Pharmacokinetics of mycophenolate mofetil for autoimmune disease in children

IgA Vasculitis: Etiology, Treatment, Biomarkers and Epigenetic Changes

IgA, previously called Henoch-Schönlein vasculitis, is an essential immune component that drives the host immune response to the external environment. As IgA has the unique characteristic of a flexible response to broad types of microorganisms, it sometimes causes an autoreactive response in the host human body. IgA vasculitis and related organ dysfunction are representative IgA-mediated autoimmune diseases; bacterial and viral infections often trigger IgA vasculitis. Recent drug developments and the presence of COVID-19 have revealed that these agents can also trigger IgA vasculitis. These findings provide a novel understanding of the pathogenesis of IgA vasculitis. In this review, we focus on the characteristics of IgA and symptoms of IgA vasculitis and other organ dysfunction. We also mention the therapeutic approach, biomarkers, novel triggers for IgA vasculitis, and epigenetic modifications in patients with IgA vasculitis.

Gastrointestinal Henoch-Schönlein purpura successfully treated with Mycophenolate Mofetil: Description of 2 case reports

RATIONALE

Henoch-Schönlein Purpura (HSP) is an acute small vessel vasculitis. It is the most common vasculitis in children. In majority of the cases, the disease is self-limited. Relapses can occur, in particular during the first year of the disease. There is no consensus on a specific treatment. The efficacy and safety of steroidal treatment in treating HSP is still controversial. Immunosuppressive treatment of HSP nephritis is used in patients with severe renal involvement (nephrotic range proteinuria and/or progressive renal impairment). The literature on immunosuppressive treatment of severe HSP without kidney involvement is scanty.

PATIENTS CONCERNS

We report 2 case reports of 2 adolescents affected from Henoch-Schönlein Purpura and severe gastrointestinal involvement. Both patients presented a poor response to steroids treatment.

DIAGNOSES

The diagnosis of HSP was made according to the diagnostic criteria published by European League against Rheumatism and Pediatric Rheumatology European Society in 2006.

INTERVENTIONS

In consideration of the recurrence of the Henoch Schönlein Purpura and the gastrointestinal involvement, we decided to start Mycophenolate Mofetil treatment.

OUTCOMES

In both patients all clinical manifestations resolved in few days.

LESSONS

In our cases of HSP with gastrointestinal involvement Mycophenolate Mofetil treatment has been very effective. This experience teaches us that immunosuppressive agents may be very useful to induce and maintain remission not only in renal involvement, but in all cases of persistent, recurrent, or complicated Henoch Schönlein Purpura in children.

Therapeutic potential of alkaloids in autoimmune diseases: Promising candidates for clinical trials

Clinical investigations have characterized numerous disorders like autoimmune diseases, affecting the population at a rate of approximately 8-10%. These disorders are characterized by T-cell and auto-antibodies responses to self-molecules by immune system reactivity. Several therapeutic options have been adopted in clinics to combat such diseases, however, most of them are recurring. Thus, the discovery of new effective agents for the treatment of autoimmune diseases is paramount. In this context, natural products might be a useful alternative to the current therapies. Plant alkaloids with their substantial therapeutic history can be particularly interesting candidates for the alleviation of autoimmune ailments. This review encompasses various alkaloids with significant effects against autoimmune diseases in preclinical trials. These results suggest further clinical assessment with respect to autoimmune illnesses. Furthermore, the application of modern technologies such as nanoformulation could be also helpful in the design of more effective therapies and thus further studies are needed to decipher their therapeutic efficacy as well as potential limitations.

The clinical effect of Prednisone in combination with Mycophenolate mofetil on idiopathic thrombocytopenic purpura (ITP) and its influence on the level of peripheral blood T lymphocytes and NK lymphocytes

Objective

To explore he curative effect and safety of Prednisone in combination with Mycophenolate in treating ITP and its influence on the level of peripheral blood T lymphocytes and NK lymphocytes.

Method

93 cases of ITP patients were divided into the observation group and the control group by the Random Number Table method, 48 cases for the observation group, 45 for another. Patients in the control group orally took 0.5 mg/kg Prednisone Acetate tablets daily, two times each in the morning and evening. And the observation group, based on the treatment of the control group, orally took Mycophenolate Mofetil Dispersible tablets twice a day, 1 g each time. According to patients’ conditions, 3 to 5 courses were set for treatment with 3 weeks a course. Compared PLT amount and the changing situation of inflammatory factors, CD3⁺ and CD3⁺CD95L⁺ before and after the treatment, the level of CD3⁺Caspase-3⁺ and CD3⁺Caspase-8⁺, NK⁺, NK⁺ CD95L⁺, NK⁺Caspase-3⁺, NK⁺Caspase-8, the curative effect and adverse events.

