Have we changed the outcome in membranous nephropathy? A propensity study on the role of immunosuppressive therapy

The effectiveness of ruxolitinib and cyclophosphamide combination on T helper 17 and regulatory T cells in rat experimental membranous glomerulonephritis

The progression and pathogenesis of membranous glomerulonephritis (MGN) are inextricably linked to chronic inflammation. Despite improving clinical remission rates due to the application of cyclophosphamide (CYC), treatment of MGN still requires further exploration. Ruxolitinib (Ruxo) negatively affects the signaling pathways participating in the production of pro-inflammatory cytokines. Hence, we investigated whether the combination of CYC and Ruxo can modulate inflammation through influencing T helper 17 (Th17) lineages and regulatory T cells (Tregs). Passive Heymann nephritis (PHN), an experimental model of MGN, was induced in a population of rats. Then, the animals were divided into five groups: PHN, CYC-receiving, Ruxo-receiving, CYC-Ruxo-receiving PHN rats, and healthy controls. After 28 days of treatment, biochemistry analysis was performed and splenocytes were isolated for flowcytometry investigation of Th17 cells and Tregs. The correlative transcription factors of the cells, alongside their downstream cytokine gene expressions, were also assessed using real-time PCR. Furthermore, serum cytokine signatures for the lymphocytes were determined through ELISA. The combination of CYC and Ruxo significantly reduced the serum values of urea in rats versus the PHN group (24.62 ± 7.970 vs. 40.60 ± 10.81 mg/dL). In contrast to Treg's activities, the functionality of Th17 cells noticeably increased not only in PHN rats but also in CYC or Ruxo-receiving PHN animals when compared with the control (10.60 ± 2.236, 8.800 ± 1.465, 8.680 ± 1.314 vs. 4.420 ± 1.551 %). However, in comparison to the PHN group, the incidence of Th17 cells notably fell in rats receiving CYC and Ruxo (10.60 ± 2.236 vs. 6.000 ± 1.373 %) in favor of the Treg's percentage (5.020 ± 1.761 vs. 8.980 ± 1.178 %), which was verified by the gene expressions and cytokine productions correlative to these lymphocytes. The combination of CYC and Ruxo was able to decline Th17 cells in favor of Tregs improvement in PHN rats, suggesting an innovative combination therapy in MGN treatment approaches.

Anti-PLA2R Antibody Levels and Clinical Risk Factors for Treatment Nonresponse in Membranous Nephropathy

BACKGROUND

The 2021 Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend following anti-phospholipase A2 receptor (PLA2R) antibody levels as a marker of treatment response in membranous nephropathy; however, the optimal timing to evaluate antibody levels and how to combine them with other clinical variables are currently unknown.

METHODS

We used a cohort of 85 patients from the Membranous Nephropathy Trial Of Rituximab (MENTOR) with anti-PLA2R antibodies ≥14 RU/ml to identify risk factors for not experiencing proteinuria remission after 12 months of treatment with cyclosporine or rituximab. Three landmark times were considered: at baseline and after 3 and 6 months of treatment. Logistic regression model performance was evaluated using C-statistics and model fit (Akaike information criterion [AIC], R 2 ).

RESULTS

The model at baseline that best predicted no remission included anti-PLA2R antibodies >323 RU/ml and creatinine clearance; the best model after 3 months included the change from baseline in both antibody and albumin levels; and the best model after 6 months included antibody levels >14 RU/ml, creatinine clearance, and the change from baseline in albumin. Compared with the model at baseline, the model at 3 months had better model fit (AIC 70.9 versus 96.4, R 2 51.8% versus 30.1%) and higher C-statistic (0.93 versus 0.83, P = 0.008). The model at 6 months had no difference in performance compared with the model at 3 months (AIC 68.6, R 2 53.0%, C-statistic 0.94, P = 0.67).

CONCLUSIONS

In patients with membranous nephropathy treated with cyclosporine or rituximab in the MENTOR trial, we found that the optimal method to evaluate risk factors for the probability of treatment response was to use anti-PLA2R antibody levels combined with albumin levels after 3 months of treatment, which was significantly better than using antibody levels alone or risk factor evaluation at baseline, with no added benefit of waiting until 6 months of treatment.

