Mizoribine treatment for childhood IgA nephropathy

Efficacy and safety of adding mizoribine to standard treatment in patients with immunoglobulin A nephropathy: A randomized controlled trial

Background

Mizoribine (MZR) is an immunosuppressive drug used in Japan for treating patients with lupus nephritis and nephrotic syndrome and has been also reportedly effective in patients with immunoglobulin A (IgA) nephropathy. However, to date, few randomized control studies of MZR are performed in patients with IgA nephropathy. Therefore, this prospective, open-label, randomized, controlled trial aimed to investigate the efficacy and safety of adding MZR to standard treatment in these patients, and was conducted between April 1, 2009, and March 31, 2016, as a multicenter study.

Methods

Patients were randomly assigned (1:1) to receiving standard treatment plus MZR (MZR group) or standard treatment (control group). MZR was administered orally at a dose of 150 mg once daily for 12 months.

Results

Primary outcomes were the percentage reduction in urinary protein excretion from baseline and the rate of patients with hematuria disappearance 36 months after study initiation. Secondary outcomes were the rate of patients with proteinuria disappearance, clinical remission rate, absolute changes in estimated glomerular filtration rate from baseline, and the change in daily dose of prednisolone. Forty-two patients were randomly assigned to MZR (n = 21) and control groups (n = 21). Nine patients in MZR group and 15 patients in the control group completed the study. No significant differences were observed between the two groups with respect to primary and secondary outcomes.

Conclusion

The addition of MZR to standard treatment has no beneficial effect on reducing urinary protein excretion and hematuria when treating patients with IgA nephropathy.

Safety and efficacy of mizoribine treatment in nephrotic syndrome complicated with hepatitis B virus infection: a clinical study

Objective The objective of this study is to explore the efficacy and safety of mizoribine (MZR) in treating nephrotic syndrome patients afflicted with hepatitis B virus (HBV). Methods The present study included 36 nephrotic syndrome patients accompanied with HBV infection. A draft of MZR (150-200 mg/d), methylprednisolone (0.6-0.8 mg/kg·d), and entecavir (0.5 mg/d) was administered to study patients over 24 weeks. The serum albumin (AlB), 24-h urine protein (24-U-TP), liver and renal functions, and HBV-DNA were quantified before and at 2, 4, 8, 12, 16, 20, and 24 weeks after the treatment. The adverse responses were recorded. Results The AlB levels of patients increased gradually after comprehensive treatment, while the 24-U-TP, serum cholesterol, and triglyceride (TG) levels declined gradually. The changes at 24 weeks post-treatment were statistically significant. Compared with the levels before treatment, the HBV-DNA, transaminase, and renal functions of the patients were not significantly altered after the treatment. No evident adverse response was found. Conclusion Treatment using MZR in combination with methylprednisolone and entecavir in HBV-positive nephrotic syndrome patients displays significant efficacy with a low incidence of adverse reactions.

Mizoribine requires individual dosing due to variation of bioavailability

BACKGROUND

Mizoribine (MZR) is an immunosuppressant used for the treatment of glomerular diseases, but there are few reports on the pharmacokinetics of MZR in children.

METHODS

First, we performed a pharmacokinetic study on nine childhood-onset glomerular disease patients. The MZR dosages ranged from 1.8 to 14.5 mg/kg/dose. Pharmacokinetic parameters were analyzed using 38 MZR concentration-time curves. Second, nine patients who were newly treated with MZR were enrolled to validate the findings obtained from prior investigation.

RESULTS

In the prior study, peak serum MZR concentration (C(max) ) was dose-dependent in each patient. Although proportionality between dosage and C(max) was observed in each patient, the regression coefficient was in a wide range from 0.075 to 1.04 and was specific to each patient. This variability was likely caused by individual variation of bioavailability. When the optimal time-point to monitor C(max) was investigated, the time-to-reach peak serum MZR concentration (T(max)) was similar among all the patients, which was from 2.5 to 3.5 h after administration of MZR. T(max) was most frequently observed at 3 h and the serum MZR concentration ratio relative to C(max) at 3 h was also highest (0.93 ± 0.07). In the following study, it was validated that monitoring C(3) is reproducible and reliable after adjusting the dosage of MZR to obtain target serum concentration.

CONCLUSION

Individual dosing is required to optimize C(max) in childhood-onset glomerular disease patients. The safe dosage of MZR for each patient could be predicted by evaluating the serum MZR concentration 3 h after administration.