Result

After treatment, PLT amount in both groups increased, and the increase in the observation group was much higher than that of the control group, the difference had statistical significance (P < 0.05). The time needed for PLT amount in the control group to reach the normal and peak values was longer than that of the observation group, whose PLT peak value was higher than another group. The difference had statistical significance (P < 0.05). After the treatment, the levels of TNF-α and IL-6 were lowered, and the value of the observation group was lower than that of another. The difference between and within the group has statistical significance. After the treatment, the level of CD3⁺, CD3⁺CD95L⁺ and CD3⁺Caspase-8⁺ is much higher and CD3⁺Caspase-3⁺ level lower than that before the treatment. The difference has statistical significance (P < 0.05). After the treatment, the level of NK⁺ and NK⁺ CD95L⁺ is higher and the level of NK⁺Caspase-8⁺ lower than that before the treatment. The difference has statistical significance (P < 0.05). After the treatment, the total effective rate 91.67% of the observation group is much higher than that 75.56% of another. The difference has statistical significance (P < 0.05). After the treatment, the incidence rate of adverse events in the control group is 11.11% (5/45), while 4.17% (2/48) in the observation group. The difference between groups has statistical significance (χ² = 3.890, P < 0.05).

Conclusion

The curative effect of Prednisone in combination with Mycophenolate on ITP patients is better than orally taking Prednisone tablets. Moreover, when it comes to Prednisone in combination with Mycophenolate, both the PLT amount and immunocompetence are improved without much adverse reaction, and the molecules of peripheral blood T lymphocytes and NK lymphocytes can be effectively adjusted to relieve the symptoms. So the method is trustworthy to be popularized for clinical practices.

Development and validation of limited sampling strategy equation for mycophenolate mofetil in children with systemic lupus erythematosus

The aim of this study was to establish a limited sample strategy (LSS) to predict the mycophenolic acid (MPA) area under the curve (AUC)_(0-12) in children with systemic lupus erythematosus (SLE). Three months after initiation of mycophenolate mofetil (MMF) 26 children with SLE presented for therapeutic drug monitoring of MPA. On the day of the test, 10 specimens were collected, analyzed, and MPA AUC_(0-12) was calculated. Using step-wise regression analysis, LSS equations were developed. Using bootstrap validation, the predictive performance was calculated. The measured mean (standard deviation) for the trough concentration and AUC_(0-12) were 2.55 (1.57) μg/ml and 62.6 (21.67) mg.h/L, respectively. The range of trough concentrations and AUC_(0-12) were 0.7-5.54 μg/ml and 22.1-104.8 mg.h/L, respectively. The interindividual variability (%CV) for dose normalized AUC_(0-12) and dose normalized C_trough was 46.5% and 61.1%, respectively. The correlation between the concentrations at the different time points and MPA AUC_(0-12) ranged from 0.05 (1.5 h) to 0.56 (4 h). Two LSS equations that included 4 or 5 time points up to 3 h were developed and validated. The 4 point LSS had a correlation (R²) of 0.88 and the 5 point LSS an R² of 0.87. With respect to the 4 point and 5 point MPA LSS AUC_(0-12), the bias was 1.92% and 1.96%, respectively, and the imprecision was 11.24% and 11.28%, respectively. A 4 point LSS which concludes within 3 h after the administration of the MMF dose was developed and validated, to determine the MPA AUC_(0-12) in children with SLE.

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.

Monitoring of mycophenolate mofetil metabolites in children with nephrotic syndrome and the proposed novel target values of pharmacokinetic parameters

The aim of the study was to estimate target values of mycophenolate mofetil (MMF) pharmacokinetic parameters in children with proteinuric glomerulopathies by calculating the pharmacokinetic parameters of MMF metabolites (mycophenolic acid [MPA], free MPA [fMPA] and MPA glucuronide [MPAG]) and assessing their relation to proteinuria recurrence. One hundred and sixty-eight blood samples were collected from children, aged 3-18 years, diagnosed with nephrotic syndrome or lupus nephritis. MMF metabolites concentrations were examined before drug administration (Ctrough) and up to 12h afterward employing high-performance liquid chromatography. Dose-normalized MPA Ctrough and area under the concentration-time curve from 0 to 12h (AUC12) were within 0.29-6.47 μg/mL/600 mg/m(2) and 9.97-105.52 μg h/mL/600 mg/m(2), respectively. MPA Ctrough was twofold lower (p=0.024) in children with proteinuria recurrence. MPA, fMPA and MPAG concentrations correlated positively to respective AUC12. It may be suggested MMF metabolites monitoring in children with proteinuric glomerulopathies is justified by MPA Ctrough<2 μg/mL in patients at risk of the proteinuria recurrence. Such a recurrence is most probably caused by not sufficient MPA concentration during proteinuric glomerulopathies treatment. MPA Ctrough>3 μg/mL may be considered as an efficient one to avoid proteinuria recurrence. Finally, MPA target AUC12 should exceed 60 μg h/mL to ensure the safe and effective treatment in children with nephrotic syndrome, however, the upper limit is still to be established.

How accurate and precise are limited sampling strategies in estimating exposure to mycophenolic acid in people with autoimmune disease?