PODCAST

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Membranous nephropathy: thinking through the therapeutic options

Idiopathic membranous nephropathy (IMN) remains the most common cause of the nephrotic syndrome in adults and one of the leading identifiable causes of end-stage kidney disease. Prior to considering the best approach to treatment, three important components need to be considered. First, the natural history of the typical membranous patient today; second, the importance of identifying the causative factors; and third, the integration of the current data on the known autoantibody/antigen systems involved in IMN into the diagnosis and management of the patient. Combining this with information on the known indicators associated with a poor prognosis plus new data on surrogate markers that provide important clues that the treatment plan is correct has provided us with a more secure platform for choosing the right treatment for each patient. This already provides a more rational and precise approach to the use of our current therapeutic options. Even today, we can slow disease progression and in the future new approaches and new therapies are likely to lead to prevention of progression or even reversal of the injury in IMN, thereby leading to improved quality of life of our patients.

Long-term outcomes for primary glomerulonephritis: New Zealand Glomerulonephritis Study

AIMS

Due to the paucity of studies focusing on primary glomerulonephritis, the second commonest cause of end-stage-kidney-disease in most of the developed world, we sought to review outcomes of these renal pathologies.

METHODS

We reviewed renal outcomes and mortality for primary glomerulonephritis patients enrolled in the New Zealand Glomerulonephritis Study between 1972 and 1983.

RESULTS

There were 765 patients with median follow-up of 30 years (range 0.1-42 years). They were predominantly New Zealand European, male and hypertensive. Poor renal outcomes and increased mortality were associated with hypertension, heavy proteinuria, impaired renal function and older age at diagnosis. Ethnicity was not significantly associated with progression to end-stage-kidney-disease although NZ Maori patients were at significantly increased risk of death. Patients with rapidly progressive glomerulonephritis had the highest risk of reaching end-stage-kidney-disease while the cumulative incidence of end-stage-kidney-disease was 20% and 30% for those with immunoglobulin-A nephropathy and membranous nephropathy respectively. Mortality risk was high for patients with rapidly progressive glomerulonephritis and anti-glomerular basement membrane disease. The era of diagnosis did not have much effect on outcomes except for patients with focal segmental glomerulosclerosis or immunoglobulin A nephropathy but this could be type II error.

CONCLUSION

We report one of the longest follow-up studies on biopsy-proven glomerulonephritides. Age, hypertension, and severity of chronic kidney disease at diagnosis were strong predictors of the development of end-stage-kidney-disease and death. The specific renal pathology had a profound impact upon prognosis and therefore should continue to drive efforts to find targeted therapeutic options for these glomerulonephritides.

The need for improved uptake of the KDIGO glomerulonephritis guidelines into clinical practice in Canada: a survey of nephrologists

Background

The lack of glomerulonephritis (GN) guidelines has historically contributed to substantial variability in the treatment of GN. We hypothesize that there are barriers to GN guideline implementation leading to incomplete translation of the 2012 KDIGO GN guidelines into patient care, and that current practice patterns deviate from guideline recommendations.

Methods

Adult nephrologists in Canada (N = 390) were surveyed using a web-based tool. The survey of 40 questions captured physician demographics, self-reported GN case load, treatment approaches and barriers to guideline implementation.

Results

The response rate was 44%. Physicians report seeing six (IQR 4,10) new cases of idiopathic GN every 6 months. The majority treat ANCA GN according to guidelines, but 9–37% treat nephrotic focal segmental glomerulosclerosis or membranous nephropathy with non-recommended immunosuppression and 6–9% do not treat with any immunotherapy, whereas 26% treat subnephrotic disease with immunosuppression. The majority indicated that standardized care tools would improve patient care, but they were only available to 25–44%. Patient education tools and nursing support are unavailable to 87 and 67%, respectively; insurance coverage for immune therapies is poorly accessible to 84%, yet 86% feel this would improve care and 96% of physicians support comparing their practice with benchmarks from provincial GN registries.

Conclusions

We show that 2 years after the publication of the KDIGO GN guidelines, 15–46% of Canadian nephrologists report treatment strategies not in keeping with guideline recommendations. We identify barriers to guideline implementation and widespread physician support for initiatives that address these barriers to improve patient care.

Cancer risk after cyclophosphamide treatment in idiopathic membranous nephropathy

BACKGROUND AND OBJECTIVES

Cyclophosphamide treatment improves renal survival in patients with idiopathic membranous nephropathy. However, use of cyclophosphamide is associated with cancer. The incidence of malignancies in patients with idiopathic membranous nephropathy was evaluated, and the cancer risk associated with cyclophosphamide use was estimated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients who attended the clinic were included prospectively from 1995 on. A crude incidence ratio for the occurrence of malignancy was calculated. Incidence ratios were subsequently standardized to potential confounders. Latency between cyclophosphamide therapy and the occurrence of cancer was estimated by stratifying for time since the start of treatment. Finally, Poisson regression was used to obtain a multiple adjusted incidence ratio and investigate the dose-response relationship between cyclophosphamide and cancer.

