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

PLA2R Antibody Does Not Outperform Conventional Clinical Markers in Predicting Outcomes in Membranous Nephropathy

Introduction

The prognostic value of PLA2R antibody (Ab) test in clinical practice remains unclear. We aimed to evaluate its ability in predicting hard outcomes in primary membranous nephropathy (PMN) after adjustments to conventional markers of disease activity.

Methods

A total of 222 patients diagnosed with PMN from January 2003 to July 2019 having had a serum PLA2R Ab test, were included from 3 centers in the north of England. Baseline conventional markers, PLA2R-Ab-status (positive vs. negative), Ab-titer (high vs. low), and time of testing (pre-PLA2R era vs. PLA2R era) were evaluated for association with outcomes. Primary outcome was time to progression (composite of doubling of creatinine, stage 5 chronic kidney disease, or death). Secondary outcomes were time to partial remission (PR) and time to immunosuppression. Cox proportional hazard testing was used.

Results

During a median follow-up of 5.26 years, progression was seen in 65 (29.3%) and PR in 179 of 222 patients (80.6%). There was a clear association of estimated glomerular filtration rate (eGFR) (standardized hazard ratio [HRZ] = 0.767, P < 0.05) and urine protein-to-creatinine ratio (uPCR) (HRZ = 1.44, P < 0.005) with time to progression among all patients, and eGFR (HRZ = 0.606, P < 0.005) in Ab-positive patients. Baseline Ab-positivity was not associated with time to progression (adjusted hazard ratio [aHR] = 0.93, P = 0.71) or time to PR (aHR = 0.84, P = 0.13). Similarly, baseline high Ab-titer was not associated with time to progression (aHR = 1.07, P = 0.77) or time to PR (aHR = 0.794, P = 0.08).

Conclusion

Once adjusted to conventional markers of disease activity, baseline PLA2R Ab-positivity or Ab-titer do not predict disease progression or time to PR. Further studies are needed to harness the utility of PLA2R Ab test in prognostication in PMN.

Contemporary Monoclonal Antibody Utilization in Glomerular Diseases

Therapeutic monoclonal antibodies (MAbs) have been one of the fastest growing drug classes in the past 2 decades and are indicated in the treatment of cancer, autoimmune disorders, solid organ transplantation, and glomerular diseases. The Food and Drug Administration has approved 100 MAbs between 1986 and 2021, and MAbs account for 20% of Food and Drug Administration's new drug approval every year. MAbs are preferred over traditional immunosuppressive agents because of their high specificity, reduced number of drug-drug interactions, and low toxicity, which make them a prime example of personalized medicine. In this review article, we provide an overview of the taxonomy, pharmacology, and therapeutic applications of MAbs in glomerular diseases. We searched the literature through PubMed using the following search terms: monoclonal antibodies, glomerular diseases, pharmacokinetics, pharmacodynamics, immunoglobulin, murine, chimeric,humanized, and fully human, and limited our search to years 2018-2023. We selected peer-reviewed journal articles with an evidence-based approach, prioritizing randomized control trials in specific glomerular diseases, if available. Advances in the MAb field have resulted in a significant paradigm shift in targeted treatment of immune-mediated glomerular diseases, and multiple randomized control trials are currently being conducted. Increased recognition is critical to expand their use in experimental research and personalized medicine.

The Role of PLA2R in Primary Membranous Nephropathy: Do We Still Need a Kidney Biopsy?

Membranous nephropathy (MN) is the most prevalent cause of nephrotic syndrome amongst the non-diabetic adult population. A fifth of idiopathic nephrotic syndrome cases can be attributed to MN, rising to more than 40% in older patients over 60 years. Most MN cases are classified as being of a primary cause, where there is absence of a secondary disease process explaining its manifestation. Traditionally, the standard approach of diagnosing MN involves performing a kidney biopsy as histological evaluation offers not only conclusive evidence of the diagnosis but also provides valuable information regarding disease chronicity and the presence of any other kidney histopathological features. Nevertheless, kidney biopsy is an invasive procedure which poses risks for the patient including bleeding and pain and bears greater costs for the health system. The identification of the phospholipase A2 receptor (PLA2R) antigen in 2009 was a landmark discovery, one which has evolved our understanding of the disease processes in MN and subsequently our management approach of this condition. Antibodies against PLA2R (PLA2RAb) have since emerged as an attractive non-invasive test option to be applied for the diagnosis and prognostication of primary MN. However, much debate and unknowns remain about the accuracy and reliability of testing for PLA2RAb across various primary MN scenarios. We provide a review summarizing the historical journey of PLA2R in relation to its significance in primary MN and, more importantly, evidence emerging over the years which contemplated the role of PLA2RAb as a diagnostic and prognostic tool in primary MN.

Monthly mini-dose rituximab for primary anti-PLA2R-positive membranous nephropathy: a personalized approach

BACKGROUND

The currently recommended dose of rituximab for primary membranous nephropathy is as high as that for lymphoma. However, the clinical manifestations of membranous nephropathy vary widely. Therefore, achieving individualized treatment is a topic that needs to be explored. This study assessed the efficacy of monthly mini-dose rituximab monotherapy in patients with primary membranous nephropathy.

METHODS

This retrospective study included 32 patients with primary membranous nephropathy treated at Peking University Third Hospital between March 2019 and January 2023. All patients were anti-phospholipase A2 receptor (PLA2R) antibody-positive and received rituximab 100 mg intravenously monthly for at least 3 months without other immunosuppressive therapy. Rituximab infusions were sustained until either remission of the nephrotic syndrome or a minimum serum anti-PLA2R titer ˂ 2 RU/mL was achieved.

RESULTS

The baseline parameters included: proteinuria, 8.5 ± 3.6 g/day; serum albumin, 24.8 ± 3.4 g/L; and anti-PLA2R antibody, 160 (20-2659) RU/mL. B-cell depletion was achieved in 87.5% patients after the first dose of rituximab 100 mg and in 100% after the second equivalent dose. The median follow-up was 24 months (range 18-38). Twenty-seven (84%) patients achieved remission, with 11 (34%) patients achieving complete remission by last follow-up. The relapse-free survival from the last infusion was 13.5 months (range 3-27). Patients were stratified into the low-titer (< 150 RU/mL, n = 17) and high-titer groups (≥ 150 RU/mL, n = 15) based on the anti-PLA2R titer. Sex, age, urinary proteins, serum albumin, and estimated glomerular filtration rate at baseline did not differ significantly between the two groups. At 18 months, compared to the low-titer group, the rituximab dose (960 ± 387 vs 694 ± 270 mg, p = 0.030) was higher, while serum albumin (37.0 ± 5.4 vs 41.3 ± 5.4 g/L, p = 0.033) and the complete remission rate (13% vs 53%, p = 0.000) were both lower in the high-titer group.

CONCLUSIONS

Monthly rituximab 100 mg appeared as a potential effective regimen for treating anti-PLA2R-associated primary membranous nephropathy with a low anti-PLA2R titer. The lower the anti-PLA2R titer, the lower the rituximab dose required to achieve remission.

TRIAL REGISTRATION

A retrospective study, registered at ChiCTR (ChiCTR2200057381) on March 10, 2022.

The Safety and Efficacy of Rituximab-Based Regimen in Atypical Membranous Nephropathy: A Single Center Retrospective Cohort Study

Purpose

There are increasing reports of atypical membranous nephropathy (AMN) cases with similar pathological characteristics to secondary membranous nephropathy (SMN) without definite underlying causes. Although rituximab has become a first-line option in treating idiopathic membranous nephropathy (IMN), the efficacy and safety of rituximab-based regimen for AMN is not clear.

Patients and Methods

This is a retrospective, single-center study. AMN patients who received rituximab-based therapy were included. IMN patients treated with rituximab during the same period were selected as the control group matched by gender, sex, baseline urinary protein and albumin levels. Baseline data and follow-up data were collected.

Results

A total of 20 AMN patients and 40 IMN patients were included. The baseline levels of urinary protein were comparable between the two groups [6.77 (IQR 3.34, 11.49) g/24 h vs 6.47 (IQR 3.4, 10.76) g/24 h, P=0.944]. The baseline levels of serum albumin were 26.15±6.71 g/L and 26.8±5.54 g/L (P=0.689) respectively. The cumulative remission rate for rituximab-based treatment at the 12th month was lower in AMN group than IMN group [13 (65%) vs 36 (90%), P=0.045]. In AMN group, non-responders showed a higher level of proteinuria and a worse renal function at baseline than those of responders. There was no significant difference in the overall adverse events or serious adverse events between the two groups.

Conclusion

In our study, AMN patients obtained proteinuria remission in a lower percentage compared with IMN patients. In general, rituximab-based therapy is effective in AMN patients with an acceptable safety profile.

Membranous nephropathy: Mechanistic insights and therapeutic perspectives

Membranous nephropathy (MN) is one of the most common causes of non-diabetic nephrotic syndrome in adults. About 80% of cases are renal limited (primary MN) and 20% are associated with other systemic diseases or exposures (secondary MN). Autoimmune reaction is the main pathogenic factor of MN, and the discovery of autoantigens including the phospholipase A₂ receptor and thrombospondin type-1 domain-containing protein 7A has led to new insights into the pathogenesis, they can induce humoral immune responses led by IgG₄ makes them suitable for the diagnosis and monitoring of MN. In addition, complement activation, genetic susceptibility genes and environmental pollution are also involved in MN immune response. In clinical practice, due to the spontaneous remission of MN, the combination of supportive therapy and pharmacological treatment is widely used. Immunosuppressive drugs are the cornerstone of MN treatment, and the dangers and benefits of this approach vary from person to person. In summary, this review provides a more comprehensive review of the immune pathogenesis, interventions and unresolved issues of MN in the hope of providing some new ideas for clinical and scientific researchers in the treatment of MN.

