sets.

Results

The best variables combination to predict rituximab underdosing included age, gender, body surface area (BSA), anti-phospholipase A2 receptor type 1 (anti-PLA2R1) antibody titer on day-0, serum albumin on day-0 and day-15, and serum creatinine on day-0 and day-15. The accuracy, sensitivity, and specificity were respectively 79.4%, 78.7%, and 81.0% (training data set), and 79.2%, 84.6% and 72.7% (testing data set). In both sets, the algorithm performed significantly better than chance (P < 0.05). Patients with an initial high probability of underdosing experienced a longer time to remission with higher rituximab cumulative doses required to achieved remission.

Conclusion

This algorithm could allow for early intensification of rituximab regimen in patients at high estimated risk of underdosing to increase the likelihood of remission.

Measurement of urinary exosomal phospholipase A2 receptor is a sensitive method for diagnosis of PLA2R-associated membranous nephropathy

Background

The discovery of phospholipase A2 receptor (PLA2R) and its antibody (aPLA2Rab) has paved the way for diagnosing PLA2R-associated membranous nephropathy (PLA2R-MN) with a high specificity of 98%. However, the sensitivity was only 40% to 83.9%, and there is ongoing discussion around determining the optimal threshold for diagnosis. Recent advancements in the use of exosomes, a novel form of "liquid biopsy," have shown great promise in identifying markers for various medical conditions.

Methods

Protein mass spectrometry and western blot were applied to verify the existence of PLA2R antigen in the urine exosome. We then evaluated the efficacy of urinary exosomal PLA2R antigen alone or combined with serum aPLA2Rab level to diagnose PLA2R-MN.

Results

The urinary exosomes contained a high abundance of PLA2R antigen as evidenced by protein mass spectrometry and western blot in 85 PLA2R-MN patients vs the disease controls (14 secondary MN patients, 22 non-MN patients and 4 PLA2R-negative MN patients) and 20 healthy controls. Of note, urinary exosomal PLA2R antigen abundance also had a good consistency with the PLA2R antigen level in the renal specimens of PLA2R-MN patients. The sensitivity of urinary exosomal PLA2R for diagnosing PLA2R-MN reached 95.4%, whereas the specificity was 63.3%. Combining detection of the urinary exosomal PLA2R and serum aPLA2Rab could develop a more sensitive diagnostic method for PLA2R-MN, especially for patients with serum aPLA2Rab ranging from 2 to 20 RU/mL.

Conclusions

Measurement of urinary exosomal PLA2R could be a sensitive method for the diagnosis of PLA2R-MN.

[State-of-the-art trends in the treatment of immune-mediated inflammatory kidney diseases: Translation of the fundamental science into clinical practice. A review]

Immune-mediated kidney diseases like glomerulonephritis and tubulointerstitial nephritis are not the most common cause of chronic kidney disease in the population, however the difficulties in their management, as well as a more rapid deterioration of kidney function, compared to diabetes mellitus and hypertension, justify the importance of this problem for internal medicine. Due to the fundamental discoveries in pathology and to the introduction of various methods of laboratory and instrumental investigation in the second half of the XX century substantial progress was made in the diagnostic approaches and treatment of these conditions. State-of-the-art diagnostic approach requires complex evaluation of the clinical, laboratory and morphological data to identify the nosological form of the disease. The accumulation of knowledge in the field of diseases' pathogenesis led to the revision of the current classification of glomerulonephritis that should be based on the immunopathogenesis of these conditions. The following phenotypes were suggested: autoimmunity-related, autoinflammation-related, alloimmunity-related, infections-related, and monoclonal gammopathy-related. The assessment of disease activity and chronicity in the kidney tissue should be mandatory. Personalized selection of the optimal treatment modality on the basis of the diagnosis, severity, and individual features of the patient is currently possible. The leading trends include rational prescription of glucocorticoids (steroid-sparing regimens) and cytotoxic agents, e.g. cyclophosphamide, as well as the introduction of multitarget regimens that include biologic agents or small molecules selectively suppressing B-cells or various complement pathways. Another mandatory component of treatment on par with immune suppression is nephroprotective therapy, which currently comprises not only traditional renin-angiotensin-aldosterone antagonists, but also endothelin receptor antagonists and sodium-glucose cotransporter-2 inhibitors. Current guidelines emphasize the importance of the non-pharmacological interventions for the implementation of the nephroprotective strategy. Rational combination of the aforementioned approaches allows for the optimization of the management of patients with immune-mediated kidney diseases, although it requires high competencies and strict adherence to the principles of the evidence-based medicine from the healthcare providers.

