Mycophenolate mofetil for steroid-dependent nephrotic syndrome: a phase II Bayesian trial

Efficacy of Mycophenolate in Steroid-Dependent and Frequently Relapsing Adult Minimal Change Disease: A Retrospective Cohort Study

Background Just like in the pediatric population, minimal change disease (MCD) in adults is characterized by a high relapse rate following steroid therapy. A significant proportion of these patients become either frequent relapsers or steroid-dependent (SD). These SD or frequently relapsing (FR) adult MCD cases require additional forms of immunosuppressive therapy to avoid steroid-related adverse effects. Aim The primary objective of this study was to evaluate the efficacy of mycophenolate (MF) in maintaining complete remission in adult MCD patients with steroid dependence or frequent relapses. The secondary objective was to assess the safety and long-term outcomes of MF therapy in this patient population. Methods This retrospective cohort study included all adult biopsy-proven FR/SD MCD cases who were prescribed MF therapy during period of January 2018 till May 2024. MF drug was prescribed for 12 months duration in MF-responsive patients. After extracting baseline demographic data, these patients were retrospectively followed up to assess induction of remission and maintenance of remission after discontinuation of MF therapy. Results In the present study, 24 adult FR/SD nephrotic syndrome cases were included for analysis. MF therapy was able to maintain steroid-free remission for the whole duration of therapy (12 months) in 20 (83.3%) patients. Four patients were non-responsive to MF therapy and relapsed once steroids were withdrawn despite patients being on full dose of MF. Among 20 MF-responsive patients, there was no relapse of nephrotic syndrome in 14 (70%) patients (sustained remission) till the last follow-up, with a mean duration of 18.78±8.07 months. In six (30%) cases, there was a relapse of nephrotic syndrome after MF drug was stopped, with a mean interval of 10.16±3.65 months. Conclusions Our study concludes that MF is effective in steroid-sparing in adult FR/SD MCD patients. The MF-based therapy was able to maintain complete remission in 83.3% cases for the whole duration of therapy. Moreover, in 70% of 20 MF responsive patients, the 12 months of MF therapy achieved sustained remission till the last follow-up.

Long-term obesity prevalence and linear growth in children with idiopathic nephrotic syndrome: is normal growth and weight control possible with steroid-sparing drugs and low-dose steroids for relapses?

BACKGROUND

Long-term steroid treatment in children is known to cause obesity and negatively affect growth. The objective of this study was to determine the prevalence of obesity and overweight and analyze linear growth in children with nephrotic syndrome.

METHODS

The study involved 265 children treated with glucocorticoids for nephrotic syndrome for a mean duration of 43 months (range: 6-167, IQR: 17, 63.3). Height, weight, and BMI SDS were recorded at each visit. Rate of change between the final and initial height, weight, and BMI was calculated (Δ score). The cumulative steroid dose (mg/kg/day) during follow-up was calculated. Relapses without significant edema were treated with low-dose steroids and steroid-sparing drugs were used in children with steroid dependency/frequent relapses.

RESULTS

Mean first BMI SDS was + 1.40 ± 1.30 and final + 0.79 ± 1.30. At initial assessment, 41.4% of the patients were obese (BMI ≥ 95^th percentile) and 19.5% were overweight (BMI 85^th-95^th percentile). At the last clinical visit, 24% were obese and 17% overweight. The children had lower BMI SDS at last clinical visit compared to initial assessment. Mean first height SDS of the cohort was - 0.11 ± 1.22 and final score 0.078 ± 1.14 (p < 0.0001). Almost 85% of patients were treated with steroid-sparing drugs.

CONCLUSIONS

Our results indicate that children with nephrotic syndrome, despite a need for steroid treatment for active disease, can improve their obesity and overweight and also improve their linear growth from their first to last visit with us.

Nephrotic Syndrome

Nephrotic syndrome (NS) encompasses a variety of disease processes leading to heavy proteinuria and edema. Minimal change disease (MCD) remains the most common primary cause of NS, as well as the most responsive to pharmacologic treatment with often minimal to no chronic kidney disease. Other causes of NS include focal segmental glomerulosclerosis, which follows MCD, and secondary causes, including extrarenal or systemic diseases, infections, and drugs. Although initial diagnosis relies on clinical findings as well as urine and blood chemistries, renal biopsy and genetic testing are important diagnostic tools, especially when considering non-MCD NS. Moreover, biomarkers in urine and serum have become important areas for research in this disease. NS progression and prognosis are variable and depend on etiology, with corticosteroids being the mainstay of treatment. Other alternative therapies found to be successful in inducing and maintaining remission include calcineurin inhibitors and rituximab. Disease course can range from recurrent disease relapse with or without acute kidney injury to end-stage renal disease in some cases. Given the complex pathogenesis of NS, which remains incompletely understood, complications are numerous and diverse and include infections, electrolyte abnormalities, acute kidney injury, and thrombosis. Pediatricians must be aware of the presentation, complications, and overall long-term implications of NS and its treatment.

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.

The safety and efficacy of mycophenolate mofetil in children and adolescents with steroid-dependent nephrotic syndrome: a single-centre study

Background

Steroid-dependent nephrotic syndrome (SDNS) patients experience frequent relapse or adverse effects on long-term treatment with steroids or cyclophosphamide. This study assessed the efficacy and side effect profile of mycophenolate mofetil (MMF) therapy in children with nephrotic syndrome in our population.

Methods

A retrospective study was performed on children with SDNS who were on MMF therapy for a minimum period of 1 year, and were on regular follow-up in the Department of Nephrology at the Institute of Child Health and hospital for children attached to Madras Medical College.

