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BackgroundMycophenolic acid (MPA) is widely utilized as an immunosuppressant in kidney and liver transplantation, with reports suggesting an independent relationship between MPA concentrations and adverse allograft outcome. Proton-pump inhibitors (PPIs) may have variable effects on the absorption of different MPA formulations leading to differences in MPA exposure.MethodsA multicentre, randomized, prospective, double-blind placebo-controlled cross-over study was conducted to determine the effect of the PPI pantoprazole on the MPA and its metabolite MPA-glucuronide (MPA-G) area under the curve (AUC) >12 h (MPA-AUC12 h) in recipients maintained on mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium (EC-MPS). We planned a priori to examine separately recipients maintained on MMF and EC-MPS for each pharmacokinetic parameter. The trial (and protocol) was registered with the Australian New Zealand Clinical Trials Registry on 24 March 2011, with the registration number of ACTRN12611000316909 (‘IMPACT’ study).ResultsOf the 45 recipients screened, 40 (19 MMF and 21 EC-MPS) were randomized. The mean (standard deviation) recipient age was 58 (11) years with a median (interquartile range) time post-transplant of 43 (20–132) months. For recipients on MMF, there was a significant reduction in the MPA-AUC12 h [geometric mean (95% confidence interval) placebo: 53.9 (44.0–65.9) mg*h/L versus pantoprazole: 43.8 (35.6–53.4) mg*h/L; P = 0.004] when pantoprazole was co-administered compared with placebo. In contrast, co-administration with pantoprazole significantly increased MPA-AUC12 h [placebo: 36.1 (26.5–49.2) mg*h/L versus pantoprazole: 45.9 (35.5–59.3) mg*h/L; P = 0.023] in those receiving EC-MPS. Pantoprazole had no effect on the pharmacokinetic profiles of MPA-G for either group.ConclusionsThe co-administration of pantoprazole substantially reduced the bioavailability of MPA in patients maintained on MMF and had the opposite effect in patients maintained on EC-MPS, and therefore, clinicians should be cognizant of this drug interaction when prescribing the different MPA formulations.

Laparoscopic sleeve gastrectomy induces weight loss via the creation of a restrictive gastric tube for early satiety and is associated with an accelerated gastric transit time. A prospective, single-dose pharmacokinetic study was performed, prior to and after laparoscopic sleeve gastrectomy, for tacrolimus, extended-release tacrolimus, mycophenolate mofetil, and enteric-coated mycophenolate sodium. The study included 12 morbidly obese patients in chronic renal failure. The median decrease in body mass index was 8.8 kg/m2 with an excess body weight loss of 54.9%. The AUC24 of all drugs were increased after laparoscopic sleeve gastrectomy by 46%, 55%, 77%, and 74%, respectively. The maximum concentrations were increased for tacrolimus, extended-release tacrolimus, and mycophenolate mofetil by 43%, 46%, and 65%. The apparent total clearances were decreased for tacrolimus, mycophenolate mofetil, and enteric-coated mycophenolate sodium by 36%, 57%, and 38%. Laparoscopic sleeve gastrectomy can be associated with significant changes in pharmacokinetics of the drugs evaluated. The mechanism is likely decreased apparent drug clearance due to an increased drug exposure (from a more distal site of intestinal absorption with decreased intestinal metabolism), or decreased clearance (liver metabolism). Adapting the monitoring of immunosuppression will be important to avoid overdosing and potential side effects.

Objective It is still unclear whether mycophenolic acid (MPA) doses should be adjusted for older patients. Therefore, we compared the pharmacokinetics of MPA, mycophenolic acid glucuronide (MPAG), and free MPA (fMPA) between older and younger renal transplant recipients. Methods We included 12 patients 60 years within the first year after renal transplantation, who were receiving enteric-coated mycophenolate sodium, tacrolimus, and steroids. Blood samples were collected up to 12 hours after drug administration. Results MPA and fMPA pharmacokinetics were similar for patients 60 years; however, the MPA area under the concentration-time curve from 0 to 12 hours (AUC0-12) was 1.2-fold lower in the older patients. MPAG pharmacokinetics were more than 1.5-fold higher in patients >60 years, which might be related to deteriorated renal function in older people. Moreover, the mean (MPAG AUC0-12)/(MPA AUC0-12) ratio was more than 2-fold higher in patients >60 years. The second maximal MPA concentration was more frequently observed in patients 60 years had MPA AUC0-12 >30 μg·h/mL within 22 to 114 days after transplantation. Conclusions MPA therapeutic monitoring should be recommended in enteric-coated mycophenolate sodium--treated patients >60 years because MPA AUC0-12 exceeded the recommended value in half of the studied patients.

Immunosuppressive therapy is used in solid organ transplant treatment, and mycophenolic acid (MPA) is one of the immunosuppressive drugs most used worldwide. It is a potent, selective, non-competitive, and reversible inosine monophosphate dehydrogenase (IMPDH) inhibitor that acts to inhibit guanine synthesis. To improve solubility, MPA is used as the prodrug mycophenolate mofetil (MMF) or as an enteric-coated mycophenolate sodium salt (EC-MPS). It is metabolized into mycophenolic acid phenyl glucuronide (MPAG), the inactive and major metabolite, and into acyl glucuronide (AcMPAG), pharmacologically active. In kidney transplantation, combined immunosuppressive therapy with cyclosporine (CsA) and tacrolimus (Tac) is widely used, showing beneficial effects. This paper aimed to review papers published in the last two decades and discuss factors that can interfere with the pharmacokinetics of MPA. Data collected confirm that MPA plasma levels should be monitored to evaluate immunosuppressive therapy since pharmacokinetics can be influenced by factors such as interpatient variability, coadministration of other immunosuppressive agents, post-transplant period, renal function, and dose. However, to perform drug monitoring, costs and facility may be limitations. Monitoring MPAG together with MPA would be a great improvement in therapy as it represents a big part of MPA levels and can be related to the increase of adverse effects.

Elderly patients are increasingly likely to be recipients of transplants. However, the pharmacokinetics of mycophenolic acid (MPA) in this population are yet to be studied in detail. The objective of this study was to assess whether there were differences in MPA pharmacokinetic parameter values between elderly recipients and younger-adult recipients during the 6 months immediately following renal transplantation.In this analysis, the longitudinal 12-h pharmacokinetics of MPA, administered as enteric-coated mycophenolate sodium (EC-MPS), were evaluated in 44 elderly renal transplant recipients and compared with the corresponding pharmacokinetics of MPA in 31 younger adult recipients. Measurements were performed at 7, 30, 60, 90, and 180 days post-transplantation. All patients received tacrolimus and prednisone.The elderly patients were 30 years older than the younger controls, with a predominance of males and Caucasians. Elderly patients had lower serum albumin than the younger controls during the first 6 months after transplantation. The mean estimated total body MPA clearance of the elderly recipients was not significantly different from that of the controls at any analyzed time point (the mean clearance across all time points was 0.31 ± 0.17 vs 0.30 ± 0.25 L/h/kg). MPA exposure, as evaluated from the area under the 12-h time versus measured MPA concentration (adjusted for dose/body weight) curve, did not differ between the groups at any time point (mean exposure across all time points was 4.68 ± 3.61 vs 5.95 ± 4.29 µg·h/mL per mg/kg for the elderly recipients and the controls).These data show that the pharmacokinetics of MPA in elderly renal transplant recipients were no different to those of younger-adult recipients in this study population. CLINICALTRIALS.GOV: NCT 01631058.

BACKGROUND Enteric-coated mycophenolate sodium is frequently used in renal transplantation. The pharmacokinetic profile of mycophenolic acid (MPA) shows a broad range of time-to-maximum concentration (Tmax) that limits the use of a single MPA concentration to calculate the area under the time-concentration curve (AUC). For both research and clinical MPA monitoring, measuring a complete AUC is troublesome to the center and patients. METHODS We obtained 171 complete MPA-AUC12h (0, 20, 40, 60, 90, 120, 180, 240, 360, 480, 600, and 720 minutes) from 59 adult (54 ± 16 years) patients (29 men and 43 whites) who have been receiving stable doses of tacrolimus/enteric-coated mycophenolate sodium and steroids. We used the 59 curves drawn at 31 ± 4 days after transplantation to develop the abbreviated equations, and the remaining 112 curves drawn at 109 ± 59 days were used to validate them. We used 5 other proposed equations to estimate MPA-AUC (eAUC) (4 with enzyme-multiplied immunoassay technique assay and one with high-performance liquid chromatography [HPLC]) and then used these results to compare with our measured AUC, the bias, and the 10% and 30% accuracy. MPA was measured by ultraperformance liquid chromatography coupled to a tandem mass spectrometry, and AUC was calculated by the trapezoidal rule. RESULTS For both MPA-measuring methods, enzyme-multiplied immunoassay technique and ultraperformance liquid chromatography coupled to a tandem mass spectrometry, the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo (HCFMUSP) equations, and others that measure MPA up to 6 hours after the dose had an acceptable low bias with more results in the 10%-30% range than those using data collected until 4 hours. A highly adequate eAUC is obtained using blood collected at 8 hours. CONCLUSIONS This analysis offers blood-sampling alternatives for MPA monitoring depending on the precision needed.