Efficacy of low-dose rituximab in minimal change disease and prevention of relapse

BACKGROUND

Minimal change disease (MCD) is a major cause of nephrotic syndrome (NS) in children and a minority of adults. The higher tendency to relapse put patients at risk for prolonged exposure to steroids and other immunosuppressive agents. B cell depletion with rituximab (RTX) may be beneficial to the treatment and prevention of frequently relapsing MCD. Therefore, this study aimed to verify the therapeutic/preventive effects of low-dose RTX on the relapse in adult with MCD.

METHODS

A total of 33 adult patients were selected for the study, including 22 patients with relapsing MCD in relapse treatment group who were treated with low-dose RTX (200 mg per week × 4 following by 200 mg every 6 months) and 11 patients in relapse prevention group with complete remission (CR) after steroid therapy were treated with RTX (200 mg ×1 every 6 months) for preventing the relapse of MCD.

RESULTS

Of the 22 patients with MCD in relapse treatment group, there were 21 cases (95.45%) of remission [2 (9.09%) partial remission (PR), 19 (86.36%) CR], 1 (4.56%) no remission (NR) and 20 (90.90%) relapse-free. The Median duration of sustained remission was 16.3 months (3, 23.5 months, inter quartile range (IQR)). 11 patients in the relapse prevention group during a follow-up of 12 months (9-31 months) had no relapse. The average dose of prednisone in two groups after RTX treatment was significantly lower than before treatment.

CONCLUSION

The results of this study suggested low-dose RTX can significantly reduce relapse rate and steroid dose in adults with MCD with fewer side effects. Low-dose RTX regimens may be beneficial for the treatment of relapsing MCD in adults and may be the preferred regimen for patients at high risk for the development of adverse events from corticosteroids.

Serum 25-hydroxyvitamin D as a predictive biomarker of clinical outcomes in patients with primary membranous nephropathy

Background

Primary membranous nephropathy (PMN) is an immune-related disease with increased morbidity and the most common cause of adult nephrotic syndrome (NS). The serum 25-hydroxyvitamin D [25(OH)D)], a biomarker of vitamin D (VD) status, tends to decline in patients with kidney disease. However, the relationship between 25(OH)D and PMN is still unclear. Therefore, this study aims to clarify the association between 25(OH)D and disease severity and therapy response of PMN.

Methods

A total of 490 participants diagnosed with PMN by biopsy from January 2017 to April 2022 were recruited at the First Affiliated Hospital of Nanjing Medical University. The correlations between baseline 25(OH)D and manifestations of nephrotic syndrome (NS) or seropositivity of anti-PLA2R Ab were confirmed by univariate and multivariate logistic analyses. Spearman's correlations were used to examine the associations between baseline 25(OH)D and other clinical parameters. In the follow-up cohort, Kaplan-Meier analysis was used to assess remission outcomes among groups with low, medium, and high levels of 25(OH)D. Furthermore, the independent risk factors for non-remission (NR) were explored by COX regression analysis.

Results

At baseline, 25(OH)D was negatively related to 24-h urinary protein and serum anti-PLA2R Ab. The lower level of baseline 25(OH)D was associated with an increased risk for the incidence of NS in PMN (model 2, OR 6.8, 95% CI 4.4, 10.7, P < 0.001) and seropositivity of anti-PLA2R Ab (model 2, OR 2.4, 95% CI 1.6, 3.7, P < 0.001). Furthermore, the lower level of 25(OH)D during follow-up was demonstrated as an independent risk factor for NR even after adjusting age, gender, MBP, 24 h UP, serum anti-PLA2R Ab, serum albumin, and serum C3 [25(OH)D (39.2-62.3 nmol/L): HR 4.90, 95% CI 1.02, 23.53 P = 0.047; 25(OH)D < 39.2 nmol/L: HR 17.52, 95% CI 4.04, 76.03 P < 0.001); vs. 25(OH)D ≥ 62.3 nmol/L]. The Kaplan-Meier survival analysis also demonstrated that the higher level of follow-up 25(OH)D had a higher possibility of remission than the lower one (log-rank test, P < 0.001).

Conclusion

Baseline 25(OH)D was significantly correlated with nephrotic proteinuria and seropositivity of anti-PLA2R Ab in PMN. As an independent risk factor for NR, a low level of 25(OH)D during follow-up might serve as a prognostic tool for sensitively identifying cases with a high probability of poor treatment response.

Update on the Application of Monoclonal Antibody Therapy in Primary Membranous Nephropathy

When first introduced, rituximab (RTX), a chimeric anti-CD20 monoclonal antibody, brought about an alternative therapeutic paradigm for primary membranous nephropathy (PMN). Rituximab was shown to be effective and safe in PMN patients with kidney dysfunction, with. patients receiving second-line rituximab therapy achieving remission as effectively as those patients who had not previously received immunotherapy. No safety issues were reported. The B cell-driven protocol seems to be as efficient as the 375 mg/m² × 4 regimen or 1 g × 2 regimen in achieving B cell depletion and remission, but patients with high M-type phospholipase A2 receptor (PLA2R) antibody levels may benefit from a higher dose of rituximab. While rituximab added another therapeutic option to the treatment regimen, it does have limitations as 20 to 40% of patients do not respond. Not all patients respond to RTX therapy for lymphoproliferative disorders either, therefore further novel anti-CD20 monoclonal antibodies have been developed and these may provide alternative therapeutic options for PMN. Ofatumumab, a fully human monoclonal antibody, specifically recognizes an epitope encompassing both the small and large extracellular loops of the CD20 molecule, resulting in increased complement-dependent cytotoxic activity. Ocrelizumab binds an alternative but overlapping epitope region to rituximab and displays enhanced antibody-dependent cellular cytotoxic (ADCC) activities. Obinutuzumab is designed to have a modified elbow-hinge amino acid sequence, leading to increased direct cell death induction and ADCC activities. In PMN clinical studies, ocrelizumab and obinutuzumab showed promising results, while ofatumumab displayed mixed results. However, there is a lack of randomized controlled trials with large samples, especially direct head-to-head comparisons. Alternative molecular mechanisms have been suggested in this context to explore novel therapeutic strategies. B cell activator-targeted, plasma cell-targeted and complement-directed treatments may lead to novel therapy paradigms for PMN. Exploratory strategies for the use of drugs with different mechanisms, such as a combination of rituximab and cyclophosphamide and a steroid, a combination of rituximab and a calcineurin inhibitor, may provide more rapid and efficient remission, but the combination of standard immunosuppression with rituximab could increase infection risk.

The characters of antibodies against PLA2R in healthy individuals and in the patient with PLA2R associated membranous nephropathy

BACKGROUND

Most primary membranous nephropathy (MN) is mediated by anti-phospholipase A2 receptor (PLA2R) antibodies. Recently, these antibodies have been revealed months to years before the disease's onset. Their production and pathogenicity need further investigation.

METHODS

Anti-PLA2R antibodies were purified from plasma of eight healthy individuals, 12 patients with PLA2R-related MN and negative circulating antibody (Ab-), and 18 patients with positive anti-PLA2R antibodies (Ab +), using affinity column coupled with recombinant human PLA2R. The antigen specificity, antibody amount, titer, IgG subclass, and affinity were assessed by Western blot, immunofluorescence, ELISA, and surface plasmon resonance.

RESULTS

The natural anti-PLA2R antibodies recognized the conformational structure of PLA2R which locates on the cell membrane of podocytes. The amount of natural IgG was 0.12 ± 0.04 g/L, which accounted for 0.80% of total IgG and was lower than that of patients (2.36%, P < 0.001). The titer of natural antibodies was lower than that of patients in Ab- and Ab + groups (1:16 vs. 1:43 vs. 1:274, P < 0.001). IgG2(45.1%) was predominant in natural antibodies, while IgG4 was predominant in Ab + group (45.7 vs. 25.0%, P < 0.001). IgG1 was increasing from natural antibodies to Ab- and Ab + groups. The affinity of natural antibodies was lower than that of patients (K_D: 641.0 vs. 269.0 vs. 99.6 nM, P = 0.002). The antibody titer, affinity, and IgG4 percentage were associated with the severity of proteinuria and the stages of membranous lesion.

CONCLUSIONS

The natural anti-PLA2R antibodies exist in healthy plasma. The antibody titer, IgG subclass, and affinity may participate in the pathogenesis of anti-PLA2R antibodies.

Immunosuppressive Agent Options for Primary Nephrotic Syndrome: A Review of Network Meta-Analyses and Cost-Effectiveness Analysis

Therapeutic options with immunosuppressive agents for glomerular diseases have widened with refinements to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines from 2012 to 2021. However, international guidelines do not necessarily match the reality in each country. Expensive therapies such as rituximab and calcineurin inhibitors are sometimes inaccessible to patients with refractory nephrotic syndrome due to cost or regulations. Under the Japanese medical insurance system, rituximab is accessible but still limited to steroid-dependent patients who developed idiopathic nephrotic syndrome in childhood. Based on international KDIGO guidelines and other national guidelines, possible applications of immunosuppressive agents for nephrotic syndrome are comprehensively examined in this review. While rituximab has become the mainstay of immunosuppressive therapy for nephrotic syndrome, clinical trials have indicated that options such as cyclophosphamide, calcineurin inhibitors, and mycophenolate mofetil would be preferable. Given the rising number of patients with nephrotic syndrome worldwide, KDIGO guidelines mention the need for further consideration of cost-effectiveness. If the new option of rituximab is to be the first choice in combination with steroids for nephrotic syndrome, its cost-effectiveness should also be verified. Among the few studies examining the cost-effectiveness of treatments for nephrotic syndrome, administration of rituximab to young adults has been shown to be cost-beneficial, at least in Japan. However, further large-scale studies involving multiple facilities are needed to verify such findings. Network meta-analyses have concluded that the efficacy of rituximab remains controversial and confirmation through high-quality studies of large cohorts is needed. To this end, the mechanisms of action underlying immunosuppressive agents, both old and new, need to be understood and experience must be accumulated to evaluate possible effects and side effects.