Results

The study included 87 patients, with a male:female ratio of 2:1. The median age at diagnosis of nephrotic syndrome was 3 years [95% confidence interval (CI): 1–8 years], which was found to be a statistically significant risk factor for MMF failure. The median duration of follow-up after initiation of MMF therapy was 3 years and 3 months (95% CI: 1 year and 3 months to 6 years and 6 months). At initial evaluation, 31 (36%) patients presented with SDNS while the remaining had frequently relapsing nephrotic syndrome progressing to SDNS. Intravenous cyclophosphamide was used as first-line therapy in 82 patients, of whom 24 patients had persistent proteinuria while the remaining 58 had attained remission for a median duration of 6 months. The median duration of treatment with MMF was 2 years and 6 months (95% CI: 1 year and 3 months to 4 years and 6 months). MMF was used at a mean dose of 28.5 mg/kg. Seventy-two (83%) patients were MMF-sensitive, and these patients had a reduction in mean prednisolone dose from 1.28 to 0.35 mg/kg (P < 0.05). Among the MMF-sensitive patients, 31 had stopped MMF after a minimum period of 2 years, following which they had a median remission period of 5 months (95% CI: 1–8 months). MMF failure occurred in 15 (17%) patients. Adverse events were documented in 19 (22%) patients.

Conclusions

Continuous MMF therapy achieved remission in 83% of patients. MMF was well tolerated in the study population and discontinuation of MMF resulted in 100% relapse.

Long-term outcome of Japanese children with complicated minimal change nephrotic syndrome treated with mycophenolate mofetil after cyclosporine

BACKGROUND

Although recent studies have shown that more than half of children with steroid-dependent nephrotic syndrome (SDNS) may continue to have active disease beyond childhood, the long-term outcome in this cohort treated with mycophenolate mofetil (MMF) after cyclosporine remains unknown, particularly in adulthood.

METHODS

We conducted a retrospective study of 44 adult patients (median age, 22.3 years) who received MMF for complicated SDNS (median age at MMF initiation, 13.3 years) at a single center. Complicated SDNS was defined as the case continuing to relapse after cyclosporine (CsA) treatment. When patients experienced relapses despite MMF initiation, they additionally received a rituximab infusion. The primary endpoint was the probability of achieving treatment-free remission for > 2 years.

RESULTS

Prior to MMF initiation, all patients received CsA for a median of 46 months and 19 received the 12-week cyclophosphamide. After switching from CsA to MMF, only four patients did not relapse during a median follow-up period of 9.6 years. At the last visit, only 15 of the 44 patients achieved treatment-free sustained remission. Multivariate analysis revealed that young age (< 6 years) at onset of nephrotic syndrome (odds ratio, 11.3) and the experience of steroid dependency during initial CsA treatment (odds ratio, 29.8) were the independent risk factors of active disease into adulthood after MMF initiation.

CONCLUSIONS

Although none developed renal insufficiency and severe adverse effects of therapy, the introduction of MMF after CsA treatment may not be necessarily associated with improved long-term outcome of children with complicated SDNS.

Randomized controlled trial on immunomodulatory effects of azithromycin in children with steroid-dependent nephrotic syndrome

BACKGROUND

Azithromycin (AZM) is a macrolide antibiotic with anti-inflammatory and immunomodulatory effects. Our aim was to compare the immunomodulatory effects of AZM combined with steroid therapy with that of steroid therapy alone in children with steroid-dependent nephrotic syndrome (SDNS).

METHODS

We enrolled 57 patients with SDNS in a multicenter randomized control trial. Patients were classified into two groups: group A (intervention group, N = 29) and group B (control group, N = 28). After achievement of remission with full-dose daily prednisone, patients in group A received AZM in conjunction with steroids which was tapered gradually, while patients in group B received steroids alone. Urine protein creatinine ratio (uPCR) and TNF-α were measured at different points of follow-up throughout the study period (5 months after achieving remission).

RESULTS

After achievement of remission by full-dose steroids, there were significant differences of TNF-α between the two groups after 1-, 3- and 5-month follow-up (p < 0.001, 0.003, and 0.001, respectively). Also, there was significant difference of TNF-α in both intervention and control groups after exclusion of the relapsed cases at 3- and 5-month follow-up (, p = 0.031 and p = 0.003, respectively). There was significant difference between both groups after 5-month follow-up as regards the number of relapsed patients (group A = 4, group B = 11, p = 0.015).

CONCLUSION

AZM was capable of reducing serum TNF-α which is one of the inflammatory cytokines implicated in the pathogenesis of NS.

Treating the idiopathic nephrotic syndrome: are steroids the answer?

The use of steroids in idiopathic nephrotic syndrome is the major discovery of the twentieth century in the field of pediatric nephrology. At onset of the twenty-first century, steroids remain the first line of treatment at first flare. All the protocols to treat the first flare are similar by a common sequence including a first phase of daily prednisolone/prednisone at a dose of 60 mg/m²/day for at least 4 weeks followed by an alternate-day regimen for several weeks. It appears that a cumulated dose of 2240 mg/m² given in 8 weeks at the first flare without tapering sequence is not inferior to increased dose and duration in terms of prevalence of frequent relapsers and the subsequent cumulated dose of steroids at 24 months of follow-up. A higher cumulated dose might only be interesting in patients aged below 4 years although a formal demonstration is still missing. Several retrospective studies are concordant to suggest that intravenous methylprednisolone pulses are useful to reach a full urinary remission in case of oral resistance to 4 weeks of oral prednisone/prednisolone. A majority of patients have multiple relapses after the treatment of the first flare and half meet the definition of steroid dependency. In those patients, long-lasting alternate-day prednisone/prednisolone therapy does not lead to long-lasting remission, opening the question of the best strategy of immunosuppression.

Effect of different rituximab regimens on B cell depletion and time to relapse in children with steroid-dependent nephrotic syndrome

BACKGROUND

Several studies have demonstrated that rituximab (RTX) improves relapse-free survival in patients with steroid-dependent nephrotic syndrome (SDNS). However, these studies used various RTX regimens and there are few data comparing these regimens in children with SDNS. In this retrospective study, we assessed the effect of three different initial RTX regimens on both time to B cell reconstitution and to first relapse.

METHODS

Sixty-one SDNS patients receiving a first course of RTX were included. Group 1 received one injection of 100 mg/m², group 2 received one injection of 375 mg/m², and group 3 received two injections of 375 mg/m² at day 0 and day 7. Time to B cell reconstitution and time to first relapse and respective risk factors were studied.

