Membranous nephropathy: quo vadis?

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Out of Africa: Complete and partial remissions as a combined outcome in patients with idiopathic membranous glomerulonephritis in Cape Town

AIM

Remission outcomes among patients with idiopathic membranous glomerulonephritis is unknown in Africa. We sought to determine remission outcomes in a cohort of South African adult patients with IMGN.

METHODS

This was a retrospective review of patients with biopsy-proven IMGN over a 10 year period. Secondary causes of MN were excluded. Demographic, clinical, biochemical and histological records were retrieved for analysis. The trends in biochemical parameters from baseline were determined. The primary outcome was the attainment of a complete or partial remission (CR / PR) at the last follow-up.

RESULTS

Fifty-six patients met the criteria for inclusion and 43 had subsequent follow-up care with a median duration of follow-up of 23.0 (13.0-48.0) months. Sixteen patients (37.2%) were treated with immunosuppression (corticosteroids and cyclophosphamide) and 81.4% received anti-proteinuric agents. There were no significant differences in demographic and clinical features of patients categorized by immunosuppression (ISP) use. Changes in level of proteinuria and estimated glomerular filtration rate (eGFR) were also not significantly different between the two groups. Eighteen patients (41.9%) reached CR or PR at the last visit. The median times-to-remission of patients according to ISP status were similar at 48.6 and 48.7 months respectively (P = 0.104) while the proportions of patients not reaching CR/PR at 12 and 24 months were 94.6% and 80.8% respectively. Gender and race did not predict remission status (P > 0.05). Predictors of CR/PR at last visit were eGFR [OR 1.01 (95%CI: 1.00 - 1.02); P = 0.041], and systolic BP (OR 0.97 [95%CI: 0.95 - 0.99); P = 0.036].

CONCLUSION

Remission outcomes in this African IMGN cohort are delayed and poor.

A Multicenter Randomized Controlled Trial of Rituximab versus Cyclosporine in the Treatment of Idiopathic Membranous Nephropathy (MENTOR)

BACKGROUND

Idiopathic membranous nephropathy remains the leading cause of nephrotic syndrome in Caucasian adults. Immunosuppressive therapy with cyclosporine (CSA) is often successful in reducing proteinuria, but its use is associated with a high relapse rate. Rituximab, a monoclonal antibody that specifically targets CD20 on the surface of B-cells, is effective in achieving a complete remission of proteinuria in patients with idiopathic membranous nephropathy. However, whether rituximab is as effective as CSA in inducing and maintaining complete or partial remission of proteinuria in these patients is unknown. The membranous nephropathy trial of rituximab (MENTOR) hypothesizes that B-cell targeting with rituximab is non-inferior to CSA in inducing long-term remission of proteinuria.

METHODS AND DESIGN

Patients with idiopathic membranous nephropathy, proteinuria ≥5 g/24 h, and a minimum of 3 months of Angiotensin-II blockade will be randomized into a 12-month treatment period with i.v. rituximab, 1,000 mg (2 infusions, 14 days apart; repeated at 6 months if a substantial reduction in proteinuria (equal to or >25%) is seen at 6 months) or oral CSA 3.5-5 mg/kg/day for 6 months (continued for another 6 months if a substantial reduction in proteinuria (equal to or >25%) is seen at 6 months). The efficacy of treatment will be assessed by the remission status (based on changes in proteinuria) at 24 months from randomization. Patient safety will be assessed via collection of adverse event data and evaluation of pre- and posttreatment laboratory data. At the 6-month post-randomization visit, patients who have been randomized to either CSA or rituximab but who do not have a reduction in proteinuria ≥25% (confirmed on repeat measurements within 2 weeks) will be considered treatment failures and exit the study.

DISCUSSION

This study will test for the first time whether treatment with rituximab is non-inferior to CSA in inducing long-term remission (complete or partial) of proteinuria in patients with idiopathic membranous nephropathy.

Depletion of B lymphocytes in idiopathic membranous glomerulopathy: results from patients with extended follow-up

Aims

To assess the long-term therapeutic benefit of temporary depletion of B lymphocytes in patients with idiopathic membranous glomerulopathy (MGN) and search for potential predictors of response.

Patients and Methods

The patients included had been diagnosed with biopsy-proven MGN in the absence of secondary causes. Estimated glomerular filtration rate should be above 30 ml/min/1.73 m² and 24-hour proteinuria 3 g/day or more. Patients who had been treated with cyclosporine or cytotoxic agents the year prior to study entry were excluded. Depletion of B cells was achieved with rituximab, which was administered intravenously for 4 consecutive weeks. Partial remission was defined as a >50% decrease in proteinuria with absolute proteinuria <3 g/day, while complete remission was defined as a >50% decrease in proteinuria and an absolute protein excretion <0.3 g/day.

