Mycophenolate mofetil versus cyclosporin A in children with frequently relapsing nephrotic syndrome

Clinical applicability of 2023 International Pediatric Nephrology Association recommended limited therapeutic drug monitoring formulae to assess mycophenolic acid exposure

BACKGROUND

The 2023 IPNA guidelines recommended a 12-h mycophenolic acid (MPA) area under the curve (AUC) estimation for managing pediatric nephrotic syndrome and MPA AUC > 50 mg * h/L for an optimal therapeutic response to mycophenolate mofetil (MMF). The IPNA guidelines endorsed two limited AUC formulae based on three-point MPA measurements to predict 12-h MPA AUC. The relative performance of these two limited AUC formulae has not been tested.

METHODS

We analyzed 156 MPA AUCs from 122 stable kidney transplant recipients to predict the 12-h AUC (10 MPA measurements analyzed with trapezoid rule) using the IPNA-recommended three-point Formula 1 and Formula 2.

RESULTS

Three-point Formula 1 and Formula 2 classified 69% and 60% limited MPA AUCs as > 50 mg * h/L (difference 8.90%, p = 0.10). Three-point Formula 1 and Formula 2 demonstrated a similar association with 12-h AUC (R2 0.72 vs. 0.71) and exhibited identical areas under ROC (AUROC) for predicting 12-h AUC > 50 mg * h/L (AUROC 0.82, 95% CI 0.75, 0.88 vs. 0.80, 95% CI 0.73, 0.86; p = 0.53). Fixed MMF dose and MPA C0 level showed a relatively weaker association (R2 0.16 and 0.43) with 12-h AUC. Four-point MPA formulae improved the prediction of 12-h AUC compared to the three-point formulae. Among all C0 thresholds, C0 > 3.5 mg/L demonstrated the best prediction of 12-h AUC > 50 mg * h/L (AUROC 0.74, 95% CI 0.66, 0.80).

CONCLUSIONS

IPNA recommended limited AUC formulae perform equivalently and improve upon MMF dose and C0 level to predict 12-h MPA AUC.

Prolonged remission after cyclophosphamide or tacrolimus treatment in childhood nephrotic syndrome: a cohort study

BACKGROUND

Steroid-sparing immunosuppression is used in 50% of children with nephrotic syndrome, to prevent relapses and steroid-related toxicity. However, rates and predictors of prolonged remission after cyclophosphamide and tacrolimus are uncertain.

METHODS

Retrospective analysis of children (1-18 years) enrolled in a longitudinal cohort. We included children diagnosed with steroid-sensitive nephrotic syndrome between 1996-2019 from Toronto, Canada. The exposure was cyclophosphamide or tacrolimus initiation. The primary outcome was prolonged remission (no further relapse or steroid-sparing immunosuppression). We evaluated predictors of prolonged remission and calcineurin inhibitor nephrotoxicity by logistic regression.

RESULTS

Of 578 children with steroid-sensitive nephrotic syndrome, 252 received cyclophosphamide and 120 received tacrolimus. Over median 5.4-year (IQR 2.4-9.1) follow-up, prolonged remission occurred in 72 (28.6%) after cyclophosphamide and 17 (14.2%) after tacrolimus. Relapse frequency decreased after initiation of either medication. Lower prior relapse rate, more recent treatment era, and female sex were predictive of prolonged remission after cyclophosphamide treatment. Use of tacrolimus as the first steroid-sparing medication was the only factor predictive of calcineurin inhibitor nephrotoxicity.

CONCLUSIONS

Less than one-third of children achieve prolonged remission after initiating cyclophosphamide or tacrolimus, although both reduce short-term relapse rates. Few factors predict prolonged remission after cyclophosphamide or tacrolimus use, or calcineurin inhibitor nephrotoxicity.

Emerging pharmacotherapies for the treatment of childhood nephrotic syndrome

INTRODUCTION

Childhood nephrotic syndrome (NS) is a relatively rare condition but an important cause of morbidity. It is classified based on histopathology and response to corticosteroid therapy.

AREAS COVERED

Children with steroid-sensitive disease have a favorable long-term prognosis with maintenance of normal kidney function. However, nearly half of these patients have persistent disease activity requiring chronic corticosteroid therapy or exposure to second-line immunosuppressive agents. The identification of anti-nephrin antibodies in many patients with steroid-sensitive disease suggests immunotherapy to reduce pathogenic antibody formation may represent a qualitative advance in treatment. Children with steroid-resistant disease are likely to have focal segmental glomerulosclerosis (FSGS). There are no approved treatments for this condition. FSGS is a heterogeneous entity, and improvements in care will likely depend on molecular classification of subtypes based on the underlying disease mechanism. This approach will enable selection of treatments that match the cause of NS in each child for precision medicine therapy.

EXPERT OPINION

Children with NS today benefit from therapeutic options not previously available, but clinical decisions still rely on steroid responsiveness at disease onset. Continued advancement in treating NS requires collaboration between basic scientists and nephrologists and the organization of a clinical trial framework to evaluate novel therapies.

Non-corticosteroid immunosuppressive medications for steroid-sensitive nephrotic syndrome in children

BACKGROUND

About 80% of children with steroid-sensitive nephrotic syndrome (SSNS) have relapses. Of these children, half will relapse frequently, and are at risk of adverse effects from corticosteroids. While non-corticosteroid immunosuppressive medications prolong periods of remission, they have significant potential adverse effects. Currently, there is no consensus about the most appropriate second-line agent in children with frequently relapsing SSNS. In addition, these medications could be used with corticosteroids in the initial episode of SSNS to prolong the period of remission. This is the fifth update of a review first published in 2001 and updated in 2005, 2008, 2013 and 2020.

OBJECTIVES

To evaluate the benefits and harms of non-corticosteroid immunosuppressive medications in SSNS in children with a relapsing course of SSNS and in children with their first episode of nephrotic syndrome.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to October 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs were included if they involved children with SSNS and compared non-corticosteroid immunosuppressive medications with placebo, corticosteroids or no treatment; different non-corticosteroid immunosuppressive medications, or different doses, durations or routes of administration of the same non-corticosteroid immunosuppressive medication.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias and extracted data from the included studies. Statistical analyses were performed using a random-effects model and results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous outcomes with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We identified 58 studies (122 reports) randomising 3720 children. Half were multicentre studies, and most studies were undertaken in South and East Asia (28 studies) and Europe (20 studies). The numbers of children randomised ranged from 14 to 211. Risk of bias assessment indicated that 32 and 33 studies were at low risk of bias for sequence generation and allocation concealment, respectively. Eleven studies were at low risk of performance bias and 13 were at low risk of detection bias. Forty-eight and 36 studies were at low risk of incomplete and selective reporting, respectively. Rituximab with or without prednisone compared with placebo with or without prednisone probably reduces the number of children experiencing relapse at six months (5 studies, 182 children: RR 0.22, 95% CI 0.11 to 0.43) and 12 months (3 studies, 108 children: RR 0.38, 95% CI 0.13 to 1.09) (moderate certainty), may increase the number with severe infusion reactions (4 studies, 162 children: RR 5.21, 95% CI 1.19 to 22.89; low certainty), but not severe infection or arthropathy (low certainty). Rituximab compared with tacrolimus probably reduces the risk of relapse at 12 months (4 studies, 238 children: RR 0.64, 95% CI 0.42 to 0.96) and may reduce the risk of relapse when compared with low dose mycophenolate mofetil (MMF) (1 study, 30 children: RR 0.17, 95% CI 0.04 to 0.62). Rituximab followed by MMF for 500 days reduces the risk of relapse compared with rituximab followed by placebo for 500 days (1 study, 78 children: RR 0.29, 95% CI 0.13 to 0.63; high certainty). Rituximab probably does not differ from ofatumumab in the riisk of relapse and 12 months (1 study, 140 children: RR 1.03, 95% CI 0.75 to 1.41; moderate certainty) or in adverse events. MMF and levamisole (1 study, 149 children: RR 0.90, 95% CI 0.70 to 1.16) may have similar effects on the number of children who relapse at 12 months (low certainty). Cyclosporin compared with MMF may reduce the risk of relapse at 12 months (3 studies, 114 children: RR 1.57, 95% CI 1.08 to 2.30) (low certainty). Levamisole compared with steroids or placebo may reduce the number of children with relapse during treatment (8 studies, 474 children: RR 0.52, 95% CI 0.33 to 0.82) (low certainty). Preliminary data from single studies indicate that levamisole and prednisone compared with prednisone alone may delay the onset of relapse after the initial episode of SSNS and that levamisole compared with increasing prednisone administration from alternate day to daily at the onset of infection may reduce the risk of relapse with infection (low certainty). Cyclosporin compared with prednisone may reduce the number of children who relapse (1 study, 104 children: RR 0.33, 95% CI 0.13 to 0.83) (low certainty). Alkylating agents compared with cyclosporin may make little or no difference to the risk of relapse during cyclosporin treatment (2 studies, 95 children: RR 0.91, 95% CI 0.55 to 1.48) (low certainty evidence) but may reduce the risk of relapse at 12 to 24 months (2 studies, 95 children: RR 0.51, 95% CI 0.35 to 0.74) (low certainty). Alkylating agents (cyclophosphamide and chlorambucil) compared with prednisone probably reduce the number of children who experience relapse at six to 12 months (6 studies, 202 children: RR 0.44, 95% CI 0.32 to 0.60) and at 12 to 24 months (4 studies, 59 children: RR 0.20, 95% CI 0.09 to 0.46) (moderate certainty).