Mycophenolic acid (MPA) is a potent immunosuppressant agent, which is increasingly being used in the treatment of patients with various autoimmune diseases. Dosing to achieve a specific target MPA area under the concentration-time curve from 0 to 12 h post-dose (AUC12) is likely to lead to better treatment outcomes in patients with autoimmune disease than a standard fixed-dose strategy. This review summarizes the available published data around concentration monitoring strategies for MPA in patients with autoimmune disease and examines the accuracy and precision of methods reported to date using limited concentration-time points to estimate MPA AUC12. A total of 13 studies were identified that assessed the correlation between single time points and MPA AUC12 and/or examined the predictive performance of limited sampling strategies in estimating MPA AUC12. The majority of studies investigated mycophenolate mofetil (MMF) rather than the enteric-coated mycophenolate sodium (EC-MPS) formulation of MPA. Correlations between MPA trough concentrations and MPA AUC12 estimated by full concentration-time profiling ranged from 0.13 to 0.94 across ten studies, with the highest associations (r (2) = 0.90-0.94) observed in lupus nephritis patients. Correlations were generally higher in autoimmune disease patients compared with renal allograft recipients and higher after MMF compared with EC-MPS intake. Four studies investigated use of a limited sampling strategy to predict MPA AUC12 determined by full concentration-time profiling. Three studies used a limited sampling strategy consisting of a maximum combination of three sampling time points with the latest sample drawn 3-6 h after MMF intake, whereas the remaining study tested all combinations of sampling times. MPA AUC12 was best predicted when three samples were taken at pre-dose and at 1 and 3 h post-dose with a mean bias and imprecision of 0.8 and 22.6 % for multiple linear regression analysis and of -5.5 and 23.0 % for maximum a posteriori (MAP) Bayesian analysis. Although mean bias was less when data were analysed using multiple linear regression, MAP Bayesian analysis is preferable because of its flexibility with respect to sample timing. Estimation of MPA AUC12 following EC-MPS administration using a limited sampling strategy with samples drawn within 3 h post-dose resulted in biased and imprecise results, likely due to a longer time to reach a peak MPA concentration (t max) with this formulation and more variable pharmacokinetic profiles. Inclusion of later sampling time points that capture enterohepatic recirculation and t max improved the predictive performance of strategies to predict EC-MPS exposure. Given the considerable pharmacokinetic variability associated with mycophenolate therapy, limited sampling strategies may potentially help in individualizing patient dosing. However, a compromise needs to be made between the predictive performance of the strategy and its clinical feasibility. An opportunity exists to combine research efforts globally to create an open-source database for MPA (AUC, concentrations and outcomes) that can be used and prospectively evaluated for AUC target-controlled dosing of MPA in autoimmune diseases.

A comprehensive review and update on the non-biologic treatment of adult noninfectious uveitis: part I

INTRODUCTION

Treatment of adult, noninfectious uveitis remains a challenge for ophthalmologists around the world. The disease accounts for almost 10% of preventable blindness in the US and can be idiopathic or associated with infectious and systemic disorders. Strong evidence is still emerging to indicate that pharmacologic strategies presently used in rheumatologic or autoimmune disease may be translated to the treatment of intraocular inflammation. Corticosteroid monotherapy is widely regarded as wholly inappropriate, due to the unfavorable risk/benefit profile and poor long-term outcomes. Treatment plans have shifted away from low-dose, chronic corticosteroid therapy for maintenance, towards medium- to high-dose therapy for acute inflammation, followed immediately by initiation of immunomodulatory therapy. These therapies follow the 'stepladder approach', whereby least to more aggressive therapies are trialed to induce remission of inflammation, eventually without corticosteroids of any form (topical, local and systemic).

AREAS COVERED

This two-part review gives a comprehensive overview of the existing medical treatment options for patients with adult, noninfectious uveitis, as well as important advances for the treatment of ocular inflammation. Part I covers classic immunomodulation and latest information on corticosteroid therapy.

EXPERT OPINION

The hazard of chronic corticosteroid use for the treatment of adult, noninfectious uveitis is well-documented. Corticosteroid-sparing therapies, which offer a very favorable risk-benefit profile when administered properly, should be substituted.

Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of adult and paediatric lupus nephritis

OBJECTIVES

To develop recommendations for the management of adult and paediatric lupus nephritis (LN).

METHODS

The available evidence was systematically reviewed using the PubMed database. A modified Delphi method was used to compile questions, elicit expert opinions and reach consensus.

RESULTS

Immunosuppressive treatment should be guided by renal biopsy, and aiming for complete renal response (proteinuria <0.5 g/24 h with normal or near-normal renal function). Hydroxychloroquine is recommended for all patients with LN. Because of a more favourable efficacy/toxicity ratio, as initial treatment for patients with class III-IV(A) or (A/C) (±V) LN according to the International Society of Nephrology/Renal Pathology Society 2003 classification, mycophenolic acid (MPA) or low-dose intravenous cyclophosphamide (CY) in combination with glucocorticoids is recommended. In patients with adverse clinical or histological features, CY can be prescribed at higher doses, while azathioprine is an alternative for milder cases. For pure class V LN with nephrotic-range proteinuria, MPA in combination with oral glucocorticoids is recommended as initial treatment. In patients improving after initial treatment, subsequent immunosuppression with MPA or azathioprine is recommended for at least 3 years; in such cases, initial treatment with MPA should be followed by MPA. For MPA or CY failures, switching to the other agent, or to rituximab, is the suggested course of action. In anticipation of pregnancy, patients should be switched to appropriate medications without reducing the intensity of treatment. There is no evidence to suggest that management of LN should differ in children versus adults.