BACKGROUND This study was designed to analyze the clinical implications of mycophenolic acid trough concentration monitoring. MATERIAL AND METHODS We collected data of patients with mycophenolic acid trough concentration monitoring after their first kidney transplant between November 2006 and March 2015 who were prescribed tacrolimus, mycophenolate, and methylprednisolone. Analyses were performed on 3 periods: 1 month, 1 month to 1 year, and after 1 year post-transplantation. To analyze factors related to acute cellular rejection, logistic regression was used for 1 month, while Cox analysis was used during 1 month to 1 year and after 1 year post-transplantation. RESULTS In the 145 patients receiving mycophenolate mofetil, mean tacrolimus trough ≥7.0 ng/mL (OR=0.177, CI=0.060-0.524, p=0.002) and mean mycophenolic acid trough ≥1.7 mg/L (OR=0.190, CI=0.040-0.896, p=0.036) were protective for rejection during 1 month. Mean mycophenolic acid trough ≥1.7 mg/L (HR=0.179, CI=0.040-0.806, p=0.025) and ≥0.7 mg/L (HR=0.142, CI=0.028-0.729, p=0.019) were related to better rejection-free survival during 1 month to 1 year and after 1 year, respectively. In 399 patients receiving enteric-coated mycophenolate sodium, mean tacrolimus trough ≥7.0 ng/mL (OR=0.258, CI=0.131-0.507, p

Most patients have serious digestive complications after renal transplantation. Therefore, it is important to protect gastrointestinal function to improve the survival rate of transplant patients. Proton pump inhibitors (PPIs) such as lansoprazole and rabeprazole are widely administered to renal transplant patients with mycophenolic acid (MPA) in the perioperative period. PPIs are metabolized by cytochrome (CYP) 2C19 enzymes. Mycophenolate sodium (MYF) and mycophenolate mofetil (MMF) have been used in immunosuppression. Clinically relevant drug-drug interactions have been described between immunosuppressive drugs. In the present study, we investigated the drug interaction between MPA and lansoparazole or rabeprazole and the impact of CYP2C19 polymorphisms on these drug interactions after renal transplantation.A total of 125 renal transplant patients taking MPA derivatives between 2012 and 2016 were included in this study. The 125 patients were divided into 6 groups: MMF/tacrolimus/steroid together with lansoprazole or rabeprazole; MYF/tacrolimus/steroid together with lansoprazole or rabeprazole and without PPI. The single nucleotide polymorphisms of CYP2C19 were determined by the polymerase chain reaction-restriction fragment length polymorphism. Plasma concentrations of MPA were measured by cloned enzyme donor immunoassay. Clinical parameters such as incidence of delayed graft function and acute rejection, the rate of change of serum creatinine, toxicity, and gastrointestinal adverse effects were analyzed retrospectively.The mean concentrations of MPA in the MYF group were higher than those in the MMF group. The mean dose-adjusted blood concentration of MPA coadministered with lansoprazole was lower than that of MPA with rabeprazole or without PPI in MMF and MYF groups (P .05). In patients with the CYP2C19*2/*2 genotype, the mean concentrations of MMF with lansoprazole were significantly lower than those with rabeprazole with MMF or without PPI (P .05). Gastrointestinal side effects were significantly higher in MMF with lansoprazole group than in MYF with lansoprazole group (P .05). However, no differences were found according to genotype distribution in all groups (P.05).Polymorphisms in CYP2C19 are related to the metabolic oxidation of drugs to varying degrees. Both genetic and clinical factors in pharmacokinetics may help to make further progress toward individualized therapy to yield maximum efficacy with minimal side effects.

Background Mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium (MPS) is now commonly used in pediatric intestinal transplantation (Tx), but to date, no clear recommendations regarding the dosing regimen have been made in this population. The aim of this study was to determine the MMF/MPS dosage required to achieve an area under the plasma concentration-time curve from 0 to 12 hours (AUC0-12) for mycophenolic acid (MPA) greater than 30 mg·h·L in children after intestinal transplantation. Methods A pharmacokinetic study was conducted in 8 children (median, 9.4 years; range, 0.75-15.8 years) at a median time of 113 months (range, 1.5-160 months) after intestinal transplantation. Results MMF was initially introduced at a low median starting dose of 687 mg·m·d (range, 310-1414 mg·m·d). One of the 3 patients who received MPS and 2 of the 6 patients who received MMF had an MPA AUC0-12 value below 30 mg.h.L. The median MMF dosage had to be increased by 91% (1319 mg·m·d versus 687 mg·m·d) to reach AUC0-12 values above the defined target level of 30 mg·h·L. Conclusions When used in combination with tacrolimus and steroids, an initial MMF dose of 600 mg/m twice a day would be recommended to children after intestinal transplantation to achieve MPA exposure similar to those observed in adults and children after the transplantation of other organs. Further studies are required to recommend a suitable dosage for pediatric intestinal transplant recipients who receive MPA.

Background: The enteric-coated mycophenolate sodium (EC-MPS), whose active constituent is mycophenolic acid (MPA), has been widely clinically used for organ transplant recipients. However, its absorption is delayed due to its special designed dosage form, which results in difficulty to monitor the exposure of the MPA in patients receiving the EC-MPS. This study was aimed at developing a relatively practical and precise model with limited sampling strategy to estimate the 12-hour area under the concentration–time curve (AUC0–12 h) of MPA for Chinese renal transplant recipients receiving EC-MPS. Methods: A total of 36 Chinese renal transplant recipients receiving the EC-MPS and tacrolimus were recruited in this study. The time point was 2 weeks after the transplantation for all the patients. The MPA concentrations were measured with enzyme-multiplied immunoassay technique for 11 blood specimens collected predose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, and 12 hours after the morning dose of EC-MPS. The measured AUC was calculated with these 11 points of MPA concentrations with the linear trapezoidal rule. Limited sampling strategy was used to develop models for estimated AUC in the model group (n = 18). The bias and precision of different models were evaluated in the validation group (n = 18). Results: C4 showed the strongest correlation with the measured AUC. The best 3 time point equation was 6.629 + 8.029 × C0 + 0.592 × C3 + 1.786 × C4 (R2 = 0.910; P < 0.001), whereas the best 4 time point equation was 3.132 + 5.337 × C0 + 0.735 × C3 + 1.783 × C4 + 3.065 × C8 (R2 = 0.959; P < 0.001). When evaluated in the validation group, the 4 time point model had a much better performance than the 3 time point model: for the 4 time point model: R2 = 0.873, bias = 0.505 [95% confidence interval (CI), −10.159 to 11.170], precision = 13.370 (95% CI, 5.186–21.555), and 77.8% of estimated AUCs was within 85%–115% of the measured AUCs; for the 3 time point model: R2 = 0.573, bias = 6.196 (95% CI, −10.627 to 23.018), precision = 21.286 (95% CI, 8.079–34.492), and 50.0% of estimated AUCs was within 85%–115% of the measured AUCs. Conclusions: It demanded at least 4 time points to develop a relatively reliable model to estimate the exposure of MPA in renal transplant recipients receiving the EC-MPS. The long time span needed restricted its application, especially for the outpatients, but it could be a useful tool to guide the personalized prescription for the inpatients.