AUTHORS' CONCLUSIONS

New studies incorporated in this review update indicate that rituximab compared with prednisone, tacrolimus, or MMF is a valuable additional agent for managing children with relapsing SSNS. Comparative studies of CNIs, MMF, and levamisole suggest that CNIs may be more effective than MMF and that levamisole may be similar in efficacy to MMF. Important new studies suggest that MMF prolongs remission following rituximab, that levamisole may prevent infection-related relapse more effectively than changing from alternate-day to daily prednisone and that levamisole and prednisone compared with prednisone alone may prolong the time to first relapse. There are currently 23 ongoing studies which should improve our understanding of how to treat children with frequently relapsing SSNS.

Efficacy and safety of oral cyclophosphamide versus mycophenolate mofetil in childhood nephrotic syndrome: an open-label comparative study

INTRODUCTION

There is a scarcity of research comparing the efficacy of cyclophosphamide and mycophenolate mofetil in childhood nephrotic syndrome. The aim was to evaluate the efficacy and safety of oral cyclophosphamide (CYC) and mycophenolate mofetil (MMF) in children with steroid-sensitive nephrotic syndrome in terms of the proportion of children who have been off steroids for at least 6 months without proteinuria (responders).

METHODS

This open-label retrospective-prospective comparative study was conducted in a pediatric nephrology clinic of a referral center for children between 1 and 18 years of age with FR/SD nephrotic syndrome. Group A consisted of patients who received oral cyclophosphamide (100, 25% female) at a dose of 2-2.5 mg/kg once daily for a period of 8-12 weeks. Group B consisted of patients who received oral mycophenolate mofetil (n = 61, 18% female) (dose: 800-1200 mg/m2) for at least 12 months. Responders were defined as children who were off steroids for at least 6 months along with absence of proteinuria.

RESULTS

In the CYC group, 50% of the patients were responders, whereas 54% of the patients in the MMF group were responders (p = 0.614). The time to first relapse with CYC was 7 months (IQR 5.25-11) compared to 7 months (IQR 3.5-12) with MMF (p = 0.092). The relapse rate in the CYC group was 1.77 relapses per patient-year compared to 1.295 relapses per patient-year in the MMF group. The difference in relapse rate was significant (-0.474; 95% CI, 0.09 to 0.86 relapses/person-year) (p value = 0.009). Multivariate analysis revealed that an age of less than 5 years at the start of treatment was a significant factor for a better response to MMF (p value = 0.039, OR = 2.988, CI -1.055-8.468).

CONCLUSIONS

The efficacy of MMF was similar to that of CYC in terms of response (6 months without steroids) in children with FR/SD nephrotic syndrome. MMF showed a favorable response in terms of the frequency of relapse and treatment failure. REGISTRATION OF THE STUDY WITH CLINICAL TRIALS REGISTRY OF INDIA: ( http://ctri.nic.in ;CTRI/2021/06/034421) (Dt: 28/06/2021).

Minimal Change Disease

Minimal change disease represents a common cause of nephrotic syndrome in both pediatric and adult patients. Although much remains to be discovered, there have been significant recent advancements in our understanding of the pathophysiology of minimal change disease, including the discovery of antinephrin antibodies as a marker for diagnosis of disease. Here we will review what is known about the pathophysiology, treatment, and prognosis of minimal change disease and the differences between pediatric and adult patients. Recent advances in our understanding of the mechanisms of disease will be noted. We will discuss how this may change the treatment of minimal change disease going forward and what remains to be studied.

Exposure to Mycophenolic Acid and Its Clinical Response in an Indian Pediatric Population with Nephrotic Syndrome

Background

Children with nephrotic syndrome experience many side effects and frequent relapses when treated with steroids and other drugs. Mycophenolic acid (MPA) is one of the effective and least toxic drug for the treatment of nephrotic syndrome. This drug needs to be monitored for maximal efficacy and minimal toxicity. The therapeutic reference range for this drug is not established for the aforementioned patient population of Indian origin.

Materials and Methods

In this observational study, children with nephrotic syndrome on mycophenolate mofetil were followed up for a minimum duration of three months. Following this, their clinical status (relapse/remission) was determined and the mycophenolate exposure was measured for over 12 hours.

Results

A total of 34 participants were included, with 17 (50%) in relapse. Median MPA Area under the curve over 12 hours (AUC0-12h) (36.5 µg·h/ml) in the remission group differed significantly compared to that in the relapse group (17.2 µg·h/ml).

Conclusion

Higher exposure to MPA AUC0-12h is associated with clinical remission of pediatric nephrotic syndrome.

Managing Lupus Nephritis in Children and Adolescents

Lupus nephritis is an important manifestation of systemic lupus erythematosus, which leads to chronic kidney disease, kidney failure, and can result in mortality. About 35%-60% of children with systemic lupus erythematosus develop kidney involvement. Over the past few decades, the outcome of patients with lupus nephritis has improved significantly with advances in immunosuppressive therapies and clinical management. Nonetheless, there is a paucity of high-level evidence to guide the management of childhood-onset lupus nephritis, because of the relatively small number of patients at each centre and also because children and adolescents are often excluded from clinical trials. Children and adults differ in more ways than just size, and there are remarkable differences between childhood- and adult-onset lupus nephritis in terms of disease severity, treatment efficacy, tolerance to medications and most importantly, psychosocial perspective. In this article, we review the 'art and science' of managing childhood-onset lupus nephritis, which has evolved in recent years, and highlight special considerations in this specific patient population.

Mycophenolate Mofetil Versus Prednisone for Induction Therapy in Steroid-Sensitive Idiopathic Nephrotic Syndrome in Children: An Observational Study

Rationale & Objective

High-dose steroids are recommended for the induction of idiopathic nephrotic syndrome. The aim of this study was to compare standard induction therapy with Mycophenolate Mofetil (MMF). We hypothesized that MMF could be noninferior to steroids in maintaining steroid-induced remission. The second aim was to reduce steroid-induced side effects.

Study Design

This was an observational study.

Setting & Population

Patients 2-11 years with first episode of nephrotic syndrome who entered remission within 2 weeks of standard steroid treatment were eligible for enrollment. Patients in the experimental group completed 12-week induction with MMF, whereas the control group continued a standard 12-week steroid protocol.

Exposures

MMF and prednisolone were used in the study.

Outcomes

The primary study outcomes were relapse rate and relapse-free interval during a 52-week follow-up.

Analytical Approach

Descriptive statistics were used for analysis.

Results

Ten of 41 eligible patients consented to participate in the MMF group and 8 completed the study. The control group included 31 patients, with 23 patients who completed 52 weeks follow-up. During the induction phase, 3 out of 10 patients (30%) in the MMF group and 1 out of 31 (3%) in the control group (P = 0.04) developed relapse. During the 52 weeks follow-up period, 7 out of 10 patients (70%) in the MMF group and 19 out of 31 (61%) in the control group developed relapse (P = 0.72). The median relapse-free interval was 11 and 19 weeks in MMF and control groups, respectively (P = 0.60). No serious side effects were recorded in either group.