Results

Twelve patients were studied (4 females/8 males) with a mean age of 51.3 years. No major adverse effects were observed. During a median follow-up time of 48 months, 11/12 (91.6%) patients achieved remission [7/12 (58.3%) complete remission and 4/12 (33.3%) partial remission], while 1 patient did not respond to therapy. Twelve months after therapy, 68.8% (p = 0.003) of cases had achieved partial and 28.4% complete remission. Measurements of lymphocyte subpopulations did not reveal any changes except for the B cell depletion. B cell infiltrates captured per mm³ of renal tissue in the diagnostic biopsy did not correlate with subsequent response.

Conclusion

Depletion of B cells in idiopathic MGN was well tolerated and resulted in significant and long-lasting response rates in a series of 12 patients.

Low- and high-molecular-weight urinary proteins as predictors of response to rituximab in patients with membranous nephropathy: a prospective study

BACKGROUND

Selective urinary biomarkers have been considered superior to total proteinuria in predicting response to treatment and outcome in patients with membranous nephropathy (MN).

METHODS

We prospectively tested whether urinary (U) excretion of retinol-binding protein (RBP), α1-microglobulin (α1M), albumin, immunoglobulin IgG and IgM and/or anti-phospholipase 2 receptor (PLA(2)R) levels could predict response to rituximab (RTX) therapy better than standard measures in MN. We also correlated changes in antibodies to PLA(2)R with these urinary biomarkers.

RESULTS

Twenty patients with MN and proteinuria (P) >5 g/24 h received RTX (375 mg/m(2) × 4) and at 12 months, 1 patient was in complete remission (CR), 9 were in partial remission (PR), 5 had a limited response (LR) and 4 were non-responders (NR). At 24 months, CR occurred in 4, PR in 12, LR in 1, NR in 2 and 1 patient relapsed. By simple linear regression analysis, UIgG at baseline (mg/24 h) was a significant predictor of change in proteinuria at 12 months (Δ urinary protein) (P = 0.04). In addition, fractional excretion (FE) of IgG, urinary alpha 1 microglobulin (Uα1M) (mg/24 h) and URBP (μg/24 h) were also predictors of response (P = 0.05, 0.04, and 0.03, respectively). On the other hand, UIgM, FEIgM, albumin and FE albumin did not predict response (P = 0.10, 0.27, 0.22 and 0.20, respectively). However, when results were analyzed in relation to proteinuria at 24 months, none of the U markers that predicted response at 12 m could predict response at 24 m (P = 0.55, 0.42, 0.29 and 0.20). Decline in anti-PLA(2)R levels was associated with and often preceded urinary biomarker response but positivity at baseline was not a predictor of proteinuria response.

CONCLUSIONS

The results suggest that in patients with MN, quantification of low-, medium- and high-molecular-weight urinary proteins may be associated with rate of response to RTX, but do not correlate with longer term outcomes.

Low-molecular-weight proteins as prognostic markers in idiopathic membranous nephropathy

BACKGROUND

Accurate prediction of prognosis in idiopathic membranous nephropathy (iMN) allows restriction of immunosuppressive therapy to patients at high risk for ESRD. Here we re-evaluate urinary low-molecular-weight proteins as prognostic markers and explore causes of misclassification.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a cohort of 129 patients with serum creatinine concentration <135 μmol/L and proteinuria ≥3.0 g/10 mmol, urinary α1- (uα1m) and β2-microglobulin (uβ2m) excretion rate was determined. Urinary α1m and uβ2m-creatinine ratio was also obtained. We defined progression as a rise in serum creatinine ≥50% or ≥25% and an absolute level ≥135 μmol/L.

RESULTS

Median survival time was 25 months, and 47% of patients showed progression. The area under the receiver operating characteristic curve for uβ2m was 0.81 (95% CI: 0.73 to 0.89). Using a threshold value of 1.0 μg/min, sensitivity and specificity were 73% and 75%, respectively. Similar accuracy was observed for the uβ2m-creatinine ratio with sensitivity and specificity of 75% and 73%, respectively, at a threshold of 1.0 μg/10 mmol creatinine. Similar accuracy was found for uα1m and uα1m-creatinine ratio. Blood Pressure and cholesterol contributed to misclassification. Repeated measurements improved accuracy in patients with persistent proteinuria: the positive predictive value of uβ2m increased from 72% to 89% and the negative predictive value from 76% to 100%.