Novel Treatments Paradigms: Membranous Nephropathy

Primary membranous nephropathy (MN) is a kidney-specific autoimmune glomerular disease and the leading cause of nephrotic syndrome (NS) in White adults, usually caused by antiphospholipase A2 receptor (PLA2R) antibodies, although several new target antigens have been recently identified. It is characterized by the diffuse thickening of the glomerular basement membrane secondary to immune complex deposition. In patients with persistent NS without response to maximizing conservative therapy including the use of renin-angiotensin system (RAS) blockers, the use of immunosuppressive agents is warranted. However, the optimal immunosuppressive treatment has not yet been established. Classical immunosuppressants, such as cyclophosphamide plus steroids, are effective but may cause clinically relevant adverse effects, limiting their use. Rituximab offers efficacy with a better safety profile whereas calcineurin inhibitors (CNIs) are marred by high relapse rates and nephrotoxicity. Nevertheless, up to 30% of patients fail to respond to standard therapy. Novel and specific therapies targeting B cells and plasma cells have shown encouraging preliminary results, in terms of clinical efficacy and safety profile, especially in patients with poor tolerance or refractory to conventional treatments. In this brief review, we discuss the benefits and limitations of the current therapeutic approach to MN and describe emerging novel therapies that target its pathogenesis.

Efficacy of low or heavy rituximab‑based protocols and comparison with seven regimens in idiopathic membranous nephropathy: a systematic review and network meta-analysis

OBJECTIVE

Numerous studies have demonstrated the efficiency of tacrolimus + rituximab and rituximab in idiopathic membranous nephropathy (IMN). But optimal dosages of rituximab for IMN are still controversial. This network meta-analysis (NMA) was conducted to compare the efficacy of different rituximab dosages and other main treatments in IMN treatment.

METHODS

Randomized controlled trials (RCTs) and observational studies analyzing nine therapeutic regimens for IMN were included from some databases. Network comparisons were performed to analyze the rates of total remission (TR) and relapse rate. The surface under the cumulative ranking area (SUCRA) was calculated to rank interventions.

RESULTS

Twelve RCTs and 12 observational studies involving 1724 patients were pooled for comparison of 9 interventions. This NMA demonstrated steroids + tacrolimus was ranked first in the aspect of total remission at 6 months (92%) and 12 months (81.3%). The total remission rate associated with tacrolimus + rituximab increased rapidly between the sixth (SUCRA 22.5%) and the twelfth month (SUCRA 63.9%). Tacrolimus and cyclosporine A were associated with higher total remission at 6 months (78.8% and 65.4%, separately) and decreased at 12 months (58.1 and 34.9%, separately). Steroids + cyclophosphamide, rituximab (Heavy dose) and rituximab (Low dose) had stable remission rates at 6 (63.7%, 46.6%, and 19.4%) and 12 months (SUCRA 66.9%, 39.6%, and 28.8%). Tacrolimus and cyclosporine A were associated with a significantly higher risk of relapse than that with steroids + cyclophosphamide, rituximab (Heavy dose), and rituximab (Low dose).

CONCLUSIONS

For IMN in adults, steroids + tacrolimus was ranked first in the aspect of total remission, followed by steroids + cyclophosphamide and steroids + cyclosporine A. The TR associated with rituximab (Heavy and Low dosage) at 12 months was higher than that at 6 months. And rituximab (Heavy dose) achieves a higher rate of total remission than that of rituximab (Low dose).

Association Between High NK-Cell Count and Remission of Primary Membranous Nephropathy: A Retrospective Chart Review and Pilot Study

PURPOSE

Primary membranous nephropathy (PMN) is the most frequent cause of nephrotic syndrome in adults. Rituximab monotherapy has emerged as a front-line treatment for patients with PMN, but potential markers for predicting the response to rituximab are unknown.

METHODS

In this single-arm retrospective pilot study, 48 patients with PMN without previous immunosuppressive therapy were enrolled. All patients were treated with rituximab and were followed up for at least 6 months. The primary end point was the achievement of complete or partial remission at 6 months. The subsets of lymphocytes were collected at baseline, 1 month, 3 months and 6 months to identify prognostic factors for achieving remission of PMN with rituximab therapy.

FINDINGS

A total of 58.3% of patients (28/48) achieved remission. Lower serum creatinine, greater serum albumin, and greater phospholipase A2 receptor antigen detected in kidney biopsy at baseline were found in the remission group. After multiple adjustments, a high percentage of natural killer (NK) cells at baseline, especially ≥15.7%, was strongly associated with remission (relative risk = 1.62; 95% CI, 1.00-2.62; P = 0.049), and patients with a response to rituximab had a greater mean percentage of NK cells during the follow-up period compared with nonresponders. Analysis using a receiver operating characteristic curve indicated prognostic value of the NK-cell percentage at baseline, with an area under the curve of 0.716 (95% CI, 0.556-0.876; P = 0.021).

IMPLICATIONS

The findings from this retrospective pilot study suggest that a high percentage, especially ≥15.7%, of NK cells at baseline might predict a response to rituximab treatment. These findings provide a basis for designing larger-scale studies to test the predictive value of NK cells in patients with PMN undergoing rituximab treatment.

Primary membranous nephropathy: an endless story

Primary membranous nephropathy (PMN) is an autoimmune disease caused by the attack of autoantibodies against podocyte antigens leading to the in situ production of immune complexes. However, the etiology is unknown and the pathogenesis is still far from being completely elucidated. MN is prevalently idiopathic or primary, but in about 20-30% of cases it is secondary to chronic infections, systemic diseases, exposure to drugs, or malignancy. The differentiation between primary and secondary MN may be difficult, particularly when MN precedes signs and symptoms of the original disease, as in some cases of cancer or systemic lupus erythematosus. The natural course of PMN is variable, but in the long term 40-60% of patients with nephrotic syndrome progress to end-stage renal disease (ESRD) or die from thrombotic or cardiovascular events. PMN is a treatable disease. Patients with asymptomatic proteinuria should receive supportive care. Immunosuppressive treatments should be given to patients with nephrotic syndrome or risk of progression. The most frequently adopted treatments rely on cyclical therapy alternating steroids with a cytotoxic agent every other month, i.e., rituximab at different doses, or calcineurin inhibitors plus low-dose steroids. A good rate of response may be obtained but relapses can occur. Randomized controlled trials, with adequate size, long-term follow-up, and fair definition of endpoints are needed to identify treatment with the best therapeutic index.

From KDIGO 2012 towards KDIGO 2021 in idiopathic membranous nephropathy guidelines: what has changed over the last 10 years?

The recommendations in the Kidney Disease: Improving Global Outcomes (KDIGO) 2021 guidelines regarding Idiopathic Membranous Nephropathy (IMN) management include significant changes as compared to those published in 2012. According to the recent guidelines, a biopsy is not always needed for IMN diagnosis; since diagnosis can be allowed for by the detection of circulating antibodies against the M-type transmembrane phospholipase A2 receptor (anti-PLA2R). Moreover, alterations in anti-PLA2R concentrations, along with other serum and urinary markers, may guide further follow-up. The findings of numerous recent studies which compared different immunosuppressive treatments resulted in substantial changes in treatment indications in the KDIGO 2021 guidelines, suggesting the stratification of patients into four risk categories. The definition of resistant cases and relapses was likewise modified. All the above will lead to a more granular and personalized approach, whose results need to be tested over time. In this commentary, we discuss the changes in the 2012 and 2021 guidelines, adding information from the most recent literature.

Glomerular diseases in pregnancy: pragmatic recommendations for clinical management

Our understanding of the various aspects of pregnancy in women with kidney diseases has significantly improved in the last decades. Nevertheless, little is known about specific kidney diseases. Glomerular diseases are not only a frequent cause of chronic kidney disease in young women, but combine many challenges in pregnancy: immunologic diseases, hypertension, proteinuria, and kidney tissue damage. An international working group undertook the review of available current literature and elicited expert opinions on glomerular diseases in pregnancy with the aim to provide pragmatic information for nephrologists according to the present state-of-the-art knowledge. This work also highlights areas of clinical uncertainty and emphasizes the need for further collaborative studies to improve maternal and fetal health.

Treatment of membranous nephropathy: Perspectives on current and future therapies

Primary membranous nephropathy remains one of the most frequent causes of nephrotic syndrome in adults. It is an autoimmune disorder in which auto-antibodies target antigens at the podocytes cell membrane-basement membrane interface. Our understanding of membranous nephropathy has expanded dramatically as of late. After the initial discovery of the phospholipase A2 receptor auto-antibody in 2009, eight more antigens have been discovered. These discoveries have led to refinement in our understanding of the pathogenesis, diagnosis, and natural history of primary membranous nephropathy. Now, many experts advocate for redefining primary membranous nephropathy based on antigen, potentially shedding the primary and secondary nomenclature. Recently, therapies for primary membranous have also expanded. Immunosuppressive therapies like cyclophosphamide and rituximab, which primarily target B-cells, remain the cornerstone of therapy. However, there is still significant room for improvement, as many as 30-40% do not respond to this therapy according to recent trials. Additionally, drugs targeting complement, and other novel therapies are also under investigation. In this review we will discuss the available therapies for primary membranous nephropathy in light of recent clinic trials like GEMRITUX, MENTOR, RI-CYCLO, and STARMEN, as well as management strategies. While the last 10 years have seen a boom in our mechanistic understanding of this ever-diversifying disease, we are likely to see a similar boom in the therapeutic options in the years to come.