Limitations

The limitations of the study were low patient numbers receiving MMF and single-center design.

Conclusions

Our small cohort of patients treated with MMF reported a higher relapse rate during the induction phase. However, by 12 months of follow-up the relapse rate and relapse-free intervals were similar between both groups. All patients tolerated MMF without significant side effects, and those who relapsed remained steroid-sensitive.

Therapeutic drug monitoring in childhood idiopathic nephrotic syndrome: a state of the art review

Immunosuppressants are commonly used as steroid-sparing agents in childhood idiopathic nephrotic syndrome (NS) to induce and sustain remissions. These drugs have narrow therapeutic indices with high inter- and intra-patient variability. Therapeutic drug monitoring (TDM) would therefore be essential to guide the prescription. Multiple factors in NS contribute to additional variability in drug concentrations, especially during relapses. In this article, we review the currently available evidence of TDM in NS and suggest a practical approach for clinicians' reference.

Retrospective Cross-Sectional Study Reviewing the Effectiveness of Mycophenolate Mofetil on Saudi Children With Nephrotic Syndrome

Background Idiopathic nephrotic syndrome (INS) is the most common form of nephrotic syndrome (NS) in children. It is often associated with minimal change disease (MCD). Corticosteroid therapy is the initial treatment, but many patients experience relapses, leading to steroid-dependent nephrotic syndrome (SDNS) or frequently relapsing steroid-sensitive nephrotic syndrome (FR-SSNS). To avoid prolonged steroid use, mycophenolate mofetil (MMF) is used as an immunosuppressive alternative. MMF is safe and effective for treating SDNS and FR-SSNS in children, with studies showing reduced relapse rates. The current study aims to evaluate MMF's effectiveness and safety in Saudi children with NS and identify factors that affect its efficacy. Methods A retrospective cross-sectional study was conducted at King Abdullah Specialized Children's Hospital (KASCH) in Riyadh, Saudi Arabia. The study included children aged one to 14 years diagnosed with NS who received MMF therapy. Data were collected from medical records from 2000 to 2020. Ethical considerations were followed, and statistical analysis was performed using IBM SPSS Statistics for Windows, version 25 (released 2017; IBM Corp., Armonk, New York, United States). Baseline characteristics and responsiveness to MMF were examined. Results In our study, 45 participants (25 males, 20 females) with NS were treated with MMF. Most participants were steroid-dependent (84.44%) and had frequent relapses. MMF was effective in 84.4% of cases, with a significant reduction in relapse; the mean number of relapses decreased from 3.5 before MMF to 1.6 after MMF (p-value = 0.00002). Moreover, 40% of the participants were completely free of relapse after the introduction of MMF. The average duration of the MMF therapy was 45 months. Post-MMF side effects were rare but documented. Gastrointestinal symptoms were extremely rare. Elevated liver enzyme levels were reported in 8.88% (four cases) of the participants. Leukopenia, a more common adverse effect, was reported in 26.66% of cases during the MMF therapy. The average daily dose of steroid was reduced from 12.5 mg/day pre MMF to 2 mg/day post MMF with a p-value of 0.00229. Conclusion Our study evaluated the use of MMF in 45 participants with NS. We found that MMF was effective in 84.4% of cases, leading to a significant reduction in the number of relapses. Post-MMF side effects were relatively rare, except for leukopenia that was reported in 26.66%. In addition, the average rate of reduction of steroid exposure before and after MMF was significant. These findings suggest that MMF is a promising treatment option for children with NS and an alternative therapy to long-term steroid use, due to its safety and effectiveness, although close monitoring for potential side effects is essential.

Childhood nephrotic syndrome

Idiopathic nephrotic syndrome is the most common glomerular disease in children. Corticosteroids are the cornerstone of its treatment, and steroid response is the main prognostic factor. Most children respond to a cycle of oral steroids, and are defined as having steroid-sensitive nephrotic syndrome. Among the children who do not respond, defined as having steroid-resistant nephrotic syndrome, most respond to second-line immunosuppression, mainly with calcineurin inhibitors, and children in whom a response is not observed are described as multidrug resistant. The pathophysiology of nephrotic syndrome remains elusive. In cases of immune-mediated origin, dysregulation of immune cells and production of circulating factors that damage the glomerular filtration barrier have been described. Conversely, up to a third of cases of steroid-resistant nephrotic syndrome have a monogenic origin. Multidrug resistant nephrotic syndrome often leads to kidney failure and can cause relapse after kidney transplant. Although steroid-sensitive nephrotic syndrome does not affect renal function, most children with steroid-sensitive nephrotic syndrome have a relapsing course that requires repeated steroid cycles with significant side-effects. To minimise morbidity, some patients require steroid-sparing immunosuppressive agents, including levamisole, mycophenolate mofetil, calcineurin inhibitors, anti-CD20 monoclonal antibodies, and cyclophosphamide. Close monitoring and preventive measures are warranted at onset and during relapse to prevent acute complications (eg, hypovolaemia, acute kidney injury, infections, and thrombosis), whereas long-term management requires minimising treatment-related side-effects. A subset of patients have active disease into adulthood.

The effect of mycophenolate mofetil on podocytes in nephrotoxic serum nephritis

Mycophenolate mofetil (MMF) is applied in proteinuric kidney diseases, but the exact mechanism of its effect on podocytes is still unknown. Our previous in vitro experiments suggested that MMF can ameliorate podocyte damage via restoration of the Ca2+-actin cytoskeleton axis. The goal of this study was to characterize podocyte biology during MMF treatment in nephrotoxic serum (NTS) nephritis (NTN). NTN was induced in three-week old wild-type mice. On day 3, half of the mice were treated with MMF (100 mg/kgBW/d p.o.) for one week. On day 10, we performed proteomic analysis of glomeruli as well as super-resolution imaging of the slit diaphragm. For multiphoton imaging of Ca2+ concentration ([Ca2+]i), the experimental design was repeated in mice expressing podocyte-specific Ca2+ sensor. MMF ameliorated the proteinuria and crescent formation induced by NTS. We identified significant changes in the abundance of proteins involved in Ca2+ signaling and actin cytoskeleton regulation, which was further confirmed by direct [Ca2+]i imaging in podocytes showing decreased Ca2+ levels after MMF treatment. This was associated with a tendency to restoration of podocyte foot process structure. Here, we provide evidence that MPA has a substantial direct effect on podocytes. MMF contributes to improvement of [Ca2+]i and amelioration of the disorganized actin cytoskeleton in podocytes. These data extend the knowledge of direct effects of immunosuppressants on podocytes that may contribute to a more effective treatment of proteinuric glomerulopathies with the least possible side effects.

Glomerular Diseases Across Lifespan: Key Differences in Diagnostic and Therapeutic Approaches

Glomerular diseases are common causes of chronic kidney disease in childhood, adolescence, and adulthood. The epidemiology of glomerular diseases differs between different age groups, with minimal change disease being the leading cause of nephrotic syndrome in childhood, while membranous nephropathy and focal segmental glomerulosclerosis are more common in adulthood. IgA vasculitis is also more common in childhood. Moreover, there is a difference in disease severity with more children presenting with a relapsing form of nephrotic syndrome and a more acute presentation of antineutrophil cytoplasmic antibody-associated vasculitis and concomitant glomerulonephritis, as highlighted by the higher percentage of cellular crescents on kidney biopsy specimens in comparison with older patients. There is also a female preponderance in antineutrophil cytoplasmic antibody-associated vasculitis and more children present with tracheobroncholaryngeal disease. This article aims to summarize differences in the presentation of different glomerular diseases that are encountered commonly by pediatric and adult nephrologists and potential differences in the management.

CD4 + and CD8 + T-lymphocyte number as predictive marker of relapse after rituximab treatment in childhood-onset refractory nephrotic syndrome

BACKGROUND

Rituximab is a promising option for refractory idiopathic nephrotic syndrome. However, no simple predictive markers for relapse after rituximab have been established. To determine such markers, we investigated the relationship between CD4 + and CD8 + cell counts and relapse after rituximab administration.