RESULTS

Median time to B cell reconstitution was 2.5 [1.8-3.5], 5.0 [3.9-6.0], and 6.6 [4.6-7.8] months in groups 1, 2, and 3, respectively. RTX regimen was associated with time to B cell reconstitution (HRs group 2 vs. 3, 4.07 [1.96-8.48]; group 1 vs. 3, 11.13 [4.04-30.67]). One-year relapse-free survival was 50% [58-77], 59% [42-76], and 72% [46-87] in groups 1, 2, and 3, respectively. RTX regimen was associated with risk of relapse (HRs group 2 vs. 3, 1.55 [0.51-4.65]; group 1 vs. 3, 4.98 [1.15-21.60]).

CONCLUSIONS

The initial dose of rituximab impacts time to B cell reconstitution and the probability of relapse. Risk of relapse is also associated with patient characteristics, suggesting that RTX regimen could be modified for each patient to balance efficacy, cost, and side effects.

Mycophenolate mofetil for sustained remission in nephrotic syndrome

The clinical application of mycophenolate mofetil (MMF) has significantly widened beyond the prophylaxis of acute and chronic rejections in solid organ transplantation. MMF has been recognized as an excellent treatment option in many immunologic glomerulopathies. For children with frequently relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS) experiencing steroid toxicity, MMF has been recommended as a steroid-sparing drug. Uncontrolled studies in patients with FRNS and SDSN have shown that many patients can achieve sustained remission of proteinuria with MMF monotherapy. Three randomized controlled trials have similarly demonstrated that MMF is beneficial in these patients, but less effective than the calcineurin inhibitors cyclosporin A or tacrolimus. Some, but not all, patients with steroid-resistant nephrotic syndrome (SRNS) may also respond to MMF, usually given in combination with other drugs, with partial or complete remission. There are important limitations to the interpretation and comparability of these studies including study design, sample size, patient selection, clinical endpoints, carry-over effects, and duration of follow-up. In all studies, MMF had relatively few side effects, no nephrotoxicity, or no systemic toxicity. MMF is teratogenic, and contraceptive advice is required in females. There is a poor correlation between MMF dose and mycophenolic acid (MPA) exposure and significant inter- and intra-patient variability in drug pharmacokinetics. A higher estimated MPA-AUC_0-12 target range than recommended for pediatric renal transplant recipients is essential to prevent relapses. Therefore, therapy should be guided by drug monitoring to avoid relapses. Further studies are needed to test the efficacy of MMF in inducing remission and, as part of a combination therapy, achieving sustained remission in patients with SRNS.

Initial treatment of steroid-sensitive idiopathic nephrotic syndrome in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial (INTENT study)

INTRODUCTION

Idiopathic nephrotic syndrome is the most common glomerular disease in childhood with an incidence of 1.8 cases per 100 000 children in Germany. The treatment of the first episode implies two aspects: induction of remission and sustainment of remission. The recent Kidney Disease Improving Global Outcomes, American Academy of Pediatrics and German guidelines for the initial treatment of the first episode of a nephrotic syndrome recommend a 12-week course of prednisone. Despite being effective, this treatment is associated with pronounced glucocorticoid-associated toxicity due to high-dose prednisone administration over a prolonged period of time. The aim of the INTENT study (Initial treatment of steroid-sensitive idiopathic nephrotic syndrom in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial) is to show that an alternative treatment regimen with mycophenolic acid is not inferior regarding sustainment of remission, but with lower toxicity compared with treatment with glucocorticoids only.

METHODS AND DESIGN

The study is designed as an open, randomised, controlled, multicentre trial. 340 children with a first episode of steroid-sensitive nephrotic syndrome and who achieved remission by a standard prednisone regimen will be enrolled in the trial and randomised to one of two treatment arms. The standard care group will be treated with prednisone for a total of 12 weeks; in the experimental group the treatment is switched to mycophenolate mofetil, also for a total of 12 weeks in treatment duration. The primary endpoint is the occurrence of a treated relapse within 24 months after completion of initial treatment.

ETHICS AND DISSEMINATION

Ethics approval for this trial was granted by the ethics committee of the Medical Faculty of the University of Heidelberg (AFmu-554/2014). The study results will be published in accordance with the Consolidated Standards of Reporting Trials statement and the Standard Protocol Items: Recommendations for Interventional Trials guidelines. Our findings will be submitted to major international paediatric nephrology and general paediatric conferences and submitted for publication in a peer-reviewed, open-access journal.

TRIAL REGISTRATION NUMBER

DRKS0006547; EudraCT2014-001991-76; Pre-result.

DATE OF REGISTRATION

30 October 2014; 24 February 2017.

Innovative Study Designs Optimizing Clinical Pharmacology Research in Infants and Children

Almost half of recent pediatric trials failed to achieve labeling indications, in large part because of inadequate study design. Therefore, innovative study methods are crucial to optimizing trial design while also reducing the potential harms inherent with drug investigation. Several methods exist to optimize the amount of pharmacokinetic data collected from the smallest possible volume and with the fewest number of procedures, including the use of opportunistic and sparse sampling, alternative and noninvasive matrices, and microvolume assays. In addition, large research networks using master protocols promote collaboration, reduce regulatory burden, and increase trial efficiency for both early- and late-phase trials. Large pragmatic trials that leverage electronic health records can capitalize on central management strategies to reduce costs, enroll patients with rare diseases on a large scale, and augment study generalizability. Further, trial efficiency and safety can be optimized through Bayesian adaptive techniques that permit planned protocol changes based on analyses of prior and accumulated data. In addition to these trial design features, advances in modeling and simulation have paved the way for systems-based and physiologically based models that individualize pediatric dosing recommendations and support drug approval. Last, given the low prevalence of many pediatric diseases, collecting deidentified genetic and clinical data on a large scale is a potentially transformative way to augment clinical pharmacology research in children.