EditorialAssignment

INTRODUCTION

Primary membranous nephropathy (PMN) is a major cause of nephrotic syndrome in adults. Rituximab has been recommended in the treatment of PMN by the updated Kidney Disease Improved Outcome guideline. However, the optimal dosing regimen of rituximab for the initial treatment of patients with PMN is unclear.

METHODS AND ANALYSIS

A comprehensive screening will be performed by searching PubMed, Embase and the CENTRAL (Cochrane Central Register of Controlled Trials) without language restriction. Studies evaluating the efficacy of rituximab monotherapy using the following types of dosing regimens will be included: high-dose regimen; standard regimen and low-dose regimen. Studies with less than 10 participants will be excluded. The primary outcome is the remission rate at 12 months. The secondary outcomes are remission rate at 6 and 24 months, complete remission rate at 6, 12 and 24 months, relapse at 6, 12 and 24 months, and side effects. Risk of Bias In Non-randomised Studies of Interventions tool will be used to assess the risk of bias for non-randomised studies and the Cochrane risk of bias assessment tool will be used for randomised controlled trials. The pooled remission rate, complete remission rate, relapse rate and side effects will be estimated using the metaprop command. All analyses will be calculated using Stata software (V.15.0; StataCorp).

ETHICS AND DISSEMINATION

Ethics approval is not required. The results of our study will be submitted to a peer-review journal.

PROSPERO REGISTRATION NUMBER

CRD42022319401.

Immunosuppressive treatment for idiopathic membranous nephropathy: An updated network meta-analysis

This network meta-analysis (NMA) aims to investigate the efficacy and safety of different pharmacological treatments for idiopathic membranous nephropathy (IMN). Thirty-four relevant studies were extracted from PubMed, Embase, Cochrane database, and MEDLINE. Treatment with tacrolimus (TAC), cyclophosphamide (CTX), mycophenolate mofetil, chlorambucil (CHL), cyclosporin A (CSA), steroids, rituximab (RTX), and conservative therapy were compared. Outcomes were measured using remission rate and incidence of side effects. Summary estimates were expressed as the odds ratio (OR) and 95% confidence intervals (CIs). The quality of findings was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. In the direct meta-analysis for comparison of complete remission (CR) rate, the curative effect of RTX is inferior to CTX (OR 0.37; CI 0.18, 0.75). In the NMA of CR rate, the results showed that the curative effects of CTX, CHL, and TAC were significantly higher than those of the control group. The efficacy of RTX is not inferior to the CTX (OR 0.81; CI 0.32, 2.01), and the level of evidence was moderate; CSA was not as effective as RTX, and the difference was statistically significant with moderate evidence (OR 2.98, CI 1.00, 8.91). In summary, we recommend CTX and RTX as the first-line drug for IMN treatment.

Prediction Models of Primary Membranous Nephropathy: A Systematic Review and Meta-Analysis

BACKGROUND

Several statistical models for predicting prognosis of primary membranous nephropathy (PMN) have been proposed, most of which have not been as widely accepted in clinical practice.

METHODS

A systematic search was performed in MEDLINE and EMBASE. English studies that developed any prediction models including two or more than two predictive variables were eligible for inclusion. The study population was limited to adult patients with pathologically confirmed PMN. The outcomes in eligible studies should be events relevant to prognosis of PMN, either disease progression or response profile after treatments. The risk of bias was assessed according to the PROBAST.

RESULTS

In all, eight studies with 1237 patients were included. The pooled AUC value of the seven studies with renal function deterioration and/or ESRD as the predicted outcomes was 0.88 (95% CI: 0.85 to 0.90; I² = 77%, p = 0.006). The paired forest plots for sensitivity and specificity with corresponding 95% CIs for each of these seven studies indicated the combined sensitivity and specificity were 0.76 (95% CI: 0.64 to 0.85) and 0.84 (95% CI: 0.80 to 0.88), respectively. All seven studies included in the meta-analysis were assessed as high risk of bias according to the PROBAST tool.

CONCLUSIONS

The reported discrimination ability of included models was good; however, the insufficient calibration assessment and lack of validation studies precluded drawing a definitive conclusion on the performance of these prediction models. High-grade evidence from well-designed studies is needed in this field.

Efficacy and safety of rituximab for primary membranous nephropathy with different clinical presentations: a retrospective study

Background

Rituximab (RTX) is gaining increasing clinical acceptance in the treatment of primary membranous nephropathy (PMN), with demonstrated efficacy and safety. However, there are few clinical studies on RTX for PMN in Asian populations, especially in China.

Methods

To observe and analyse the efficacy and safety of RTX treatment, 81 patients with PMN suffering from nephrotic syndrome (NS) were enrolled and divided into an initial therapy group, a conventional immunosuppressive therapy relapse group, and a conventional immunosuppressive therapy ineffective group according to their pre-RTX treatment background. Patients in each group were followed up for 12 months. The primary outcome was clinical remission at 12 months, and the secondary outcomes were safety and the occurrence of adverse events.

Results

At 12 months, 65 of 81 (80.2%) patients achieved complete (n=21, 25.9%) or partial (n=44, 54.3%) remission after rituximab treatment. Thirty-two of 36 (88.9%) patients in the initial therapy group, 11 of 12 (91.7%) patients in the relapse group and 22 of 33 (66.7%) patients in the ineffective group achieved clinical remission. All 59 patients with positive anti-PLA2R antibodies showed a decreasing trend in antibody levels after RTX treatment, and 55 (93.2%) of them achieved antibody clearance (<20 U/mL). Logistic regression analysis showed that a high anti-PLA2R antibody titer (OR=0.993, P=0.032) was an independent risk factor for nonremission. Adverse events occurred in 18 (22.2%) patients, of which 5 (6.2%) were serious adverse events, and none were malignant or otherwise fatal.

Conclusion

RTX alone can effectively induce remission PMN and maintain stable renal function. It is recommended as the first choice of treatment and is also effective in patients who relapse and have poor responses to conventional immunosuppressive therapy. Anti-PLA2R antibodies can be used as a marker for RTX treatment monitoring, and antibody clearance is necessary to achieve and improve the rates of clinical remission.

Toxic Occupational Exposures and Membranous Nephropathy

BACKGROUND AND OBJECTIVES

Membranous nephropathy is a rare autoimmune kidney disease whose increasing prevalence in industrialized countries pleads for the involvement of an environmental factor in the development of the disease. In addition, the predominance of men in membranous nephropathy, classically attributed to biologic or genetic differences between men and women, could also be due to different occupational exposures. To support this hypothesis, we sought to describe the toxic occupational exposures of patients with membranous nephropathy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this observational epidemiologic study, we compared the occupations and toxic occupational exposures of 100 patients with membranous nephropathy with those of the general population, consisting of two cohorts of 26,734,000 and 26,500 French workers. We then compared the characteristics of patients exposed to an occupational toxic substance with those of unexposed patients.

RESULTS

Patients with membranous nephropathy worked more frequently in the construction sector than the general population (33% versus 7%, P<0.001). This difference remained significant by age and sex. They were also more frequently exposed to toxic substances, such as asbestos (16% versus 5%, P<0.001), lead (9% versus 1%, P<0.001), or organic solvents (37% versus 15%, P<0.001), than the general population. The predominance of men in the subgroup of patients occupationally exposed to toxic substances was not observed in unexposed individuals (organic solvents: 80% men versus 41%, P<0.001; asbestos: 90% men versus 55%, P=0.004). In addition, patients with phospholipase A2 receptor 1 (PLA2R1) epitope spreading were more frequently exposed to asbestos and organic solvents than patients without epitope spreading (32% versus 7%, P=0.02 and 74% versus 43%, P=0.02, respectively), with a dose-dependent effect.

CONCLUSIONS

Patients with membranous nephropathy were more frequently exposed to certain occupational toxic substances, such as asbestos and organic solvents, than the general population. This occupational exposure was more frequent in men and in patients with PLA2R1 epitope spreading.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Immunopathological Analysis in a French National Cohort of Membranous Nephropathy (IHMN), NCT04326218.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_10_25_CJN02930322.mp3.

Rituximab Dosing in Glomerular Diseases: A Scoping Review

Purpose of Review

Rituximab is increasingly prescribed for glomerular diseases. However, the recently published Kidney Disease Improving Global Outcomes (KDIGO) 2021 Clinical Practice Guideline for the Management of Glomerular Diseases lacks details on recommended dosing regimens for most individual glomerular diseases. We performed this scoping review summarizing the evidence for rituximab dosing in glomerular disease.

Sources of Information

PubMed database.

Methods

The PubMed search methodology was developed with a medical librarian and performed by the first, with review by a second, author. Randomized controlled trials (RCTs) and prospective cohort studies (PCSs) examining rituximab efficacy and/or safety in antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV), membranous nephropathy (MN), lupus nephritis (LN), or podocytopathies (minimal change disease or focal segmental glomerulosclerosis [FSGS]) were included. Fifty-three studies (14 RCTs and 39 PCSs) were included.

Key Findings

We identified 16 different rituximab dosing regimens studied as induction therapy for one or more of the 5 glomerular diseases of interest. The most frequently studied rituximab induction regimens were 1000 mg as 2 doses 2 weeks apart (17 studies, 32%) and 4 doses of 375 mg/m²/week (18 studies, 33.9%). Twenty-six studies (49%) examined rituximab as monotherapy or in conjunction with corticosteroids alone, while the remaining studies examined rituximab as part of combination immunosuppression. Adapting treatment to achieve B-cell depletion, with frequent evaluation of disease-specific biomarkers, might prove the optimal approach to achieving and maintaining remission. Rituximab might also enable steroid minimization or avoidance.