Combination therapy with steroids and mizoribine in juvenile SLE: a randomized controlled trial

The initial treatment of childhood-onset systemic lupus erythematosus (SLE) is not standardized. Although corticosteroids are the first-line therapy for SLE, long-term, high-dose steroid therapy is associated with various side effects in children. The Japanese Study Group for Renal Disease in Children (JSRDC) has carried out a multi-center, randomized, controlled trial to evaluate the efficacy and safety of corticosteroid and mizoribine (MZB) therapy as an initial treatment for newly diagnosed juvenile SLE. Twenty-eight patients were treated with a combination steroid and MZB (4-5 mg/kg/day) (group S+M) drug therapeutic regimen, while 29 patients were treated with steroid only (group S); both groups were followed up for 1 year. The time to the first flare from treatment initiation was not significantly different between the two groups (Kaplan-Meier method, p = 0.09). During the period when the steroid was given daily (day 0-183), the time to the first flare from treatment initiation was significantly longer in the patients of group S+M than in those of group S (log-rank test, p = 0.02). At the end of the study period, there were no differences in the severity of proteinuria and renal function impairment between the two groups. No patients dropped out of the trial due to adverse events. In conclusion, our combined steroid and MZB drug therapeutic regimen was not shown to be significantly better than the steroid-only therapy as initial treatment for juvenile SLE. Whether MZB administered in a higher dose would be therapeutically advantageous can only be answered by further studies.

Mizoribine: a new approach in the treatment of renal disease

Mizoribine (MZB) is an imidazole nucleoside and an immunosuppressive agent. The immunosuppressive effect of MZB has been reported to be due to the inhibition of DNA synthesis in the S phase of the cell cycle. Because of its relative lack of toxicity, during the past decade MZB has been frequently used instead of azathioprine as a component of immunosuppressive drug regimens. MZB is being used to treat renal transplantation patients, IgA nephropathy, lupus erythematosus, and childhood nephrotic syndrome (NS), and some recent studies have assessed the efficacy of oral MZB pulse therapy for severe lupus nephritis, steroid-resistant NS, and frequently relapsing-steroid-dependent NS. This review summarizes the published findings on the efficacy of MZB for renal disease including IgA nephropathy, lupus nephritis, and NS, as well as of oral MZB pulse therapy for severe lupus nephritis and NS, and also the mechanism of the effect of oral MZB pulse therapy on the lymphocyte cell cycle.

Combination therapy with mizoribine for severe childhood IgA nephropathy: a pilot study

In two previous randomized controlled trials we showed that treatment of severe childhood immunoglobulin A nephropathy (IgA-N) using prednisolone, azathioprine, heparin-warfarin, and dipyridamole prevented any increase of sclerosed glomeruli and that prednisolone alone did not prevent a further increase of sclerosed glomeruli. Accordingly, the immunosuppressant is considered to be important. Often, however, we were unable to complete azathioprine regimen due to toxicity. Therefore, a different but effective immunosuppressant may be worth trying. Mizoribine, like azathioprine, is an antimetabolite that exerts its immunosuppressant effect by inhibiting lymphocyte proliferation. In this pilot study, we administered mizoribine instead of azathioprine as part of the combination therapy for treating 23 children with severe IgA-N and evaluated the efficacy and safety. Eighteen patients reached the primary endpoint (urine protein/creatinine ratio <0.2) during the 2-year treatment period. The cumulative disappearance rate of proteinuria determined by Kaplan-Meier was 80.4%. Median protein excretion was reduced from 1.19 g/m(2)/day to 0.05 g/m(2)/day (p < 0.0001). After treatment, the median percentage of glomeruli showing sclerosis was unchanged in comparison with that before treatment. No patients required a change of treatment. In conclusion, the efficacy and safety of the mizoribine combination seems to be acceptable for treating children with severe IgA-N.