Background Therapeutic drug monitoring of mycophenolic acid (MPA) is usually performed with a limited sampling strategy (LSS), which relies on a limited number of blood samples and subsequent extrapolation of the global exposure to MPA. LSS is usually performed successfully with mycophenolate mofetil (MMF), but data on enteric-coated mycophenolate sodium (EC-MPS) are scarce. Here, we evaluated the feasibility of 6-h LSS therapeutic drug monitoring with EC-MPS compared with MMF monitoring among kidney transplant recipients. Methods Sixty-two patients who received EC-MPS during the first 6 months of transplantation were compared with a matched group of 64 MMF-treated kidney transplant recipients. The area under the curve (AUC) was computed by LSS using multiple concentration time points (0, 1, 2, 3 and 6 h post-dose) and a trapezoidal rule. Patients had MPA therapeutic drug monitoring performed on two occasions, one within 2 weeks and the second after 3-4 months of transplantation. Results EC-MPS monitoring and MMF therapeutic drug monitoring were not interpretable in 34.5% (n = 40/116) and 1.8% (n = 2/112) of patients, respectively {relative risk [RR] 19.3 [95% confidence interval (CI) 4.8-78.0]; P < 0.0001}. The main cause of abnormal EC-MPS therapeutic drug monitoring was delayed absorption of both the previous evening and the morning dose, resulting in MPA plasma levels before the next morning dose being higher than MPA plasma levels measured at 1, 2 and 3 h after taking EC-MPS. Cyclosporin in association with MMF significantly increased the risk of low AUC values (30% during the first 6 months of renal transplantation. Delayed pharmacokinetics was the main reason. In contrast, the risk of therapeutic drug monitoring failure was substantially lower with MMF., SCOPUS: ar.j, info:eu-repo/semantics/published

Introduction: Whether an early, short-term, adequate exposure to mycophenolic acid (MPA) under tacrolimus-based immunosuppression regimen in kidney transplantation from donation after circulatory death (DCD) was effective and safe is yet unknown. Material and Methods: The study was a single-center, retrospective, cohort study of DCD transplantation in China. Intensified and standard dosage regimens of enteric-coated mycophenolate sodium (EC-MPS) were week 1, 2,160 vs. 1,440 mg/day. The incidences of biopsy-proven acute rejection (BPAR), delayed graft function, infection, and patient and graft survival were compared between the 2 groups. Results: A total of 209 patients (n = 82 in intensified group and n = 127 in standard group) were enrolled from August 2013 to December 2014. The incidence of BPAR at 12 months was significantly lower in the intensified group as compared to that of the standard group. (2.4 vs. 10.2%, p = 0.035). The mean MPA area under curve (AUC) levels at day 7 was significantly higher in the intensified group than that in the standard group (66.18 ± 35.48 vs. 45.30 ± 23.5 mg·h/L, p < 0.001). MPA AUC levels were significantly decreased in patients with BPAR as compared to those with NO-BPAR. Conclusion: An early, short-term regimen of intensified EC-MPS with tacrolimus increased early MPA exposure and achieved a low rate of BPAR in kidney transplantation from DCD.

Background. Although colonic injury is a well-known complication of mycophenolic acid (MPA), the involvement of the upper gastrointestinal tract is less extensively documented. We present the occurrence of celiac-like duodenopathy manifested as a severe diarrhea syndrome in 2 renal transplant recipients on enteric-coated mycophenolate sodium. Methods. The patients belong to a setting of 16 renal transplant recipients under MPA suffering from chronic diarrhea in the absence of MPA-related colitis. Results. Both patients had a history of persistent diarrhea with significant weight loss. Colonic mucosa was unremarkable, whereas duodenal biopsies revealed celiac-like changes with increased epithelial cell apoptosis. Clinical symptoms completely resolved, and follow-up biopsies demonstrated normalization of histology after enteric-coated mycophenolate sodium withdrawal and switching to azathioprine. Conclusions. Celiac-like enteropathy seems to represent a rare side effect of MPA-associated immunosuppressive therapy and should be taken into account in the differential diagnosis of diarrhea in transplant recipients treated with MPA particularly in the absence of MPA-related colitis. As macroscopic lesions are usually missing, blind duodenal biopsies are necessary to establish the diagnosis.

We assessed the relations between MPA, free MPA (fMPA) and MPA glucuronide (MPAG) pharmacokinetics and the clinical condition of renal transplant recipients treated with EC-MPS and tacrolimus (Tac) in the first post-transplant year. In 18 adult patients blood samples were collected up to 12 h after EC-MPS oral administration. EC-MPS metabolites’ plasma concentrations were determined using validated HPLC methods. All patients reached MPA area under the time–concentration curve (AUC0–12) above 30 µg h/mL. Most of the MPA, fMPA and all MPAG concentrations correlated significantly with respective AUC0–12 values. Some fMPA and all MPAG pharmacokinetic parameters correlated negatively with creatinine clearance and positively with creatinine concentration, whereas no such correlation was observed for MPA. Lower hemoglobin concentrations were observed in patients with higher MPA or fMPA C 0. The significant correlations between MPA C 3 as well as MPA C 4 and MPA AUC0–4 and MPA AUC0–12 may be of importance in further studies including larger number of patients in regard to establishing LSS. In patients treated with EC-MPS and Tac, monitoring MPA C 0 may be important, as too high MPA C 0 may contribute to anemia onset. In EC-MPS treated patients, MPAG concentration is related to renal function as MPAG pharmacokinetics were higher in patients with renal impairment.

BACKGROUND: Chronic lung allograft dysfunction (CLAD), Predominantly manifest as bronchiolitis obliterans syndrome (BUS), is the primary cause of morbidity and death after lung transplantation. We assessed the efficacy and safety of 2 de novo immunosuppression protocols to prevent BUS.METHODS: This was a multicenter, prospective, international, randomized (1:1) open-label superiority study of de novo enteric-coated mycophenolate sodium (MPS) vs delayed-onset everolimus (RAD), both arms in combination with cyclosporine (CsA) monitored by 2-hour post-dose (C-2) levels, and corticosteroids. Target C-2 levels were lower in the RAD group because RAD is known to potentiate CsA nephrotoxicity. Cytolytic induction therapy was not used. Patients were stratified at entry for cystic fibrosis. Confirmation of anastomotic healing was required for randomization. Primary efficacy was freedom from BUS Grade 1 on intention-to-treat (ITT) analysis. Secondary efficacy parameters were patient and graft survival and severity of rejection. Treatment failure was defined by graft loss, patient death, drug cessation, or need for other therapy.RESULTS: The 3-year freedom from BUS Grade 1 was 70% for MPS (n = 80) vs 71% for RAD (n = 84; p = 0.95 by log-rank) in ITT but was lower in the RAD arm of the per-protocol population (p = 0.03). The 3-year survival was 84% (MPS) vs 76% (RAD; p = 0.19 by log-rank). Thirteen patients switched from MPS vs 31 from RAD (p CONCLUSIONS: This 3-year ITT analysis found no significant difference between arms but was underpowered to accept the null hypothesis that RAD and MPS have equivalent efficacy in preventing BOS or death after lung transplantation. (C) 2015 International Society for Heart and Lung Transplantation. All rights reserved.

Background: It remains unclear whether overall degree of immunosuppression or specific effects of individual immunosuppressive agents are causal for increased occurrence of BK polyomavirus (BKPyV) infection in renal transplant recipients (RTR).Methods: A prospective, multicenter, open-label randomized controlled trial in 361 de novo RTR was performed. A total of 224 RTR were randomized at 6months into three treatment groups with dual therapy consisting of prednisolone (Pred) plus either cyclosporine (CsA), mycophenolate sodium (MPS), or everolimus (EVL). Primary outcomes were incidence of BK viruria, BK viremia, and BKPyV-associated nephropathy (BKVAN).Results: From 6months, incidence of BK viruria in the MPS group (43.6%) was significantly higher than in the other groups (CsA: 16.9%, EVL: 19.8%) (P=.003). BKVAN was diagnosed in 3 patients, all treated with MPS (7.8%, P=.001). Longitudinal data analysis showed a lower BKPyV load and a significantly faster clearance of BK viruria in the CsA group compared to the MPS group (P=.03).Conclusions: Treatment with MPS was associated with an increased incidence of BK viruria. Dual immunosuppressive therapy with CsA and Pred was associated with the lowest rate of BKPyV replication and the fastest clearance of the virus.

Enteric-coated mycophenolate sodium (EC-MPS) is effective and safe in preventing rejection after transplantation and is mainly transported by ABCs and OATPs and metabolized by UGTs. The genetic polymorphisms affect the inter-individual variation in drug disposition and elimination. The aims of this study were to develop a population pharmacokinetic (PK) model and to evaluate the influence of genetic and clinical factors on the PK of mycophenolic acid (MPA) in Korean renal transplant recipients. Population analysis of EC-MPS was performed using non-linear mixed effects modeling (NONMEM). After clinical and genetic factors were evaluated using a stepwise covariate method, we selected clinically relevant covariates considering covariate effects. The final model was validated by bootstrap and visual predictive check. At last, we performed the model-based simulations in order to explore an optimal dose to achieve target area under the curve (AUC) in hypothetical scenarios. From 166 plasma concentrations (n=34), a time-lagged two-compartment with a flip-flop model best describes the PK of MPA. The covariate analysis identified lower creatinine clearance (CLcr) and SLCO1B1 variant genotype were correlated with lower MPA clearance, on the contrary, UGT1A9 variant had decreased distribution of MPA, contributing to lower absorption. When considering to UGT1A9, SLCO1B1 genotypes, and renal function, the new recommended dose of 540 mg twice daily resulted in a higher success of achieving the target AUC0-12h in the 30-60 mg.h/L. CLcr, UGT1A9 and SLCO1B1 genotypes seem to be promising parameters to predict the pharmacokinetics with flip-flop phenomenon of EC-MPS in transplant recipient having stable renal function. This model on clinical practice may help prevent overexposure and achieve a proper AUC in the Korean population.

