Membranous nephropathy: response to steroids and immunosuppression

An Updated Review of Membranous Nephropathy

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

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.

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.

A review of therapeutic studies of idiopathic membranous glomerulopathy

The treatment of idiopathic membranous glomerulopathy remains an enigma. We have reviewed many of the important clinical trials concerning membranous glomerulopathy using a meta-analysis and a secondary pooled analysis to test the effects of corticosteroid or alkylating, therapy compared with no treatment on renal survival and complete remission of the nephrotic syndrome. A search was performed using MEDLINE (1968 through 1993) for articles on idiopathic membranous glomerulopathy and glomerulonephritis. Bibliographies of articles were reviewed for completeness. Sixty-nine articles were reviewed. Meta-analysis was performed for four trials that evaluated corticosteroids compared with no treatment and for three trials that evaluated alkylating therapy compared with no treatment. Pooled analysis was performed on randomized and prospective studies (10 studies) and then with 22 case series added. All studies evaluated renal biopsy-proven disease. Meta-analysis was performed on the relative chance of being in complete remission for each study. Renal survival could be evaluated by pooled analysis only. For pooled analyses, Cox's proportional hazard and logistic regression models were used to test the effect of therapy on renal survival and the nephrotic syndrome, respectively. Data concerning gender, nephrotic syndrome, and geographic region were used in all statistical models. Evaluation of renal survival revealed no differences by treatment group (P > 0.1). By meta-analysis, the relative chance of complete remission was not improved for corticosteroid-treated patients (1.55; 95% confidence interval, 0.99 to 2.44; P > 0.1), but was improved for patients treated with alkylating agents (4.8; 95% confidence interval, 1.44 to 15.96; P < 0.05) when compared with no treatment. Pooled analysis of randomized and prospective studies, as well pooled analysis with all studies, supported the findings of the meta-analysis. Corticosteroids or alkylating therapy did not improve renal survival in idiopathic membranous glomerulopathy. Complete remission of the nephrotic syndrome was observed more frequently with the use of alkylating agents.

Cyclophosphamide provides no additional benefit to steroid therapy in the treatment of idiopathic membranous nephropathy

Thirty-six patients with idiopathic membranous nephropathy were retrospectively studied. The mean age was 47 years and the male to female ratio 25 to 11. Twenty-eight patients (77.8%) had nephrotic syndrome at first investigation. Nineteen patients received corticosteroids alone (group A) and 17 received corticosteroids combined with cyclophosphamide (group B). The mean period of follow-up was 58.9 months (range, 12 to 156 months). The two groups did not differ in clinical or laboratory features at the time of biopsy or at the start of treatment. In the entire series a complete remission of proteinuria occurred in 13 of 36 patients (36.1%) and a partial remission occurred in 13 (36.1%); 10 patients (27.8%) had no response. Optimal remission of proteinuria was usually recorded 6 to 12 months after the start of treatment. The two groups showed no statistical differences regarding the rate of complete (seven v six patients; P = not significant) or partial (six v seven patients; P = not significant) remissions. Two patients (one from each group) entered end stage renal failure during follow-up. At last assessment, the number of patients with complete remission (four v three patients; P = not significant), nonnephrotic proteinuria (nine v nine patients; P = not significant), or nephrotic syndrome (five v four patients; P = not significant) was similar in both groups. In addition, final plasma creatinine did not differ significantly between the two groups (1.8 +/- 2.3 mg/dL v 2.6 +/- 2.6 mg/dL; P = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Methylprednisolone plus chlorambucil as compared with methylprednisolone alone for the treatment of idiopathic membranous nephropathy. The Italian Idiopathic Membranous Nephropathy Treatment Study Group

BACKGROUND AND METHODS

Treatment with methylprednisolone and chlorambucil may protect renal function and increase the chance of remission of the nephrotic syndrome in patients with idiopathic membranous nephropathy. To determine whether similar results might be obtained with methylprednisolone alone, we compared the effects of methylprednisolone and chlorambucil with those of methylprednisolone alone in 92 patients with the nephrotic syndrome caused by idiopathic membranous nephropathy. The patients were randomly assigned to receive either alternating one-month courses of methylprednisolone and then chlorambucil for a total of six months (group 1) or methylprednisolone alone for six months at the same cumulative dosage (group 2).