METHODS

We retrospectively investigated patients with refractory nephrotic syndrome who received rituximab followed by immunosuppressive as maintenance therapy. Patients were divided into no relapse in 2 years after rituximab treatment or relapse group. After rituximab treatment, CD4 + /CD8 + cell counts were measured monthly, at prednisolone discontinuation, and at B-lymphocyte recovery. To predict relapse, these cell counts were analyzed using receiver operating characteristic (ROC). Additionally, relapse-free survival was reevaluated based on the result of ROC analysis for 2 years.

RESULTS

Forty-eight patients (18 in the relapse group) were enrolled. At prednisolone discontinuation (52 days after rituximab treatment), the relapse-free group showed significantly lower cell counts than the relapse group (median CD4 + cell count: 686 vs. 942 cells/µL, p = 0.006; CD8 + : 613 vs. 812 cells/µL, p = 0.005). In the ROC analysis, CD4 + cell count > 938 cell/µL and CD8 + cell count > 660 cells/µL could predict relapse in 2 years (sensitivity, 56% and 83%; specificity, 87% and 70%). The patient group with both lower CD4 + and CD8 + cell counts showed significantly longer 50% relapse-free survival (1379 vs. 615 days, p < 0.001 and 1379 vs. 640 days, p < 0.001).

CONCLUSIONS

Lower CD4 + and CD8 + cell counts in the early phase after rituximab administration may predict a lower risk of relapse.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-sensitive nephrotic syndrome

Idiopathic nephrotic syndrome is the most frequent pediatric glomerular disease, affecting from 1.15 to 16.9 per 100,000 children per year globally. It is characterized by massive proteinuria, hypoalbuminemia, and/or concomitant edema. Approximately 85-90% of patients attain complete remission of proteinuria within 4-6 weeks of treatment with glucocorticoids, and therefore, have steroid-sensitive nephrotic syndrome (SSNS). Among those patients who are steroid sensitive, 70-80% will have at least one relapse during follow-up, and up to 50% of these patients will experience frequent relapses or become dependent on glucocorticoids to maintain remission. The dose and duration of steroid treatment to prolong time between relapses remains a subject of much debate, and patients continue to experience a high prevalence of steroid-related morbidity. Various steroid-sparing immunosuppressive drugs have been used in clinical practice; however, there is marked practice variation in the selection of these drugs and timing of their introduction during the course of the disease. Therefore, international evidence-based clinical practice recommendations (CPRs) are needed to guide clinical practice and reduce practice variation. The International Pediatric Nephrology Association (IPNA) convened a team of experts including pediatric nephrologists, an adult nephrologist, and a patient representative to develop comprehensive CPRs on the diagnosis and management of SSNS in children. After performing a systematic literature review on 12 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, recommendations were formulated and formally graded at several virtual consensus meetings. New definitions for treatment outcomes to help guide change of therapy and recommendations for important research questions are given.

Therapeutic trials in difficult to treat steroid sensitive nephrotic syndrome: challenges and future directions

Steroid sensitive nephrotic syndrome is a common condition in pediatric nephrology, and most children have excellent outcomes. Yet, 50% of children will require steroid-sparing agents due to frequently relapsing disease and may suffer consequences from steroid dependence or use of steroid-sparing agents. Several steroid-sparing therapeutic agents are available with few high quality randomized controlled trials to compare efficacy leading to reliance on observational data for clinical guidance. Reported trials focus on short-term outcomes such as time to first relapse, relapse rates up to 1-2 years of follow-up, and few have studied long-term remission. Trial designs often do not consider inter-individual variability, and differing response to treatments may occur due to heterogeneity in pathogenic mechanisms, and genetic and environmental influences. Strategies are proposed to improve the quantity and quality of trials in steroid sensitive nephrotic syndrome with integration of biomarkers, novel trial designs, and standardized outcomes, especially for long-term remission. Collaborative efforts among international trial networks will help move us toward a shared goal of finding a cure for children with nephrotic syndrome.

"Clinical Efficacy of Mycophenolate Mofetil versus Levamisole Therapy in Frequently Relapsing and Steroid Dependent Childhood Nephrotic Syndrome" - A retrospective comparative analysis

BACKGROUND

Children with Frequently relapsing (FR) or Steroid dependent (SD) Nephrotic Syndrome (NS) often develop side effects of corticosteroids. Various steroid-sparing agents are in practice, but only a few studies exist so far which have compared the safety and efficacy of these two commonly used agents.

METHODS

We did a retrospective medical records review of children with FRNS or SDNS who had Levamisole or MMF as a steroid-sparing agent with a minimum follow-up period of 12 months. The aim was to compare the course of our patients on MMF and Levamisole. Our primary objective was to determine the number of children in sustained remission and those with the infrequently relapsing course on Levamisole and MMF and, the median time to relapse in months in the two groups. The secondary objective was to compare time to first relapse and number of relapses in FRNS and SDNS group children on MMF and Levamisole.

RESULTS

A total of 88 children (34% female) with diagnosis FR/SDNS (44 each) were included in the study. Thirty-nine patients took Levamisole, while forty-nine received MMF therapy. The median age of presentation at the relapsing course was 4.2 years. The proportion of children with sustained remission or infrequent relapsing (IFR) course on MMF was 73.6%, compared to 48.71% on Levamisole (p-value 0.015). Also, the median time to first relapse was 12 months (24, 1.5) and 4.5 months (24, 1) on respective medications.

CONCLUSIONS

Clinical outcome was superior in the MMF group than Levamisole, especially in SDNS patients, and also MMF was more efficacious in maintaining sustained remission. This article is protected by copyright. All rights reserved.

Population Pharmacokinetics And Bayesian Estimation of Mycophenolate Mofetil In Patients With Autoimmune Hepatitis

BACKGROUND

Mycophenolate mofetil (MMF) is the most widely used second-line agent in auto-immune hepatitis (AIH). Individual dose adjustment of MMF may avoid adverse outcomes while maximizing efficacy. The aim of the present study was to develop population pharmacokinetic (popPK) models and Maximum A-Posteriori Bayesian estimators (MAP-BEs) to estimate MPA inter-dose area under the curve (AUC_0-12h ) in AIH patients administered MMF using nonlinear mixed effect modelling.

METHODS

We analyzed 50 MPA PK profiles from 34 different patients, together with some demographic, clinical, and laboratory test data. The median number of plasma samples per profile, immediately preceding and following the morning MMF dose, was 7 [4 - 10]. PopPK modeling was performed using parametric, top-down, nonlinear mixed effect modelling with NONMEM 7.3. MAP-BEs were developed based on the best popPK model and the best limited sampling strategy (LSS) selected among several.

RESULTS

The pharmacokinetic data were best described by a 2-compartment model, Erlang distribution to describe the absorption phase, and a proportional error. The mean (RSE) of popPK parameter estimates of clearance, intercompartmental clearance, central volume and absorption rate with the final model were: 21.6 L.h^-1 (11%), 22.7 L.h^-1 (19%), 35.9 L (21%) and 8.7 h^-1 (9%), respectively. The peripheral volume was fixed to 300 L. The best MAP-BE relied on the LSS at 0.33, 1 and 3 hours after mycophenolate mofetil dose administration and was very accurate (bias=5.6%) and precise (RMSE<20%).

CONCLUSION

The precise and accurate Bayesian estimator developed in this study for AIH patients on MMF can be used to improve the therapeutic management of these patients.

Second and Third Generational Advances in Therapies of the Immune-Mediated Kidney Diseases in Children and Adolescents

Therapy of immune-mediated kidney diseases has evolved during recent decades from the non-specific use of corticosteroids and antiproliferative agents (like cyclophosphamide or azathioprine), towards the use of more specific drugs with measurable pharmacokinetics, like calcineurin inhibitors (cyclosporine A and tacrolimus) and mycophenolate mofetil, to the treatment with biologic drugs targeting detailed specific receptors, like rituximab, eculizumab or abatacept. Moreover, the data coming from a molecular science revealed that several drugs, which have been previously used exclusively to modify the upregulated adaptive immune system, may also exert a local effect on the kidney microstructure and ameliorate the functional instability of podocytes, reducing the leak of protein into the urinary space. The innate immune system also became a target of new therapies, as its specific role in different kidney diseases has been de novo defined. Current therapy of several immune kidney diseases may now be personalized, based on the detailed diagnostic procedures, including molecular tests. However, in most cases there is still a space for standard therapies based on variable protocols including usage of steroids with the steroid-sparing agents. They are used as a first-line treatment, while modern biologic agents are selected as further steps in cases of lack of the efficacy or toxicity of the basic therapies. In several clinical settings, the biologic drugs are effective as the add-on therapy.