Limitations

Restriction of the search to a single database and to studies published in the English language, and with an accompanying abstract, could have led to selection bias. While the search was limited to prospective observational studies and RCTs, no formal assessment of study quality was performed.

A low rate of end-stage kidney disease in membranous nephropathy: A single centre study over 2 decades

INTRODUCTION

Membranous nephropathy is the commonest cause of nephrotic syndrome in non-diabetic Caucasian adults over the age of 40 years. Primary membranous nephropathy is limited to the kidneys. Clinical management aims to induce remission, either spontaneously with supportive care, or with immunosuppression. Here, we describe the natural history of this condition in a large tertiary centre in the UK.

METHODS

178 patients with primary membranous nephropathy were identified over 2 decades. We collected data on demographics, baseline laboratory values, treatment received and outcomes including progression to renal replacement therapy and death. Analysis was performed on the whole cohort and specific subgroups. Univariate and multivariate Cox regression was also performed.

RESULTS

Median age was 58.3 years with 63.5% male. Median baseline creatinine was 90μmol/L and urine protein-creatinine ratio 664g/mol. Remission (partial or complete) was achieved in 134 (75.3%), either spontaneous in 60 (33.7%) or after treatment with immunosuppression in 74 (41.6%), and of these 57 (42.5%) relapsed. Progression to renal replacement therapy was seen in 10.1% (much lower than classically reported) with mortality in 29.8%. Amongst the whole cohort, those who went into remission had improved outcomes compared to those who did not go into remission (less progression to renal replacement therapy [4.5% vs 28%] and death [20.1% vs 67%]. Those classified as high-risk (based on parameters including eGFR, proteinuria, serum albumin, PLA2R antibody level, rate of renal function decline) also had worse outcomes than those at low-risk (mortality seen in 52.6% vs 10.8%, p<0.001). The median follow-up period was 59.5 months.

CONCLUSION

We provide a comprehensive epidemiologic analysis of primary membranous nephropathy at a large tertiary UK centre. Only 10.1% progressed to renal replacement therapy. For novelty, the KDIGO risk classification was linked to outcomes, highlighting the utility of this classification system for identifying patients most likely to progress.

Efficacy and Safety of Rituximab in the Treatment of Idiopathic Membranous Nephropathy: A Meta-Analysis

Background

Primary membranous nephropathy (MN), sometimes referred to as idiopathic membranous nephropathy (IMN), is a kind of MN whose pathogenesis is yet unclear. According to research reports, the incidence of IMN is about 9.8-26.8%, and it is on the rise.

Methods

The computer retrieves eight databases to obtain controlled trials at home and abroad on the rituximab (RTX) actions in IMN management. After a rigorous literature quality evaluation, software called RevMan 5.3 was used for data analysis.

Results

This meta-analysis finally contained 8 papers. They were all regarded as controlled trials. Six studies reported serum creatinine (standardized mean difference [SMD]: -6.87; 95% CI: -14.09, 0.35; P = 0.062), ALB (SMD: 1.91; 95% CI: -0.31, 4.14; P = 0.092), and adverse reactions (OR: 0.56; 95% CI: 0.36, 0.90; P < 0.01), all of which were significantly higher in the test group than in the control group (OR: 1.37; 95% CI: 1.07, 1.76; P < 0.01).

Conclusion

The overall effective rate, serum creatinine, adverse effects, and ALB of this trial indicate that RTX may be beneficial for individuals with IMN, but further high-quality research is required to confirm these findings.

PLA2R-IgG4 antibody as a predictive biomarker of treatment effectiveness and prognostic evaluation in patients with idiopathic membranous nephropathy: a retrospective study

Background

The Kidney Disease Improving Global Outcomes (KDIGO) 2021 guidelines recommend Rituximab (RTX) as the first-line therapy and phospholipase A2 receptor (PLA2R) antibody as a biomarker for remission and prognosis in patients with idiopathic membranous nephropathy (IMN).

Methods

This study was a retrospective analysis of 70 patients with IMN treated with either rituximab (RTX) or cyclophosphamide (CTX) and steroid. Quantitative detection of PLA2R-IgG and PLA2R-IgG4 antibodies at sixth month after treatment, determined using time-resolved fluoroimmunoassay (TRFIA), were used for treatment effectiveness analysis and prognostic evaluation in patients with IMN.

Results

After 12 months of therapy, the remission rate of proteinuria, including complete remission (CR) and partial remission (PR) in the RTX group and the CTX group, were 74% versus 67.5% (P = 0.114), respectively. Both PLA2R-IgG and PLA2R-IgG4 levels were decreased in patients with remission of proteinuria after 6 months of therapy. Receiver operating characteristic curve (ROC) curve analysis exhibited that the AUC of PLA2R-IgG4 and the PLA2R-IgG as laboratory criteria for proteinuria remission were 0.970 versus 0.886 (P = 0.0516), respectively, after 6 months of treatment. The cut-off value of PLA2R-IgG4 was 7.67 RU/mL and the sensitivity and specificity of remission rate at 6th month were 90.9% and 100%, respectively. Furthermore, the AUC of the PLA2R-IgG4 and PLA2R-IgG to predict the outcome after 12 months of treatment were 0.922 versus 0.897 (P = 0.3270), respectively. With the cut-off value of PLA2R-IgG4 being 22.985 RU/mL, the sensitivity and specificity of remission rate at 12th month were 100% and 87.1%, respectively. Logistic regression analysis revealed that the PLA2R-IgG4 level (P = 0.023), the rate of decrease of PLA2R-IgG4 level (P = 0.034), and eGFR level (P = 0.012) were significantly associated with remission.

Conclusions

We found that the patients in the RTX group and CTX group achieved effective remission of proteinuria after 12 months of treatment. PLA2R-IgG4 may be a more effective biomarker for treatment effectiveness analysis and prognostic assessment, compared with anti-PLA2R-IgG for PLA2R associated IMN.

Efficacy of long-term repeated rituximab treatment in refractory phospholipase A2 receptor-antibody-related membranous nephropathy

Aims: To evaluate the efficacy of long-term repeated rituximab treatment in refractory PLA2R-Ab-related membranous nephropathy (MN). Materials & methods: Rituximab was administered at a single dose of 375 mg/m² and repeated if peripheral B-cell levels were >5/ul in 46 patients with refractory PLA2R-Ab-related MN. Results: The median frequency of rituximab treatment was 3 (IQR 2.0-4.0). A total of 32 (32/46) patients achieved remission (completed remission [CR] or partial remission [PR]) over a median time of 17.0 months, and 10 patients eventually progressed to CR. The proportion of serum PLA2R-Ab depletion was 73.91% (34/46) over a median time of 9 months. Antibody depletion preceded proteinuria remission. Conclusions: Long-term repeated rituximab treatment achieved high kidney and immunological response rates in refractory PLA2R-Ab related MN, and antibody depletion was a prerequisite for proteinuria remission.

Sexual dimorphic response to rituximab treatment: A longitudinal observational study in a large cohort of patients with primary membranous nephropathy and persistent nephrotic syndrome

Rituximab is one of the first-line therapies for patients with membranous nephropathy (MN) at high risk of progression towards kidney failure. We investigated whether the response to Rituximab was affected by sex and anti-PLA2R antibody levels in 204 consecutive patients (148 males and 56 females) with biopsy-proven MN who were referred to the Nephrology Unit of the Azienda Socio Sanitaria Territoriale Papa Giovanni XXIII from March 2001 to October 2016 and managed conservatively for at least 6 months. The primary outcome was a combined endpoint of complete (proteinuria <0.3 g/24 h) or partial (proteinuria <3.0 g/24 h and >50% reduction vs. baseline) remission. Patients gave written informed consent to Rituximab treatment. The study was internally funded. No pharmaceutical company was involved. Anti-PLA2R antibodies were detectable in 125 patients (61.3%). At multivariable analyses, female gender (p = 0.0198) and lower serum creatinine levels (p = 0.0108) emerged as independent predictors of better outcome (p = 0.0198). The predictive value of proteinuria (p = 0.054) and anti-PLA2R titer (p = 0.0766) was borderline significant. Over a median (IQR) of 24.8 (12.0-36.0) months, 40 females (71.4%) progressed to the combined endpoint compared with 73 males (49.3%). Anti-PLA2R titers at baseline [127.6 (35.7-310.8) vs. 110.1 (39.9-226.7) RU/ml] and after Rituximab treatment were similar between the sexes. However, the event rate was significantly higher in females than in males [HR (95%): 2.12 (1.44-3.12), p = 0.0001]. Forty-five of the 62 patients (72.3%) with anti-PLA2R titer below the median progressed to the combined endpoint versus 35 of the 63 (55.6%) with higher titer [HR (95%): 1.97 (1.26-3.07), p < 0.0029]. The highest probability of progressing to the combined endpoint was observed in females with anti-PLA2R antibody titer below the median (86.7%), followed by females with anti-PLA2R antibody titer above the median (83.3%), males with titer below the median (68.1%), and males with titer above the median (44.4%). This trend was statistically significant (p = 0.0023). Similar findings were observed for complete remission (proteinuria <0.3 g/24 h) and after analysis adjustments for baseline serum creatinine. Thus, despite similar immunological features, females were more resilient to renal injury following Rituximab therapy. These findings will hopefully open new avenues to identify the molecular pathways underlying sex-related nephroprotective effects.

Profile and primary treatment outcomes in membranous nephropathy

OBJECTIVES

To assess the clinical profile and primary treatment response and outcomes in idiopathic membranous nephropathy (IMN) patients.

