A review of therapeutic studies of idiopathic membranous glomerulopathy

Immunosuppressive treatment for idiopathic membranous nephropathy in adults with nephrotic syndrome

BACKGROUND

Idiopathic membranous nephropathy (IMN) is the most common form of nephrotic syndrome in adults. The disease shows a benign or indolent course in the majority of patients, with a rate of spontaneous complete or partial remission of nephrotic syndrome as high as 30% or more. Despite this, 30-40% of patients progress toward end-stage renal failure (ESRF) within 5-15 years.

OBJECTIVES

To assess the benefits and harms of immunosuppressive treatment for IMN in adults.

SEARCH STRATEGY

We searched the Cochrane Renal Group Specialised Register (December 2003), The Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 4, 2003), MEDLINE and Pre-MEDLINE (1966 - December 2003), EMBASE (1980 - December 2003), reference lists of nephrology textbooks, review articles, prospective trial registers, relevant trials and abstracts from nephrology scientific meetings and the internet without language restriction. We also contacted principal investigators of controlled studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing any immunosuppressive interventions for the treatment of IMN in adults.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed and extracted information. Information was collected on method, participants, interventions and outcomes (death, ESRF, proteinuria, serum creatinine, GRF, remission, adverse events).

MAIN RESULTS

A total of 18 trials with 1025 patients were included. No differences were found when we combined data of all treatment categories as a group and compared them with placebo or no treatment. Oral glucocorticoids. No beneficial effect on any of the end points chosen for efficacy was observed. Alkylating agents showed a significant beneficial effect on complete remission (RR 2.37, 95%CI 1.32 to 4.25, P = 0.004) but not on partial remission (RR 1.22, 95%CI 0.63 to 2.35, P = 0.56) or complete or partial remission (RR 1.55, 95%CI 0.72 to 3.34, P = 0.27). Cyclophosphamide treatment resulted in significantly lower rate of discontinuations due to adverse events as compared to chlorambucil (RR 2.34, 95%CI 1.25 to 4.39, P = 0.008). There was no evidence of clinically relevant differences in favour of cyclosporin and there was insufficient data on anti-proliferative agents.

REVIEWERS' CONCLUSIONS

This review failed to show any long-term effect of immunosuppressive treatment on patient and/or renal survival. There was an increased number of discontinuations due to adverse events in immunosuppressive treatment groups. Within the class of alkylating agents there is weak evidence supporting the efficacy of cyclophosphamide as compared to chlorambucil. On the other hand, cyclophosphamide had fewer side effects leading to patient withdrawal than chlorambucil.

Pathologic findings of initial biopsies reflect the outcomes of membranous nephropathy

BACKGROUND

A considerable diversity of prognosis is seen with idiopathic membranous nephropathy (IMN). The initial factors affecting long-term outcome remain unclear.

METHODS

We studied retrospectively 105 patients with IMN who had been followed up for at least 5 years, or until end-stage renal failure (ESRF) (primary outcome), or death (secondary outcome). We analyzed the initial clinicopathologic factors affecting primary and secondary outcomes. We assigned the patients to two groups and one subgroup, based on the electron microscopic findings. The groupings were: homogeneous type with synchronous electron dense deposits; homogeneous type with large dense deposits (deep subgroup); and heterogeneous type with various phases of dense deposits.

RESULTS

No differences in the initial clinicopathologic states were seen between the homogeneous (N= 60) and heterogeneous types (N= 45), apart from hypertension and disease history before biopsy. In the homogeneous type, only one patient developed ESRF, which was drug-induced, and remission occurred earlier than in the heterogeneous type. With regard to secondary outcomes, increased age, male gender, heterogeneous type, and deep subgroup were independent risk factors. There were no significant differences attributable to therapeutic regime with respect to primary or secondary outcome in either group.

CONCLUSION

Our results indicate that an electron microscopic classification, at initial biopsy, as heterogeneous type or deep subgroup type with dense deposits are independent indicators of poor prognosis in IMN.

Idiopathic membranous nephropathy: Definition and relevance of a partial remission

BACKGROUND

Membranous nephropathy (MGN) remains the most common cause of adult onset nephrotic syndrome, and within the primary glomerulonephritis group is a leading cause of renal failure. A complete remission (CR) confers an excellent long-term prognosis, but the quantitative benefits of partial remissions (PR) have not been defined.

METHODS

This study evaluated the rate of renal function decline (slope), relapse, and renal survival in nephrotic MGN patients with CR, PR, or no remission (NR). Multivariate analysis included clinical and laboratory data at presentation and over follow-up, blood pressure control and agents employed, and immunosuppressive therapy.