Update on the treatment of steroid-sensitive nephrotic syndrome

Steroid-sensitive nephrotic syndrome (SSNS) is a rare condition that develops primarily in preadolescent children after the age of 1 year. Since the 1950s, oral corticosteroids have been the mainstay of treatment of all children presenting with nephrotic syndrome, with most patients responding within 4 weeks to an oral course of prednisone (PDN). However, corticosteroids have important side effects and 60-80 % of patients relapse, developing frequently relapsing or steroid-dependent forms. For these reasons, many patients require second-line steroid-sparing immunosuppressive medications that have considerably improved relapse-free survival, while avoiding many PDN-related toxicities. Since most patients will eventually heal from their disease with a normal kidney function, the morbidity of SSNS is primarily related to side effects of drugs that are used to maintain prolonged remission. Therefore, treatment is essentially based on balancing the use of different drugs to achieve permanent remission with the lowest cumulative number of side effects. Treatment choice is based on the severity of SSNS, on patient age, and on drug tolerability. This review provides an update of currently available therapeutic strategies for SSNS.

Efficacy of rituximab versus tacrolimus in difficult-to-treat steroid-sensitive nephrotic syndrome: an open-label pilot randomized controlled trial

BACKGROUND

Rituximab and tacrolimus are therapies reserved for patients with frequently relapsing or steroid-dependent nephrotic syndrome who have failed conventional steroid-sparing agents. Given their toxicities, demonstrating non-inferiority of rituximab to tacrolimus may enable choice between these medications.

METHODS

This investigator-initiated, single-center, open-label, pilot randomized controlled trial examined the non-inferiority of two doses of intravenous (IV) rituximab given one-week apart to oral therapy with tacrolimus (1:1 allocation), in maintaining sustained remission over 12 months follow-up, in patients with difficult-to-treat steroid-sensitive nephrotic syndrome, defined as frequently relapsing or steroid-dependent disease that had failed ≥ 2 steroid-sparing strategies. Secondary outcomes included frequency of relapses, proportion with frequent relapses, time to relapse and frequent relapses, and adverse events (CTRI/2018/11/016342).

RESULTS

Baseline characteristics were comparable for 41 patients randomized to receive rituximab (n = 21) or tacrolimus (n = 20). While 55% of patients in each limb were in sustained remission at 1 year, non-inferiority of rituximab to tacrolimus was not demonstrated (mean difference 0%; 95% CI - 30.8%, 30.8%; non-inferiority limit - 20%; P = 0.50). Frequent relapses were more common in patients administered rituximab compared to tacrolimus (risk difference 30%, 95% CI 7.0, 53.0, P = 0.023). Both groups showed similar reductions in relapse rates and prednisolone use. Common adverse events were infusion-related with rituximab and gastrointestinal symptoms with tacrolimus.

CONCLUSIONS

Therapy with rituximab was not shown to be non-inferior to 12-months treatment with tacrolimus in maintaining remission in patients with difficult-to-treat steroid-sensitive nephrotic syndrome. Frequent relapses were more common with rituximab. While effective, both agents require close monitoring for adverse events. A higher resolution version of the Graphical abstract is available as Supplementary information.

Randomised controlled trial comparing rituximab to mycophenolate mofetil in children and young adults with steroid-dependent idiopathic nephrotic syndrome: study protocol

INTRODUCTION

Glucocorticoids induce remission in 90% of children with idiopathic nephrotic syndrome (INS). Some become steroid-dependent (SD) and require the addition of steroid sparing drugs such as calcineurin-inhibitors (CNI) or cyclophosphamide, to maintain remission. Considering the toxicity of these drugs, alternative interventions are needed for long-term treatment. The anti-CD20 antibody rituximab has shown promising steroid-sparing properties, with conflicting results in complicated forms of SD-INS. Mycophenolate mofetil (MMF) resulted effective in maintaining free-steroid remission, however, studies are limited to few uncontrolled trials with reported different dose of MMF.

METHODS AND ANALYSIS

This open-label, two-parallel-arm, superiority controlled randomised clinical trial will enrol children with SD-INS maintained in remission with oral glucocorticoids or CNI. Children and young adults will be randomised to either MMF (1.200 mg/m²) or rituximab (375 mg/m²) infusion. After enrolment, glucocorticoids will be tapered until complete withdrawal. We will enrol 160 children and young adults to detect as significant at the two-sided p value of 0.01 with a power >0.8 a reduction in the risk of 1-year relapse (primary end-point). As secondary endpoints, we will compare the amount of glucocorticoids required to maintain complete remission at 6 and 24 months.

ETHICS AND DISSEMINATION

The trial was approved by the local ethics boards (Comitato Etico Regione Liguria CER Liguria https://www.portalericerca-liguria.it/). We will publish the study results at international scientific meetings.

TRIAL REGISTRATION NUMBERS

NCT004585152.

Recent Advances in Therapeutic Drug Monitoring of Voriconazole, Mycophenolic Acid, and Vancomycin: A Literature Review of Pediatric Studies

The review includes studies dated 2011-2021 presenting the newest information on voriconazole (VCZ), mycophenolic acid (MPA), and vancomycin (VAN) therapeutic drug monitoring (TDM) in children. The need of TDM in pediatric patients has been emphasized by providing the information on the differences in the drugs pharmacokinetics. TDM of VCZ should be mandatory for all pediatric patients with invasive fungal infections (IFIs). Wide inter- and intrapatient variability in VCZ pharmacokinetics cause achieving and maintaining therapeutic concentration during therapy challenging in this population. Demonstrated studies showed, in most cases, VCZ plasma concentrations to be subtherapeutic, despite the updated dosages recommendations. Only repeated TDM can predict drug exposure and individualizing dosing in antifungal therapy in children. In children treated with mycophenolate mofetil (MMF), similarly as in adult patients, the role of TDM for MMF active form, MPA, has not been well established and is undergoing continued debate. Studies on the MPA TDM have been carried out in children after renal transplantation, other organ transplantation such as heart, liver, or intestine, in children after hematopoietic stem cell transplantation or cord blood transplantation, and in children with lupus, nephrotic syndrome, Henoch-Schönlein purpura, and other autoimmune diseases. MPA TDM is based on the area under the concentration-time curve; however, the proposed values differ according to the treatment indication, and other approaches such as pharmacodynamic and pharmacogenetic biomarkers have been proposed. VAN is a bactericidal agent that requires TDM to prevent an acute kidney disease. The particular group of patients is the pediatric one. For this group, the general recommendations of the dosing may not be valid due to the change of the elimination rate and volume of distribution between the subjects. The other factor is the variability among patients that concerns the free fraction of the drug. It may be caused by both the patients' population and sample preconditioning. Although VCZ, MMF, and VAN have been applied in pediatric patients for many years, there are still few issues to be solve regarding TDM of these drugs to ensure safe and effective treatment. Except for pharmacokinetic approach, pharmacodynamics and pharmacogenetics have been more often proposed for TDM.

A Systematic Review of Multiple Linear Regression-Based Limited Sampling Strategies for Mycophenolic Acid Area Under the Concentration-Time Curve Estimation

Background and Objective

One approach of therapeutic drug monitoring in the case of mycophenolic acid (MPA) is a limited sampling strategy (LSS), which allows the evaluation of the area under the concentration–time curve (AUC) based on few concentrations. The aim of this systematic review was to review the MPA LSSs and define the most frequent time points for MPA determination in patients with different indications for mycophenolate mofetil (MMF) administration.