Efficacy and safety of rituximab in elderly patients with membranous nephropathy

Objectives: Advancing age is a risk factor for treatment-related side effects and mortality in membranous nephropathy (MN) patients treated with traditional immunosuppressive regimens. This study aimed to determine the efficacy and safety of rituximab (RTX) in the treatment of elderly patients with MN. Methods: We performed a single center retrospective review of 37 consecutive MN patients aged 70 and older at the time of RTX infusion. We also enrolled 76 young patients (<70 years old) with MN as the control group. We assessed clinical and laboratory indices, remission rates, and adverse events at RTX infusion, 3 months, and last visit. Results: A total of 37 elderly patients with MN were included, with a median follow-up period of 15.50 (10.00, 24.40) months. Of the 37 patients, 75.68% were male, and mean age was 71.89 ± 2.47 years. At last visit, 7 (18.92%) patients achieved complete remission, and 26 (70.27%) patients achieved complete or partial remission. There were no differences in the complete remission rate and complete or partial remission rate at last visit compared to young patients (26.32% vs. 18.92%, p = 0.387; 85.53% vs. 70.27%, p = 0.055). After RTX treatment, three of 6 elderly patients with pneumonia died due to ineffective treatment of the infection in RTX therapy courses. The results of multivariant regression analysis showed that elderly patients have an increased risk of serious infection, compared with patients younger than 70 years (OR = 32.874, 95% CI 1.300-831.490, p = 0.034). For each increase of 1 g/L in serum albumin, the risk of serious infection would decrease by 43.2% (OR = 0.568, 95% CI 0.334-0.969, p = 0.038). Conclusion: This study demonstrates that RTX is effective in the treatment of elderly patients with MN. However, we also observed a high incidence of infectious complications. Our experience was limited by its retrospective design and relatively small sample size, and further randomized controlled studies with large sample size are needed to confirm our preliminary findings.

Clinical advances in immunotherapy for immune-mediated glomerular diseases

BACKGROUND AND OBJECTIVE

Due to the suboptimal therapeutic efficacy and potential adverse effects associated with traditional immunosuppressive medications, there has been an increasing emphasis on the development and utilization of immunotherapies. This paper aims to provide clinicians with valuable insights for selecting appropriate therapeutic approaches and contribute to the development of novel immunotherapeutic drugs.

MAIN BODY

This paper categorizes the immunotherapeutic drugs that are used for the treatment of immune-mediated glomerular diseases into three groups: immunotherapies targeting antigen-presenting cells (anti-CD80), immunotherapies targeting T/B cells (anti-CD20, anti-CD22, BAFF and APRIL inhibitors, CD40-CD40L inhibitors, proteasome inhibitors, Syk inhibitors, and Btk inhibitors), and immunotherapies targeting the complement system (C5 inhibitors, C5a/C5aR inhibitors, C3 inhibitors, MASP2 inhibitors, factor B inhibitors, and factor D inhibitors). The article then provides a comprehensive overview of advances related to these immunotherapeutic drugs in clinical research.

CONCLUSION

Certain immunotherapeutic drugs, such as rituximab, belimumab, and eculizumab, have exhibited notable efficacy in treating specific immune-mediated glomerular diseases, thereby providing novel therapeutic approaches for patients. Nonetheless, the efficacy of numerous immunotherapeutic drugs remains to be substantiated.