METHODS

This study was carried out between December 2013 and January 2019 in a tertiary care hospital in North India on 2 years retrospective and 3 years prospective renal biopsy proven patients with IMN presenting with nephrotic syndrome. Basic baseline investigations carried out were urinary proteins, serum albumin, serum creatinine, other special tests wherever necessary or possible (including phospholipase A2 receptor antibodies), and different treatment regimens were offered for treatment. The patients were followed up for a minimum period of 6 months after administration of treatment.

RESULTS

The study was carried out in 120 patients with mean age of 43±14.6 years and male female ratio of 1.65:1. Hypertension was noted in 36%, microscopic hematuria in 13%, and mean 24 hours urinary proteinuria 10.5±3.1 gm. Complete or partial response at 6 months was observed in 57% and 34% cases to cyclophosphamide, 60% and 40% to modified Ponticelli treatment, 81% and 19% to tacrolimus, and 40% and 36% cases to rituximab. Relapse was observed in 6% of cyclophosphamide and 13% in tacrolimus groups.

CONCLUSION

Our results show a good and comparable response to cyclophosphamide, tacrolimus, and rituximab at 6 months of follow up. The cases which achieved complete remission had significantly lower baseline proteinuria compared to those who did not respond.

Pediatric membranous nephropathy: In the novel antigens era

Membranous nephropathy (MN) falls within the scope of a glomerular disease. MN exhibits subepithelial immune- complex deposition and capillary wall thickening which could occur in all age groups. In comparison with adult patients with MN, MN in pediatric population has a lower incidence and more secondary factors (e.g., systemic lupus erythematosus, infection, malignancy, or drug toxicity). Two target antigens for the immune complexes, PLA2R (identified in 2009) and THSD7A (in 2014), found in previous studies and first presented in adult MN, are found in pediatric patients suffering from MN and their antibodies are now an effective tool for diagnosis and monitoring in children and adolescents. Several novel antigens have been identified (e.g., EXT1/EXT2, NELL1, Sema3B, PCDH7, HTRA1, and NCAM1) over the past few years. Each of them represents different clinical and pathologic findings. In-depth research should be conducted to gain insights into the outcomes and pathophysiology of the above novel antigen-associated MN. Targeted treatment opinions for different novel antigen-related MN are under development both in adults and pediatric patients.

Efficacy and safety of 12 immunosuppressive agents for idiopathic membranous nephropathy in adults: A pairwise and network meta-analysis

Background: Immunosuppressants have been applied in the remedy of idiopathic membranous nephropathy (IMN) extensively. Nevertheless, the efficacy and safety of immunosuppressants do not have final conclusion. Thus, a pairwise and network meta-analysis (NMA) was carried out to seek the most recommended therapeutic schedule for patients with IMN.

Methods: Randomized controlled trials (RCTs) including cyclophosphamide (CTX), mycophenolate mofetil (MMF), tacrolimus-combined mycophenolate mofetil (TAC + MMF), cyclosporine (CsA), tacrolimus (TAC), leflunomide (LEF), chlorambucil (CH), azathioprine (AZA), adrenocorticotropic hormone (ACTH), non-immunosuppressive therapies (CON), steroids (STE), mizoribine (MZB), and rituximab (RIT) for patients with IMN were checked. Risk ratios (RRs) and standard mean difference (SMD) were reckoned to assess dichotomous variable quantities and continuous variable quantities, respectively. Total remission (TR) and 24-h urine total protein (24-h UTP) were compared using pairwise and NMA. Then interventions were ranked on the basis of the surface under the cumulative ranking curve (SUCRA).

Results: Our study finally included 51 RCTs and 12 different immunosuppressants. Compared with the CON group, most regimens demonstrated better therapeutic effect in TR, with RR of 2.1 (95% CI) (1.5–2.9) for TAC, 1.9 (1.3–2.8) for RIT, 2.5 (1.2–5.2) for TAC + MMF, 1.9 (1.4–2.7) for CH, 1.8 (1.4–2.4) for CTX, 2.2 (1.0–4.7) for ACTH, 1.6 (1.2–2.1) for CsA, 1.6 (1.0–2.5) for LEF, and 1.6 (1.1–2.2) for MMF. In terms of 24-h UTP, TAC (SMD, −2.3 (95% CI −3.5 to −1.1)), CTX (SMD, −1.7 (95% CI −2.8 to −0.59)), RIT (SMD, −1.8 (95% CI −3.5 to −0.11)), CH (SMD, −2.4 (95% CI −4.3 to −0.49)), AZA (SMD, −−4.2 (95% CI −7.7 to −0.68)), and CsA (SMD, −1.7 (95% CI −3 to −0.49)) were significantly superior than the CON group. As for adverse effects (AEs), infections, nausea, emesia, myelosuppression, and glucose intolerance were the collective adverse events for most immunosuppressants.

Conclusion: This study indicates that TAC + MMF performed the best in terms of TR, and TAC shows the best effectiveness on 24-h UTP compared with other regimens. On the contrary, there seems to be little advantage on STE alone, LEF, AZA, and MZB in treating patients with IMN compared with CON.

Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD42021287013]

Treatment of rituximab in patients with idiopathic membranous nephropathy: a case series and literature review

BACKGROUND/AIMS

Membranous nephropathy (MN) is a major cause of nephrotic syndrome in adults. This study aimed to evaluate the effect of rituximab (RTX) in patients with idiopathic MN (iMN) who have a high risk of progression.

METHODS

We retrospectively analyzed data of 13 patients with iMN, who received RTX treatments from January 2014 to July 2020. RTX was indicated in patients with iMN with severe proteinuria and decreasing estimated glomerular filtration rate (eGFR) in the previous 6 months despite other immunosuppressive therapies.

RESULTS

The patients were predominantly males (n = 11) and with a mean age of 55.3 years; median eGFR, 37.0 mL/min/1.73 m2 (interquartile range [IQR], 26.3 to 66.5); serum albumin level, 2.6 g/dL (IQR, 1.9 to 3.1); and spot urine protein-to-creatinine ratio at baseline, 6.6 g/g (IQR, 5.7 to 12.9). In a median follow-up of 22 months, eight patients (61.5%) achieved complete or partial remission. In responder group (n = 8), median eGFR increased from 31.5 to 61.5 mL/min/1.73 m2 (p = 0.049) and serum albumin level increased from 2.3 to 4.2 g/dL (p = 0.017) from RTX initiation to last follow-up. Antiphospholipase A2 receptor antibody (anti-PLA2R-Ab) was positive in six among seven tested patients, which markedly decreased in the responder group. There were no adverse events after RTX.

CONCLUSION

This study suggests that RTX is a safe and effective treatment option for patients with iMN who have a high risk of progression. Individualized therapy based on anti-PLA2R-Ab titer would be needed for better outcomes.

Rituximab May Have Positive Effect on Refractory Nephrotic Syndrome: A Meta-Analysis of Randomized Trials

Purpose

This study was aimed at demonstrating the role of rituximab (RTX) on the influence of nephrotic syndrome (NS) and on urinary protein which was not significant.

Methods

The clinical randomized controlled trials were performed by eight databases. Meanwhile, the confidence interval (CI) of either relative risk or mean difference was set to 95%. Besides, the heterogeneity of the research results is tested by I 2.

Results

A total of 1658 references were found using the search method. This meta-analysis will be done by the ultimately eight different studies. Each study is described as random controlled trial. According to these eight studies, the remission of test group and control group was quite higher (OR: 1.60; 95% Cl: 1.17, 2.20; P < 0.01) than the control group, serum albumin (SMD: 4.19; 95% Cl: 1.49, 6.89; P < 0.01), and urine protein (SMD: 0.79; 95% Cl: -0.64, 2.22; P = 0.28). Despite the fact that the remission rate's funnel plot was asymmetrically distributed, Egger's test and Begg's test revealed no probable publish bias.

Conclusion

The results of this study suggest that rituximab (RTX) may be effective in RNS, as evidenced by remission rates and serum albumin. However, the effect on urinary protein was not significant. The clear evidence is missing in this literature. Therefore, large sample, multicenter, low risk of bias clinical studies, as well as basic medical research, is needed.

Steroids as treatment for glomerulonephritis: time for a rethink

Glucocorticoids have been a cornerstone of treatment for inflammatory and autoimmune kidney diseases for almost 70 years, yet it is fair to say, we still do not know how ‘best’ to use them. Significant adverse events are associated with their continued use, which contribute to premature patient mortality. Steroid avoidance or minimization is possible and has been tested in various glomerular diseases, as a result of novel agents or innovative regimens using established therapeutics. It is now time to seriously address our use of steroids and educate physicians on better ways of managing inflammatory kidney diseases.

Recent Advances in Clinical Diagnosis and Pharmacotherapy Options of Membranous Nephropathy

Membranous nephropathy (MN) is the most common cause of nephrotic syndrome among adults, which is the leading glomerular disease that recurs after kidney transplantation. Treatment for MN remained controversial and challenging, partly owing to absence of sensitive and specific biomarkers and effective therapy for prediction and diagnosis of disease activity. MN starts with the formation and deposition of circulating immune complexes on the outer area in the glomerular basement membrane, leading to complement activation. The identification of autoantibodies against the phospholipase A₂ receptor (PLA₂R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) antigens illuminated a distinct pathophysiological rationale for MN treatments. Nowadays, detection of serum anti-PLA₂R antibodies and deposited glomerular PLA₂R antigen can be routinely applied to MN. Anti-PLA₂R antibodies exhibited much high specificity and sensitivity. Measurement of PLA₂R in immune complex deposition allows for the diagnosis of PLA₂R-associated MN in patients with renal biopsies. In the review, we critically summarized newer diagnosis biomarkers including PLA₂R and THSD7A tests and novel promising therapies by using traditional Chinese medicines such as Astragalus membranaceus, Tripterygium wilfordii, and Astragaloside IV for the treatment of MN patients. We also described unresolved questions and future challenges to reveal the diagnosis and treatments of MN. These unprecedented breakthroughs were quickly translated to clinical diagnosis and management. Considerable advances of detection methods played a critical role in diagnosis and monitoring of treatment.