Idiopathic nephrotic syndrome in children

The incidence of idiopathic nephrotic syndrome (NS) is 1·15-16·9 per 100 000 children, varying by ethnicity and region. The cause remains unknown but the pathogenesis of idiopathic NS is thought to involve immune dysregulation, systemic circulating factors, or inherited structural abnormalities of the podocyte. Genetic risk is more commonly described among children with steroid-resistant disease. The mainstay of therapy is prednisone for the vast majority of patients who are steroid responsive; however, the disease can run a frequently relapsing course, necessitating the need for alternative immunosuppressive agents. Infection and venous thromboembolism are the main complications of NS with also increased risk of acute kidney injury. Prognosis in terms of long-term kidney outcome overall is excellent for steroid-responsive disease, and steroid resistance is an important determinant of future risk of chronic or end-stage kidney disease.

Mycophenolate mofetil following glucocorticoid treatment in Henoch-Schönlein purpura nephritis: the role of early initiation and therapeutic drug monitoring

BACKGROUND

Henoch-Schönlein purpura (HSP) is the most common vasculitis in childhood and traditionally considered as a self-limiting disease. However, renal involvement can unfavorably determine long-term prognosis. The reported regimens to treat HSP nephritis (HSPN) are diverse, indicating that the most effective treatment remains controversial.

METHODS

This retrospective, single-center study involved 18 patients presenting with HSPN and nephrotic-range proteinuria. We aimed to investigate the efficacy and safety of mycophenolate mofetil (MMF) and identify a cut-off level for estimated mycophenolic acid area under the curve (eMPA-AUC_0-12h) values, which can predict complete remission with high sensitivity.

RESULTS

Despite prior insufficient therapeutic response to corticosteroids, 89% of patients showed a significant decrease in proteinuria after 1 month of MMF treatment. None of them relapsed during treatment; however, two children relapsed after discontinuation. Based on results of a receiver operating characteristic (ROC) analysis, an eMPA-AUC_0-12h >56.4 mg*h/l was a predictor for complete remission within 3 months (80% sensitivity, 83.3% specificity, p = 0.035). During MMF administration, we encountered no adverse event requiring discontinuation of treatment.

CONCLUSION

Our study demonstrates that MMF is a safe and potentially effective secondary treatment option for children with HSPN to achieve and maintain long-term remission without serious side effects. To achieve complete remission within 3 months, resolve severe inflammatory glomerular lesions, and avoid progression to chronic kidney disease, we propose timely diagnosis and early initiation of MMF with an eMPA-AUC_0-12h value of 56.4 mg*h/l.

Efficacy of Mycophenolate Mofetil as a Remission Maintaining Agent in Idiopathic Childhood Nephrotic Syndrome

Of all cases of idiopathic steroid-sensitive nephrotic syndrome (NS) in children, 40%-75% cases need long-term continuous steroids and/or other immunosuppressants to maintain remission, the effects of which on growth and renal function remain an issue of concern. The study aimed at exploring the safety and efficacy of mycophenolate mofetil (MMF) as a remission-maintaining agent in children with a diagnosis of frequent relapsing or steroid-dependent NS (FRNS/SDNS) requiring continuous medication for at least 1 year. Thirty-two children thus included received MMF (1000-1200 mg/m²/day) for 7 months along with tapering doses of oral prednisolone if it was being given from before with an attempt at tapering at 0.25 mg/kg/month ultimately stopping it altogether. Individuals were followed up for at least 5 more months after stopping MMF. Out of 32 children, 26 had SDNS and 6 had FRNS with male:female ratio being 2.2:1. The mean standard deviation (± SD) age of onset of disease was 2.72 ± 1.3 years and that entry to the study was 7.17 ± 2.2 years. Significant fall in number of relapses was observed following the introduction of MMF (110 in pre-MMF12 month period vs. 52 in post-MMF 12 months [p = 0.002]). The mean relapse rate/year/patient also decreased from 3.43 ± 1.26 to 1.62 ± 1.14 after entry in the study. Significant reduction of the cumulative dose of steroid regarding mean ± SD of mg/kg/year was also found following the introduction of MMF (190.9 ± 47.81 vs. 119.09 ± 60.09 [p = 0.001]). MMF is an efficacious agent in maintaining remission and reducing steroid requirement in children with FRNS and SDNS.

[Treatments of steroid-dependent nephrotic syndrome in children]

Primary nephrotic syndrome (NS) is the most common glomerular disease in children. It is characterized by massive proteinuria and hypoalbuminemia. It typically has a sudden onset and more than 70% of patients will experience at least one relapse. An immunological origin has long been postulated, although the precise molecular mechanisms underlying the disease remain debated. Steroids are the first-line therapy with cumulative dose and duration of initial treatment varying among countries. Steroid-sparing agents may be indicated in case of steroid-dependency or frequent relapses. However, no consensus exists regarding the different treatment options. These treatments are mostly suspensive and therefore, need to be prolonged for several months. Levamisole, an antihelminthic drug, also has an immunomodulatory function, and alone or in combination with steroids, it can decrease cumulative steroid dose and relapses. It is usually well tolerated, and its principal side effects are cytopenia and elevated liver enzymes. Mycophenolate mofetil is an immunosuppressive agent whose reported side effects are cytopenia and diarrhea. Calcineurin inhibitors (cyclosporine or tacrolimus) have long been used in steroid-dependent patients. Their major side effects are hirsutism, gum hypertrophy, and nephrotoxicity, leading to interstitial kidney fibrosis and chronic kidney disease. Cyclophosphamide is an efficient treatment but its gonadal toxicity is a major drawback to its use. More recent drugs such as rituximab are very effective but require hospitalization for the infusion and induce an increased risk of opportunistic infection, prolonged neutropenia, and anaphylaxis. In this review, we present the available treatments, their indications, and the side effects.

Efficacy of mycophenolate treatment in adults with steroid-dependent/frequently relapsing idiopathic nephrotic syndrome

BACKGROUND

This study assessed the efficacy of therapy with mycophenolate (MF) and reduced doses of steroids in adults with steroid-dependent/frequently relapsing idiopathic nephrotic syndrome (SD/FR-INS).