RESULTS

Data were available for 272 patients; the mean age was 51 years, and 70% of the patients were men. Median follow-up was 6.0 years (interquartile range=3.6-9.5), and 127 patients were treated with cyclophosphamide. Cancer incidence was 21.2 per 1000 person-years in treated patients compared with 4.6 per 1000 person-years in patients who did not receive cyclophosphamide, resulting in crude and adjusted incidence ratios of 4.6 (95% confidence interval, 1.5 to 18.8) and 3.2 (95% confidence interval, 1.0 to 9.5), respectively.

CONCLUSION

Cyclophosphamide therapy in idiopathic membranous nephropathy gives a threefold increase in cancer risk. For the average patient, this finding translates into an increase in annual risk from approximately 0.3% to 1.0%. The increased risk of malignancy must be balanced against the improved renal survival.

Pathological predictors of renal outcomes in nephrotic idiopathic membranous nephropathy with decreased renal function

BACKGROUND AND OBJECTIVES

The outcome of idiopathic membranous nephropathy (IMN) in adults with nephrotic-range proteinuria and decreased renal function has seldom been described and the predictive value of pathological features is debated. This study aimed to describe the clinical course of this patient subgroup and to identify independently predictive pathological features.

MATERIALS AND METHODS

We evaluated 129 adults with biopsy-proven IMN diagnosed from 2002 to 2011. All patients had chronic kidney disease (CKD) stages 2-4 and nephrotic-range proteinuria (≥3.5 g/day). Primary outcomes were a 20 or 50 % decline in renal function, progression to end-stage renal disease (ESRD), or all-cause mortality.

RESULTS

Of 129 patients, 38 (30 %) presented with proteinuria ≥8.0 g/day and 37 (29 %) with CKD stages 3-4. Thirteen (10 %) presented with segmental sclerosis, 97 (75 %) with arteriosclerosis, 42 (33 %) with moderate-to-severe tubulointerstitial injury, and 86 (67 %) with C3 deposition. Over a median follow-up of 34 months (range 12-135), 51 patients (40 %) had a 20 % decline in renal function, 27 (21 %) a 50 % decline, 14 (11 %) developed ESRD, and 19 (15 %) died. Segmental sclerosis and tubulointerstitial injury but not arteriosclerosis or C3 deposition were independent risk factors for 20 and 50 % renal function decline and progression to ESRD.

CONCLUSIONS

Segmental sclerosis and tubulointerstitial injury predict renal outcomes independent of clinical data in nephrotic IMN patients with decreased renal function.

Long-term outcomes in idiopathic membranous nephropathy using a restrictive treatment strategy

Recently published Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend limiting the use of immunosuppressive drugs in idiopathic membranous nephropathy to patients at the highest risk of kidney failure. However, recommendations are based on natural history rather than direct assessment of a restrictive treatment strategy. Here, we describe the long-term outcomes of treating a large cohort of patients with idiopathic membranous nephropathy according to a restrictive treatment policy. We analyzed data for 254 patients who visited our outpatient clinic between 1995 and 2009. All patients were treated with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers. Immunosuppressive therapy was recommended in cases of deteriorating renal function or untreatable nephrotic syndrome. Primary outcomes for the present study were renal replacement therapy and death. Secondary outcomes included adverse events during follow-up and remission of proteinuria. In total, 124 patients (49%) received immunosuppressive therapy, which predominantly consisted of cyclophosphamide combined with steroids. Ten-year cumulative incidence rates were 3% for renal replacement therapy and 10% for death. Partial remission rates were 39%, 70%, and 83% after 1, 3, and 5 years, respectively; complete remission rates were 5%, 24%, and 38% at 1, 3, and 5 years, respectively. A serious adverse event occurred in 23% of all patients. The most notable complications were infections (17%), leukopenia (18%), cardiovascular events (13%), and malignancies (8%). In conclusion, the use of a restrictive treatment strategy in this cohort of patients with idiopathic membranous nephropathy yielded favorable outcomes while limiting the number of patients exposed to toxic drugs. These results support current KDIGO guidelines.