How to Choose the Right Treatment for Membranous Nephropathy

Membranous nephropathy is an autoimmune disease affecting the glomeruli and is one of the most common causes of nephrotic syndrome. In the absence of any therapy, 35% of patients develop end-stage renal disease. The discovery of autoantibodies such as phospholipase A2 receptor 1, antithrombospondin and neural epidermal growth factor-like 1 protein has greatly helped us to understand the pathogenesis and enable the diagnosis of this disease and to guide its treatment. Depending on the complications of nephrotic syndrome, patients with this disease receive supportive treatment with diuretics, ACE inhibitors or angiotensin-receptor blockers, lipid-lowering agents and anticoagulants. After assessing the risk of progression of end-stage renal disease, patients receive immunosuppressive therapy with various drugs such as cyclophosphamide, steroids, calcineurin inhibitors or rituximab. Since immunosuppressive drugs can cause life-threatening side effects and up to 30% of patients do not respond to therapy, new therapeutic approaches with drugs such as adrenocorticotropic hormone, belimumab, anti-plasma cell antibodies or complement-guided drugs are currently being tested. However, special attention needs to be paid to the choice of therapy in secondary forms or in specific clinical contexts such as membranous disease in children, pregnant women and patients undergoing kidney transplantation.

Overlap of Primary Membranous Nephropathy, IgA Nephropathy, and Diabetic Nephropathy: A Case Report

The coexistence of primary membranous nephropathy (PMN), immunoglobulin A nephropathy (IgAN), and diabetic nephropathy (DN) in the same patient has been a subject of clinical and pathological investigation, yielding inconclusive results. The limited availability of cases and resource materials has hindered a comprehensive understanding of this phenomenon. We present the case of a 70-year-old Saudi Arabian man diagnosed with type 2 diabetes mellitus and nephrotic syndrome. A kidney biopsy revealed the coexistence of PMN, IgAN, and DN. The patient presented with an unusual and rare combination of PMN, IgAN, and DN. To address his condition, the patient consented to rituximab therapy and planned follow-up with the kidney transplant team. However, before the first dose of rituximab could be administered, the patient experienced severe septic shock secondary to pneumonia, which tragically led to his demise. The simultaneous occurrence of PMN, IgAN, and DN represents a rare and scarcely documented condition. The purpose of this article is to report this exceptional case, emphasizing the significance of further research to deepen the understanding of the underlying pathology behind these concurrent renal disorders. This report aims to shed light on the complexities of managing such complex cases and advancing therapeutic approaches in the future.

Development and External Validation of a Nomogram for Predicting the Effect of RTX on the Treatment of Membranous Nephropathy

Introduction

Rituximab (RTX) has been shown to be effective in inducing immunological remission in patients with membranous nephropathy (MN). Some patients required more than one course of RTX to achieve immunological remission. Identifying patients who need more courses of RTX to achieve immunological remission is beneficial for better physician-patient communication, the assessment of treatment course, and the evaluation of medical costs. This study aims to establish a practical model to predict the probability of immunological remission after receiving one cycle of RTX.

Methods

This study enrolled 106 patients from the First Affiliated Hospital of Zhengzhou University in the modeling group and 30 patients from Henan Provincial Hospital of Traditional Chinese Medicine in the external validation group. Patients in the modeling group were divided into responders or nonresponders according to whether they achieved immunological remission or not after following up for 6 months. A nomogram was established based on the results of logistic regression analysis. The predictive performance of the nomogram was evaluated by the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis (DCAs).

Results

In the modeling group, 75 (70.8%) patients achieved immunological remission within 6 months after receiving one cycle of RTX. Significant differences were observed between nonresponders and responders. Risk factors used in nomogram included PLA2R antibody, hemoglobin, and gender. The AUC value of nomogram was 0.797 (95% CI 0.701-0.894, P<0.001). The calibration curves demonstrated acceptable agreement between the predicted outcomes by the nomogram and the actual values. DCA curves showed good positive net benefits in the predictive model. The external validation also demonstrated the reliability of the prediction nomogram.

Conclusion

A predictive nomogram including PLA2R antibody, hemoglobin, and gender may provide a basis to predict the doses of RTX needed in MN patients.