MORE was a four-yr, prospective, observational study at 40 transplant centers in the US. Data were analyzed to evaluate changes in mycophenolic acid (MPA) dosing over time in 904 de novo kidney transplant recipients receiving enteric-coated mycophenolate sodium (EC-MPS, n = 616) or mycophenolate mofetil (MMF, n = 288) with tacrolimus. Induction therapy and steroid treatment were similar in the two subpopulations. The proportion of patients receiving the maximal recommended MPA dose was 80.5%, 43.9%, 39.2%, 34.6%, and 30.1% at baseline and years 1, 2, 3, and 4, respectively. More patients received the maximal recommended MPA dose with EC-MPS vs. MMF at month 1 (79.2% vs. 71.7%, p = 0.016), month 3 (68.5% vs. 56.9%, p = 0.001), and month 6 (52.9% vs. 44.0%, p = 0.028). Multivariate analysis showed the risk of biopsy-proven acute rejection, graft loss or death to be similar for EC-MPS vs. MMF. Estimated glomerular filtration rate (GFR) was similar with EC-MPS vs. MMF at all time points. There were no significant differences in any category of adverse event between the EC-MPS and MMF cohorts during follow-up, including gastrointestinal events. In conclusion, MPA dose was maintained more effectively in the first six months after kidney transplantation using EC-MPS vs. MMF, without an increase in adverse events.

Enteric-coated mycophenolate sodium (EC-MPS) and mycophenolate mofetil (MMF), two prodrugs of mycophenolic acid (MPA), have been used in immunosuppressive regimens. After being taken orally, both of them transform to MPA to achieve immune suppression effects; however, the main site of absorption and metabolism of EC-MPS is different from that of MMF in vivo. Therefore, combined application with related drugs may result in different MPA levels and have different clinical effects in kidney transplant recipients.To evaluate the efficacy of EC-MPS compared with MMF in Chinese renal transplant patients comedicated with a proton pump inhibitor (PPI).Our subjects were 88 patients who received renal transplants at the 309th Hospital of the Chinese PLA from May 2010 to April 2013. These were made up of two groups including 27 patients with EC-MPS and 61 with MMF. The immunosuppression regimen was EC-MPS/MMF + cyclosporine/tacrolimus + steroid hormone, comedicated with a PPI (omeprazole). The patients' levels of exposure of MPA within 1 week after operation were monitored. Clinical indicators such as incidence of delayed graft function and acute rejection, the rate of change of serum creatinine hemoglobin, leucocytes, and neutrophils, as well as clinical adverse drug reactions and drug conversion were analyzed retrospectively.The kidney function of patients recovered to normal in both the EC-MPS and MMF groups. The mean concentration to peak (Cmax), the mean half-life (t1/2), and the area under the concentration-time curve (AUC0-12) of MPA in the EC-MPS group were higher than those in the MMF group (P.05). This indicated that the pharmacokinetic parameters for MPA when EC-MPS is co-administered with a PPI in kidney transplant patients in China is better than for comedication with MMF and a PPI. The MMF group had a higher incidence of drug withdrawal because of higher infection rates, leucocyte decrease, and more gastrointestinal side effects than the EC-MPS group (P.05). No significant differences in the clinical effect on kidney transplant recipients were observed in the limited observation time.

Summary Aims There are few pharmacokinetic data for enteric-coated mycophenolate sodium (EC-MPS) in Chinese kidney transplant recipients. Previously, we demonstrated that patients with 540 mg EC-MPS reached target exposure on day 4 after transplantation. The aim of this study was further to confirm that mycophenolic acid (MPA) delivery with a daily total dose 1080 mg EC-MPS is adequate during the early-phase posttransplantation and preliminarily assess the pharmacokinetics after a single dose and multiple doses of EC-MPS in Chinese live-donor kidney transplant recipients. Methods Twelve patients (eight men and four women, mean age 41.3 ± 6.78 years) treated with EC-MPS, cyclosporine and corticosteroids were included in this study. Patients received a single oral dose of EC-MPS 540 mg, then 540 mg twice daily. MPA concentrations were measured by high-performance liquid chromatography. Twelve-hour pharmacokinetic profiles were obtained after the single oral dose and multiple doses on day 4 postoperation. The pharmacokinetic parameters were compared between a single dose and multiple doses. By using multiple stepwise regression analysis, we obtained two predictive equations of MPA systemic exposure. Bland–Altman analysis was developed to test agreement between the observed MPA area under the concentration–time curve (AUC) and the predicted MPA AUC. Results The mean (range) MPA AUC was 42 ± 14.67 (29.29–75.95) mg/l h after the first dose, and 44.72 ± 14.57 (32.06–80.79) mg/l h on day 4 after operation. MPA exposure provided by a single dose and multiple doses were similar (p > 0.05). The best equations obtained were the following: 20.003 + 1.181C6 h + 7.22C8 h (r = 0.936) and 17.023 + 3.11C1 h + 1.245 + 4.988C8 h (r = 0.964). These equation models showed an optimal agreement between the observed MPA AUC and the predicted MPA AUC. Conclusions Lower dosing of EC-MPS, compared with the standard dose (720 mg twice daily), may provide enough MPA exposure for Chinese live-donor kidney transplant patients on day 4. Given that the MPA exposure by AUC correlates with the incidence of acute rejection episodes and transplant vasculopathy, the present findings may have clinical implications, and the optimum dose range of EC-MPS for patients in all ranges of body weight should also be determined.

BACKGROUND Patients with a simultaneous pancreas-kidney transplant (SPKT), especially those with gastroparesis, often have gastro-intestinal (GI) disorders that can modify immunosuppressant pharmacokinetics. We compared the MPA 12-hours area under the curve (AUC(0-12)) in SKPT patients with severe gastroparesis receiving mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium (EC-MPS). MATERIAL/METHODS Fifteen SKPT patients having a severe gastroparesis were switched, at 182 (69-1523) days post-transplantation, from MMF to EC-MPS because of GI disorders. MPA AUC(0-12) values were obtained before and after the switch, ie, under MMF (500 mg b.i.d.) at 169 (51-1522) days post-transplantation and EC-MPS (360 mg b.i.d.) at 102 (26-355) days after the switch. RESULTS Mean MPA AUC(0-12) h did not differ significantly under MMF and EC-MPS, ie, 40.13±14 and 38.24±15.5 mg*h/L, respectively. Trough and maximal MPA concentrations were similar with both MPA formulations. Although all patients had GI disorders under MMF (100%), only 3 had persistent GI disorders under EC-MPS (20%) (p

The most common immunosuppressive regimens after renal transplantation include calcineurin inhibitors (CNI). However, due to renal toxicity long-term graft survival does not seem to be positively affected by CNIs.In the present study, we investigated 17 patients, in which the CNI immunosuppression was converted to a CNI-free, mycophenolate sodium (MPS) regimen. Conversion was performed due to progressive impairment of the graft function from suspected CNI toxicity. We retrospectively analyzed graft function as well as toxicity and surrogate markers for 4 years before and 4 years after conversion using a repeated-measures mixed model data analysis and/or a paired sample t-test.The mean time point of therapy conversion was 11.2 ± 4.6 years after transplantation. Within 1 month of CNI discontinuation, allograft function improved significantly, remaining at a significant level for 2 years. The estimated glomerular filtration rate increased from 43.4 ± 14.8 to a maximum of 55.7 ± 21.7 mL/min at 1 year after conversion (P = .0027). After 4 years, the end of the observation period, renal function was similar to the baseline. There were no significant side effects.These data suggested that, when chronic CNI-toxicity is suspected, renal allograft recipients may benefit from CNI withdrawal in favor of a MPS-including immunosuppressive regimen.