CONCLUSIONS

Recommendations for the management of LN were developed using an evidence-based approach followed by expert consensus.

Graft loss due to recurrent disease in pediatric kidney transplant recipients on a rapid prednisone discontinuation protocol

Recurrent disease is the fourth most common cause of graft loss (GL) in pediatric KTx recipients. We studied the incidence of recurrent disease and GL due to recurrent disease in pediatric KTx recipients on a RDP protocol. Between 2002 and 2010, we performed 74 KTxs in patients aged 5-18 yr using an RDP protocol, 25 (34%) were at risk of recurrence of primary disease. Outcomes were compared to 69 historical controls (18 [26%] at risk of recurrence), KTx between 1996 and 2000. Follow-up period was 39 ± 25 months in RDP and 124 ± 38 months in controls. The incidence of recurrent disease at three yr post-KTx was 16% in RDP and 28% in controls (p = NS). Mean time to recurrent disease was 22 ± 26 months in RDP and 46 ± 48 months in controls (p = 0.54). Nine (12%) grafts were lost in the RDP group (1-recurrence) and 32 (46%) in the control group (4-recurrence). Time to GL was 85 months in the RDP recipient and 46 ± 21 months in controls. An RDP protocol in pediatric KTx recipients may not be associated with increased risk of graft loss due to recurrent disease.

Consensus treatment plans for induction therapy of newly diagnosed proliferative lupus nephritis in juvenile systemic lupus erythematosus

OBJECTIVE

To formulate consensus treatment plans (CTPs) for induction therapy of newly diagnosed proliferative lupus nephritis (LN) in juvenile systemic lupus erythematosus (SLE).

METHODS

A structured consensus formation process was employed by the members of the Childhood Arthritis and Rheumatology Research Alliance after considering the existing medical evidence and current treatment approaches.

RESULTS

After an initial Delphi survey (response rate = 70%), a 2-day consensus conference, and 2 followup Delphi surveys (response rates = 63-79%), consensus was achieved for a limited set of CTPs addressing the induction therapy of proliferative LN. These CTPs were developed for prototypical patients defined by eligibility characteristics, and included immunosuppressive therapy with either mycophenolic acid orally twice per day, or intravenous cyclophosphamide once per month at standardized dosages for 6 months. Additionally, the CTPs describe 3 options for standardized use of glucocorticoids, including a primarily oral, a mixed oral/intravenous, and a primarily intravenous regimen. There was consensus on measures of effectiveness and safety of the CTPs. The CTPs were well accepted by the pediatric rheumatology providers treating children with LN, and up to 300 children per year in North America are expected to be candidates for the treatment with the CTPs.

CONCLUSION

CTPs for induction therapy of proliferative LN in juvenile SLE based on the available scientific evidence and pediatric rheumatology group experience have been developed. Consistent use of the CTPs may improve the prognosis of proliferative LN, and support the conduct of comparative effectiveness studies aimed at optimizing therapeutic strategies for proliferative LN in juvenile SLE.

Consensus treatment plans for induction therapy of newly diagnosed proliferative lupus nephritis in juvenile systemic lupus erythematosus

OBJECTIVE

To formulate consensus treatment plans (CTPs) for induction therapy of newly diagnosed proliferative lupus nephritis (LN) in juvenile systemic lupus erythematosus (SLE).

METHODS

A structured consensus formation process was employed by the members of the Childhood Arthritis and Rheumatology Research Alliance after considering the existing medical evidence and current treatment approaches.

RESULTS

After an initial Delphi survey (response rate = 70%), a 2-day consensus conference, and 2 followup Delphi surveys (response rates = 63-79%), consensus was achieved for a limited set of CTPs addressing the induction therapy of proliferative LN. These CTPs were developed for prototypical patients defined by eligibility characteristics, and included immunosuppressive therapy with either mycophenolic acid orally twice per day, or intravenous cyclophosphamide once per month at standardized dosages for 6 months. Additionally, the CTPs describe 3 options for standardized use of glucocorticoids, including a primarily oral, a mixed oral/intravenous, and a primarily intravenous regimen. There was consensus on measures of effectiveness and safety of the CTPs. The CTPs were well accepted by the pediatric rheumatology providers treating children with LN, and up to 300 children per year in North America are expected to be candidates for the treatment with the CTPs.

CONCLUSION

CTPs for induction therapy of proliferative LN in juvenile SLE based on the available scientific evidence and pediatric rheumatology group experience have been developed. Consistent use of the CTPs may improve the prognosis of proliferative LN, and support the conduct of comparative effectiveness studies aimed at optimizing therapeutic strategies for proliferative LN in juvenile SLE.