CONCLUSIONS

Urinary excretion of uα2m and uβ2m predict prognosis in iMN. A spot urine sample can be used instead of a timed sample. A repeated measurement after 6 to 12 months increases prognostic accuracy.

Comparison of the influence of angiotensin-converting enzyme inhibitor lisinopril and angiotensin II receptor antagonist losartan in patients with idiopathic membranous nephropathy and nephrotic syndrome

OBJECTIVE

In this prospective study, the effects of an angiotensin-converting enzyme inhibitor [lisinopril (LIS)] and an angiotensin II receptor antagonist [losartan (LOS)] were compared in nephrotic patients with idiopathic membranous nephropathy.

MATERIAL AND METHODS

Twenty-seven patients (13 males, mean age +/- SD 51.3 +/- 15.4 years) were treated with LIS (13 patients, six males, mean age 52.1 +/- 15.3 years) or LOS (14 patients, seven males, mean age 50.5 +/- 15.5 years) for 12 months. At baseline and after the treatment period, serum albumin, total cholesterol, estimated glomerular filtration rate (GFR), 24 h proteinuria and mean arterial pressure were determined.

RESULTS

Proteinuria (g/24 h) was significantly reduced in both groups (LIS from 4.82 +/- 1.26 to 1.75 +/- 0.64, p < 0.0001; LOS from 4.55 +/- 1.09 to 2.54 +/- 1.94, p = 0.002) (all results +/- SD). Serum albumin levels (g/dl) increased significantly in both groups (LIS 2.27 +/- 0.41 to 3.17 +/- 0.63, p < 0.0001; LOS 2.93 +/- 0.40 to 3.55 +/- 0.44, p < 0.0001). GFR (ml/min x 1.73 m(2)) did not change significantly in either group (LIS 55 +/- 17 to 56 +/- 17, p = 0.65; LOS 64 +/- 18 to 59 +/- 16, p = 0.13). Total cholesterol (mg/dl) was significantly reduced only in the lisinopril group (LIS 347 +/- 81 to 266 +/- 64, p < 0.0001; LOS 306 +/- 58 to 263 +/- 77, p = 0.138). Mean arterial pressure (mmHg) was reduced in both groups (LIS 107 +/- 12 to 95 +/- 6, p < 0.0001; LOS 104 +/- 10 to 96 +/- 5, p = 0.003). In the comparison between the two groups, serum albumin levels were higher in the losartan group at baseline (p < 0.0001) and after 12 months (p = 0.029). There were no significant differences between the baseline and end-of-study values for the rest of the studied parameters.

CONCLUSION

Treatment with lisinopril and losartan in nephrotic patients with idiopathic membranous nephropathy results in similar (and significant) effects on renal function, hypoalbuminaemia, proteinuria and blood pressure.

Normoalbuminaemia is associated with IgA nephropathy in primary glomerulopathy with nephrotic-range proteinuria in Chinese patients

BACKGROUND

Massive proteinuria is often associated with hypoalbuminaemia in glomerulopathy. However, patients may have normal levels of serum albumin despite heavy proteinuria in many circumstances. This study analysed factors affecting serum levels of albumin in primary glomerulopathy patients with nephrotic-range proteinuria.

METHODS

The renal histopathological data of 780 consecutive adult patients (age ≥ 18 years old) with primary glomerulopathy and nephrotic-range proteinuria, who received native renal biopsies in Peking University First Hospital from 1998 to 2007, were retrospectively analysed.

RESULTS

Compared with patients with hypoalbuminaemia (serum albumin < 30 g/L), patients without hypoalbuminaemia were significantly younger (P < 0.001) and had significantly lower levels of proteinuria (P < 0.001). Patients without hypoalbuminaemia had a significantly higher proportion of IgA nephropathy (66.0% vs. 17.2%, P < 0.001). The independent predictors of hypoalbuminaemia in nephrotic-range proteinuria patients included age, gender, interval between onset of the disease and renal biopsy, proteinuria level, and pathological type of glomerulopathy. A serum level of albumin ≥ 35 g/L could predict IgA nephropathy with a specificity of 95.8%, and specificity increased with age.

CONCLUSIONS

Among patients with primary glomerulopathy and nephrotic-range proteinuria, normoalbuminaemia is associated with IgA nephropathy.