Aim Cyclosporine (CsA), dosed to achieve C2 targets, has been shown to provide safe and efficacious immunosuppression when used with a mycophenolate and steroids for de novo kidney transplant recipients. This study examined whether use of enteric-coated mycophenolate sodium (EC-MPS) together with basiliximab and steroids would enable use of CsA dosed to reduced C2 targets in order to achieve improved graft function. Methods Twelve-month, prospective, randomized, open-label trial in de novo kidney transplant recipients in Australia. Seventy-five patients were randomized to receive either usual exposure (n = 33) or reduced exposure (n = 42) CsA, EC-MPS 720 mg twice daily, basiliximab and corticosteroids. Results There was no significant difference in mean Cockcroft-Gault CrCl (creatinine clearance) (60.2 ± 17.6 mL/min per 1.73 m2 vs 63.2 ± 24.3, P = 0.64 for usual versus reduced exposure respectively) at 6 months. There was no significant difference between treatment groups in the incidence of treatment failure defined as biopsy proven acute rejection, graft loss or death (secondary endpoint: 30.3% full exposure vs 35.7% reduced exposure). At 12 months the incidence of overall adverse events was the same in both groups. Conclusion This exploratory study suggests de novo renal transplant patients can safely receive a treatment regimen of either full or reduced exposure CsA in combination with EC-MPS, corticosteroids and basiliximab, with no apparent difference in efficacy or graft function during the first year after transplant.

Aim Mycophenolate mofetil has proven efficacy in the prophylaxis of acute rejection in solid organ transplantation; however, gastrointestinal intolerance can risk this efficacy because of associated dose adjustments and discontinued treatment. Enteric-coated mycophenolate sodium has demonstrated improved gastrointestinal tolerability, but the data in Asian subjects are scarce. Methods This was a Phase-IIIb, open-label, single-arm, multicentre, prospective 6-month study which investigated safety and graft function in stable maintenance renal transplant recipients of Asian origin, after switching from mycophenolate mofetil to enteric-coated mycophenolate sodium at least 3 months after transplantation. Primary end-points included renal allograft function and safety parameters. Results The study recruited patients from 16 centres in Asian countries. The intention-to-treat and safety populations both included 122 patients. Graft function remained stable over the course of the study as measured by creatinine clearance and glomerular filtration rate. At 6 months the incidence of any gastrointestinal adverse events was 20.5% (n = 25), none of which required dose adjustments. There were only three cases of biopsy proven acute rejection with no reports of graft loss or death. Conclusion This study demonstrated that enteric-coated mycophenolate sodium is a safe and effective alternative to mycophenolate mofetil in Asian kidney transplant recipients.

Mycophenolic acid (MPA) is an immunosuppression agent for the prophylaxis of organ rejection in patients receiving allogeneic transplants. The drug is administered based in 2 formulations, mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS). MPA acts by specific, reversible, uncompetitive inhibition of inosine monophosphate dehydrogenase (IMPDH) and thus blocks the proliferation of both T- and B-activated lymphocytes. Therapeutic drug monitoring (TDM) constitutes an important part of immunosuppressive treatment because of the demonstrated significant intraindividual and interindividual variability of its pharmacokinetic behavior. TDM is required to optimize immunosuppressive efficacy. We present the analytical validation of a homogeneous particle-enhanced turbidimetric inhibition immunoassay (PETINIA) technique for determination of MPA in human plasma, and compare with a homogeneous enzyme immunoassay technique (EMIT; reference method), both methods adapted on a Dimension analyzer (Siemens). We examined 50 human plasma samples from kidney transplant recipients treated with MMF or EC-MPA, which were analyzed simultaneously by both methods. The interassay precision was 5.95% at a concentration of 1.0 μg/mL, 3.47% at 7.5 μg/mL, and 3.75% at 12.0 μg/mL. The bias of PETINIA-MPA for each of the 3 quality control sample was

In solid organ transplant patients, it is important to maintain a fine balance between preventing rejection and reducing adverse effects. Several immunosuppressive agents such tacrolimus, cyclosporine, sirolimus and everolimus require therapeutic drug monitoring. The study of germline variation of the genome has opened novel opportunities to individualize therapy. Among the currently available immunosuppressive agents, cyclosporine, tacrolimus and mycophenolic acid are in vitro substrates of the UGT1A and 2B families of glucuronidation enzymes. Mycophenolic acid, either given as mycophenolate mofetil or mycophenolate sodium, is the most frequently used antiproliferative immunosuppressant. Mycophenolic acid is a prodrug which is rapidly de-esterified in the gut wall, blood, liver and tissue to the active moiety, mycophenolic acid (MPA). MPA undergoes significant hepatic metabolism to several metabolites. The 7-hydroxyglucuronide MPA is the major metabolite and is inactive. This paper reviews the current status of the genetic associations between germline UGT variants and the pharmacokinetics and pharmacodynamics of mycophenolic acid. Our conclusive assessment of the studies conducted so far is that these germline markers are not ready to be used in the clinic to individualize mycophenolic acid dosing and improve outcome. Novel approaches are required to identify new genetic determinants of outcomes in transplantation.

Background and aim Everolimus (EVR) use in liver transplantation (OLT) has been prescribed with calcineurin inhibitors (CNIs), steroids, and monoclonal antibodies. The aim of our study was to evaluate the safety, feasibility, and impact on renal function of EVR ab initio, in combination with enteric-coated mycophenolate sodium (EC-MPS) without the use of induction treatment, steroids, or CNIs. Patients and methods We retrospective analyzed nine consecutive patients who underwent OLT at our institution. The initial dose of EVR (1.5 mg/d) was adjusted to achieve trough levels of 8 to 12 ng/mL. EC-MPS introduced at 1080 mg/d was maintained at the same dose over time. Results At a mean follow-up of 21.48 (standard deviation [SD] 1.4) months from OLT, 7/9 recipients were alive with stable graft function. The 2-year patient and graft survivals were 77%. One recipient died due to cerebral hemorrhage and one, lung failure. No clinical evidence of an acute rejection episode was observed. Mean estimated glomerular filtration rate value, according to the Modification of Diet in Renal Disease formula increased from 59.5 (SD 9.89) mL/min/1.73 m 2 at OLT to 100.2 (SD 47.5) mL/min/1.73 m 2 ( P = .03) after 12 months and 98.71 (SD 33.74) mL/min/1.73 m 2 ( P = .03) after 24 months' follow-up. Conclusion A double immunosuppression therapy with EVR and EC-MPS ab initio seemed to be efficacions and safe, representing a valid alternative to CNIs to prevent renal failure after OLT.

Background Approximately half of cyclosporine A-treated renal transplant recipients do not reach sufficient mycophenolic acid (MPA) exposure in the first weeks posttransplantation with standard MPA dosing regimens. Methods Here, we present a prospectively planned meta-analysis of data from two 6-month parallel-run studies that evaluated the effect of an initially intensified versus standard dosing regimen of enteric-coated mycophenolate sodium (EC-MPS). Four hundred forty-one de novo renal transplant recipients were randomized (1:1) to intensified (2 weeks 2880 mg/d; subsequently 4 weeks 2160 mg/d; followed by 1440 mg/d) or standard (1440 mg/d) EC-MPS, with concomitant cyclosporine A treatment and steroids with or without anti-IL-2R induction. Primary endpoint was treatment failure (biopsy-proven acute rejection [BPAR], graft loss, or death) at month 6 posttransplantation. Results Treatment failure rates were 17.4% in intensified and 22.4% in standard groups (P=0.110). The incidence of BPAR was 13.8% (intensified) vs. 19.3% (standard; P=0.034). A total of 80.5% (intensified) versus 39.0% (standard) of patients achieved 12 hr MPA-area under the curve more than 30 μg·hr/mL as early as day 3 posttransplant. Renal function, gastrointestinal symptom rating scores, and safety profiles were comparable between treatment groups. Conclusion The initially intensified EC-MPS dosing regimen was associated with higher MPA exposure, significantly lower rate of BPAR, and comparable safety. However, the intensified regimen did not affect graft function or survival.