Methods

The literature was comprehensively searched in July 2021 using PubMed, Scopus, and Medline databases. Original articles determining multiple linear regression (MLR)-based LSSs for MPA and its free form (fMPA) were included. Studies on enteric-coated mycophenolic sodium, previously established LSS, Bayesian estimator, and different than twice a day dosing were excluded. Data were analyzed separately for (1) adult renal transplant recipients, (2) adults with other than renal transplantation indication, and (3) for pediatric patients.

Results

A total of 27, 17, and 11 studies were found for groups 1, 2, and 3, respectively, and 126 MLR-based LSS formulae (n = 120 for MPA, n = 6 for fMPA) were included in the review. Three time-point equations were the most frequent. Four MPA LSSs: 2.8401 + 5.7435 × C0 + 0.2655 × C0.5 + 1.1546 × C1 + 2.8971 × C4 for adult renal transplant recipients, 1.783 + 1.248 × C1 + 0.888 × C2 + 8.027 × C4 for adults after islet transplantation, 0.10 + 11.15 × C0 + 0.42 × C1 + 2.80 × C2 for adults after heart transplantation, and 8.217 + 3.163 × C0 + 0.994 × C1 + 1.334 × C2 + 4.183 × C4 for pediatric renal transplant recipients, plus one fMPA LSS, 34.2 + 1.12 × C1 + 1.29 × C2 + 2.28 × C4 + 3.95 × C6 for adult liver transplant recipients, seemed to be the most promising and should be validated in independent patient groups before introduction into clinical practice. The LSSs for pediatric patients were few and not fully characterized. There were only a few fMPA LSSs although fMPA is a pharmacologically active form of the drug.

Conclusions

The review includes updated MPA LSSs, e.g., for different MPA formulations (suspension, dispersible tablets), generic form, and intravenous administration for adult and pediatric patients, and emphasizes the need of individual therapeutic approaches according to MMF indication. Five MLR-based MPA LSSs might be implemented into clinical practice after evaluation in independent groups of patients. Further studies are required, e.g., to establish fMPA LSS in pediatric patients.

The Evaluation of Multiple Linear Regression-Based Limited Sampling Strategies for Mycophenolic Acid in Children with Nephrotic Syndrome

We evaluated mycophenolic acid (MPA) limited sampling strategies (LSSs) established using multiple linear regression (MLR) in children with nephrotic syndrome treated with mycophenolate mofetil (MMF). MLR-LSS is an easy-to-determine approach of therapeutic drug monitoring (TDM). We assessed the practicability of different LSSs for the estimation of MPA exposure as well as the optimal time points for MPA TDM. The literature search returned 29 studies dated 1998–2020. We applied 53 LSSs (n = 48 for MPA, n = 5 for free MPA [fMPA]) to predict the area under the time-concentration curve (AUC_pred) in 24 children with nephrotic syndrome, for whom we previously determined MPA and fMPA concentrations, and compare the results with the determined AUC (AUC_total). Nine equations met the requirements for bias and precision ±15%. The MPA AUC in children with nephrotic syndrome was predicted the best by four time-point LSSs developed for renal transplant recipients. Out of five LSSs evaluated for fMPA, none fulfilled the ±15% criteria for bias and precision probably due to very high percentage of bound MPA (99.64%). MPA LSS for children with nephrotic syndrome should include blood samples collected 1 h, 2 h and near the second MPA maximum concentration. MPA concentrations determined with the high performance liquid chromatography after multiplying by 1.175 may be used in LSSs based on MPA concentrations determined with the immunoassay technique. MPA LSS may facilitate TDM in the case of MMF, however, more studies on fMPA LSS are required for children with nephrotic syndrome.

Mycophenolate Mofetil in the Treatment of Steroid-Dependent or Frequently Relapsing Nephrotic Syndrome in Children: A Meta-Analysis

Objectives: This meta-analysis aims to evaluate the efficacy and safety of the mycophenolate mofetil (MMF) in the treatment of steroid-dependent nephrotic syndrome (SDNS) or frequently relapsing nephrotic syndrome (FRNS) in children. Methods: We searched for the studies especially the randomized controlled trials in PubMed, Cochrane Library, Embase, China National Knowledge Infrastructure, and Wan Fang database. The data were analyzed by Review Manager 5.3 software. We used the GRADE pro-Guideline Development Tool online software to evaluate the quality of evidence. Results: Finally, we identified 620 studies, of which we included five randomized controlled trials and one prospective cohort study with 447 children. The results showed the following: (1) the relapse-free survival rate within 1 year-the MMF group was superior to the levamisole group [ratio difference (RD) = 0.13, 95% CI (0.02, 0.24), P = 0.02] but not to the calcineurin inhibitors (CNIs) group [RD = -0.27, 95%CI (-0.40, -0.14), P < 0.0001]; (2) the number of relapses within 1 year-the MMF group was less than that in the CNIs and levamisole group [mean difference (MD) = -0.26, 95%CI (-0.45, -0.08), P = 0.005]; (3) the cumulative prednisone dosage-the MMF group was lower than that in the control group [standardized mean difference (SMD) = -0.32, 95%CI (-0.53, -0.11), P = 0.003]; (4) incidence of adverse reactions-there was no significant difference between the MMF group and the control group [RD = 0.02, 95%CI (-0.04, 0.09), P = 0.46]. Conclusion: The therapy of mycophenolate mofetil in the treatment of SDNS or FRNS in children has a certain advantage in reducing the number of relapses and cumulative prednisone dosage within 1 year when compared with the CNIs and levamisole. However, due to the limited quantity and quality of the included studies, the conclusions above need to be confirmed by more high-quality randomized controlled trials.

Rituximab vs Low-Dose Mycophenolate Mofetil in Recurrence of Steroid-Dependent Nephrotic Syndrome in Children and Young Adults: A Randomized Clinical Trial

This randomized clinical trial examines the superiority of a single dose of rituximab vs low-dose mycophenolate mofetil in preventing the recurrence of steroid-dependent nephrotic syndrome in children and young adults.

Steroid Sensitive Nephrotic Syndrome: Revised Guidelines

JUSTIFICATION

Steroid sensitive nephrotic syndrome (SSNS) is one of the most common chronic kidney diseases in children. These guidelines update the existing Indian Society of Pediatric Nephrology recommendations on its management.

OBJECTIVE

To frame revised guidelines on diagnosis, evaluation, management and supportive care of patients with the illness.

PROCESS

The guidelines combine evidence-based recommendations and expert opinion. Formulation of key questions was followed by review of literature and evaluation of evidence by experts in two face-to-face meetings.

RECOMMENDATIONS

The initial statements provide advice for evaluation at onset and follow up and indications for kidney biopsy. Subsequent statements provide recommendations for management of the first episode of illness and of disease relapses. Recommendations on the use of immunosuppressive strategies in patients with frequent relapses and steroid dependence are accompanied by suggestions for step-wise approach and plan of monitoring. Guidance is also provided regarding the management of common complications including edema, hypovolemia and serious infections. Advice on immunization and transition of care is given. The revised guideline is intended to improve the management and outcomes of patients with SSNS, and provide directions for future research.

Predictors of poor kidney outcome in children with C3 glomerulopathy

BACKGROUND

C3 glomerulopathy (C3G) is characterized by heterogeneous clinical presentation, outcome, and predominant C3 accumulation in glomeruli without significant IgG. There is scarce outcome data regarding childhood C3G. We describe clinical and pathological features, treatment and outcomes, and risk factors for progression to chronic kidney disease stage 5 (CKD5) in the largest pediatric series with biopsy-proven C3G.

METHODS

Sixty pediatric patients with C3G from 21 referral centers in Turkey were included in this retrospective study. Patients were categorized according to CKD stage at last visit as CKD5 or non-CKD5. Demographic data, clinicopathologic findings, treatment, and outcome data were compared and possible risk factors for CKD5 progression determined using Cox proportional hazards model.

RESULTS

Mean age at diagnosis was 10.6 ± 3.0 years and follow-up time 48.3 ± 36.3 months. Almost half the patients had gross hematuria and hypertension at diagnosis. Nephritic-nephrotic syndrome was the commonest presenting feature (41.6%) and 1/5 of patients presented with nephrotic syndrome. Membranoproliferative glomerulonephritis was the leading injury pattern, while 40 patients had only C3 staining. Patients with DDD had significantly lower baseline serum albumin compared with C3GN. Eighteen patients received eculizumab. Clinical remission was achieved in 68.3%. At last follow-up, 10 patients (16.6%) developed CKD5: they had lower baseline eGFR and albumin and higher frequency of nephrotic syndrome and dialysis requirement than non-CKD5 patients. Lower serum albumin and eGFR at diagnosis were independent predictors for CKD5 development.