The place of cyclical therapy for the treatment of membranous nephropathy in the era of rituximab

Primary membranous nephropathy (MN) is the most frequent cause of nephrotic syndrome in adults, due to a variety of autoantibodies, most frequently against phospholipase A2 receptor (PLA2R). In severe cases or when spontaneous remission is not achieved, immunosuppression is required. Cyclical therapy, based on glucocorticoids and cyclophosphamide on alternate months for 6 months, has proven effective to induce remission and reduce the risk of end-stage renal disease. Since the early 2000s, rituximab (RTX) has emerged as a key player in the management of MN, showing overall comparable effectiveness and likely better safety compared with the cyclical regimen, despite the lack of adequately powered trials comparing the two approaches head to head. For these reasons, RTX is now considered the agent of choice for most patients with MN. However, there are still uncertainties. Around 20-40% of patients are resistant to RTX, especially in the setting of high anti-PLA2R levels, and this drug remains relatively unexplored in patients with the most severe disease. In these scenarios, although the expanding therapeutic armamentarium is probably going to provide further options, the cyclical regimen still plays a key role as a safety net. The aim of this article is to illustrate the role of cyclical therapy in the RTX era.

Anti-CD20 should be the first-line treatment in high-risk membranous nephropathy

Membranous nephropathy (MN) is a common cause of nephrotic syndrome (NS) in adults and if untreated can progress to endstage kidney disease. Factors considered to place a patient at high or very high risk for progression include elevated serum creatinine at baseline, declining kidney function, persistent heavy proteinuria (>8 g/24 h), or persistent NS, presence of life-threatening complications related to NS (such as venous thromboembolic events), or very high anti-PLA2R antibody titers (>150 RU/ml). Patients who are at high or very high risk of progression should be treated with immunosuppression therapy to induce remission of proteinuria and to avoid progressive loss of kidney function. Traditional forms of immunosuppression for patients with MN have included the use of cyclic courses of corticosteroids with cyclophosphamide or calcineurin inhibitors. These forms of therapy are associated with significant toxicity, e.g. corticosteroids (infections, diabetes, weight gain), cyclophosphamide (infertility, severe leukopenia, malignancy), and calcineurin inhibitors (hypertension, nephrotoxicity). The introduction of anti-CD20+ B-cell therapies in the late 1990s has changed the landscape. In this article we will argue that anti-CD20+ B therapy should be the treatment of choice for patients at high/very high risk of progression when considering its efficacy and side-effect profile.

Rituximab, Use and B Cell Depletion in Patients with Membranous Nephropathy- A Retrospective, Observational Study

Introduction

Rituximab (Rtx), an anti-CD20 monoclonal antibody, results in selective B-cell depletion and has emerged as an important therapeutic option in idiopathic membranous nephropathy (MN). We conducted a retrospective observational study to evaluate the efficacy and tolerability of Rtx in MN with respect to the B-cell count depletion.

Methods

Twenty patients with biopsy proven primary MN, both treatment naïve and treatment resistant, who received a fixed dose protocol of 500mg IV Rtx 1month apart were retrospectively observed with a minimum follow-up period of 12 months. The primary clinical outcome was complete (CR) or partial remission (PR) at 12 months in relation to B-cell depletion at 6 and 12 months.

Results

All were patients (men, 90%) of PLA2R-Ab positive with MN with a mean age of 37.7 ± 12.5 years. The mean 24-h urinary protein was 7.5 ± 2.15 gm/day, serum albumin was 2.01 ± 0.6gm/dL, and eGFR was 86.5 ± 20 mL/min/1.73m2. Primary composite outcome at 12 months was 66.7%, with 5.6% CR and 61.1% PR.The mean PLA2R-Ab at 12 months was low in those with remission compared to those who did not achieve (17.8 ± 21.2 RU/mL vs 311.7 ± 356.0; P = 0.01). Sustained B cell depletion at 6 months was seen in 84.3% (OR = 2.2, 95% CI = 0.11-42.7; P = 0.53) and 32% at 12 months (OR = 2.25, 95% CI = 0.18-27.7, and P = 0.66).