Treatment of idiopathic membranous nephropathy

Immunosuppressive treatment of patients with idiopathic membranous nephropathy (iMN) is heavily debated. The controversy is mainly related to the toxicity of the therapy and the variable natural course of the disease-spontaneous remission occurs in 40-50% of patients. The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for Glomerulonephritis provides guidance for the treatment of iMN. The guideline suggests that immunosuppressive therapy should be restricted to patients with nephrotic syndrome and persistent proteinuria, deteriorating renal function or severe symptoms. Alkylating agents are the preferred therapy because of their proven efficacy in preventing end-stage renal disease. Calcineurin inhibitors can be used as an alternative although efficacy data on hard renal end points are limited. In this Review, we summarize the KDIGO guideline and address remaining areas of uncertainty. Better risk prediction is needed to identify patients who will benefit from immunosuppressive therapy, and the optimal timing and duration of this therapy is unknown because most of the randomized controlled trials were performed in low-risk or medium-risk patients. Alternative therapies, directed at B cells, are under study. The discovery of anti-M type phospholipase A2 receptor-antibodies is a major breakthrough and we envisage that in the near future, antibody-driven therapy will enable more individualized treatment of patients with iMN.

Immunosuppression for progressive membranous nephropathy: a UK randomised controlled trial

BACKGROUND

Membranous nephropathy leads to end-stage renal disease in more than 20% of patients. Although immunosuppressive therapy benefits some patients, trial evidence for the subset of patients with declining renal function is not available. We aimed to assess whether immunosuppression preserves renal function in patients with idiopathic membranous nephropathy with declining renal function.

METHODS

This randomised controlled trial was undertaken in 37 renal units across the UK. We recruited patients (18-75 years) with biopsy-proven idiopathic membranous nephropathy, a plasma creatinine concentration of less than 300 μmol/L, and at least a 20% decline in excretory renal function measured in the 2 years before study entry, based on at least three measurements over a period of 3 months or longer. Patients were randomly assigned (1:1:1) by a random number table to receive supportive treatment only, supportive treatment plus 6 months of alternating cycles of prednisolone and chlorambucil, or supportive treatment plus 12 months of ciclosporin. The primary outcome was a further 20% decline in renal function from baseline, analysed by intention to treat. The trial is registered as an International Standard Randomised Controlled Trial, number 99959692.

FINDINGS

We randomly assigned 108 patients, 33 of whom received prednisolone and chlorambucil, 37 ciclosporin, and 38 supportive therapy alone. Two patients (one who received ciclosporin and one who received supportive therapy) were ineligible, so were not included in the intention-to-treat analysis, and 45 patients deviated from protocol before study end, mostly as a result of minor dose adjustments. Follow up was until primary endpoint or for minimum of 3 years if primary endpoint was not reached. Risk of further 20% decline in renal function was significantly lower in the prednisolone and chlorambucil group than in the supportive care group (19 [58%] of 33 patients reached endpoint vs 31 [84%] of 37, hazard ratio [HR] 0·44 [95% CI 0·24-0·78]; p=0·0042); risk did not differ between the ciclosporin (29 [81%] of 36) and supportive treatment only groups (HR 1·17 [0·70-1·95]; p=0·54), but did differ significantly across all three groups (p=0·003). Serious adverse events were frequent in all three groups but were higher in the prednisolone and chlorambucil group than in the supportive care only group (56 events vs 24 events; p=0·048).

INTERPRETATION

For the subset of patients with idiopathic membranous nephropathy and deteriorating excretory renal function, 6 months' therapy with prednisolone and chlorambucil is the treatment approach best supported by our evidence. Ciclosporin should be avoided in this subset.

FUNDING

Medical Research Council, Novartis, Renal Association, Kidney Research UK.

Rituximab therapy in nephrotic syndrome: implications for patients' management

Rituximab offers an alternative to current immunosuppressive therapies for difficult-to-treat nephrotic syndrome. The best outcomes are seen in patients with steroid-dependent nephrotic syndrome who have failed to respond to multiple therapies. By contrast, the benefits of rituximab therapy are limited in patients with steroid-resistant nephrotic syndrome, particularly those with focal segmental glomerulosclerosis (FSGS). Therapy with plasma exchange and one or two doses of rituximab has shown success in patients with recurrent FSGS. Young patients and those with normal serum albumin at recurrence of nephrotic syndrome are most likely to respond to rituximab therapy. A substantial proportion of rituximab-treated patients with idiopathic membranous nephropathy show complete or partial remission of proteinuria, and reduced levels of phospholipase A(2) receptor autoantibodies, which are implicated in the pathogenesis of this disorder. Successful rituximab therapy induces prolonged remission and enables discontinuation of other medications without substantially increasing the risk of infections and other serious adverse events. However, the available evidence of efficacy of rituximab therapy is derived chiefly from small case series and requires confirmation in prospective, randomized, controlled studies that define the indications for use and predictors of response to this therapy.

Mortality and renal outcome of primary glomerulonephritis in Korea: observation in 1,943 biopsied cases

BACKGROUND

Previous epidemiological studies have focused on the prevalence of primary glomerulonephritis (GN), but few have explored long-term patient outcomes. This study was conducted to investigate the long-term patient and renal outcomes of primary GN.