Background In this prospective study we investigated the impact of the proton pump inhibitor (PPI) pantoprazole on the bioavailability of mycophenolic acid (MPA) after oral administration of enteric-coated mycophenolate sodium (EC-MPS; Myfortic) in heart or lung transplant recipients. Previously we demonstrated that pantoprazole reduces the MPA exposure of mycophenolate mofetil (MMF; CellCept) by 34% in area under the concentration–time curve (AUC). Because gastrointestinal side-effects are common after organ transplantation, we investigated the effect of PPI on MPA levels in patients receiving EC-MPS. Methods MPA plasma concentrations and inosine monophosphate dehydrogenase (IMPDH) activity at baseline, 30 minutes and 1, 2, 3 and 4 hours were obtained from 21 patients. These patients were treated with pantoprazole 40 mg once daily and EC-MPS twice daily at a mean dose of 960 mg. Measurements were repeated after pantoprazole withdrawal. Results MPA concentrations and IMPDH activities did not reveal any significant difference during PPI treatment and after withdrawal. MPA AUC, MPA C max (maximal MPA concentration), the time until C max was reached (T max ) and IMPDH activity AUC all showed no significant difference. Conclusion We did not find an influence of pantoprazole on EC-MPS pharmacokinetics such as we did for MMF in our previous investigation. A further prospective, large, cross-over study is planned to support these preliminary results. Given that MPA exposure by AUC correlates with the incidence of acute rejection episodes and transplant vasculopathy, the present findings may have clinical implications.

International audience; UNLABELLED: This article summarizes part of a consensus meeting about mycophenolate (MPA) therapeutic drug monitoring held in Rome under the auspices of The Transplantation Society in November 2008 (Clin J Am Soc Nephrol. 2010;5:341-358). This part of the meeting focused on the clinical pharmacokinetics of MPA and included discussion on how to measure MPA (active drug) exposure and the differences between the currently available formulations. SUMMARY POINTS: Because of variability in the dose-concentration relationship, MPA exposure should be measured and doses should be adjusted accordingly to achieve optimal clinical outcomes. Suggested therapeutic exposures derived for MPA from mycophenolate mofetil (MMF) may differ to those that could be useful for MPA from enteric-coated mycophenolate sodium (EC-MPS), particularly if limited sampling strategies or single concentration, especially trough concentrations, is used, as the concentration-time profiles of MPA from the 2 formulations are quite different. The 2 MPA formulations cannot be considered as bioequivalent. The area under the concentration-time curve (AUC 0-12) is considered the criterion standard for monitoring of MPA, which is a reflection of exposure to the drug over the entire dosing period. If a limited sampling protocol coupled with multilinear regression or Bayesian estimation is used to estimate this parameter, it should be used only for the population in which the model has been developed and should preferably include at least one time point after 4 hours (preferably around 8 or 9 hours after MMF dosing). If a single time point is to be used as a surrogate for an AUC 0-12, trough concentration of MPA may be the most practical but, from a pharmacokinetic standpoint, is not the most informative time point to choose. Because limited sampling strategies to estimate MPA exposure from EC-MPS have not yet been well developed and fully evaluated, nor have accurate Bayesian estimators been reported, AUC 0-12 measurement is still necessary to obtain reliable estimates of MPA exposure in patients treated with EC-MPS. The measurement of MPA trough concentrations should not be used at all for MPA exposure assessment following administration of EC-MPS. Because limited sampling strategies to estimate MPA exposure from EC-MPS have not yet been well developed and fully evaluated, nor have accurate Bayesian estimators been reported, AUC 0-12 measurement is still necessary to obtain reliable estimates of MPA exposure in patients treated with EC-MPS. The measurement of MPA trough concentrations should not be used at all for MPA exposure assessment following administration of EC-MPS. Lower (or higher) than expected total MPA exposure in patients with severe renal impairment may still indicate sufficient free MPA exposure. Mycophenolate free exposure measurement/estimation is likely to be beneficial in patients with severe renal impairment (creatinine clearance b25 mL/min) to guide dosage estimation, especially because renal function changes over time after transplant, while recognizing that robust prospective studies to show the clinical advantage of measuring free MPA exposure are still required. Lower total measured MPA exposure in patients with hypoalbuminemia may still indicate sufficient free MPA exposure. Mycophenolate free concentration measurement and estimation of exposure are likely to be beneficial in patients with a serum albumin less than or equal to 31 g/L to guide interpretation of MPA exposure. A 1.5-g twice-daily starting dose of MMF rather than a 1-g twice-daily starting dose of MMF is more likely to achieve the minimum target MPA exposure in adult transplant recipients receiving concomitant cyclosporine therapy. Because the cyclosporine dose is progressively tapered following transplantation, MPA exposure should be measured repeatedly and MMF should be doses adjusted accordingly to achieve optimal clinical outcome. Mycophenolate exposure should be measured in the first week after transplant, then each week for the first month, each month until month 3, and subsequently every 3 months up to 1 year with appropriate dosage adjustment, as AUC is likely to increase over time. After 1 year, if dosage requirement has stabilized, MPA exposure can be assessed each time the immunosuppressive regimen is changed or a potentially interacting drug is introduced or withdrawn. Assessment of UGT1A9 single nucleotide polymorphisms (-275TNA, -2152CNT, -440CNT, -331TNC) should be considered before transplantation to assist in dosing decisions to achieve optimal MPA exposure immediately after transplant. Consideration of the points summarized above should lead to more effective dosage adjustment based on sound applied pharmacokinetic and pharmacodynamic principles.

Mycophenolate acid (MPA) therapy is associated with a decrease in acute rejection rates and excellent renal allograft survival. Unfortunately, mycophenolate mofetil (MMF) is associated with significant adverse effects (AE), which, in many cases, preclude full-dose therapy. Previously, lower MMF drug exposure was significantly associated with a greater risk of rejection. Patients who had a ≥50% dose reduction of MMF experienced a lower graft survival compared to those who tolerated full-dose MMF. Mycophenolate sodium (MPS) was designed to lessen MPA-associated AE. In this retrospective study, we studied the tolerability and long-term outcomes in renal transplant recipients (RTR) treated with MPS versus MMF. Four hundred forty-nine RTRs who received MPS or MMF for more than 3 months were classified into three groups: group 1: MMF-treated; group 2: MPS-treated; and group 3; patients who converted from MMF to MPS due to AE. Donor and recipient demographics as well as induction and maintenance immunosuppressive therapies were similar in all groups. Patient survival was not different in all groups. However, long-term graft survival was lower in patients whose dose of either MPS or MMF was reduced by ≥50%. Moreover, a ≥50% MPA dose reduction was associated with a higher rate of rejection compared to full dose (38% vs 21%, respectively, P < .01). Compared to patients treated initially with MMF, fewer MPS-treated recipients required dose reductions (65% vs 42%, respectively, P < .001). Furthermore, 38% of patients in group 3 tolerated full-dose MPS despite previous intolerance to MMF. Finally, the long-term graft survival was best in MPS-treated RTR and worst in those who converted from MMF to MPS due to AE. We conclude that MPS is better tolerated than MMF, which may explain the superior graft outcome in RTR who were treated with MPS from the onset.

Mycophenolate drug levels are decreased by co-administration of cyclosporine. However, mycophenolate levels may be associated with insufficient immunosuppression. We investigated the pharmacokinetics of 720 mg mycophenolate sodium (EC-MPS) and inosine monophosphate dehydrogenase (IMPDH) activity under co-medication with cyclosporine and steroids within the first 30 d after kidney transplantation (n = 24). Blood samples were drawn at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, and 12 h after the morning dose. Plasma concentrations of mycophenolic acid, its glucuronide metabolites (MPAG; AcMPAG), and free MPA were determined using validated HPLC-DAD. IMPDH activity in leukocytes was analyzed chromatographically. Only six of 24 patients had an MPA-AUC(12h) within the putative therapeutic range of 40-60 mg/L·h. MPA clearance was high with 29 L/h. fMPA-AUC(12h) (r = -0.429, p = 0.04) and MPAG-AUC(12h) correlated significantly with the glomerular filtration rate, while total MPA did not. The MPAG-AUC(12h) was about 52-fold higher than the corresponding values for MPA, whereas the AcMPAG-AUC(12h) reached about 20.4% of the respective MPA-AUC(12h.) We found significant correlations between IMPDH inhibition and MPA concentration (r = -0.665; p < 0.0001), fMPA (r = -0.446; p = 0.003), and AcMPAG (r = -0.459; p = 0.002) but not with MPAG. Only 25% of the patients attained the therapeutic range for MPA-AUC under standard EC-MPS dose during the early-phase post-transplantation. We recommend that EC-MPS should be given in higher doses (3 × 720 mg) in the early post-transplant period when co-administered with cyclosporine.