RESULTS

Four of the 45 patients in group 1 (9 percent) and 1 of the 47 in group 2 (2 percent) stopped treatment because of side effects. At one, two, and three years, the percentage of patients who did not have the nephrotic syndrome was significantly higher in group 1 than in group 2. It was 58, 54, and 66 percent, respectively, in group 1, as compared with 26, 32, and 40 percent in group 2 (P = 0.002, 0.029, and 0.011). By year 4, the difference was no longer statistically significant: 62 percent of the patients in group 1 and 42 percent of those in group 2 did not have the nephrotic syndrome (P = 0.102). The patients in group 1 were in remission longer than those in group 2 (P = 0.008).

CONCLUSIONS

In patients with the nephrotic syndrome caused by idiopathic membranous nephropathy, treatment with methylprednisolone and chlorambucil for six months induces an earlier remission of the nephrotic syndrome than methylprednisolone alone, but the difference may diminish with time.

Long-term benefits of therapy with cyclophosphamide and prednisone in patients with membranous glomerulonephritis and impaired renal function

Long-term follow-up data are provided for a previously reported study of patients with membranous glomerulonephritis (MGN), nephrotic syndrome, and renal function impairment. Nine patients were treated with cyclophosphamide (1 to 2 mg/kg) and six of these received concurrent prednisone; they are compared with 17 concurrent controls (14 of whom had received prednisone at some time). The mean follow-up is 83 +/- 13 months in the treated patients and 64 +/- 7 months in the controls. Of the nine treated patients, four achieved a complete remission from the nephrotic syndrome (proteinuria less than 0.5 g/d), and five a partial remission (proteinuria decreased by at least 50% and to less than 3.5 g/d). One of the nine treated patients and 10 of the 17 controls have reached end-stage renal disease (ESRD) (P less than 0.05). Nine of the controls reaching ESRD had persistent nephrotic syndrome, whereas of the seven controls who have not yet reached ESRD, only two have persistent nephrotic syndrome (chi 2, P less than 0.02). There have been four relapses in three treated patients, and three of the four have responded to repeat therapy. One patient refused full therapy and remains nephrotic. Life-table analysis demonstrates significantly increased survival from ESRD in treated patients as compared with controls (P = 0.04).

Long-term effects of steroid and cytostatic treatment on the clinical course of idiopathic membranous glomerulonephritis (retrospective study)

The clinical course of 30 patients with idiopathic membranous glomerulonephritis has been followed up for 8.1 +/- 3.4 (4-17) years. First, in each case a long-term prednisone treatment was administered. During this therapy 12 (40%) patients improved and 9 had remission. In the 18 (60%) steroid resistant cases the treatment was combined with cytostatic drugs. After a combined regime for 1.9 +/- 0.8 years, 8 patients have improved, 2 of whom remitted. It has been suggested that due to a long-term immunomodulator therapy the level of urinary protein excretion might be reduced in 77% of patients. There was no effect of the applied treatment in 7% of cases, still in 16% a gradual deterioration was observed. Relapsing nephrotic syndrome has occurred in 3 (10%) of the total cases. Side effects requiring cessation of treatment were not observed.