METHODS

Twenty-nine nephrotic patients (including 16 males and 13 females; mean age: 40 years, range: 18-74) were treated. Starting doses of MF were 2000 mg/day for mofetil MF (1500 mg/day in one patient) or 1440 mg/day for sodium MF. The initial prednisone (PDN) dose was 10 mg/day in 14 patients, 5 mg/day in two patients and no steroids in one patient. In the remaining 12 patients, moderate initial doses of PDN were administered (mean: 23.7 mg/day, range: 15-40), tapering to 10 mg/day after 1 month.

RESULTS

Nephrotic syndrome remission was achieved in 27/29 cases (93.1%) (25 complete, 2 partial). Two patients showed resistance to the prescribed schedule. The first cycle of MF therapy was concluded in 20 patients after a mean (range) of 16.9 months (12-49). Maintenance of remission was observed in 11 of these 20 cases (55%) after a mean follow-up of 32.8 months (12-108). In nine patients with nephrotic syndrome relapse after tapering of MF (MF dependency), the same MF-PDN schedule was restarted, leading again to remission in all nine. The remaining seven MF-sensitive patients are still receiving their first therapeutic cycle. To date, the mean time under therapy in the 27 MF-sensitive patients is 38 months (4-216). Regarding complications, only minor digestive disorders and a slight decrease in blood haemoglobin levels were observed in a few patients.

CONCLUSIONS

MF plus reduced doses of PDN is an effective and well-tolerated therapy for adult SD/FR-INS. Though MF dependence is observed, its low toxicity could allow long periods of therapy if it is required to maintain nephrotic syndrome remission.

Evaluation of Mycophenolate Mofetil and Low-Dose Steroid Combined Therapy in Moderately Severe Henoch-Schönlein Purpura Nephritis

Background

The most appropriate management of Henoch-Schönlein Purpura (HSP) nephritis with nephrotic-range proteinuria remains uncertain. The aim of this study was to evaluate the clinical therapeutic effects of mycophenolate mofetil and low-dose steroid in Henoch-Schönlein purpura nephritis (HSPN) with nephrotic-range proteinuria and pathological classification less than IV in children.

Material/Methods

The clinical effects of MMF and low-dose steroid therapy were studied in children with Henoch-Schönlein purpura nephritis manifested with nephrotic-range proteinuria, normal kidney function, and <50% crescents or sclerosing lesions on renal biopsy. We enrolled 32 boys and 29 girls with nephrotic-range proteinuria, normal kidney function, and pathological classification less than IV on renal biopsy. We treated 41 cases (67.2%) with mycophenolate mofetil and low-dose prednisone combined therapy and 20 cases (32.8%) were treated with full-dose prednisone alone.

Results

Short-term response was significantly different between 2 groups (χ²=4.371, P=0.037), while no significant difference was found in long-term prognosis (χ²=0.419, P=0.522) after follow-up. The ROC curve showed that the most appropriate cutoff value was 30.67 μg·h/ml for MPA-AUC and the area under the ROC curve was 0.731, with 85.2% sensitivity and 64.3% specificity.

Conclusions

Mycophenolate mofetil and low-dose prednisone combined therapy is a reasonable treatment choice which can promote the remission of proteinuria without increasing obvious adverse reactions in pediatric HSPN with nephrotic state and pathological classification less than grade IV. MPA-AUC more than 30 μg·h/ml was an appropriate value for MMF in the combined therapy with MMF and steroid for treating children with HSPN.

The Roche Total Mycophenolic Acid® assay: An application protocol for the ABX Pentra 400 analyzer and comparison with LC-MS in children with idiopathic nephrotic syndrome

Background

For TDM of mycophenolate acid (MPA), the Roche Total Mycophenolic Acid® assay based on the inhibition of recombinant inosine monophosphate dehydrogenase (IMPDH) has been shown to be a simple and reliable alternative to chromatographic methods. We have adapted this assay on the ABX Pentra 400 analyzer (HORIBA).

Objective

To investigate the analytical performances of the Roche Total Mycophenolic Acid® assay on the ABX Pentra 400 and to compare it to an LC-MS method using samples from children with nephrotic syndrome treated with mycophenolate mofetil (MMF).

Material and methods

Configuration of the open-channel on the ABX Pentra 400 was based on the Roche MPA assay package insert. Precision was determined as described in the CLSI protocol EP5-A2. Comparison with the LC-MS method was performed using 356 plasma samples from 42 children with nephrotic syndrome (8 h pharmacokinetic profiles).

Results

The enzymatic assay demonstrated high precision. The %CV for Within Run Imprecision ranged from 5.5% at 1.2 mg/L to 1.5% at 14.1 mg/L and Total Imprecision ranged from 9.3% to 2.5%. The method comparison with plasma samples from children yielded overall a good correlation and a good agreement between both methods. The Passing Bablok regression analysis showed the following results: [Roche MPA assay]=1.058 [MPA LC-MS] −0.06; rho=0.996.

Conclusion

The Roche Total Mycophenolic Acid® assay is adaptable to the ABX Pentra 400 analyzer, and demonstrates accurate and precise measurement of MPA in plasma obtained from children with nephrotic syndrome.

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Adaptation of the Roche Total Mycophenolic Acid® assay to the Pentra 400 analyzer.

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Comparison with LC-MS in children with idiopathic nephrotic syndrome.

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Therapeutic drug monitoring of mycophenolate mofetil.

Mycophenolate Mofetil Therapy in Children With Idiopathic Nephrotic Syndrome: Does Therapeutic Drug Monitoring Make a Difference?

BACKGROUND

Idiopathic nephrotic syndrome (INS) necessitates administration of corticosteroids or corticoid-sparing agents in 60% of the cases for prolonged periods resulting in serious adverse effects.

METHODS

To avoid these complications, we investigated the efficacy and safety of mycophenolate mofetil (MMF) in our retrospective single-center study with 15 patients presenting with complicated courses of INS and aspired to estimate a cutoff level for mycophenolic acid-area under the curve (MPA-AUC) values, which can predict relapses with high sensitivity.