METHODS

A total of 1,943 biopsy-proven primary GN patients were included. The outcomes were mortality and end-stage renal disease (ESRD) progression. The relative mortality rate was expressed by the standardized mortality ratio (SMR) and the 95% confidence interval (CI).

RESULTS

During the median follow-up of 90 months, 325 (16.7%) patients progressed to ESRD and 164 (8.4%) patients died. Patients with minimal change disease exhibited the best renal and patient outcomes, whereas those with membranoproliferative GN had the worst. IgA nephropathy patients appeared to have a good survival rate in spite of their considerable progression to ESRD, and focal segmental glomerulosclerosis patients showed poor renal and patient outcomes. Mortality was 67% higher in primary GN patients than in the age- and sex-matched general population (SMR, 1.67; 95% CI, 1.42-1.95). The difference was more prominent in women (SMR, 2.95; 95% CI, 2.27-3.77) than in men (SMR, 1.31; 95% CI, 1.07-1.60). Renal risk factors, e.g. hypertension, proteinuria and initial renal dysfunction, were all associated with higher mortality, and the relative mortality rate increased with the number of risk factors.

CONCLUSIONS

In patients with primary GN, mortality is significantly higher than in the age-/sex-matched general population, especially in women. Moreover, the presence of renal risk factors is positively associated with both relative mortality and progression to ESRD.

Kidney biopsy is a sensitive tool for retrospective diagnosis of PLA2R-related membranous nephropathy

BACKGROUND

Antibodies against M-type phospholipase A2 receptor (PLA2R) are serological markers of disease activity in patients with idiopathic membranous nephropathy (iMN). To determine the most sensitive test for the diagnosis of PLA2R-related membranous nephropathy (MN) irrespective of sampling time, we investigated the presence of PLA2R in glomerular immune deposits and assessed circulating anti-PLA2R antibodies in a retrospective cohort of Czech patients with idiopathic, lupus and other few secondary MN.

METHODS

We tested archival paraffin-embedded kidney biopsies of 84 consecutive patients with biopsy-proven MN, for the presence of PLA2R in glomerular immune deposits and we measured circulating anti-PLA2R antibodies using the indirect immunofluorescence test, all reagents being commercially available.

RESULTS

In 45 of 65 (69%) patients with iMN, PLA2R was detected in a finely granular pattern in sub-epithelial deposits along glomerular capillary loops. Circulating anti-PLA2R antibodies were detected in 20 of 31 (65%) sera from patients sampled during active disease. Six patients with active disease were negative for circulating anti-PLA2R antibodies despite PLA2R antigen positivity in the kidney biopsies. Only 8 of 37 (22%) sera sampled at the time of remission were PLA2R positive while PLA2R antigen was found in 22 of the 37 (59%) corresponding biopsies. PLA2R was found in immune deposits in 3 patients with secondary MN (2 with hepatitis B, and 1 with sarcoidosis) but in none of the 16 patients with lupus.

CONCLUSIONS

In case of delayed serum sampling, assessment of PLA2R antigen in biopsy specimens is more sensitive than the serological test for the diagnosis of PLA2R-related MN which can be established retrospectively.

Rituximab in idiopathic membranous nephropathy

Selective depletion of B cells with the mAb rituximab may benefit the autoimmune glomerular disease idiopathic membranous nephropathy (IMN). Here, we describe our experience treating 100 consecutive IMN patients with persistent nephrotic syndrome with rituximab. We defined complete remission as persistent proteinuria <0.3 g/24 h and partial remission as persistent proteinuria <3 g/24 h, each also having >50% reduction in proteinuria from baseline. During a median follow-up of 29 months after rituximab administration, 65 patients achieved complete or partial remission. The median time to remission was 7.1 months. All 24 patients who had at least 4 years of follow-up achieved complete or partial remission. Rates of remission were similar between patients with or without previous immunosuppressive treatment. Four patients died and four progressed to ESRD. Measured GFR increased by a mean 13.2 (SD 19.6) ml/min per 1.73 m(2) among those who achieved complete remission. Serum albumin significantly increased and albumin fractional clearance decreased among those achieving complete or partial remission. Proteinuria at baseline and the follow-up duration each independently predicted the decline of proteinuria. Furthermore, the magnitude of proteinuria reduction significantly correlated with slower GFR decline (P=0.0001). No treatment-related serious adverse events occurred. In summary, rituximab achieved disease remission and stabilized or improved renal function in a large cohort of high-risk patients with IMN.