RESULTS

The study cohort consisted of 348 nephrotic MGN patients with a minimum of 12 months follow-up identified from the Toronto Glomerulonephritis Registry. Over a median follow-up of 60 months, 102 experienced a CR, 136 had a PR, and 110 had no remission. A PR was independently predictive of slope and survival from renal failure by multivariate analysis (hazard ratio 0.08, 95% CI 0.03-0.19, P < 0.001). Benefit from immunosuppression could only be shown in a subset of high-risk patients. Treatment-related PR had the same long-term implication as spontaneous ones. Relapses from PR were high (47%) but often reversible.

CONCLUSION

A partial remission is an important therapeutic target with implications for both progression rate and renal survival.

Nephrotic syndrome caused by membranous nephropathy: response to a short course of cyclophosphamide alternating with prednisolone

OBJECTIVE

The optimal duration of immunosuppressive therapy and the timing of treatment for treating membranous nephropathy (MN) have yet to be established. We examined outcomes of a short course of cyclophosphamide alternating with prednisolone for MN patients with nephrotic syndrome.

METHODS AND PATIENTS

Cyclophosphamide (2 mg/kg/day for 8 weeks) combined with prednisolone (1 mg/kg every 48 hours for 8 weeks, then tapering off for 1 year) was prescribed for 28 MN patients (12 men and 16 women; mean age 52.4+/-2.25 years SEM). We first evaluated the response rates to this combined therapy, then compared the clinical characteristics of those who achieved remission (group A) with those who did not (group B) within 6 months of the start of treatment.

RESULTS

The incidences of complete and partial remission increased with the follow-up period; 32 and 21% by 6 months, 54 and 29% by 12 months, and 79 and 11% by 24 months, respectively. Serum IgG (906+/-100.8 versus 562+/-66.1 mg/day; p<0.01) was significantly higher in group A, and the selectivity index (C(IgG)/C(albumin) 0.16+/-0.015 versus 0.30+/-0.040; p<0.01), significantly lower. Nephrotic syndrome persisted in 3 group B patients (23%), who finally had impaired renal function.

CONCLUSION

MN patients with nephrotic syndrome responded favorably to a short course of cyclophosphamide combined with prednisolone. The serum IgG level and selectivity index may serve as markers of early response to this treatment.

Mycophenolate mofetil and cyclosporine therapy in membranous nephropathy

Idiopathic membranous nephropathy (IMN) remains one of the most common causes of the nephrotic syndrome (NS) in adults. Although the natural history is extremely variable, approximately two thirds of the patients will have persistent high-grade proteinuria and/or develop renal failure over a decade of observation. On the other hand, the remaining third of patients will remit spontaneously and potentially toxic therapy should be avoided in this group. Our capacity to predict which patient will progress at an early stage of the disease has improved substantially in the past 10 years. We present the data from studies of cyclosporine (CSA) and mycophenolate mofetil (MMF) treatment of IMN with their level of evidence in support of efficacy. In addition, based on data related to predicting prognosis, we assign a risk for progression category to the trial patients at entry into these studies. The data are presented in this format so the reader will be able to better discern the risk benefit of treatment within each category and the rationale for our subsequent grade of recommendation for the use of these agents in IMN. CSA has been shown in randomized controlled trials in both the medium and high risk of progression categories of IMN patients to improve proteinuria and preserve renal function at least in the short term in up to two thirds of patients. Other studies suggest prolonged therapy beyond 6 months to 1 year may reduce the high relapse rate after CSA treatment supporting more long-term, continuous, or combination therapy in IMN treatment. The data in favor of MMF treatment of this disease is much weaker and are derived from pilot studies. Only one report applied MMF specifically to IMN patients. In these medium to high risk of progression patients, approximately one-half had a 50% reduction in their baseline proteinuria without a significant alteration in their serum creatinine level. MMF's role as a single agent or as adjunctive therapy in the treatment of IMN needs more rigorous evaluation.

Developments in the Immunotherapy of Glomerular Disease

Glomerular diseases span a broad spectrum of clinical syndromes, with varied clinical manifestations, underlying etiologies, and pathogenic mechanisms. They can be secondary to underlying infectious, toxic, environmental, or drug exposures, or present as “primary entities.” In the latter case, most glomerular diseases are thought to be due to autoimmune dysregulation, and their treatment is primarily immunosuppressive. The armamentarium for immunomodulation includes corticosteroids, alkylating agents, anti-metabolites, calcineurin inhibitors, and new biological agents designed to block specific inflammatory pathways. The choice of therapy for an individual patient must be based on the specific character of the glomerular disease and its acuity and severity, as well as the patient’s comorbidities, history of prior exposure to immunosuppressive drugs, and risk factors for developing complications of the disease or its treatment. The complexities of such therapy can best be addressed by an experienced team of care givers in which the clinical pharmacist can help minimize, if not eliminate, potential sources of drug induced toxicities and adverse effects. This article will describe the major agents and modalities used in the management of the most common glomerular diseases.

