High-dose mizoribine treatment for adolescents with systemic lupus erythematosus

Long-term Survival Analysis of Kidney Transplant Recipients Receiving Mizoribine as a Maintenance Immunosuppressant: A Single-Center Study

BACKGROUND

Mizoribine (MZR) has been developed as an immunosuppressant and is widely used in Asia. However, most studies on MZR have been performed in Japan, and there remains a lack of reports on long-term use in other countries. The purpose of this study is to evaluate the efficacy and safety of MZR's use in Korean kidney transplant recipients by observing their clinical courses and analyzing their long-term patent and graft survival rates.

METHODS

We studied 129 subjects who had received MZR as a maintenance immunosuppressant since January 2000. Our analysis was based on the patients' medical records from January 2000 to December 2017.

RESULTS

The overall survival rates of the kidney transplant recipients were 100% at 1 year, 99.1% at 5 years, 96.8% at 10 years, and 92.5% at 15 years. The graft survival rates were 100% at 1 year, 98.3% at 5 years, 93.2% at 10 years, and 82.2% at 15 years. There were differences in the recipient survival and graft survival rates according to the kidney donor and the use of renal replace therapy before transplant. There were no differences in the survival rates according to the MZR dose, the type of underlying disease, or other clinical factors.

CONCLUSIONS

The use of low doses of MZR as a maintenance immunosuppressant could be an effective means of ensuring relatively good long-term patient and graft survival rates in cases of kidney transplant.

Mizoribine therapy combined with steroids and mizoribine blood concentration monitoring for idiopathic membranous nephropathy with steroid-resistant nephrotic syndrome

Background

We designed a prospective and randomized trial of mizoribine (MZR) therapy combined with prednisolone (PSL) for idiopathic membranous nephropathy (IMN) with steroid-resistant nephrotic syndrome (SRNS).

Methods

Patients with IMN were divided into 2 groups, and MZR combined with PSL was administered for 2 years. PSL was initially prescribed at 40 mg/day and tapered. MZR was given once-a-day at 150 mg and 3-times-a-day at 50 mg each to groups 1 and 2. Serum MZR concentrations from 0 to 4 h after administration were examined within one month of treatment. The concentration curve and peak serum level (C_max) of MZR were estimated by the population pharmacokinetic (PPK) parameters of MZR.

Results

At 2 years, 10 of 19 patients (52.6 %) in group 1 and 7 of 18 patients (38.9 %) in group 2 achieved complete remission (CR). The time-to-remission curve using the Kaplan–Meier technique revealed an increase in the cumulative CR rate in group 1, but no significant difference between the groups. Meanwhile, there was a significant difference in C_max between groups 1 and 2 (mean ± SD: 1.20 ± 0.52 vs. 0.76 ± 0.39 μg/mL, p = 0.04), and C_max levels in CR cases were significantly higher than those in non-CR cases. Receiver operating characteristic analysis showed that C_max more than 1.1 µg/mL was necessary for CR in once-a-day administration.

Conclusion

Administration of MZR once a day is useful when combined with PSL for treatment of IMN with SRNS. In addition, it is important to assay the serum concentration of MZR and to determine C_max, and more than 1.1 µg/mL of C_max is necessary for CR.

Pharmacokinetic modeling of therapies for systemic lupus erythematosus

With the increasing use of different types of therapies in treating autoimmune diseases such as systemic lupus erythematosus (SLE), there is a need to utilize pharmacokinetic (PK) strategies to optimize the clinical outcome of these treatments. Various PK analysis approaches, including population PK modeling and physiologically based PK modeling, have been used to evaluate drug PK characteristics and population variability or to predict drug PK profiles in a mechanistic manner. This review outlines the PK modeling of major SLE therapies including immunosuppressants (methotrexate, azathioprine, mycophenolate and cyclophosphamide, among others) and immunomodulators (intravenous immunoglobulin). It summarizes the population PK modeling, physiologically based PK modeling and model-based individualized dosing strategies to improve the therapeutic outcomes in SLE patients.