RESULTS

Seven of 15 patients stayed in remission while receiving MMF. Average frequency of relapses was 1.39 (0.28-2.5) per year. In case of relapses, patients had lower predose and estimated AUC0-12 levels of MPA (P = 0.02 and 0.001, respectively). Based on the results of receiver operating characteristic analysis, we consider an estimated MPA-AUC0-12 lower than 44.6 mg·h·L(-1) as a risk factor for future relapses (91% sensitivity, 57% specificity, P = 0.06) because the prevalence of relapse is significantly lower (0.07 versus 0.5, P = 0.02), if the estimated MPA-AUC0-12 is >44.6 mg·h·L(-1). During MMF administration, we did not detect any adverse event requiring discontinuation of treatment.

CONCLUSIONS

In conclusion, we demonstrate MMF as an alternative treatment for children with complicated INS to maintain remission without serious side effects. Furthermore, we propose a higher therapeutic target range of MPA-AUC0-12 (>45 mg·h·L(-1)) than used in transplanted children underlining the crucial role of therapeutic drug monitoring.

Mycophenolate mofetil in steroid-dependent idiopathic nephrotic syndrome

BACKGROUND

Prospective studies have established the mycophenolate mofetil (MMF) efficiency in childhood idiopathic nephrotic syndrome (INS) but reports on the long-term outcome are lacking. Moreover, the search for factors influencing its efficiency would be useful to define its place among the other treatments.

METHODS

We performed a monocentric retrospective study including 96 children with steroid-dependent INS followed for 4.7 years (median) (IQ 3-6) after the onset of MMF treatment. The characteristics of responder patients (n = 74), as defined by a 50 % decrease of relapse rate and/or a 60 % decrease of steroid dose, and of non-responder patients (n = 22) were compared by univariate analysis and multivariate logistic regression.

RESULTS

Withdrawal of prednisone was achieved in 48/96 patients after a median duration of 18.1 months (IQ 7.8-30.0) of MMF. Only 26/48 patients did not relapse under MMF alone. After MMF was stopped in these patients, only six remained in remission without any treatment at last follow-up. Responders had a shorter time to remission at the first flare (9.5 vs. 15 days, p = 0.02), a shorter disease duration prior to the onset of MMF (22.2 vs. 94.5 months, p = 0.001), and were younger at the MMF initiation (6.7 vs. 10.1 years, p = 0.02) than non-responder patients. The age of MMF initiation was an independent factor associated with efficiency (OR = 0.80, 95 % CI [0.69, 0.93], p < 0.01).

CONCLUSIONS

MMF is more efficient in young patients treated early in the disease course. Nevertheless, MMF has no remnant effect while nearly all patients relapsed after withdrawal of the drug.

Mycophenolic Acid Pharmacokinetics and Relapse in Children with Steroid-Dependent Idiopathic Nephrotic Syndrome

BACKGROUND AND OBJECTIVES

Therapeutic drug monitoring of mycophenolic acid can improve clinical outcome in organ transplantation and lupus, but data are scarce in idiopathic nephrotic syndrome. The aim of our study was to investigate whether mycophenolic acid pharmacokinetics are associated with disease control in children receiving mycophenolate mofetil for the treatment of steroid-dependent nephrotic syndrome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a retrospective multicenter study including 95 children with steroid-dependent nephrotic syndrome treated with mycophenolate mofetil with or without steroids. Area under the concentration-time curve of mycophenolic acid was determined in all children on the basis of sampling times at 20, 60, and 180 minutes postdose, using Bayesian estimation. The association between a threshold value of the area under the concentration-time curve of mycophenolic acid and the relapse rate was assessed using a negative binomial model.

RESULTS

In total, 140 areas under the concentration-time curve of mycophenolic acid were analyzed. The findings indicate individual dose adaptation in 53 patients (38%) to achieve an area under the concentration-time curve target of 30-60 mg·h/L. In a multivariable negative binomial model including sex, age at disease onset, time to start of mycophenolate mofetil, previous immunomodulatory treatment, and concomitant prednisone dose, a level of area under the concentration-time curve of mycophenolic acid >45 mg·h/L was significantly associated with a lower relapse rate (rate ratio, 0.65; 95% confidence interval, 0.46 to 0.89; P=0.01).

CONCLUSIONS

Therapeutic drug monitoring leading to individualized dosing may improve the efficacy of mycophenolate mofetil in steroid-dependent nephrotic syndrome. Additional prospective studies are warranted to determine the optimal target for area under the concentration-time curve of mycophenolic acid in this population.

A single-centre retrospective study of the safety and efficacy of mycophenolate mofetil in children and adolescents with nephrotic syndrome

Background

The aim of the study was to investigate the efficacy and side effect profile of mycophenolate mofetil (MMF) therapy in children with nephrotic syndrome (NS).

Methods

A retrospective case note review was performed on all patients with NS who were commenced on MMF between 1 January 2000 and 31 December 2009 and were followed up for a minimum of 1 year.

Results

The sample size was 73 patients. The duration of follow-up was for a median of 3.2 years, interquartile range (IQR) (1.7–4.7 years). The median age at diagnosis was 3.2 years, IQR (2.3–5.7 years). The median age of MMF commencement was 11 years, IQR (7.9–13.6 years). There were more boys (67%) than girls. The majority were Caucasian (77%), with 18% Asian 4%, Black Africans and 1% other ethnicities. At initial diagnosis, 61 (84%) were steroid sensitive, 9 (12%) steroid resistant, 3 (4%) steroid dependent (SD). Forty-five (74%) of the 61 steroid-sensitive patients became SD, 4 (7%) of them became steroid resistant, 1 (1%) remained steroid-sensitive and 11 (18%) became frequent relapsers. As to the previous use of second-line immunosuppressants, none were used in 5 (7%) patients, one agent in 17 (23%), two in 27 (37%) and three or more agents were used in 23 (32%) patients. MMF was effective in 45 (62%) patients. Of these, 38 (52%) of them were in remission for >2 years; and in 7 (10%) MMF worked for 1 to 2 years (MMF therapy electively stopped/ongoing). MMF therapy allowed 27 (37%) patients to wean steroids completely and 8 (11%) to achieve complete steroid and immunosuppressant withdrawal. A further 8 (11%) had steroids partially weaned. MMF failures were seen in 13 (18%) within the first year and 5 (7%) in the second year. MMF was stopped due to side effects in 4 (6%) and non-compliance in 4 (6%). The majority of patients had no side effects [51 (70%)]. Seven (9%) had gastrointestinal side effects (diarrhoea/abdominal pain); 5 (7%) had immunological side effects (leucopenia/infections); 3 (4%) had both immunological and gastrointestinal side effects; and 2 (3%) suffered arthralgia.