Advances in the Management of Primary Membranous Nephropathy and Rituximab-Refractory Membranous Nephropathy

Primary membranous nephropathy (pMN) is an auto-immune disease characterized by auto-antibodies targeting podocyte antigens resulting in activation of complement and damage to the glomerular basement membrane. pMN is the most common cause of nephrotic syndrome in adults without diabetes. Despite a very heterogeneous course of the disease, the treatment of pMN has for many years been based on uniform management of all patients regardless of the severity of the disease. The identification of prognostic markers has radically changed the vision of pMN and allowed KDIGO guidelines to evolve in 2021 towards a more personalized management based on the assessment of the risk of progressive loss of kidney function. The recognition of pMN as an antibody-mediated autoimmune disease has rationalized the use immunosuppressive drugs such as rituximab. Rituximab is now a first line immunosuppressive therapy for patients with pMN with proven safety and efficacy achieving remission in 60-80% of patients. For the remaining 20-40% of patients, several mechanisms may explain rituximab resistance: (i) decreased rituximab bioavailability; (ii) immunization against rituximab; and (iii) chronic glomerular damage. The treatment of patients with rituximab-refractory pMN remains controversial and challenging. In this review, we provide an overview of recent advances in the management of pMN (according to the KDIGO 2021 guidelines), in the understanding of the pathophysiology of rituximab resistance, and in the management of rituximab-refractory pMN. We propose a treatment decision aid based on immunomonitoring to identify failures related to underdosing or immunization against rituximab to overcome treatment resistance.

Immunosuppression therapy for idiopathic membranous nephropathy: systematic review with network meta-analysis

BACKGROUND

Idiopathic membranous nephropathy is a common cause of nephrotic syndrome in adults. The Kidney Disease Improving Global Outcomes guidelines recommend rituximab or cyclophosphamide and steroids, or calcineurin inhibitor-based therapy. However, there have been few or no head-to-head comparisons of the relative efficacy and safety of different immunosuppression regimens. We conducted a network meta-analysis to evaluate the comparative efficacy and safety of available immunosuppression strategies compared to cyclophosphamide in adults with idiopathic membranous nephropathy.

METHODS

We performed a systematic search of MEDLINE, Embase and CENTRAL for randomized controlled trials in the treatment of adults with idiopathic membranous nephropathy. The primary outcome was complete remission. Secondary outcomes were kidney failure, partial remission, estimated glomerular filtration rate, doubling of serum creatinine, proteinuria, serious adverse events, discontinuation of treatment, serious infection and bone marrow suppression.

RESULTS

Cyclophosphamide had uncertain effects on inducing complete remission when compared to rituximab (OR 0.35, CI 0.10-1.24, low certainty evidence), mycophenolate mofetil (OR 1.81, CI 0.69-4.71, low certainty), calcineurin inhibitor (OR 1.26, CI 0.61-2.63, low certainty) or steroid monotherapy (OR 2.31, CI 0.62-8.52, low certainty). Cyclophosphamide had a higher probability of inducing complete remission when compared to calcineurin inhibitor plus rituximab (OR 4.45, CI 1.04-19.10, low certainty). Compared to other immunosuppression strategies, there was limited evidence that cyclophosphamide had different effects on other pre-specified outcomes.

CONCLUSIONS

The comparative effectiveness and safety of immunosuppression strategies compared to cyclophosphamide is uncertain in adults with idiopathic membranous nephropathy.

The Role of Anti-PLA2R and Anti-THSD7A Antibodies in the Pathogenesis and Diagnostics of Primary Membranous Nephropathy: A Review of Current Knowledge for Clinical Practice

Primary membranous nephropathy (PMN) is considered a major cause of nephrotic syndrome. The discovery of circulating autoantibodies directed against glomerular podocytes helped to classify them as autoimmune diseases. Over the past years, there has been an increasing significance of anti-Phospholipase A2 Receptor (anti-PLA₂R), which has been detected in 70–80% of PMN cases, and relevance of anti-Thrombospondin type I domain-containing 7A (anti-THSD7A) even though they are present in 2–5% of patients. The results of clinical and experimental studies indicate that these antibodies are pathogenic. It radically changed the diagnostic and therapeutic approach. Measurement of antibody titers in the serum seems to be a valuable tool for identifying PMN and for the assessment of disease activity. By monitoring pathogenic antibodies levels rather than proteinuria or reduced glomerular filtration rate (GFR) as an indicator of glomerular disease, physicians would easier divide patients into those with active and inactive PMN disease and decide about their therapy. The aim of this review is to evaluate scientific evidence about the role of autoantibodies, namely anti-PLA₂R and anti-THSD7A, as PMN biomarkers. The present manuscript focuses on PMN pathogenesis and key data of diagnosis, monitoring of the disease, and treatment strategies that are currently being used in clinical practice.

Screening of Medications for Idiopathic Membranous Nephropathy Using Glomerular Whole-Genome Sequencing

Objective

To explore medications that have a therapeutic effect on idiopathic membranous nephropathy (IMN) using the Gene Expression Omnibus (GEO), the Connectivity Map (CMap) database, and bioinformatics approaches.

Methods

IMN patients' glomerular whole-genome sequencing data were retrieved and screened in the GEO database, differentially expressed genes were identified using GEO2R analysis, a PPI network was built in the STRING database, node degree values were calculated, and topological analysis was performed using the degree value to identify core genes. The WebGestalt database was used to perform GO enrichment and KEGG pathway analyses on the core genes. Candidate medications for the therapy of IMN were collected from the CMap database, and the candidate medications were then searched and analyzed.

Results

113 core genes were identified by topological analysis from the 1157 genes that were shown to be differentially expressed. The enrichment analysis identified several important gene functions and signaling pathways related to IMN. Some possible medications for the treatment of IMN have been found using the CMap database. Naringin, with the lowest CMap score, meaningful P value, and specificity score, was predicted as the most likely medication.

Conclusion

The GEO and CMap databases can be used to understand the molecular changes of IMN and to provide new ideas for medication research. However, medication candidates must undergo clinical and experimental testing.

Evaluation of efficacy of rituximab for membranous nephropathy: A systematic review and meta-analysis of 11 studies

INTRODUCTION

The use of traditional immunosuppressive medicines for the treatment of membranous nephropathy is being challenged, owing to its limited efficacy and tolerability. Research on M-type phospholipase A2 receptor antibodies has provided a new way for evaluating the efficiency and prognosis of treatment of membranous nephropathy. However, the relationship between rituximab, a monoclonal antibody against CD20, and antiphospholipase A2 receptor antibodies and the drug regimen of rituximab for membranous nephropathy is uncertain. We conducted a meta-analysis to evaluate the efficacy of rituximab treatments in membranous nephropathy and compared the clinical effects of first-line and second-line rituximab therapies.

METHODS

PubMed, Embase, Web of Science, Scopus, the Cochrane Central Register ofControlled Trials, and ClinicalTrials.gov were searched to find articles about rituximab treatment of patients with membranous nephropathy between January 2000 and August 2020. The outcomes included remission, antiphospholipase A2 receptor antibodies, relapse, and adverse events. The Grading of Recommendations Assessment Development and Evaluation criteria were used to evaluate the strength of evidence.

RESULTS

A total of 723 participants from 11 trials were included in this meta-analysis. The other treatments included cyclosporine, cyclophosphamide, steroids, and non-immunosuppressive antiproteinuric treatment. Rituximab significantly improved cumulative remission (P=0.007; Odds Ratio [OR]=3.06; 95% confidence interval [CI]=1.35-6.94) compared with other treatments. It significantly reduced relapse (P<0.00001; OR=0.06; 95% CI=0.02-0.19), antiphospholipase A2 receptor antibody levels (P=0.0009; SMD=-0.52; 95% CI=-0.83 to -0.21), and the proportion of patients positive for anti-PLA2R antibodies (P=0.003; OR=6.11; 95% CI=1.85-20.24) compared with other treatments. Compared with the second-line, first-line rituximab therapy achieved a higher rate of cumulative remission (P=0.03; OR=0.32, 95% CI=0.11-0.91).

CONCLUSIONS

Rituximab can improve the rate of clinical remission in patients with membranous nephropathy. Rituximab was more effective than other treatments in reducing relapse, antiphospholipase A2 receptor antibody levels, and the proportion of patients positive for antiphospholipase A2 receptor antibodies. The clinical remission rate following first-line rituximab therapy was better than that of second-line rituximab therapy for membranous nephropathy.

Strategies Towards Antigen-Specific Treatments for Membranous Nephropathy

Membranous nephropathy (MN) is a rare but potentially severe autoimmune disease and a major cause of nephrotic syndrome in adults. Traditional treatments for patients with MN include steroids with alkylating agents such as cyclophosphamide or calcineurin inhibitors such as cyclosporine, which have an undesirable side effect profile. Newer therapies like rituximab, although superior to cyclosporine in maintaining disease remission, do not only affect pathogenic B or plasma cells, but also inhibit the production of protective antibodies and therefore the ability to fend off foreign organisms and to respond to vaccination. These are undesired effects of general B or plasma cell-targeted treatments. The discovery of several autoantigens in patients with MN offers the great opportunity for more specific treatment approaches. Indeed, such treatments were recently developed for other autoimmune diseases and tested in different preclinical models, and some are about to jump to clinical practice. As such treatments have enormous potential to enhance specificity, efficacy and compatibility also for MN, we will discuss two promising strategies in this perspective: The elimination of pathogenic antibodies through endogenous degradation systems and the depletion of pathogenic B cells through chimeric autoantibody receptor T cells.