Use of mizoribine as a rescue drug for steroid-resistant pediatric IgA nephropathy

Recent clinical trials have shown a beneficial effect of mizoribine (Miz), an immunosuppressive drug, in the treatment of new-onset pediatric IgA nephropathy (IgAN). In this study, we evaluated the efficacy of Miz treatment in three children with established steroid-resistant IgAN. The patients had IgAN featuring persistent proteinuria and diffuse mesangial proliferation and had failed to respond to 2 years of treatment with prednisolone. Based upon the second biopsy results, patients were given methylprednisolone (mPSL) pulse therapy that induced a transient reduction in proteinuria, which was reversed when the mPSL dose was tapered. Miz therapy was then instigated in place of pulse mPSL. All three patients showed a substantial reduction in proteinuria and resolution of hematuria within 5 months. A follow-up biopsy in two of the patients showed a substantial reduction in the severity of glomerular lesions and a decrease in the number of activated macrophages. In conclusion, Miz therapy was found to be a safe and effective therapy in three cases of steroid-resistant pediatric IgAN. The ability of Miz to reduce the number of activated macrophages may be an important mechanism by which this drug ameliorated renal disease in these patients.

Mycophenolate mofetil alleviates persistent proteinuria in IgA nephropathy

BACKGROUND

Mycophenolate mofetil (MMF) is increasingly used to treat primary glomerulopathies. Its effectiveness in IgA nephropathy (IgAN) remains unclear.

METHODS

Forty IgAN patients with persistent proteinuria (>1 g/24 hours) despite conventional treatment with blockers of the renin-angiotensin system were randomized to receive MMF for 24 weeks (group 1) or continue conventional therapy (group 2), and followed for 72 weeks. The primary end point was reduction of proteinuria by 50% or more over entry level.

RESULTS

Sixteen patients (80%) in group 1 versus six patients (30%) in group 2 reached the primary end point (P= 0.0019). Time-averaged change in proteinuria showed a significant decline in group 1, while control subjects displayed a modest rise (P= 0.003). By 72 weeks, the mean proteinuria was 62.0 +/- 7.7% (P= 0.003) and 120.5 +/- 14.1% (P= 0.351) that of the corresponding baseline value in group 1 and group 2, respectively. There was concomitant increase in serum albumin and decrease in serum IgA levels in group 1 but not group 2 patients. Baseline histologic grades, blood pressure control, and the rates of change in serum creatinine and creatinine clearance were not different between the two groups. Normalization in binding of polymeric IgA to cultured mesangial cells and serum interleukin-6 (IL-6) levels, which sustained to study end, was observed in group 1 but not group 2 subjects.

CONCLUSION

In selected patients with IgAN, MMF is effective in lowering proteinuria and ameliorating some of the putative pathogenetic abnormalities.

Induction therapy with low-dose intravenous cyclophosphamide, oral mizoribine, and steroids for severe lupus nephritis in children

Although immunosuppressive regimens of corticosteroids combined with high-dose intravenous cyclophosphamide (IVCY) have been reported to suppress the activity of lupus nephritis, there is controversy regarding its application for children and adolescents, because of its potential toxicity including gonadal dysfunction. On the basis of the recent finding that a low-dose IVCY regimen for induction therapy in adult lupus nephritis effectively achieves renal remission comparable with that achieved with a conventional high-dose IVCY regimen, we treated two children with severe lupus nephritis by low-dose (fixed dose of 500 mg m(-2), cumulative dose 3 g m(-2), approximately one-fourth of the conventional high-dose IVCY regimen) IVCY and oral mizoribine (5 mg kg(-1) day(-1)) and steroids (3 methylprednisolone pulse followed by oral prednisolone). They responded well to this regimen, showing remarkable improvement in both histological and clinical manifestations in a short period of time. From these findings we suggest that the new low-dose IVCY regimen may be as effective as the conventional high-dose IVCY regimen, without significant adverse effect, for induction therapy in children with severe lupus nephritis (class III or IV).

Efficacy of multidrug therapy combined with mizoribine in children with diffuse IgA nephropathy in comparison with multidrug therapy without mizoribine and with methylprednisolone pulse therapy

AIM

To evaluate the efficacy of prednisolone, warfarin, and dipyridamole therapy combined with mizoribine (PWDM) in the treatment of diffuse immunoglobulin A (IgA) nephropathy in comparison with prednisolone, warfarin, and dipyridamole therapy without mizoribine (PWD) and with methylprednisolone pulse therapy (PWD pulse).

METHODS

We collected data on 61 patients diagnosed with diffuse IgA nephropathy, and these patients were retrospectively divided into three groups without randomization. Group A included 21 patients before 1987 who were treated with PWD for 24 months, group B included 20 patients from 1987 to 1989 who were treated with PWD pulse therapy for 24 months, and group C included 20 patients after 1990 who were treated with PWDM for 24 months. Clinical features and pathological findings in each group were analyzed retrospectively.