Conclusion

Acceptable remission rates were seen with Rtx in both treatment naïve and treatment-resistant patients with MN. There was no significant association between B-cell depletion and remission.

Present and Future of IgA Nephropathy and Membranous Nephropathy Immune Monitoring: Insights from Molecular Studies

IgA Nephropathy (IgAN) and Membranous Nephropathy (MN) are primary immune-mediated glomerular diseases with highly variable prognosis. Current guidelines recommend that greater immunologic activity and worse prognosis should guide towards the best treatment in an individualized approach. Nevertheless, proteinuria and glomerular filtration rate, the current gold standards for prognosis assessment and treatment guidance in primary glomerular diseases, may be altered with chronic damage and nephron scarring, conditions that are not related to immune activity. In recent years, thanks to the development of new molecular technologies, among them genome-wide genotyping, RNA sequencing techniques, and mass spectrometry, we have witnessed an outstanding improvement in understanding the pathogenesis of IgAN and MN. In addition, recent genome-wide association studies have suggested potential targets for immunomodulating agents, stressing the need for the identification of specific biomarkers of immune activity. In this work, we aim to review current evidence and recent progress, including the more recent use of omics techniques, in the identification of potential biomarkers for immune monitoring in IgAN and MN.

[State-of-the-art paradigm of corticosteroid therapy for immune-mediated inflammatory kidney diseases]

Since 1950's corticosteroids (CS) have remained the cornerstone of immunosuppressive therapy for immune-mediated kidney diseases. However multiple adverse events, associated with the prolonged CS therapy, became the basis for the development of novel treatment approaches. Current evidence supports the implementation of the steroid-sparing regimens for the treatment of different types of glomerulonephritis. Randomised controlled trial PEXIVAS demonstrated the efficacy and safety of early steroid tapering, starting from the second week of therapy, in patients with ANCA-associated vasculitis with kidney involvement. Several trials showed the efficacy of oral prednisolone 0.3-0.5 mg/kg/daily as a part of multitarget therapy for severe proliferative lupus nephritis. A combination of calcineurin inhibitors and low-dose CS are effective for remission induction in membranous nephropathy, as well as the steroid-free rituximab regimen for the patients with moderate risk of disease progression. Medium dose CS showed promising effect in patients with IgA-nephropathy. Long-term high dose CS remain the standard-of-care for the treatment of minimal change disease and focal segmental glomerulosclerosis, however patients with steroid-dependent and relapsing disease tacrolimus and rituximab can help to achieve steroid-sparing effect. The role of CS pulse-therapy is currently debated, nevertheless it remains a compulsory treatment in several conditions. Thus, overall trend is directed towards the minimization of the maximal doses of CS and/or treatment duration. However, to implement this approach morphological verification of the diagnosis and personalized assessment of the potential risk and benefit are required.

Future landscape for the management of membranous nephropathy

Among all glomerular diseases, membranous nephropathy (MN) is perhaps the one in which major progress has been made in recent decades, in both the understanding of the pathogenesis and treatment. Despite the overall significant response rates to these therapies-particularly rituximab and cyclical regimen based on corticosteroids and cyclophosphamide-cumulative experience over the years has shown, however, that 20%-30% of cases may confront resistant disease. Thus, these unmet challenges in the treatment of resistant forms of MN require newer approaches. Several emerging new agents-developed primarily for the treatment of hematological malignancies or rheumatoid diseases-are currently being evaluated in MN. Herein we conducted a narrative review on future therapeutic strategies in the disease. Among the different novel therapies, newer anti-CD20 agents (e.g. obinutuzumab), anti-CD38 (e.g. daratumumab, felzartamab), immunoadsorption or anti-complement therapies (e.g. iptacopan) have gained special attention. In addition, several technologies and innovations developed primarily for cancer (e.g. chimeric antigen receptor T-cell therapy, sweeping antibodies) seem particularly promising. In summary, the future therapeutic landscape in MN seems encouraging and will definitely move the management of this disease towards a more precision-based approach.