Cyclosporine in patients with steroid-resistant membranous nephropathy: a randomized trial

BACKGROUND

A clinical trial of cyclosporine in patients with steroid-resistant membranous nephropathy (MGN) was conducted. Although MGN remains the most common cause of adult-onset nephrotic syndrome, its management is still controversial. Cyclosporine has been shown to be effective in cases of progressive MGN, but it has not been used in controlled studies at an early stage of the disease.

METHODS

We conducted a randomized trial in 51 biopsy-proven idiopathic MGN patients with nephrotic-range proteinuria comparing 26 weeks of cyclosporine treatment plus low-dose prednisone to placebo plus prednisone. All patients were followed for an average of 78 weeks, and the short- and long-term effects on renal function were assessed.

RESULTS

Seventy-five percent of the treatment group versus 22% of the control group (P < 0.001) had a partial or complete remission of their proteinuria by 26 weeks. Relapse occurred in 43% (N = 9) of the cyclosporine remission group and 40% (N = 2) of the placebo group by week 52. The fraction of the total population in remission then remained almost unchanged and significant different between the groups until the end of the study (cyclosporine 39%, placebo 13%, P = 0.007). Renal function was unchanged and equal in the two groups over the test medication period. In the subsequent follow-up, renal insufficiency, defined as doubling of baseline creatinine, was seen in two patients in each group, but remained equal and stable in all of the other patients.

CONCLUSION

This study suggests that cyclosporine is an effective therapeutic agent in the treatment of steroid-resistant cases of MGN. Although a high relapse does occur, 39% of the treated patients remained in remission and were subnephrotic for at least one-year post-treatment, with no adverse effect on filtration function.

Treatment of idiopathic membranous nephropathy (IMN)

The best treatment of idiopathic membranous nephropathy remains an area of clinical controversy. At the moment only patients with nephrotic syndrome and/or declining renal function should be treated. Despite the negative trials, prolonged oral administration of corticosteroids alone may be a safe and an effective first-line treatment in nephrotic patients. If corticosteroids are ineffective, prolonged use of cyclosporine in low-doses can be recommended as an alternative treatment, that diminishes rapidly proteinuria in the majority of patients. Both treatments (intravenous high doses of corticosteroids and cyclosporine) may also be effective in patients with declining renal function. Because of their toxicity, the routine use of alkylating agents for patients with nephrotic syndrome is not justified. They may be retained for patients, in whom other treatment modalities have failed. Chlorambucil may be preferred over cyclophosphamide since it carries less toxicity. A lower dose of chlorambucil, than that usually suggested, for a short period of time seems to be prudent in an effort to avoid serious side-effects.

Use of mycophenolate mofetil in resistant membranous nephropathy

Membranous nephropathy (MN) is a common cause of nephrotic syndrome. Optimal therapy for this disease is still debated. We report our experience using mycophenolate mofetil (MMF), an immunosuppressive agent widely used in transplant recipients, to treat 16 nephrotic patients with MN. All patients had biopsy-documented MN; secondary forms were ruled out. Fifteen patients had steroid-resistant disease; cytotoxic agents had failed in 6 patients and cyclosporine therapy had failed in 5 patients. Patients were treated with MMF (dose range, 500 to 2,000 mg) for a mean of 8 months. Six patients experienced a halving of proteinuria, which occurred after a mean duration of 6 months of therapy. Partial remissions occurred in 2 patients. There were no significant changes in mean values for serum creatinine, serum albumin, or proteinuria. Mean cholesterol levels were significantly less. Side effects of MMF were infrequent and generally mild. In summary, MMF appears to reduce proteinuria in some patients with idiopathic MN previously resistant to steroids, cytotoxic agents, or cyclosporine. Further trials with this agent are warranted.

Cyclosporin treatment of glomerular diseases

Cyclosporin is a potent immunosuppressive agent that has become the first line therapy in organ transplantation. Its efficacy has led to its use in a variety of immune-mediated glomerular diseases. A selection of controlled and uncontrolled trials has studied the effects of cyclosporin in patients with minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), IgA nephropathy, membranoproliferative glomerulonephritis (MPGN) and lupus nephritis. We review the recent literature and suggest recommendations for using cyclosporin in these diseases, based on this evidence and our experience.