Conclusions

MMF is well tolerated and effective as a second-line agent in treating steroid-sensitive NS. The drug permitted prolonged remission and steroid weaning or other second-line agent withdrawal in a majority of cases.

Long-term efficacy and safety of common steroid-sparing agents in idiopathic nephrotic children

BACKGROUND

Calcineurin inhibitors (CNI), mycophenolate mofetil (MMF), and levamisole are common treatment choices for patients with frequently relapsing (FRNS) and steroid-dependent nephrotic syndrome (SDNS).

METHODS

In this retrospective cohort study, we analyzed the relative efficacy and safety of tacrolimus, MMF, and levamisole over a period of 30 months, in treating 340 children with idiopathic FRNS/SDNS. The children received either MMF 1200 mg/m² daily, or levamisole 2.5 mg/kg on alternate days, or tacrolimus 0.1-0.2 mg/kg daily along with tapering doses of alternate-day prednisolone.

RESULTS

Tacrolimus was associated with a higher rate of 30-month relapse-free survival when compared to MMF (61.7 vs. 38.5 %, p < 0.001), or levamisole (61.7 vs. 24 %, p < 0.001). However, relapse rate increased almost threefold once tacrolimus was stopped, resulting in a higher relapse rate per patient-year when compared to the MMF group (2.0 vs. 1.5, p = 0.013). The cumulative prednisolone dose per patient during the last year of the study period was also increased among tacrolimus group in comparison with MMF group (96.4 vs. 74.4 mg/kg/year, p = 0.004). Independent of the impact of drug choice, the relapse risk was higher in patients with steroid dependency at baseline (HR 2.14, 95 %CI 1.79-2.96, p < 0.0001). In comparison with few minor adverse events in other two cohorts, several serious adverse events were documented in the tacrolimus group.

CONCLUSIONS

Although there are serious safety concerns regarding tacrolimus, it is more effective than MMF or levamisole in maintaining relapse-free survival. However, unlike MMF, the relative efficacy of tacrolimus in preventing further relapses is seen only when the patient is on the drug. Taking together the long-term efficacy and safety data observed, MMF appears as a safe and effective alternative to tacrolimus in managing pediatric FRNS/SDNS.

Pharmacokinetics of mycophenolic acid in children with clinically stable idiopathic nephrotic syndrome receiving cyclosporine

BACKGROUND

The suitable dosage regime of mycophenolate mofetil (MMF) based on the pharmacokinetics of mycophenoric acid (MPA) for pediatric patients with idiopathic nephrotic syndrome (INS) is controversial. The pharmacokinetics of MPA is influenced by renal function, serum albumin concentration, and concomitant medications, especially calcineurin inhibitors. This study analyzed the pharmacokinetics of MPA in clinically stable children with INS receiving cyclosporine (CyA).

METHODS

This retrospective study enrolled children with INS receiving MMF (Cellcept^®) (30-40 mg/kg/day in two divided doses) combined with CyA (Neoral^®) without relapse and renal dysfunction. Pharmacokinetic parameters, including the area under the concentration-time curve (AUC) calculated by the trapezoid method, were calculated from seven serial blood samples.

RESULTS

Thirty-two patients (22 males) of median age 11.0 years were included; 32 pharmacokinetic studies were performed. The median MMF dose was 16.2 mg/kg/time or 470.4 mg/m²/time. The median AUC0-12 was 44.3 ng h/mL. AUC0-12 of all patients showed excellent correlations with C2 (r ²  = 0.6405, P < 0.0001), resulting in a regression formula of AUC0-12 = 21.971 + 2.6059 C2. Comparisons of dose/body weight-normalized AUC0-12 values among age groups showed a lower value in the youngest group (≤5 years).

CONCLUSION

In children with clinically stable INS receiving CyA, C2 monitoring was the most useful single parameter for estimating MPA pharmacokinetics. Younger children required higher MMF doses.

The Value of Monitoring the Serum Concentration of Mycophenolate Mofetil in Children with Steroid-Dependent/Frequent Relapsing Nephrotic Syndrome

BACKGROUND

Mycophenolate mofetil (MMF) is an alternative treatment strategy in children with steroid sensitivity who have frequent relapses or steroid-dependent nephrotic syndrome (FRNS/SDNS).

METHODS

From January 2009 to January 2015, 31 cases of children with FRNS/SDNS were prospectively recruited and administered MMF and prednisone; then, serum samples were collected, and the area under the curve (AUC) of mycophenolic acid (MPA-AUC) was calculated.

RESULTS

A MPA-AUC of 27.99 μg·h/ml had a diagnostic sensitivity of 65.2% and a specificity of 87.5% in discriminating relapsing from non-relapsing patients (receiver operating characteristic-AUC 0.848). The 31 patients were then grouped according to the results of the MPA-AUC as follows: low-AUC group, <30 μg·h/ml and high-AUC group, ≥30 μg·h/ml. The results indicated that there was a significant difference in the remission rate between the groups (x03C7;2 = 6.645, p = 0.01) during the 6 months of follow-up. Compared with the results before MMF therapy, the steroid dosage in both groups was significantly reduced at the 6- and 12-month follow-ups. Furthermore, the steroid dose was reduced more significantly in the high-AUC group than in the low-AUC group (0.447 ± 0.254 vs. 0.219 ± 0.161 mg/kg/day, p = 0.006) at the 6-month follow-up. Compared with the low-AUC group at the 6-month follow-up, the number of patients with relapse and relapse episodes in the high-AUC group were also significantly reduced (7/16 vs. 1/15, p = 0.037, and 15/27 vs. 1/29, p = 0.014, respectively).