Tacrolimus combined with corticosteroids in treatment of nephrotic idiopathic membranous nephropathy: a multicenter randomized controlled trial

BACKGROUND

Idiopathic membranous nephropathy (IMN), a common cause of nephrotic syndrome in adults, is usually treated with corticosteroids in combination with cyclophosphamide or cyclosporine. A recent placebo-controlled study suggested that tacrolimus monotherapy was effective in IMN. However, the effectiveness of tacrolimus versus classic regimen and its potential nephrotoxicity remain inconclusive. This study evaluated the efficacy and safety of tacrolimus plus prednisone in patients with nephrotic IMN.

METHODS

Seventy-three patients with nephrotic IMN were recruited in this multicenter randomized controlled trial, 39 receiving tacrolimus and prednisone, while 34 receiving cyclophosphamide and prednisone. Tacrolimus was given at 0.1 mg/kg/d initially and adjusted to a blood trough level at 5 to 10 ng/mL for 6 months and then reduced to 2 to 5 ng/mL in the subsequent 3 months.

RESULTS

Intention-to-treat analysis suggested that the remission rate at the end of the sixth month was significantly higher in tacrolimus group than that in cyclophosphamide group (85% versus 65%, P < 0.05). The decrease of proteinuria was significantly greater in tacrolimus group. At the end of the 12th month, the remission rates were comparable between these 2 groups. Patients treated with tacrolimus were more likely to develop glucose intolerance (or diabetes mellitus), infection, and hypertension. No obvious nephrotoxicity of calcineurin inhibitor was found in repeat renal biopsy.

CONCLUSIONS

Tacrolimus plus corticosteroids is an alternative therapeutic regimen for nephrotic IMN. The short-term efficacy might be better than cyclophosphamide plus prednisone.

Rituximab treatment of idiopathic membranous nephropathy

Idiopathic membranous nephropathy is a common cause of nephrotic syndrome whose pathogenesis may involve B-cell functions. Rituximab is a monoclonal antibody that binds to the CD20 antigen on B cells thereby deleting them. We conducted an open-label pilot trial of rituximab treatment in 15 severely nephrotic patients with proteinuria refractory to angiotensin-converting enzyme inhibition and/or receptor blockade but with adequately controlled blood pressure. Rituximab was given 2 weeks apart and, at 6 months, patients who remained proteinuric but had recovered B-cell counts were given a second course of treatment. Proteinuria was significantly decreased by about half at 12 months. Of the 14 patients who completed follow-up, full remission was achieved in two and partial remission in six patients based upon the degree of proteinuria. Side effects were minor; however, we found no relationship between the response and number of B cells in the blood, CD20 cells in the kidney biopsy, degree of tubulointerstitial fibrosis, starting proteinuria or creatinine values. Rituximab appears effective in reducing proteinuria in some patients with idiopathic membranous nephropathy but prospective identification of responsive patients was not possible.

Use of Mycophenolate Mofetil in Autoimmune and Renal Diseases

Progress in understanding the pathogenesis and treatment of rheumatologic and glomerular diseases such as systemic lupus erythematosus and particularly lupus nephritis has been closely linked with the development of newer immunosuppressive agents. With improved patient survival following the institution of cyclophosphamide and corticosteroid therapy, longer-term management issues came to the forefront, especially how to decrease adverse effects of the immunosuppressive regimen. Many of the immunosuppressive regimens used in lupus patients were first established as efficacious and safe through their use in solid organ transplantation. Mycophenolate mofetil (MMF) is now widely used in the field of transplantation. Following anecdotal reports describing benefits of MMF in lupus and lupus nephritis patients, small studies and finally large randomized, controlled trials have established the use of MMF in these patients, particularly those with lupus nephritis. MMF use in other rheumatologic and renal diseases has been evaluated in only smaller studies and very few randomized controlled trials. Nevertheless, many studies currently are ongoing with this immunosuppressive agent. This article will review the published data and the experience of two major New York medical centers with the use of MMF in autoimmune and renal diseases.

18. Immune-mediated renal disease

Immune-mediated renal diseases can be classified by the clinical syndromes they produce, by the attendant renal pathology, or by the dominant immune effector mechanism of renal injury. The major clinical syndromes produced by immune-mediated renal injury include the nephrotic syndrome, the nephritic syndrome, rapidly progressive glomerulonephritis, and acute renal failure. The notion of clinical syndromes facilitates diagnosis and treatment, but does not accurately define disease pathogenesis. In this summary, we discuss pathologically defined immune-mediated renal diseases under the clinical syndrome with which they are most frequently associated. There is overlap between the clinical syndromes, but the syndromes provide a useful framework. Relevant information regarding the proposed pathogenesis of disease entities is included under specific disease entities.