Mycophenolic acid differentially impacts B cell function depending on the stage of differentiation

Production of pathogenic Abs contributes to disease progression in many autoimmune disorders. The immunosuppressant agent mycophenolic acid (MPA) has shown clinical efficacy for patients with autoimmunity. The goal of these studies was to elucidate the mechanisms of action of MPA on B cells isolated from healthy individuals and autoimmune patients. In this study, we show that MPA significantly inhibited both proliferation and differentiation of primary human B cells stimulated under various conditions. Importantly, MPA did not globally suppress B cell responsiveness or simply induce cell death, but rather selectively inhibited early activation events and arrested cells in the G0/G1 phase of the cell cycle. Furthermore, MPA blocked expansion of both naive and memory B cells and prevented plasma cell (PC) differentiation and Ab production from healthy controls and individuals with rheumatoid arthritis. Finally, whereas MPA potently suppressed Ig secretion from activated primary B cells, terminally differentiated PCs were not susceptible to inhibition by MPA. The target of MPA, IMPDH2, was found to be downregulated in PCs, likely explaining the resistance of these cells to MPA. These results suggest that MPA provides benefit in settings of autoimmunity by directly preventing activation and PC differentiation of B cells; however, MPA is unlikely to impact autoantibody production by preexisting, long-lived PCs.

Mycophenolate mofetil monotherapy in the management of paediatric uveitis

PURPOSE

To evaluate effectiveness and safety of mycophenolate mofetil (MMF) monotherapy in paediatric autoimmune uveitis.

METHODS

We reviewed medical records of patients, 18 years of age or younger, with autoimmune uveitis treated with MMF at our practice from 2005 to 2009. The dose and duration of MMF therapy, inflammation status, visual acuity, previous immunomodulatory therapies, and adverse effects were recorded. In addition, the following subgroups were defined: (1) Durable Disease Control: patients whose uveitis remained quiescent for at least 2 years on MMF monotherapy, with no more than two flare-ups successfully treated with an increase in MMF dosage and/or a short course (<1 month) of corticosteroids; (2) Short-term Inflammation Control: patients whose uveitis remained quiescent for less than 2 years, with no more than one flare-up successfully treated with an increase in MMF dosage and/or a short course of corticosteroids, or who initially achieved inflammation control but discontinued MMF because of significant adverse effects.

RESULTS

A total of 38 out of 52 patients (73.1%) obtained inflammation control following 2 months of MMF monotherapy, achieving ≤ 0.5+ grading in anterior chamber cell/flare and vitreous haze. In the cross-sectional analysis, 25 patients (48.1%) met the criteria for Durable Disease Control, and 13 others (25.0%) qualified for Short-term Inflammation Control. Visual acuity remained stable or improved in 94.2% of the study population. Six patients (11.5%) discontinued MMF because of significant adverse effects, the most common of which was gastrointestinal disturbances.

CONCLUSION

MMF monotherapy appears to be an effective and safe treatment in paediatric autoimmune uveitis.

Development of a Bayesian estimator for the therapeutic drug monitoring of mycophenolate mofetil in children with idiopathic nephrotic syndrome

The use of mycophenolate mofetil (MMF) in children with idiopathic nephrotic syndrome (INS) is increasing. However, the clinical benefit of its monitoring has been scarcely studied, and little is known about its pharmacokinetics in this context. The objectives of the present study were: (i) to study and model the pharmacokinetics of mycophenolic acid (MPA; the active moiety of MMF) in paediatric patients with INS given MMF, at all stages of the disease; (ii) to develop a Bayesian estimator (MAP-BE) for individual inter-dose area under the concentration-time curve (AUC) prediction in this population, using a limited blood sampling strategy (LSS). Full-pharmacokinetic (PK) profiles of MPA collected in paediatric inpatients with INS already treated with a maintenance immunosuppressive therapy based on MMF (with no calcineurin inhibitors; CNI) were studied. A classical iterative two-stage (ITS) method was applied to model the data and develop MAP-BEs using a one-compartment open model where the absorption is described by a double gamma law allowing the description of a potential enterohepatic recirculation. The performance of the MAP-BE developed for individual exposure assessment was evaluated by the bias and precision of predicted AUCs with respect to measured, trapezoidal AUCs (reference value), and by the proportion of predicted AUCs with absolute error >20%. These PK tools were tested in an independent group of patients. Sixty PK profiles of MPA from children receiving MMF in association to corticosteroids or given alone were included in the study. Forty-five of these PK profiles were used to develop a PK model and a MAP-BE, and 15 for their validation. In the building group, the PK model fitted accurately the PK profiles of MPA: mean residual error of modelled vs. reference AUC was m±SD=-0.015±0.092 (range: -0.153 to 0.204). The MAP-BE which allowed the estimation of MPA AUC on the basis of a 20 min-60 min-180 min LSS was then developed. In the independent group of patients, its mean residual error vs. reference AUCs was m±SD=-0.036±0.145 (range: -0.205 to 0.189). Thus, a PK model and its derived MAP-BE for MMF (without any associated CNI) when given to children with INS have been developed. Clinical trials using these PK tools could test the potential impact of the therapeutic drug monitoring of MMF based on the AUC on the clinical evolution of INS.