CONCLUSIONS

MMF is a reasonable treatment choice to reduce the number of relapse episodes and steroid administration in children with FRNS/SDNS. Moreover, children in the high-AUC group (MPA-AUC ≥30 μg·h/ml) tended to require lower steroid doses and had greater remission rates than the patients in the low-AUC group (<30 μg·h/ml) at the 6-month follow-up.

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.

WITHDRAWN: Efficacy and Safety of Mycophenolate Mofetil Versus Levamisole in Children and Adolescents With Idiopathic Nephrotic Syndrome: Results of a Randomized Clinical Trial

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[Treatment of idiopathic nephrotic syndrome in children]

The annual incidence of the nephrotic syndrome has been estimated to be 1-3 per 100,000 children<16 year of age. In children, the most common cause of nephrotic syndrome is idiopathic nephrotic syndrome (INS). INS is defined by the presence of proteinuria and hypoalbuminemia and by definition is a primary disease. Renal biopsy study shows non-specific histological abnormalities of the kidney including minimal changes, focal and segmental glomerular sclerosis, and diffuse mesangial proliferation. Steroid therapy is applied in all cases of INS. Renal biopsy is usually not indicated before starting corticosteroid therapy. The majority of patients (80-90%) are steroid-responsive. Children with INS who do not achieve a complete remission with corticosteroid therapy commonly present focal and segmental glomerular sclerosis and require treatment with calcineurin inhibitors (cyclosporine or tacrolimus), mycophenolate mofetil or rituximab, plus renin-angiotensin system blockade. In this article we review the recent accepted recommendations for the treatment of children with INS.

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

The severe side effects of long-term corticosteroid or cyclosporin A (CsA) therapy complicate the treatment of children with frequently relapsing steroid-sensitive nephrotic syndrome (FR-SSNS). We conducted a randomized, multicenter, open-label, crossover study comparing the efficacy and safety of a 1-year treatment with mycophenolate mofetil (MMF; target plasma mycophenolic acid trough level of 1.5-2.5 µg/ml) or CsA (target trough level of 80-100 ng/ml) in 60 pediatric patients with FR-SSNS. We assessed the frequency of relapse as the primary endpoint and evaluated pharmacokinetic profiles (area under the curve [AUC]) after 3 and 6 months of treatment. More relapses per patient per year occurred with MMF than with CsA during the first year (P=0.03), but not during the second year (P=0.14). No relapses occurred in 85% of patients during CsA therapy and in 64% of patients during MMF therapy (P=0.06). However, the time without relapse was significantly longer with CsA than with MMF during the first year (P<0.05), but not during the second year (P=0.36). In post hoc analysis, patients with low mycophenolic acid exposure (AUC <50 µg⋅h/ml) experienced 1.4 relapses per year compared with 0.27 relapses per year in those with high exposure (AUC>50 µg⋅h/ml; P<0.05). There were no significant differences between groups with respect to BP, growth, lipid levels, or adverse events. However, cystatin clearance, estimated GFR, and hemoglobin levels increased significantly with MMF compared with CsA. These results indicate that MMF is inferior to CsA in preventing relapses in pediatric patients with FR-SSNS, but may be a less nephrotoxic treatment option.

Outcome of severe steroid-dependent nephrotic syndrome treated with mycophenolate mofetil

BACKGROUND

Mycophenolate mofetil (MMF) is used as a steroid-sparing agent in pediatric nephrotic syndrome (NS). However, data about its long-term efficacy and safety is limited.

METHODS

We report the long-term outcome of MMF therapy in 46 NS patients who remained steroid dependent (SD) despite previous treatment with levamisole and cyclophosphamide.

RESULTS

After 1 year of MMF initiation, 32 (70 %) patients had reduced steroid requirement: 12 with decreased threshold dose and 20 were able to stop steroids. At follow-up of mean 3.56 (standard deviation + 1.76) years, 25 (54 %) children required no further alternative immunosuppression (IS), having infrequent or no relapses, of which 14 stopped MMF after a mean 2.4 (standard deviation + 0.9) years; 11 are continuing on MMF for a median of 2.25 years (range 1.33-7.75 years). One patient had a psoriasis flare, and MMF was stopped. No other patient required permanent drug withdrawal due to side effects. The outcome of patients who did not require further alternate IS was significantly better than those who did, with 56 % vs. 10.5 %, respectively, being off regular medications at last follow-up.

CONCLUSIONS

We conclude that MMF therapy is safe in the long term and allows >50 % of severe SDNS patients to avoid further toxic IS.

Bayesian cohort and cross-sectional analyses of the PINCER trial: a pharmacist-led intervention to reduce medication errors in primary care

Background

Medication errors are an important source of potentially preventable morbidity and mortality. The PINCER study, a cluster randomised controlled trial, is one of the world’s first experimental studies aiming to reduce the risk of such medication related potential for harm in general practice. Bayesian analyses can improve the clinical interpretability of trial findings.

Methods

Experts were asked to complete a questionnaire to elicit opinions of the likely effectiveness of the intervention for the key outcomes of interest - three important primary care medication errors. These were averaged to generate collective prior distributions, which were then combined with trial data to generate Bayesian posterior distributions. The trial data were analysed in two ways: firstly replicating the trial reported cohort analysis acknowledging pairing of observations, but excluding non-paired observations; and secondly as cross-sectional data, with no exclusions, but without acknowledgement of the pairing. Frequentist and Bayesian analyses were compared.

Findings

Bayesian evaluations suggest that the intervention is able to reduce the likelihood of one of the medication errors by about 50 (estimated to be between 20% and 70%). However, for the other two main outcomes considered, the evidence that the intervention is able to reduce the likelihood of prescription errors is less conclusive.

Conclusions

Clinicians are interested in what trial results mean to them, as opposed to what trial results suggest for future experiments. This analysis suggests that the PINCER intervention is strongly effective in reducing the likelihood of one of the important errors; not necessarily effective in reducing the other errors. Depending on the clinical importance of the respective errors, careful consideration should be given before implementation, and refinement targeted at the other errors may be something to consider.