SciCombinator

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Concept: Mycophenolic acid

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Preventing xenograft rejection is one of the greatest challenges of transplantation medicine. Here, we describe a reproducible, long-term survival of cardiac xenografts from alpha 1-3 galactosyltransferase gene knockout pigs, which express human complement regulatory protein CD46 and human thrombomodulin (GTKO.hCD46.hTBM), that were transplanted into baboons. Our immunomodulatory drug regimen includes induction with anti-thymocyte globulin and αCD20 antibody, followed by maintenance with mycophenolate mofetil and an intensively dosed αCD40 (2C10R4) antibody. Median (298 days) and longest (945 days) graft survival in five consecutive recipients using this regimen is significantly prolonged over our recently established survival benchmarks (180 and 500 days, respectively). Remarkably, the reduction of αCD40 antibody dose on day 100 or after 1 year resulted in recrudescence of anti-pig antibody and graft failure. In conclusion, genetic modifications (GTKO.hCD46.hTBM) combined with the treatment regimen tested here consistently prevent humoral rejection and systemic coagulation pathway dysregulation, sustaining long-term cardiac xenograft survival beyond 900 days.

Concepts: Immune system, DNA, Gene expression, Blood, Immunology, Organ transplant, Mycophenolic acid, Mycophenolate mofetil

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OBJECTIVES: To determine the mycophenolic acid pharmacokinetic profile early after transplant in Iranian kidney graft recipients. MATERIALS AND METHODS: A cross-sectional study was performed during 6 months in 31 patients who recently had kidney transplant and received fixed doses of mycophenolate mofetil (2 g/d). The plasma levels of mycophenolic acid were determined by high performance liquid chromatography. RESULTS: The mean first mycophenolic acid peak level was 10 ± 5 mg/L. The mean mycophenolic acid area under the curve was 26 ± 19 mgh/L and apparent clearance was 57 ± 55 L/h. The mycophenolic acid area under the curve values of only 8 patients (26%) were within the therapeutic range (30-60 mgh/L). The first, second, and third mycophenolic acid peak levels correlated significantly with mycophenolic acid area under the curve (P < .05). Mycophenolic acid concentration at 10 hours had the highest correlation with mycophenolic acid area under the curve (r=0.962; P < .05). No statistically significant differences were evident in the mean mycophenolic acid area under the curve between men and women. CONCLUSIONS: There was a high degree of variation between different patients in mycophenolic acid pharmacokinetics early after kidney transplant.

Concepts: Pharmacology, Statistics, Statistical significance, High performance liquid chromatography, Kidney transplantation, Pharmacokinetics, Mycophenolic acid, Mycophenolate mofetil

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Lupus nephritis is a common and severe manifestation of systemic lupus erythematosus, and an important cause of both acute kidney injury and end-stage renal disease. Despite its aggressive course, lupus nephritis is amenable to treatment in the majority of patients. The paradigm of immunosuppressive treatment for lupus nephritis has evolved over the past few decades from corticosteroids alone to corticosteroids combined with cyclophosphamide. Sequential treatment regimens using various agents have been formulated for induction and long-term maintenance therapy, and mycophenolate mofetil has emerged as a standard of care option for both induction and maintenance immunosuppressive treatment. The current era has witnessed the emergence of multiple novel therapeutic options, such as calcineurin inhibitors and biologic agents that target key pathogenetic mechanisms of lupus nephritis. Clinical outcomes have improved in parallel with these therapeutic advances. This Review discusses the evidence in support of current standard of care immunosuppressive treatments and emerging therapies, and describes their roles and relative merits in the management of patients with lupus nephritis.

Concepts: Nephrology, Corticosteroid, Systemic lupus erythematosus, Glomerulonephritis, Immunosuppressive drug, Lupus nephritis, Cyclophosphamide, Mycophenolic acid

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The options for long-term maintenance therapy in lupus nephritis (LN) remain controversial. This meta-analysis of randomized controlled trials (RCTs) assessed the prognosis and safety of mycophenolate mofetil (MMF) versus azathioprine (AZA) used as maintenance therapy for lupus nephritis.

Concepts: Mycophenolic acid

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Mycophenolate mofetil (MMF) is used for prevention of allograft rejection in transplantation medicine. In dermatology it is used as a corticosteroid-sparing agent. The pharmacokinetics of MMF are known to vary by individual. Therapeutic dose monitoring of mycophenolic acid (MPA), the active metabolite of MMF, is used as a guide in transplantation medicine, but limited data exist on the benefit of measuring MPA levels in the management of dermatologic disease.

Concepts: Pharmacology, Medicine, Disease, Organ transplant, Cyclophosphamide, Mycophenolic acid, Mycophenolate mofetil, Dermatology

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Idiopathic focal segmental glomerulosclerosis (FSGS) is among the most common, morbid and treatment-resistant conditions faced by nephrologists. While glucocorticoids have traditionally been the mainstay of initial treatment, they induce remission in only a minority of patients. A variety of other immunosuppressants have been utilized against steroid-resistant FSGS, but few have been rigorously examined in well-controlled trials. Recently, the results were published from a National Institutes of Health (NIH)-sponsored multicenter randomized trial comparing cyclosporine (CSA) with a combination of mycophenolate mofetil (MMF) and pulse dexamethasone (DEX) for the treatment of steroid-resistant FSGS. No difference in treatment effectiveness was shown between the two groups, and adverse effects were comparable. This was the largest randomized trial ever undertaken in FSGS, but it was unfortunately underpowered to show clinically relevant differences in response rates. This shortcoming, along with particularities of the study population and outcome measures, makes it challenging to draw definitive conclusions from the trial results. Despite these limitations, the trial does provide valuable insights into treatment strategies for FSGS and offers important lessons for planning future research.