CONCLUSIONS

Children with C3G who have impaired kidney function and hypoalbuminemia at diagnosis should be carefully monitored for risk of progression to CKD5. Graphical abstract.

Personalized Therapy for Mycophenolate: Consensus Report by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology

ABSTRACT

When mycophenolic acid (MPA) was originally marketed for immunosuppressive therapy, fixed doses were recommended by the manufacturer. Awareness of the potential for a more personalized dosing has led to development of methods to estimate MPA area under the curve based on the measurement of drug concentrations in only a few samples. This approach is feasible in the clinical routine and has proven successful in terms of correlation with outcome. However, the search for superior correlates has continued, and numerous studies in search of biomarkers that could better predict the perfect dosage for the individual patient have been published. As it was considered timely for an updated and comprehensive presentation of consensus on the status for personalized treatment with MPA, this report was prepared following an initiative from members of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT). Topics included are the criteria for analytics, methods to estimate exposure including pharmacometrics, the potential influence of pharmacogenetics, development of biomarkers, and the practical aspects of implementation of target concentration intervention. For selected topics with sufficient evidence, such as the application of limited sampling strategies for MPA area under the curve, graded recommendations on target ranges are presented. To provide a comprehensive review, this report also includes updates on the status of potential biomarkers including those which may be promising but with a low level of evidence. In view of the fact that there are very few new immunosuppressive drugs under development for the transplant field, it is likely that MPA will continue to be prescribed on a large scale in the upcoming years. Discontinuation of therapy due to adverse effects is relatively common, increasing the risk for late rejections, which may contribute to graft loss. Therefore, the continued search for innovative methods to better personalize MPA dosage is warranted.

Steroid Sensitive Nephrotic Syndrome: Revised Guidelines

Justification

Steroid sensitive nephrotic syndrome (SSNS) is one of the most common chronic kidney diseases in children. These guidelines update the existing Indian Society of Pediatric Nephrology recommendations on its management.

Objective

To frame revised guidelines on diagnosis, evaluation, management and supportive care of patients with the illness.

Process

The guidelines combine evidence-based recommendations and expert opinion. Formulation of key questions was followed by review of literature and evaluation of evidence by experts in two face-to-face meetings.

Recommendations

The initial statements provide advice for evaluation at onset and follow up and indications for kidney biopsy. Subsequent statements provide recommendations for management of the first episode of illness and of disease relapses. Recommendations on the use of immunosuppressive strategies in patients with frequent relapses and steroid dependence are accompanied by suggestions for step-wise approach and plan of monitoring. Guidance is also provided regarding the management of common complications including edema, hypovolemia and serious infections. Advice on immunization and transition of care is given. The revised guideline is intended to improve the management and outcomes of patients with SSNS, and provide directions for future research.

Polysaccharide mycophenolate-based nanoparticles for enhanced immunosuppression and treatment of immune-mediated inflammatory diseases

Immune-mediated inflammatory diseases (IMIDs) are characterized by immune dysregulation and severe inflammation caused by the aberrant and overactive host immunological response. Mycophenolic acid (MPA)-based immunosuppressive drugs are potential treatments for IMIDs because of their mild side-effect profile; however, their therapeutic effects are limited by the high albumin binding rate, unsatisfactory pharmacokinetics, and undefined cellular uptake selectivity.

Methods: Polysaccharide mycophenolate was synthesized by conjugating MPA molecules to dextran (a typical polysaccharide widely used in drug delivery) and encapsulated extra free MPA molecules to fabricate MPA@Dex-MPA nanoparticles (NPs). The efficacy of these NPs for mediating immunosuppression and treatment of IMIDs was evaluated in imiquimod-induced psoriasis-like skin inflammation in Balb/c mice, a representative IMID model.

Results: The MPA@Dex-MPA NPs exhibited high MPA loading efficiency, low albumin binding rates, and sustained MPA release, resulting in improved pharmacokinetics in vivo. Compared to free MPA, MPA@Dex-MPA NPs induced more robust therapeutic effects on IMIDs. Mechanistic studies indicated that MPA@Dex-MPA NPs were primarily distributed in dendritic cells (DCs) and significantly suppressed the overactivated DCs in vivo and in vitro. Furthermore, the recovered DCs rehabilitated the IL-23/Th17 axis function and significantly ameliorated imiquimod-induced psoriasis-like skin inflammation. Importantly, MPA@Dex-MPA NPs showed favorable safety and biocompatibility in vivo.

Conclusion: Our results indicated the polysaccharide mycophenolate-based NPs to be highly promising for IMID treatment.

A global antiB cell strategy combining obinutuzumab and daratumumab in severe pediatric nephrotic syndrome

BACKGROUND

Steroid-sensitive nephrotic syndrome (SSNS) is, in most patients, a chronic disease with 80% experiencing at least one relapse after first flare. B cell depletion using rituximab is effective in preventing relapse in steroid-dependent (SDNS) patients but fails to maintain long-term remission following B cell recovery, possibly due to development of autoreactive long-lived plasma cells. We investigated sequential combination of antiCD20 antibody targeting all B cell subsets, and antiCD38 antibody with high plasma cell cytotoxicity in patients with uncontrolled SDNS after failure of one or several attempts at B cell depletion.

METHODS

Fourteen patients with median disease duration 7.8 years received 1000 mg/1.73 m² obinutuzumab followed by 1000 mg/1.73 m² daratumumab 2 weeks later. Oral immunosuppression was discontinued within 6 weeks, and biological monitoring performed monthly until B cell recovery.

RESULTS

Median age at treatment was 11.0 [IQR 10.4-14.4] years. B cell depletion was achieved in all patients, and B cell reconstitution occurred in all at median 9.5 months after obinutuzumab injection. After median follow-up 20.3 months (IQR 11.5-22.6), 5/14 patients relapsed including 4 within 100 days following B cell repletion. Relapse-free survival was 60% at 24 months from obinutuzumab infusion. Mild infusion reactions were reported in 3/14 patients during obinutuzumab and 4/14 during daratumumab infusions. Mild transient neutropenia (500-1000/mm³) occurred in 2/14 patients. Intravenous immunoglobulins were given to 12/14 patients due to hypogammaglobulinemia. Low IgA and IgM levels were noted in 8 and 14 patients, respectively. No severe infection was reported.

CONCLUSION

Global antiB cell strategy combining obinutuzumab and daratumumab induces prolonged peripheral B cell depletion and remission in children with difficult-to-treat SDNS.

Current understandings in treating children with steroid-resistant nephrotic syndrome

Steroid-resistant nephrotic syndrome (SRNS) remains a challenge for paediatric nephrologists. SRNS is viewed as a heterogeneous disease entity including immune-based and monogenic aetiologies. Because SRNS is rare, treatment strategies are individualized and vary among centres of expertise. Calcineurin inhibitors (CNI) have been effectively used to induce remission in patients with immune-based SRNS; however, there is still no consensus on treating children who become either CNI-dependent or CNI-resistant. Rituximab is a steroid-sparing agent for patients with steroid-sensitive nephrotic syndrome, but its efficacy in SRNS is controversial. Recently, several novel monoclonal antibodies are emerging as treatment option, but their efficacy remains to be seen. Non-immune therapies, such as angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, have been proven efficacious in children with SRNS and are recommended as adjuvant agents. This review summarizes and discusses our current understandings in treating children with idiopathic SRNS.

Pediatric idiopathic steroid-sensitive nephrotic syndrome: diagnosis and therapy -short version of the updated German best practice guideline (S2e) - AWMF register no. 166-001, 6/2020

Idiopathic nephrotic syndrome is the most frequent glomerular disease in children in most parts of the world. Children with steroid-sensitive nephrotic syndrome (SSNS) generally have a good prognosis regarding the maintenance of normal kidney function even in the case of frequent relapses. The course of SSNS is often complicated by a high rate of relapses and the associated side effects of repeated glucocorticoid (steroid) therapy. The following recommendations for the treatment of SSNS are based on the comprehensive consideration of published evidence by a working group of the German Society for Pediatric Nephrology (GPN) based on the systematic Cochrane reviews on SSNS and the guidelines of the KDIGO working group (Kidney Disease - Improving Global Outcomes).