Mycophenolate mofetil: a possible therapeutic agent for children with juvenile dermatomyositis

OBJECTIVE

To determine if mycophenolate mofetil (MMF) diminishes skin and muscle disease activity in children with juvenile dermatomyositis (DM), thereby permitting a decrease in corticosteroid dose.

METHODS

A retrospective data review for 50 children with juvenile DM (mean ± SD age 12.2 ± 5.0 years) who had received MMF for 12 months identified the following characteristics: 38 (76%) were girls, 39 (78%) were white, 10 (20%) were Hispanic, and 1 (2%) was African American. The MMF dose and frequency, type of infection, white blood cell (WBC) count, corticosteroid dose, and the validated disease activity score (DAS) subscores for skin (DAS-S) and muscle (DAS-M) were obtained.

RESULTS

Twelve months after the start of MMF, the mean ± SD DAS-S decreased from 5.24 ± 0.29 to 3.72 ± 0.29 (P = 0.001), and the mean ± SD DAS-M decreased from 2.44 ± 0.39 to 1.17 ± 0.28 (P = 0.002). The mean ± SD prednisone dosage decreased from 0.39 ± 0.06 to 0.23 ± 0.02 mg/kg/day (P = 0.0001), with resumption of linear growth (P = 0.008). The WBC/lymphocyte count was unchanged over the 12 months on MMF. The infection rate was assessed in a subset of 26 children with juvenile DM who were observed for 12 months before the start of MMF and then compared with the ensuing 12 months of MMF therapy. There was no significant difference between the pretreatment period and the first 6 months of MMF therapy (P = 0.44), but the infection rate decreased in months 7-12 (P = 0.001).

CONCLUSION

MMF appears to be worthy of consideration as an additional therapeutic modality for treatment of children with juvenile DM. These data suggest that the use of MMF decreases skin and muscle disease activity and is steroid sparing. MMF appears to be well tolerated, but patients should be monitored for infection.

Treatment of complicated henoch-schönlein purpura with mycophenolate mofetil: a retrospective case series report

Background. Henoch-Schönlein purpura (HSP) is the most common childhood vasculitis with an incidence of approximately 10 per 100 000 children. There is some evidence to support steroid therapy in the treatment of severe abdominal pain, severe nephritis, and central nervous system involvement. However, the routine use of corticosteroids is controversial. Frequent relapses, lack of response to steroid, steroid dependency, and steroid side effects may occur in some patients. Mycophenolate mofetil (MMF) gains increasing popularity in the treatment of autoimmune disorders, but hitherto, the available evidence to support the use of MMF in HSP is limited to some case study reports. Case Presentation. We report six children with HSP who failed to respond to systemic steroid therapy, whereas MMF successfully treated the manifestations of the disease. Conclusion. The manifestations of HSP disappeared mainly during the first week of treatment with MMF and all the patients were in a complete remission at the end and after discontinuation of the therapy. In our experience, MMF appeared to be safe and effective for the maintenance of remission in the HSP patients.

Pharmacokinetics of mycophenolic acid in severe lupus nephritis

Mycophenolic acid (MPA) is an effective treatment for active lupus nephritis despite its variable efficacy in different ethnic groups. Here we tested whether pharmacokinetic monitoring may help to optimize dosing of MPA in an Asian population. Patients with biopsy-proven class III or IV lupus nephritis (ISN/RPS category) were treated with mycophenolate mofetil or enteric-coated mycophenolate sodium. One month after initiating treatment we measured plasma MPA levels in eight samples taken over a 12-h period after drug administration. The mean area under the time-dependent curve for MPA of responding patients was significantly higher than those not responding. Successful treatment was seen in patients with areas >45 mg h/l. The dosage of the drug was not related to MPA pharmacokinetics. In the mycophenolate mofetil group, however, MPA-area under the curve was positively, and significantly, correlated with trough or 1 h after dose concentrations and associated with a therapeutic response. Thus, our study shows that MPA pharmacokinetics were positively correlated with therapeutic responses of mycophenolate, suggesting that controlling the concentrations may improve its therapeutic efficacy in lupus nephritis. As the absorption and pharmacokinetic peak of enteric-coated tablets is slower, it is important to take different formulations into account when determining optimal MPA concentrations.

Random pharmacokinetic profiles of EC-MPS in children with autoimmune disease

BACKGROUND

: Therapy with mycophenolate mofetil (MMF) has become a valuable therapeutic option in children with autoimmune disease. MMF prescription in children with autoimmune diseases differs from that in transplant recipients in terms of different dosing regimen, and concomitant administration of other immunosuppressive medications. Recently, another formulation of the same active compound, mycophenolic acid (MPA), has become available as enteric-coated Mycophenolate Sodium (EC-MPS). Dosing and pharmacokinetics of EC-MPS in pediatric autoimmune disease have never been studied.