The aim of the study is to characterize the pharmacokinetics and the gastrointestinal side effect profiles of enteric-coated mycophenolate sodium (EC-MPS) in de novo kidney transplant patients of Hispanic ethnicity.The pharmacokinetic study of EC-MPS was conducted in 11 de novo kidney transplant patients of Hispanic ethnicity. Eight blood samples were obtained after EC-MPS was given at the steady state. Blood concentrations of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) were measured.The mean age (± standard deviation) was 39.4 (± 12.3) years. The mean daily dose of EC-MPS at the time of the pharmacokinetic study was 1408 ± 108 mg. For MPA and MPAG, the time to peak concentration was 2.5 ± 1.3 hours and 4.6 ± 3.1 hours, respectively; the peak concentration (Cmax) was 19.3 ± 17.2 mg/L and 109.4 ± 49.2 mg/L; and the area under the curve from 6 to 12 hours (AUC6-12) was 32.2 ± 19.3 mg·hr/L and 373.7 ± 235.8 mg·hr/L, respectively, which represents 41.3% and 43.0% of AUC0-12. The AUC0-12 for MPA measured 77.8 ± 53.1 mg·hr/L and for MPAG 869.2 ± 388.8 mg·hr/L. Seven patients (64%) exhibited a second peak at approximately 8.3 hours after the dose at a mean concentration (± standard deviation) of 10.3 ± 7.6 mg/L. The Cmax or AUC of MPA does not correlate with overall Gastrointestinal Symptom Rating Scale scores or subscale scores, but the Cmax of MPAG correlates with indigestion subscale (P = 0.022), diarrhea (P = 0.032), and overall scores (P = 0.028). The AUC of MPAG also correlates with acid reflux (P = 0.024) and indigestion (P = 0.032).The pharmacokinetics of EC-MPS has a high variability in de novo kidney transplant patients of the Hispanic ethnicity, which was similar to other ethnic groups. The MPA exposure expressed by the AUC appears to be higher in Hispanic patients than those reported in other ethnic groups, which may be the result of various factors such as difference of the uridine diphosphate glucuronosyltransferase enzyme genotypes, but gastrointestinal side effects were acceptable and the Cmax or AUC of MPAG showed correlations with gastrointestinal symptoms.

In this retrospective study, we compared the outcome of renal transplanted patients who received everolimus (EVR) (C0: 8-12 ng/mL)+cyclosporine (CsA) (C2: 150-300 ng/mL)+steroids, vs those who received enteric-coated mycophenolate sodium (EC-MPS) (1,440 mg/d)+CsA (C2: 500-700 ng/mL)+steroids. Efficacy was evaluated at 5 years. We found a nonsignificant trend toward a better 5-year graft survival (81.2% vs 68.6%) and better graft function (estimated glomerular filtration rate 71.8±35.7 vs 60.0±26.2 mL/min, P=.114) in favor of the EVR group. In our experience, EVR with a very low dose of CsA was associated with a nonstatistical trend toward better renal function and graft survival compared to a standard regimen of CsA and EC-MPS.

Mycophenolic acid (MPA) therapy is a fundamental component of most post-transplant immunosuppressive regimens. Side effects, however, are common and frequently necessitate dose reductions or discontinuations.Enteric-coated mycophenolate sodium (EC-MPS) is designed to improve the gastrointestinal (GI) tolerability of MPA. This review assesses the pharmacology, efficacy and safety of EC-MPS.An understanding of the use of EC-MPS in solid organ transplantation and the key trials examining the GI impact of EC-MPS versus the immediate-release mycophenolate mofetil (MMF) formulation. The article also addresses the possible impact of proton pump inhibitor therapy, and the optimal MPA dose with different concomitant immunosuppressants.Evidence from blinded trials using standard reporting measures or patient-reported outcomes has not confirmed a significant improvement in the GI symptom burden using EC-MPS. Several open-label studies, however, have consistently shown an improvement in GI tolerability with EC-MPS, which can permit restoration of the optimal MPA dose. EC-MPS has equal efficacy and possibly a different tolerability profile to MMF, thus offering a choice to physicians and their patients, particularly those experiencing MMF-related GI symptoms, diabetic patients or those in whom an MPA dose reduction is required.

Tedesco-Silva H, Felipe CR, Park SI, Pinheiro-Machado PG, Garcia R, Slade A, Schmouder R, Medina-Pestana JO. Randomized crossover study to assess the inter- and intrasubject variability of morning mycophenolic acid concentrations from enteric-coated mycophenolate sodium and mycophenolate mofetil in stable renal transplant recipients. Clin Transplant 2010: 24: E116–E123. © 2009 John Wiley & Sons A/S. Abstract: The delayed release of mycophenolic acid (MPA) from enteric-coated mycophenolate sodium (EC-MPS, myfortic®) may have an impact on the variability of MPA trough (C0 h) levels. A randomized, two-period crossover study was performed in 24 maintenance renal transplants to evaluate the inter- and intrasubject variability of MPA predose levels from EC-MPS and mycophenolate mofetil (MMF, CellCept®), both in combination with cyclosporine. Patients received EC-MPS (720 mg b.i.d.) and MMF (1000 mg b.i.d.) for a period of 21 d each. MPA plasma levels were measured over the final seven consecutive days at −1, 0, 1, 2, and 3 h after the morning MPA dose. Intersubject coefficients of variation (%CV) for MPA troughs were 47.5% (95% CI, 34.1–80.3) and 54.4% (40.0–86.8) for EC-MPS and MMF, respectively; intrasubject %CVs were 62.7% (55.1–72.9) and 42.8% (37.9–49.2). High MPA C0 h levels >10 μg/mL were rarely observed with both EC-MPS (1.8%) and MMF (0.6%). Mean MPA area under the curve (AUC)0–3 h was comparable between treatments, while MPA C0 h was on average 46% higher with EC-MPS. In conclusion, predose MPA trough level monitoring appears of limited value during EC-MPS and MMF therapy given the large intrasubject variability in MPA C0 h levels with both treatments.

A main cause for gastrointestinal (GI) complications in graft recipients is the routinely administered inosine monophosphate dehydrogenase inhibitor mycophenolic acid (MPA). MPA is available in two formulations, the prodrug mycophenolate mofetil (MMF) and the enteric-coated sodium salt (EC-MPS). Clinical results point to a better GI tolerability of EC-MPS as compared to MMF. We performed an open surveillance study in 397 organ graft recipients to investigate the clinical tolerability of EC-MPS in renal graft recipients who were converted from MMF to EC-MPS (maintenance) or who received EC-MPS as a new component of their immunsuppressive regimen (de novo). Physicians recorded GI symptoms (nausea, emesis, anorexia, diarrhea, abdominal cramps) at the start of EC-MPS treatment (visit 1) and at the next two visits in the clinic (visits 2 and 3); general tolerability (very good/good/moderate/poor) was assessed at visit 2 and 3. Two hundred seventy-five patients were on maintenance treatment with MMF and were converted to equimolar doses of EC-MPS, and 122 patients received EC-MPS de novo. The mean time since transplantation was 4.2 +/- 4.4 years. Median time until visit 2 was 28 days and until visit 3, 65 days. In 63.0% of patients, tolerability was rated as very good at visit 2 and in 64.7% at visit 3. Most patients who had suffered from GI complications during preceding MMF treatment reported improvement or total disappearance of their symptoms after conversion to EC-MPS. In conclusion, EC-MPS is a useful means to reduce GI complications in MPA-treated patients.

Dose reductions or discontinuations of mycophenolate mofetil (MMF) result in higher incidences of acute rejection and graft loss. Converting renal transplant patients experiencing MMF-related gastrointestinal (GI) side effects to equimolar enteric-coated mycophenolate sodium (EC-MPS) may relieve GI symptoms.In this prospective 12-month study, renal transplant patients maintained on suboptimal MMF doses (1500 mg/d) due to GI intolerance were converted to equimolar EC-MPS followed by incremental EC-MPS dose increases (180 mg/d) every 7 weeks to an established maximum, if well tolerated. Changes in GI symptoms were assessed by physician judgment and Gastrointestinal Symptom Rating Scale (GSRS).Twenty-five patients (mean age: 52.0 +/- 13.6 years) were converted from MMF (930.0 +/- 153.4 mg/d) to equimolar EC-MPS (669.6 +/- 110.5 mg/d) at day 0. Twenty-three of 25 patients tolerated equimolar dose conversion and one or more EC-MPS dose increments at week 28. Compared to baseline, patients received significantly more EC-MPS at week 28 and week 49 (mean dose: 1033.0 +/- 164.8 mg/d, P.0001 and 1001.7 +/- 209.0 mg/d, P.0001, respectively). Two patients dropped out by week 7 for reasons unrelated to EC-MPS. The mean serum creatinine remained stable and no clinical acute rejection episodes occurred over 12 months. Mean GSRS total score remained stable through month 12 when compared to day 0 despite increases in EC-MPS dose.In renal transplant patients receiving suboptimal MMF doses due to GI symptoms, conversion to EC-MPS enabled equimolar prescription and subsequent dose increase without increased GI intolerance.