Therapies for Membranous Nephropathy: A Tale From the Old and New Millennia

Primary Membranous Nephropathy (PMN) is the most frequent cause of nephrotic syndrome in adults. If untreated, PMN can lead to end-stage renal disease; moreover, affected patients are at increased risk of complications typical of nephrotic syndrome such as fluid overload, deep vein thrombosis and infection. The association of PMN with HLA-DQA1 and the identification in around 70% of cases of circulating autoantibodies, mainly directed towards the phospholipase A2 receptor, supports the autoimmune nature of the disease. In patients not achieving spontaneous remission or in the ones with deteriorating kidney function and severe nephrotic syndrome, immunosuppression is required to increase the chances of achieving remission. The aim of this review is to discuss the evidence base for the different immunosuppressive regimens used for PMN in studies published so far; the manuscript also includes a section where the authors propose, based upon current evidence, their recommendations regarding immunosuppression in the disease, while highlighting the still significant knowledge gaps and uncertainties.

Revisiting immunological and clinical aspects of membranous nephropathy

Idiopathic or primary membranous nephropathy (IMN) is one of the most frequent causes of nephrotic syndrome in adults and the elderly. It is characterized by a thickening of the wall of the glomerular capillaries due to the presence of immune complex deposits. 85% of membranous nephropathy cases are classified as primary or idiopathic (IMN). The rest are of secondary origin (SMN), caused by autoimmune conditions or malignant tumors as lung cancer, colon and melanomas. It is an organ-specific autoimmune disease in which the complement system plays an important role with the formation of the membrane attack complex (MAC; C5b-9), which produces an alteration of the podocyte structure. The antigen responsible for 70-80% of IMN is a podocyte protein called M-type phospholipase A2 receptor (PLA2R). More recently, another podocyte antigen has been identified, the "Thrombospondin type-1 domain-containing 7A" (THSD7A), which is responsible for 10% of the cases of negative IMN for anti- PLA2R.

Negative anti-phospholipase A2 receptor antibody status at three months predicts remission in primary membranous nephropathy

Background

The value of anti-phospholipase A2 receptor antibody (anti-PLA2R ab) monitoring at 3 months after diagnosis in membranous nephropathy (MN) remains uncertain.

Methods

We retrospectively examined the outcome on 1 August 2020 of 59 adult patients (age 54 (44, 68) years, 69% male, SCr 1.0 (0.9, 1.3) mg/dL) diagnosed with MN (kidney biopsy, positive serum anti-PLA2R ab). The outcomes were: kidney survival; partial and/or complete remission.

Results

Most of the studied patients (97%) received immunosuppression, cyclophosphamide regimens were the most frequent (87%), followed by cyclosporine (10%). The median time to remission was 12.0 months and the cumulative remission rates were 34% at 6, 54% at 12, and 73% at 24 months. Forty (69%) patients had negative anti-PLA2R ab at 3 months, they had similar age, serum creatinine, albumin, proteinuria, and treatment with the group with positive ab at 3 months. In the Cox proportional hazard model, three months anti-PLA2R ab negativization (HR 0.4 (95%CI 0.1, 0.9)) was an independent predictor for remission, while baseline hypoalbuminemia (HR 3.0 (95%CI 1.5, 5.7)) was associated with absence of remission. Six (10%) patients died, mostly due to cardiovascular disease and infections. A total of five (9%) patients started dialysis. Mean kidney survival time was 50.3 months and there was no survival difference in relation to baseline anti-PLA2R ab titer (p .09) or 3 months negativization (p .8).

Conclusions

Three months anti-PLA2R ab negativization seems to be a late predictor of remission, and lower serum albumin at diagnosis is an early marker for remission absence. Abbreviations: anti-P LA2R ab, anti-phospholipase A2 receptor antibody; eGFR, estimated glomerular filtration rate; ESKD, end stage kidney disease; MN, membranous nephropathy; NELL-1, neural epidermal growth factor-like 1 protein; RAAS: renin–angiotensin–aldosterone system; RBC: red blood cells; RRT, renal replacement therapy; T HSD7A, thrombospondin type-1 domain containing 7A

Recent Clinical Trials Insights into the Treatment of Primary Membranous Nephropathy

Immunosuppressive therapy is mandatory for primary membranous nephropathy with persistent nephrotic proteinuria or anti-phospholipase A2 receptor antibodies, reduced kidney function, or another risk factor for progression. Rituximab has demonstrated efficacy for proteinuria remission compared with renin-angiotensin system blockade or cyclosporine in two well-powered randomized controlled trials. More recently, STARMEN showed that alternating glucocorticoid-cyclophosphamide is superior to sequential tacrolimus-rituximab for proteinuria remission, although it was associated with a higher risk of non-serious adverse events. However, sequential tacrolimus-rituximab involved delayed lower dose rituximab and was the worst-performing rituximab regimen among those tested in randomized clinical trials. The RI-CYCLO pilot study did not demonstrate superiority of glucocorticoid-cyclophosphamide over rituximab and found no difference in adverse events. Overall, STARMEN and RI-CYCLO confirmed the efficacy of glucocorticoid-cyclophosphamide in patients with high-risk membranous nephropathy and the role of rituximab as a valid alternative. However, none of the trials tested an optimized rituximab protocol involving a second rituximab cycle before declaring treatment failure. Calcineurin inhibitors should be considered third-line drugs and sequential use of calcineurin inhibitor rituximab did not add over rituximab-only regimens. We critically review recent randomized controlled trials, propose a research agenda, and call for multinational pragmatic trials that enroll patients at referral centers to address unmet research needs.

Efficacy and Safety of Different Immunosuppressive Therapies in Patients With Membranous Nephropathy and High PLA2R Antibody Titer

Background: This study aimed to evaluate clinical features and prognosis and therapy option of patients with different risk ranks based on antibody against the M-type phospholipase-A2-receptor (PLA2Rab) level in seropositive M-type phospholipase-A2-receptor (PLA2R)-associated membranous nephropathy (MN) in a large sample size, multi-center study. Method: Based on the unvalidated cut-off value of PLA2Rab above 150 RU/ml as one of the clinical criteria for high risk of progressive kidney function loss in MN according to 2020 Kidney Disease: Improving Global Outcomes (KDIGO) draft guidelines recommendation, a total of 447 patients who received cyclophosphamide (CTX) or tacrolimus (TAC) combined with corticosteroids treatment for 12 months were divided into high titer (>150 RU/ml) group and non-high titer (20-150 RU/ml) group, which were subdivided into CTX subgroup and TAC subgroup. The overall cohort was classified into CTX group and TAC group as well. Clinical parameters levels and remission rates were recorded at 3, 6, and 12 months follow-up. PLA2Rab was tested by enzyme-linked immunosorbent assay. Results: Patients with high titer PLA2Rab were associated with more severe proteinuria and hypoalbuminemia compared to those with non-high titer antibody, accompanied by lower complete remission (CR) and total remission (TR) rates at 3, 6, and 12 months, which even took longer to remission. Similar remission rates differences between the two titer groups were observed in the CTX and TAC groups, respectively. PLA2Rab level at baseline was an independent predictive factor for CR and TR. In the high titer group, CR and TR rates in the CTX subgroup were significantly higher than those in the TAC subgroup at 12 months, although serious adverse events were more frequent in the former. Conclusion: High-risk rank patients with PLA2Rab level above 150 RU/ml have higher disease activity and worse prognosis among patients with seropositive PLA2R-associated MN, even under different immunosuppressive therapeutic models; moreover, CTX combined with corticosteroids was preferred compared to TAC plus corticosteroids, although serious adverse events were more frequent in the former. Additionally, baseline PLA2Rab level was an independent predictive factor for clinical remission.

Treatment of Idiopathic Membranous Nephropathy for Moderate or Severe Proteinuria: A Systematic Review and Network Meta-Analysis

OBJECTIVE

Numerous studies have demonstrated that the efficacy of drugs differs in idiopathic membranous nephropathy (IMN) patients with moderate or high proteinuria. However, there is no systematic comparison confirming it. This network meta-analysis (NMA) was performed to respectively compare the efficacy of ten IMN treatments in patients with moderate and high proteinuria and compare the risk of adverse events with 10 IMN regimens.

METHODS

Randomized controlled trials (RCTs) and observational studies analyzing the main therapeutic regimens for IMN were included from some databases. Network comparisons were performed to analyze the rates of total remission (TR), bone marrow suppression, and gastrointestinal symptoms. The surface under the cumulative ranking area (SUCRA) was calculated to rank interventions.

RESULTS

Seventeen RCTs and eight observational studies involving 1778 patients were pooled for comparison of ten interventions. Steroid + tacrolimus (TAC) showed the highest probabilities of TR whether patients had severe proteinuria or not (SUCRA 89.5% and 88.9%, separately). Rituximab (RTX) was more beneficial for TR on patients with proteinuria <8 g/d (SUCRA 66.0%) and was associated with a lower risk of bone marrow suppression and gastrointestinal symptoms (SUCRA 21.7% and 21.4%, separately). TAC + RTX and steroids + cyclophosphamide induced the highest rates of bone marrow suppression (SUCRA 90.6% and 88.3%, separately) and gastrointestinal symptoms (SUCRA 86.0% and 72.1%, separately).

CONCLUSIONS

Steroids + TAC showed significant efficacy in patients with all degrees of proteinuria, while RTX was more effective in patients with moderate proteinuria and was safer in bone marrow suppression and gastrointestinal symptoms.