METHOD

S: We therefore performed a pilot study on 6 patients, who were treated with EC-MPS. All patients underwent 1-2 full 10-point pharmacokinetic (PK) profiles over a 12-hour dosing interval. We compared the results with that of 22 similar patients on MMF therapy.

RESULTS

: Median EC-MPS dose was 724 mg/m2 (range 179-933 mg/m2). The MPA Area-Under-The-(Time-Concentration)-Curves (AUCs) on MMF and EC-MPS were comparable (54.4 mg x h/L on MMF and 44.0 mg x h/L on EC-MPS, n.s., Mann Whitney). After correcting for bioequivalence, the dose-normalized AUCs were also similar on both the formulations. However, PK profiles on EC-MPS were quite random, and time to maximum concentration varied from 30 minutes to 720 minutes. The concentration at six-hour correlated best with the AUC. This was different from a homogenous PK-profile on MPA.

CONCLUSIONS

: EC-MPS has a different PK profile from MMF. The data suggest that patients on EC-MPS must undergo a complete PK profile to assess adequate exposure. The 6-hour concentration provides an estimate of the exposure and should be targeted between 3-4 mg/L.

Mycophenolate mofetil in patients with systemic lupus erythematosus: a prospective pharmacokinetic study

Few studies have assessed the pharmacokinetics of mycophenolic acid (MPA) in non-transplanted patients treated with mycophenolate mofetil (MMF), and little information is available concerning a concentration-effect relationship between the MPA area under the curve (AUC) and the immunological parameters in patients treated for systemic lupus erythematosus (SLE). We evaluated the variations in pharmacokinetics for MPA in patients with SLE and the relationship between MPA-AUC and markers of disease activity. MPA blood concentrations were measured through enzyme-multiplied immunotechnique (T(0), T(30'), T(1h), T(2h), T(3h) and T(4h)) to determine the MPA AUC(0-4h) in patients treated with MMF since at least 4 weeks for SLE. Clinical examination, biochemical analyses and immunological analyses were performed on the same day. The relationship between MPA exposure and disease activity markers was assessed. A total of 20 patients were included in the study. The diagnosis of SLE had been made 87 +/- 72 months before and patients had been treated with MMF for 31 +/- 30 months. Mean dose of MMF on the day of the study was 1600 +/- 447 mg/day. Mean MPA AUC(0-4h) was 28.4 +/- 13.6 mg h/L, mean dose-normalised AUC(0-4h) was 35.5 +/- 13.8 mg h/L and mean MPA C(0) was 3.1 +/- 2.2 mg/L. There was a high correlation between MPA AUC(0-4h) and MPA C(0), (r = 0.80; P < 0.001). AUC(0-4h) tended to be lower in patients who had low complement C3 concentration (<0.67 g/L) and low complement C4 concentration (<0.14 g/L). Moreover, there was a significant relationship between MPA trough levels and complement C4 concentrations (P = 0.043). We confirmed high inter-individual variability of MPA AUC in patients treated with MMF for SLE. This suggests that MPA exposure may be unpredictable with a fixed MMF dose. There was a concentration-effect relationship between MPA exposure (C(0)) and immunological disease activity parameters.

Insights on chronic-relapsing opsoclonus-myoclonus from a pilot study of mycophenolate mofetil

Opsoclonus-myoclonus syndrome is characterized by abnormal lymphocyte trafficking into brain. The authors hypothesized that mycophenolate mofetil, a lymphocyte proliferation inhibitor, might be therapeutic. The cerebrospinal fluid and blood immunophenotypes of 15 children with predominantly chronic-relapsing opsoclonus-myoclonus syndrome were compared before and after treatment by flow cytometry. Mycophenolate mofetil reduced the cerebrospinal fluid expansion of HLA-DR+ activated T cells (-40%); the frequency of other T-cell or natural killer cell subsets remained unchanged, but cerebrospinal fluid B cells increased significantly. Adrenocorticotropic hormone dose was lowered by 64% over an average of 1.5 years, yet 73% eventually relapsed despite therapeutic drug levels. Prior treatment with rituximab prevented relapse-associated increase in cerebrospinal fluid B cells, without hindering mycophenolate mofetil-induced reduction in T-cell activation. These data demonstrate resistant immunologic problems in chronic-relapsing opsoclonus-myoclonus syndrome. Mycophenolate mofetil did not prevent relapse. The novel effect of mycophenolate mofetil on chronically activated T cells may contribute to its efficacy in T-cell mediated neurological disorders.