Concepts: Clinical trial, Effectiveness, Clinical research, The Trial, Immunosuppressants, Mycophenolic acid, Focal segmental glomerulosclerosis, Glomerulosclerosis

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: The influence of the conversion from cyclosporine (CsA) to everolimus (EVR) on the chronopharmacokinetics of mycophenolic acid (MPA) and its glucuronide (MPAG) and acyl glucuronide (acyl-MPAG) metabolites in patients receiving enteric-coated mycophenolate sodium (EC-MPS) has not been studied.

Concepts: Organ transplant, Kidney transplantation, Transplant rejection, Immunosuppressants, Mycophenolic acid, Mycophenolate mofetil, Novartis

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Every month, new releases on the relationship between pharmacogenetic biomarkers and immunosuppressive drug therapy in kidney transplantation are published. However, the systematic clinical application of these discoveries occurs at a very slow pace, and the usefulness of knowing a patient’s genotype remains an important matter of debate. This can be partially ascribed to the lack of consistency when looking at the different associations reported across several studies but also the need for a broad-spectrum view and a rigorous analysis of the relevance of the different associations observed to date. For that purpose, we performed a comprehensive analysis of the strength of the different reported genetic associations, and in this article we discuss their potential for clinical implementation in kidney transplantation. For tacrolimus, it is likely that a genotype-based drug dosage can benefit patient outcome, while for ciclosporin A, the data appear less convincing. For the mammalian target of rapamycin inhibitors, sirolimus and everolimus - given the lack of data and the absence of large prospective studies - it is premature to implement pharmacogenetics, but some novel and promising leads have recently been reported. For mycophenolate mofetil, the complex metabolic pathways of its active moiety, mycophenolic acid, complicate analysis of the various published associations. However, at present, some interesting findings can be highlighted and offer potential value to assist clinicians in decision making.

Concepts: Pharmacology, Kidney transplantation, Transplant rejection, Immunosuppressive drug, Immunosuppressants, Mycophenolic acid, Mycophenolate mofetil, Liver transplantation

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Overexpression of soluble urokinase receptor (suPAR) causes pathology in animal models similar to primary FSGS, and one recent study demonstrated elevated levels of serum suPAR in patients with the disease. Here, we analyzed circulating suPAR levels in two cohorts of children and adults with biopsy-proven primary FSGS: 70 patients from the North America-based FSGS clinical trial (CT) and 94 patients from PodoNet, the Europe-based consortium studying steroid-resistant nephrotic syndrome. Circulating suPAR levels were elevated in 84.3% and 55.3% of patients with FSGS patients in the CT and PodoNet cohorts, respectively, compared with 6% of controls (P<0.0001); inflammation did not account for this difference. Multiple regression analysis suggested that lower suPAR levels associated with higher estimated GFR, male sex, and treatment with mycophenolate mofetil. In the CT cohort, there was a positive association between the relative reduction of suPAR after 26 weeks of treatment and reduction of proteinuria, with higher odds for complete remission (P=0.04). In the PodoNet cohort, patients with an NPHS2 mutation had higher suPAR levels than those without a mutation. In conclusion, suPAR levels are elevated in geographically and ethnically diverse patients with FSGS and do not reflect a nonspecific proinflammatory milieu. The associations between a change in circulating suPAR with different therapeutic regimens and with remission support the role of suPAR in the pathogenesis of FSGS.

Concepts: Immune system, Regression analysis, Clinical trial, Pathology, Nephrotic syndrome, Proteinuria, Mycophenolic acid, Focal segmental glomerulosclerosis

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BACKGROUND: Nephrotic syndrome (NS) is a recognized complication of immune tolerance induction (ITI) therapy, a treatment strategy used to treat inhibitors in patients with hemophilia B receiving factor IX concentrate. CASE DIAGNOSIS/TREATMENT: We present a 4-year-old boy with hemophilia B and an inhibitor who underwent ITI, and developed NS 19 months into this therapy. A percutaneous renal biopsy was safely performed with factor IX (FIX) concentrate administration both preceding and following the procedure. The patient’s inhibitor level had increased to 1.4-1.6 Bethesda Units just prior to the onset of proteinuria. Histology confirmed segmental membranous nephropathy (MGN). The patient was continued on FIX concentrate as ITI and also received 4 weekly doses of rituximab and ongoing immunosuppression with mycophenolate mofetil. This resulted in the complete resolution of his inhibitor and his NS. He continues with a modified ITI regimen and remains inhibitor-free without proteinuria >12 months post-biopsy. CONCLUSIONS: Hemophilia B patients undergoing ITI should be regularly screened for NS. At first detection of proteinuria, with proper precautions, a percutaneous kidney biopsy can be performed safely in patients with low levels of inhibitor. Our patient had segmental MGN with complete remission of NS.

Concepts: Kidney, Patient, Nephrotic syndrome, Proteinuria, Haemophilia B, Mycophenolic acid, Mycophenolate mofetil, Nephritic syndrome