A controlled trial of cyclophosphamide in patients with membranous glomerulonephritis

Patients with membranous glomerulonephritis (MGN), impaired renal function and the nephrotic syndrome are at high risk of developing renal failure. Twenty-six such patients were studied with serum creatinine concentrations exceeding 135 microM, and 24-hour urine protein excretion of at least 3.5 g/day to determine the potential benefit of cyclophosphamide therapy. Cyclophosphamide (mean 1.5 mg/kg/day) was given to nine patients for 23 +/- 4 months. These patients were compared with 17 concurrent controls. The two groups did not differ in clinical or laboratory features at the time of biopsy or start of treatment or its equivalent. Six of the nine cyclophosphamide treated patients and 15 of the 17 controls had received prednisone therapy. The total follow-up was 49 +/- 10 months in the treated group and 50 +/- 6 months in the controls. At last observation, serum creatinine values exceeded 400 microM in eight controls (4 on dialysis) and in none of the treated patients. The mean serum creatinine level was significantly lower (P less than 0.02) in the treated group (173 +/- 24 microM) than in controls (433 +/- 71 0.02) in the treated group (173 +/- 24 microM) than in controls (433 +/- 71 microM). The mean serum albumin level and 24-hour urine protein excretion both improved significantly with treatment as compared with controls. There were four complete remissions, five partial remissions and no patient with persistent nephrotic syndrome after treatment. In the controls, there were no complete remissions, six partial remissions and 11 patients had persistent nephrotic syndrome (P less than 0.001). Thus, cyclophosphamide therapy appears to be of benefit in patients with MGN, the nephrotic syndrome and impaired renal function.

Forms of nephrotic syndrome more likely to progress to renal impairment

In this article, emphasis is placed on those conditions that appear as the idiopathic nephrotic syndrome but that are more likely to result in progressive renal failure. Four conditions, membranoproliferative glomerulonephritis (mesangiocapillary glomerulonephritis), mesangial proliferative glomerulonephritis, membranous nephropathy, and focal segmental glomerulocosclerosis, account for 12 to 15 per cent of cases of idiopathic nephrotic syndrome during childhood. The further aim of this article is to focus on recent progress in our understanding of these conditions and to remind readers that little is known regarding the etiology and pathogenesis of each, and that effective, clearly proven forms of treatment for each are not apparent currently.

Corticosteroid agents in renal disease

Corticosteroid agents have a major role in the treatment of several renal disorders which have an immune basis. They remain the treatment of choice for minimal-change glomerulonephritis, inducing remission in over 90% of patients. The role of corticosteroid therapy in patients with membranous glomerulonephritis remains controversial, although an extensive controlled trial indicated benefit from a two-month course of alternate-day therapy. Intravenously-administered methylprednisolone has been shown to benefit rapidly progressive crescentic glomerulonephritis; the benefit is probably comparable to that which is obtained with immunosuppression and plasma exchange. Corticosteroid therapy has improved dramatically the prognosis of glomerulonephritis that is associated with systemic lupus erythematosus and the various forms of vasculitis (excluding Wegener's granulomatosis), although the concomitant use of immunosuppressive therapy in these disorders reduces the required doses of corticosteroid drugs. For the last 20 years prednisolone and azathioprine have been standard therapy to prevent renal allograft rejection. However, corticosteroid agents are used currently in much lower doses or have been replaced by cyclosporin A.

Controlled trial of methylprednisolone and chlorambucil in idiopathic membranous nephropathy

Sixty-seven adults with idiopathic membranous nephropathy and the nephrotic syndrome were randomly assigned to symptomatic treatment only or to a six-month course of methylprednisolone alternated with chlorambucil every other month. Patients were followed for one to seven years. At the end of follow-up (mean of 31.4 +/- 18.2 months for the treated group and 37.0 +/- 22.0 for the control group) 23 of 32 treated patients were in complete or partial remission, as compared with 9 of 30 control patients (P = 0.001). Twelve of the treated patients were in complete remission, as compared with only two of the controls. In the treated group there were no changes in renal function during follow-up, whereas in the control group the reciprocal of the plasma creatinin level, which is proportional to the creatinine clearance, decreased significantly (P = 0.00017) after two years of follow-up. Side effects were minimal in all treated patients except two, who were dropped from the study because of peptic ulcer and gastric intolerance to chlorambucil. We conclude that steroid and chlorambucil treatment for six months favors remission of the nephrotic syndrome in adults with idiopathic membranous nephropathy and can preserve renal function for at least some years.