Mycophenolate mofetil versus cyclosporine for remission maintenance in nephrotic syndrome

We performed a multi-centre randomized controlled trial to compare the efficacy of mycophenolate mofetil (MMF) to that of cyclosporine A (CsA) in treating children with frequently relapsing nephrotic syndrome and biopsy-proven minimal change disease. Of the 31 randomized initially selected patients, seven were excluded. The remaining 24 children received either MMF 1200 mg/m(2) per day (n = 12) or CsA 4-5 mg/kg per day (n = 12) during a 12-month period. Of the 12 patients in the MMF group, two discontinued the study medication. Evaluation of the changes from the baseline glomerular filtration rate showed an overall significant difference in favour of MMF over the treatment period (p = 0.03). Seven of the 12 patients in the MMF group and 11 of the 12 patients in the CsA group remained in complete remission during the entire study period. Relapse rate in the MMF group was 0.83/year compared to 0.08/year in the CsA group (p = 0.08). None of the patients reported diarrhea. Pharmacokinetic profiles of mycophenolic acid were performed in seven patients. The patient with the lowest area under the curve had three relapses within 6 months. In children with frequently relapsing minimal change nephrotic syndrome, MMF has a favourable side effect profile compared to CsA; however, there is a tendency towards a higher relapse risk in patients treated with MMF.

Association between mycophenolic acid 12-h trough levels and clinical endpoints in patients with autoimmune disease on mycophenolate mofetil

BACKGROUND

Triggered by heightened interest in mycophenolate mofetil (MMF) for the treatment of autoimmune diseases (AID) and encouraged by the results from a previous study, we hypothesized that therapeutic drug monitoring of mycophenolic acid (MPA) based on troughs may be useful for effective MMF dosing in patients with AID.

METHODS

A two-step approach was pursued. First, we confirmed in 38 AID patients (26 with antineutrophil cytoplasmic antibody-associated vasculitis; 12 with systemic lupus erythematosus) a significant correlation (r = 0.545, P < 0.001) between MPA C(12 h) and MPA exposure (AUC). Second, we performed an analysis of 294 MPA 12-h trough levels serially collected from 39 patients (same indications) receiving MMF for remission maintenance therapy to elucidate possible associations with disease activity and MMF toxicity.

RESULTS

Higher MPA trough levels were associated with better protection from recurrence of active disease. While at levels <3 mg/L 29% of collected samples (43/147) were from patients with active disease, this was only the case in 2% of samples (3/147) with an MPA concentration of >or=3 mg/L. Remission persisted in all patients with MPA troughs >or=3.5 mg/L. Upon combined analysis of efficacy and safety data, most favourable results were obtained with MPA troughs between 3.5 and 4.5 mg/L. There was no discernable relationship between MMF dose and clinical endpoints.

CONCLUSION

The target range proposed by this explorative study may serve as an initial guidance for MPA monitoring in the context of further prospective controlled trials in patients with AID.

Mycophenolate mofetil in the treatment of uveitis in children

BACKGROUND

Mycophenolate mofetil (MMF) is a new immunosuppressive agent that effectively controls the intraocular inflammation in adults.

PURPOSE

To assess the efficacy of MMF in uveitis in children and to analyse the possible side effects.

PARTICIPANTS AND METHODS

A retrospective analysis was carried out on 17 children (32 eyes) with intraocular inflammation treated with MMF and followed up at the University Eye Hospital Tuebingen, Tuebingen, Germany, between 2000 and 2005. All children had chronic non-infectious uveitis and received MMF for at least 6 months. All patients were given steroids or other immunosuppressive agents before initiating treatment with MMF.

RESULTS

17 children (10 boys and 7 girls) with a mean age of 8 (range 2-13) years at the onset of uveitis were examined. The average duration of follow-up after initiation of MMF was 3 (range 2-5) years. A steroid-sparing effect was achieved in 88% of the patients. The oral prednisolone was successfully discontinued in 41% children and reduced to a daily dose of < or =5 mg in 47% of the children. 24% of the patients remained relapse-free during the treatment, but a reduction in the relapse rate was observed in all other patients except one. Visual acuity was increased or maintained in 13 children (76%). Mild side effects (headache, rash, gastrointestinal discomfort) occurred in 7 patients (41%) and were the cause of discontinuation of MMF in 1 patient.

CONCLUSION

The results of our study are encouraging and suggest that MMF is an effective agent also in the treatment for uveitis in children, with marked steroid-sparing potential and an acceptable side effect profile.

To what extent does the understanding of pharmacokinetics of mycophenolate mofetil influence its prescription

Within a short period, we have witnessed a dramatic increase in the use of mycophenolate mofetil (MMF) in pediatric renal transplantation, with the drug often replacing azathioprine in combination with calcineurin inhibitor therapy. When the drug was introduced, the manufacturer considered therapeutic drug monitoring (TDM) unnecessary. However, TDM studies revealed substantial inter- and intra-individual variability and drug interactions. There is a substantial drug interaction between MMF and cyclosporine, and lower doses are required in combination with tacrolimus (~500-800 mg/m(2) per day) than with cyclosporine (~1,200 mg/m(2) per day). Patients with autoimmune disease require an intermediate dose when receiving no concomitant calcineurin inhibitor (~900 mg/m(2) per day). It has been possible to detect drug interactions and to minimize adverse events only with TDM. This is especially important with increasing use of combination therapies. Pharmacodynamic monitoring (measuring the biological response to a drug) coupled with pharmacokinetics allow optimization of drug dosing, with maximum efficacy and minimal toxicity. More work is required to establish specific target ranges with the various drug combinations--especially for the pediatric population.