Autoimmunity in Focal Segmental Glomerulosclerosis: A Long-Standing Yet Elusive Association

Focal segmental glomerulosclerosis (FSGS) is a histological term that describes a pathologic renal entity affecting both adults and children, with a wide array of possible underlying etiologies. Podocyte damage with scarring, the hallmark of this condition, leads to altered permeability of the glomerular barrier, which may result in massive proteinuria and relentless renal function deterioration. A definite cause of focal segmental glomerulosclerosis can be confirmed in a minority of cases, while most forms have been traditionally labeled as primary or idiopathic. Despite this definition, increasing evidence indicates that primary forms are a heterogenous group rather than a single disease entity: several circulating factors that may affect glomerular permeability have been proposed as potential culprits, and both humoral and cellular immunity have been implicated in the pathogenesis of the disease. Consistently, immunosuppressive drugs are considered as the cornerstone of treatment for primary focal segmental glomerulosclerosis, but response to these agents and long-term outcomes are highly variable. In this review we provide a summary of historical and recent advances on the pathogenesis of primary focal segmental glomerulosclerosis, focusing on implications for its differential diagnosis and treatment.

Therapeutic drug monitoring of mycophenolate mofetil in pediatric patients: novel techniques and current opinion

Introduction: Mycophenolate mofetil (MMF) is an ester prodrug of the immunosuppressant mycophenolic acid (MPA) and is recommended and widely used for maintenance immunosuppressive therapy in solid organ and stem-cell transplantation as well as in immunological kidney diseases. MPA is a potent, reversible, noncompetitive inhibitor of the inosine monophosphate dehydrogenase (IMPDH), a crucial enzyme in the de novo purine synthesis in T- and B-lymphocytes, thereby inhibiting cell-mediated immunity and antibody formation. The use of therapeutic drug monitoring (TDM) of MMF is still controversial as outcome data of clinical trials are equivocal. Areas covered: This review covers in great depth the existing literature on TDM of MMF in the field of pediatric (kidney) transplantation. In addition, the relevance of TDM in immunological kidney diseases, in particular childhood nephrotic syndrome is highlighted. Expert opinion: TDM of MMF has the potential to optimize therapy in pediatric transplantation as well as in nephrotic syndrome. Limited sampling strategies to estimate MPA exposure increase its feasibility. Future perspectives rather encompass approaches reflecting total immunosuppressive load than single drug TDM.

Thrombotic thrombocytopenic purpura and defective apoptosis due to CASP8/10 mutations: the role of mycophenolate mofetil

Immunological dysregulation may underlie unusual autoimmune diseases, which also deserve to be investigated from a genetic point of view.

Generation and Validation of a Limited Sampling Strategy to Monitor Mycophenolic Acid Exposure in Children With Nephrotic Syndrome

BACKGROUND

Mycophenolate mofetil (MMF) plays an increasingly important role in the treatment of children with nephrotic syndrome, especially in steroid sparing protocols. Recent publications show the relationship of exposure to its active moiety mycophenolic acid (MPA) and clinical efficacy. Performance of full-time pharmacokinetic (PK) profiles, however, is inconvenient and laborious. Established limited sampling strategies (LSS) to estimate the area under the concentration (AUC) versus time curve of MPA (MPA-AUC) in pediatric renal transplant recipients cannot be easily transferred to children suffering from nephrotic syndrome, mainly because of the lack of concomitant immunosuppressive therapy. We therefore aimed for the generation and validation of a LSS to estimate MPA exposure to facilitate therapeutic drug monitoring in children with nephrotic syndrome.

METHODS

We performed 27 complete PK profiles in 23 children in remission [mean age (±SD):12.3 ± 4.26 years] to generate and validate an LSS. Sampling time points were before administration (C0) and 0.5, 1, 1.5, 2, 4, 6, 8, and 12 hours after the administration of MMF. MPA was measured by enzyme multiplied immunoassay technique. There was no concomitant treatment with calcineurin inhibitors.

RESULTS

Mean daily dose of MMF was 927 ± 209 mg/m of body surface area resulting in a mean MPA-AUC0-12 value of 59.2 ± 29.3 mg × h/L and a predose level of 3.03 ± 2.24 mg/L. Between-patient variability of dose-normalized MPA-AUC0-12 was high (coefficient of variation: 45.5%). Correlation of predose levels with the corresponding MPA-AUC0-12 was moderate (r = 0.59) in a subgroup of 18 patients (20 PK profiles, generation group). An algorithm based on 3 PK sampling time points during the first 2 hours after MMF dosing (estimated AUC0-12 = 8.7 + 4.63 × C0 + 1.90 × C1 + 1.52 × C2) was able to predict MPA-AUC with a low percentage prediction error (3.88%) and a good correlation of determination (r = 0.90). Validation of this algorithm in a randomized separate group of 6 patients (7 PK profiles, validation group) resulted in comparably good correlation (r = 0.95) and low percentage prediction error (5.57%).

CONCLUSIONS

An abbreviated profile within the first 2 hours after MMF dosing gives a good estimate of MPA exposure in children with nephrotic syndrome and hence has the potential to optimize MMF therapy.

Podocytopathies

Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-resistant nephrotic syndrome

Idiopathic nephrotic syndrome newly affects 1-3 per 100,000 children per year. Approximately 85% of cases show complete remission of proteinuria following glucocorticoid treatment. Patients who do not achieve complete remission within 4-6 weeks of glucocorticoid treatment have steroid-resistant nephrotic syndrome (SRNS). In 10-30% of steroid-resistant patients, mutations in podocyte-associated genes can be detected, whereas an undefined circulating factor of immune origin is assumed in the remaining ones. Diagnosis and management of SRNS is a great challenge due to its heterogeneous etiology, frequent lack of remission by further immunosuppressive treatment, and severe complications including the development of end-stage kidney disease and recurrence after renal transplantation. A team of experts including pediatric nephrologists and renal geneticists from the International Pediatric Nephrology Association (IPNA), a renal pathologist, and an adult nephrologist have now developed comprehensive clinical practice recommendations on the diagnosis and management of SRNS in children. The team performed a systematic literature review on 9 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, formulated recommendations and formally graded them at a consensus meeting, with input from patient representatives and a dietician acting as external advisors and a voting panel of pediatric nephrologists. Research recommendations are also given.

Rituximab in maintaining remission in adults with podocytopathy

Rituximab is currently used after the conventional agents have failed in the management of steroid-dependent (SD)/ steroid-resistant (SR) podocytopathies and have a safer toxicity profile. We report 53 adults with podocytopathies who were managed effectively with CD19-targeted rituximab therapy.

METHODS

This was a prospective study carried out at a tertiary care centre in India between January 2014 and June 2019. Adults between 16 and 60 years with SD, frequently relapsing (FR), and SR nephrotic syndrome (NS) due to podocytopathy received rituximab in a CD19-targeted approach.

PRIMARY OUTCOME

Percentage of patients who were in remission at 6 and 12 months. Secondary outcome: Percentage of patients in remission at the last follow-up, rituximab dose and adverse events of rituximab therapy.

RESULTS

Fifty-three adults with SD/FR/SR NS received CD19-targeted rituximab. The median age at the time of first rituximab injection was 30.09 ± 13.21 (16.53) years. At the time of first rituximab infusion, all patients were in remission with steroids and/or calcineurin inhibitors (CNIs). Fifty (94.33%) patients were in remission at the end of 6 and 12 months and the last follow-up (median: 36 months). The mean total dose of rituximab at 1 year was 788.7 ± 128.1 (6 001 100) mg. At last follow-up (median 36 months), 42 (79%) patients did not require any additional CNI or steroids therapy. No serious adverse events to rituximab were noted.

CONCLUSION

CD19-targeted rituximab therapy is safe and efficacious in the management of SD/SR adult podocytopathy. Also, rituximab is effective in maintaining remission in treatment naïve adult SD or FR podocytopathy.