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.

An investigation of the correlation between blood concentration of mizoribine and its efficacy in treatment of rheumatoid arthritis based on indices of drug survival and improvement in DAS28-CRP

OBJECTIVES

The efficacy of mizoribine (MZR) in treatment of rheumatoid arthritis (RA) was retrospectively investigated in terms of drug survival, improvement in Disease Activity Score-28 (DAS28)-C-reactive protein (CRP), and blood MZR concentration obtained 3 h after dosing (MZR-C3).

METHODS

To compare the efficacy of MZR administered via different regimens, the subjects were divided into 2 groups: those receiving a single dose of MZR at 100-150 mg every other day (group A) and those receiving 2 or 3 divided doses of the drug on consecutive days, which is the usual dosing method of the drug (group B).

RESULTS

Group A had significantly higher MZR-C3 levels compared with group B, as well as significantly greater improvement in DAS28-CRP. Moreover, drug survival was significantly longer in group A. The primary regression equation suggested that the effective blood MZR concentration in RA treatment is MZR-C3 of 1.47 µg/mL or more.

CONCLUSIONS

The results of the present study indicate that it is possible to increase the efficacy of MZR in a blood concentration-dependent manner, and also to control RA over a prolonged period, using single administration of MZR on alternate days at an increased dose.

Recent advances in the treatment of lupus nephritis

Lupus nephritis is a common complication of systemic lupus erythematosus (SLE) which is associated with significant morbidity and mortality. The concept of two phases of therapy for lupus nephritis, such as an induction phase and a maintenance phase, is widely accepted. Since the renal involvement in SLE is heterogeneous, the treatment of lupus nephritis is governed by its pathological type and ranges from nonspecific measures, such as maintenance of adequate blood pressure control and blockade of the renin-angiotensin-aldosterone system, to the use of immunosuppressive agents. Cyclophosphamide (CYC) in combination with prednisone has been the standard method of treatment of the proliferative forms of lupus nephritis. However, the high rates of progression to end-stage renal disease coupled with the adverse effects of CYC and prednisone have led to an intensive search for more effective and less toxic therapies for lupus nephritis. We review the options available for the treatment of proliferative and membranous lupus nephritis and summarize the results of recently published clinical trials that add new perspectives to the management of kidney disease in SLE.

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.

Prophylactic treatment of antibody-mediated rejection with high-dose mizoribine and pharmacokinetic study

Although mizoribine (MZ), which inhibits inosine monophosphate dehydrogenase in the same way as mycophenolate mofetil, recently proved more effective when higher doses were administered than previously approved, neither the optimal dosage nor blood concentration has yet been clarified. We aimed at investigating the effect of high-doses of MZ on prevention of anti-donor antibody (Ab) production and acute Ab-mediated rejection (AMR) on the basis of the pharmacokinetic profile in a pig kidney transplantation model. Group 1 (n = 5) received cyclosporin microemulsion (6 mg/kg) and prednisolone (0.1 mg/kg). Groups 2, 3 and 4 (each n = 5) were treated, respectively, with 30, 10 and 3 mg/kg of MZ in addition to cyclosporin and prednisolone. The incidences of AMR in groups 1, 2, 3 and 4 were 5/5, 1/5, 3/5 and 5/5, respectively. Anti-donor IgG/IgM Ab levels (relative to pretransplantation levels) on day 14 in groups 1, 2, 3 and 4 were 10.3/9.3, 1.8/1.0, 2.3/1.8 and 6.5/3.5, respectively. While only 2 (28.6%) of seven pigs with Cmax > 3 microg/ml during the first 2 weeks had AMR, 7 (87.5%) of eight pigs with Cmax < 3 microg/ml elicited anti-donor Abs and experienced AMR (P = 0.0406). Effective Cmax seemed to be over 3 microg/ml at minimum. Higher doses of MZ efficiently prevented AMR. However, therapeutic drug monitoring is essential before clinical application.