Effect of gender on the progression of nondiabetic renal disease: a meta-analysis

There is previously published evidence that male gender is associated with a more rapid rate of progression of nondiabetic chronic renal disease. However, some investigators have concluded that no such association exists. To help resolve this issue, a meta-analysis was performed using 68 studies that met defined criteria and contained a total of 11,345 patients to evaluate the effect of gender on the progression of nondiabetic chronic renal disease. The results indicate that men with chronic renal disease of various etiologies show a more rapid decline in renal function with time than do women.

Management of idiopathic membranous nephropathy: evidence-based recommendations

Membranous nephropathy is a frequent cause of nephrotic syndrome in adults, and in one third of these patients, it leads to end-stage renal disease. Based on an extensive critical review of the literature, the following recommendations are offered. Oral high-dose corticosteroids are ineffective in producing either a sustained remission of nephrotic syndrome or in preserving renal function in patients with membranous nephropathy, and should not be used as the sole therapy (grade A recommendation). The use of azathioprine is not associated with any significant benefits, so its use is not justified (grade C). The alkylating agents cyclophosphamide and chlorambucil are both effective in the management of membranous nephropathy. Because of growing concern about long-term toxicity, especially with cyclophosphamide, these drugs should be reserved for patients who exhibit clinical features, such as severe or prolonged nephrosis, renal insufficiency, or hypertension, that predict a high likelihood of progression to end-stage renal disease. Chlorambucil in conjunction with oral steroids is the drug of first choice (grade A). Cyclophosphamide and oral steroids are alternatives (grade B). Cyclosporine may, in the future, become the agent of choice for membranous nephropathy. Currently, it is recommended (grade B) that cyclosporine use be considered in patients at high risk for progression in membranous nephropathy or if alkylating agents are contraindicated or ineffective.

Cyclosporine treatment of glomerular diseases

Cyclosporine-A is primary therapy for organ transplantation. Its immunosuppressive effect might suggest a therapeutic role in autoimmune diseases, including several idiopathic and secondary glomerular conditions. Various forms of idiopathic nephrotic syndrome, including focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), and membranous nephropathy (MN), may respond well to cyclosporine in selected patients. However, frequent relapse limits its use to those who have failed to respond to, or were intolerant of, steroids or cytotoxics. Cyclosporine's efficacy in other glomerulopathies, such as IgA nephropathy (IgAN) and membranoproliferative glomerulonephritis (MPGN) remains poorly studied and, given the risk of nephrotoxicity, cannot be recommended for treatment of these entities until further data are available. Cyclosporine demonstrates some efficacy in treating proliferative lupus nephritis and, based on pilot study data, membranous lupus as well. Again, given relapse rates and potential nephrotoxicity, it should be used only in combination with azathioprine and steroids, assuming cytotoxic therapy has failed. Finally, cyclosporine toxicity is briefly reviewed.

Idiopathic membranous nephropathy in the elderly: a comparative study

This is a retrospective study of 74 elderly patients (60 years of age or older) with idiopathic membranous nephropathy. They represented 23% of the total of 323 cases of idiopathic membranous nephropathy who presented during the 19-year review period. The mean age of these patients was 67 years versus 41 in the younger-onset group. The median presenting serum creatinine in the elderly group was higher (1.3 mg/dL v 1.0 mg/dL, P < 0.001), and the median creatinine clearance calculated by Cockcroft-Gault to correct for age, gender, and weight was lower (55 mL/min v 95 mL/min, P < 0.0001). The incidence of chronic renal insufficiency, defined as a creatinine clearance of less than 50 mL/min, was significantly worse in the elderly after a mean observation period of 47 months (59% v 25%, P < 0.0001) although end-stage renal failure (ESRF) was not (18% v 12%). The rate of change of renal function, however, as measured by the time to doubling of baseline creatinine, was similar in both groups, as was the complete remission rate. Forty-six percent of patients (33 of 74) in the elderly group received treatment: steroids alone (76%), immunosuppression drugs alone (9%), or a combination (15%). There was no benefit noted in terms of complete remission rate or incidence of chronic renal insufficiency. In summary, more elderly patients with membranous nephropathy develop chronic renal insufficiency, but this appears to be related to their age and decreased functional reserve, because the rate of decline in renal function after initiation of the disease is no different than in the younger age-group. The data also indicate that an accurate assessment of renal function in this older age-group requires an estimated or calculated creatinine clearance, given the inaccuracy when only serum creatinine is used. There was no evidence of improved outcome with prednisone therapy, and in view of the increased incidence of complications associated with this drug in the elderly as well as the decreased reserve at presentation, we suggest that routine steroid treatment of these patients should not be undertaken.