RESULTS

The time from initiation of therapy in group A, group B, and group C was 8.9 +/- 5.2, 8.1 +/- 3.9, and 7.7 +/- 3.8 years, respectively. At the latest follow-up examination, the mean urinary protein excretion (mg/m2/h) was 17 +/- 10 in group A, 22 +/- 20 in group B, and 6 +/- 6 in group C and had decreased significantly in group C as compared with the other groups. The activity index in all three groups was lower at the second biopsy than that at the first biopsy (5.1 +/- 0.8 vs. 6.5 +/- 2.1 in group A, p < 0.05; 5.6 +/- 0.9 vs. 6.6 +/- 1.7 in group B, p < 0.01, and 4.5 +/- 1.0 vs. 6.8 +/- 1.9 in group C, p < 0.01). The chronicity index in groups A and B at second biopsy was higher than at first biopsy (7.3 +/- 1.4 vs. 4.8 +/- 1.0 in group A, p < 0.01, and 8.1 +/- 2.0 vs. 5.3 +/- 0.9 in group B, p < 0.01), but was unchanged in group C. At the latest follow-up examination, 1 patient (4.8%) in group A, 3 patients (15%) in group B, and none (0%) in group C had renal insufficiency.

CONCLUSION

These results suggest that PWDM appears to be more effective than PWD or PWD pulse in ameliorating proteinuria and histological severity of patients with IgA nephropathy.

Combined therapy of enalapril and losartan attenuates histologic progression in immunoglobulin A nephropathy

BACKGROUND

It has been reported that combined therapy of angiotensin converting enzyme inhibitor and angiotensin receptor blocker significantly decreases proteinuria in immunoglobulin A (IgA) nephropathy. However, histologic alterations following the therapy have not been reported.

METHODS

A total of nine Japanese children with severe proteinuric IgA nephropathy who received a prompt immunosuppressive therapy were enrolled the study, four of whom received a combined therapy of angiotensin converting enzyme inhibitor, enalapril and angiotensin receptor blocker, losartan (Group A), while the remaining five did not (Group B). All underwent renal biopsy before and approximately 12 months after the first renal biopsy.

RESULTS

At presentation, urine protein excretion and the histologic indices of mean activity index, mean chronicity index and tubulointerstitial scores did not show a statistical difference between the two groups: Group A (2.6 +/- 0.6 g/day; mean activity index, 5.0 +/- 1.0; mean chronicity index, 5.0 +/- 1.0; tubulointerstitial scores, 4.3 +/- 1.0) and Group B (2.2 +/- 0.6 g/day; mean activity index, 4.8 +/- 0.8; mean chronicity index, 4.8 +/- 1.3; tubulointerstitial scores, 3.6 +/- 0.5, respectively). All had normal blood pressure and renal function. Urine protein excretion and the activity index decreased at the second renal biopsy, while the chronicity index and the tubulointerstitial scores slightly increased or remained unchanged. In comparison with Group B, a significant suppression in increasing the chronicity index and the tubulointerstitial scores obtained at the second renal biopsy were observed in Group A [Group A: 4.3 +/- 1.2 and 3.0 +/- 0.0, respectively, vs Group B: 6.0 +/- 0.7 and 4.4 +/- 0.9, respectively (P < 0.05)]. One patient in Group B developed chronic renal insufficiency thereafter.

CONCLUSIONS

Although only a small number of patients were examined, these clinical findings suggest that a combined therapy of enalapril and losartan may attenuate histologic progression in at least a proportion of patients with severe proteinuric IgA nephropathy.

Use of corticosteroids, other immunosuppressive therapies, and tonsillectomy in the treatment of IgA nephropathy

Because IgA nephropathy (IgAN) was originally regarded as a benign condition, the indication of corticosteroids or other immunosuppressive therapies have been highly restricted because of potential side effects, and such drugs have been used for a specific subgroup of patients with IgAN, taking the risk/benefit ratio into consideration. During the last decade, however, with the recognition that the overall long-term prognosis of IgAN is a nonbenign condition, more aggressive treatments, including high-dose corticosteroids, various immunosuppressive agents, and tonsillectomy, have been used for wider subgroups of patients with IgAN. Moreover, recent studies have suggested that clinical remission as well as histopathologic regression of the nephropathy could be obtained by such treatments if treatment is initiated in its relatively early stage. Thus, the possibility has now been raised that the goal of treatment for patients with IgAN will shift from "slowing the progression of nephropathy" to "remission of nephropathy."