Introduction. Chronic allograft nephropathy is the main cause of long-term renal transplant failure. Chronic use of calcineurin inhibitors contributes to its pathogenesis. Here, we report on a multicenter randomized trial to study the effects of withdrawal of cyclosporine A (CsA) from a triple immunosuppressive regimen containing CsA, prednisolone (P), and mycophenolate sodium (MPS) early after transplantation.Methods. Patients continued on P/CsA, P/MPS, or P and everolimus (EVL). Before withdrawal, a transplant biopsy was performed ensuring no subclinical rejection was present. Drug levels were closely monitored. The primary outcome was interstitial graft fibrosis and hyalinosis. Secondary outcome was among others graft rejection.Results. According to trial regulations, an interim analysis was performed after enrollment of half of the intended number of patients (n = 113). Mean follow-up was 14 5 months from transplantation and 8 +/- 5 months from conversion. After conversion, acute rejection percentages were 3% in the P/CsA group, 22% in the P/MPS group, and 0% in the P/EVL group (PConclusions. We conclude that switching immunosuppressive therapy from P/CsA/MPS to therapy with P/CsA or P/EVL at 6 months after renal transplantation is effective in preventing rejection. Double therapy with P/MPS after withdrawal of P/CsA resulted in an increase in severe acute rejection episodes. These results were the immediate reason to halt the P/MPS arm. Serum creatinine values at the latest follow-up (8 +/- 5 months after conversion and 14 +/- 5 months after transplantation) in the P/EVL group were lower than in the P/CsA group.

Despite the potential tolerability advantage of enteric-coated mycophenolate sodium (EC-MPS), no prospective, randomized trial has evaluated whether conversion from mycophenolate mofetil (MMF) to EC-MPS permits mycophenolic acid dose to be increased or gastrointestinal side-effects to be ameliorated. In a randomized, multicenter, open-label trial, kidney transplant recipients experiencing gastrointestinal side-effects either remained on MMF or switched to an equimolar dose of EC-MPS, adjusted 2 weeks subsequently to target the highest tolerated dose up to 1440 mg/day (EC-MPS) or 2000 mg/day (MMF). Patients were followed up to 12 weeks postrandomization. One hundred and thirty-four patients were randomized. The primary efficacy endpoint, the proportion of patients receiving a higher mycophenolic acid (MPA) dose at week 12 than at randomization, was significantly greater in the EC-MPS arm (32/68, 47.1%) than the MMF arm (10/61, 16.4%; P < 0.001). At the final visit, 50.0% (34/68) of EC-MPS patients were receiving the maximum recommended dose versus 26.2% (16/61) of MMF patients (P = 0.007). Kidney transplant patients receiving reduced-dose MMF because of gastrointestinal side-effects can tolerate a significant increase in MPA dose after conversion to EC-MPS. Patient-reported gastrointestinal outcomes with higher doses of EC-MPS remained at least as good as in MMF-treated controls.

Background. Mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS) are well established in immunosuppressive therapy after renal transplantation. The active substance, mycophenolic acid, leads to an inhibition of inosine-monophosphate-dehydrogenase (IMPDH) activity in peripheral mononuclear cells. Therefore, we analyzed the effect of different dosing patterns of MMF and EC-MPS on IMPDH activity in stable patients after renal transplantation. Methods. IMPDH activity (pmol/s per pmol AMP) was measured in patients in the maintenance phase after renal transplantation. Besides MMF or EC-MPS, immunosuppressive therapy consisted of calcineurin inhibitor with or without steroids. We performed 260 measurements in 110 patients (82 on MMF, and 28 on EC-MPS). Results. Mean patient age range of 43 women and 67 men was 22 to 74 years. Mean serum creatinine in the MMF group was 1.7 ± 1.3 mg/dL compared to 1.48 ± 0.45 mg/dL in the EC-MPS group (P < .05). The median IMPDH activity in the EC-MPS patients was lower than in the MMF patients (10 vs 24 pmol/s pmol AMP; P < .005). This was especially pronounced in patients on 1440 mg/d EC-MPS compared with 2000 mg/d MMF (P < .001). Conclusion. Measurement of IMPDH activity in renal transplantation patients adds additional information on the degree of immunosuppression. The inhibition of IMPDH activity with EC-MPS seemed more pronounced than MMF despite formally equipotent doses.

Mycophenolic acid (MPA) dose reduction is associated with increased risk of rejection and graft loss in renal transplantation. This analysis investigated the impact of MPA dose changes with enteric-coated mycophenolate sodium (EC-MPS) or mycophenolate mofetil (MMF) in de novo heart transplant recipients. In a 12-month, single-blind trial, 154 patients (EC-MPS, 78; MMF, 76) were randomized to either EC-MPS (1080 mg bid) or MMF (1500 mg bid) in combination with cyclosporine and steroids. The primary efficacy variable was the incidence of treatment failure, comprising a composite of biopsy-proven (BPAR) and treated acute rejection, graft loss or death. Significantly fewer patients receiving EC-MPS required > or =2 dose reductions than patients on MMF (26.9% vs. 42.1% of patients, p = 0.048). Accordingly, the average daily dose of EC-MPS as a percentage of the recommended dose was significantly higher than for MMF (88.4% vs. 79.0%, p = 0.016). Among patients requiring > or =1 dose reduction, the incidence of treated BPAR grade > or =3A was significantly lower with EC-MPS compared with MMF (23.4% vs. 44.0%, p = 0.032). These data suggest that EC-MPS-treated heart transplant patients are less likely to require multiple dose reductions than those on MMF which may be associated with a significantly lower risk of treated BPAR > or =3A.

Background and objectives: The introduction of mycophenolate mofetil has improved graft survival after organ transplantation; however, its use may be limited by important adverse effects. For overcoming these problems, an enteric-coated formulation of mycophenolate sodium has been developed, but pharmacokinetic data of mycophenolic acid release from this formulation are scanty. Design, setting, participants, & measurements: Pharmacokinetic studies in 32 kidney transplant recipients who were given the enteric-coated formulation of mycophenolate sodium (n 12) or mycophenolate mofetil (n 20) were performed. The profiles of mycophenolic acid from the two formulations at months 6, 12, 18, and 24 after transplantation were compared. Subsequently, all patients who were receiving the enteric-coated formulation were shifted to mycophenolate mofetil, and the pharmacokinetic evaluations were repeated. Results: At month 6 after surgery, aberrant and variable pharmacokinetic curves were found in patients who were given the enteric-coated formulation, whereas those who were taking mycophenolate mofetil had regular mycophenolic acid kinetic profiles. Patients who were taking the enteric-coated formulation had mycophenolic acid time of occurrence for maximum drug concentration that ranged from 0 to 480 min and higher dosage-adjusted mycophenolic acid trough levels compared with patients who were given mycophenolate mofetil. Conversion from the enteric-coated formulation of mycophenolate sodium to mycophenolate mofetil resulted in an improvement of the mycophenolic acid kinetics profiles. Conclusions: Given the emerging clinical benefit of mycophenolic acid monitoring in the transplant setting, therapeutic drug monitoring problems with the enteric-coated formulation of mycophenolate sodium should be taken into account. Clin J Am Soc Nephrol 2: 1147–1155, 2007. doi: 10.2215/CJN.02820707

Following 10 years of clinical use of mycophenolate mofetil (MMF), a prodrug of mycophenolic acid, the FDA has approved enteric-coated mycophenolate sodium (EC-MPS). EC-MPS was developed to reduce the upper-gastrointestinal (GI) effects of MMF. Unlike oral MMF, where absorption starts in the stomach, EC-MPS releases MPA in the small intestine. Along with the pharmacology and pharmacokinetics, three randomized, controlled clinical trials in solid-organ transplantation, comparing MMF and EC-MPS, are reviewed. Disappointingly, EC-MPS was similar to MMF in efficacy and safety and did not significantly improve the GI side effects. Moreover, bioequivalence dosing has only been established with concomitant ciclosporin. The pharmacokinetic characteristics must be studied in greater detail. EC-MPS is a safe and effective immunosuppressive agent approved for use in the prevention of acute rejection after renal transplantation. However, the anticipated improvement of GI side effects has not been forthcoming.

The delayed release of mycophenolic acid (MPA) from enteric-coated mycophenolate sodium (EC-MPS) may lead to different MPA predose (C0) levels compared with mycophenolate mofetil (MMF). A post hoc analysis was performed on MPA morning predose values assessed in 88 maintenance renal transplant patients from three studies converted from MMF (1000 mg twice a day) to equimolar EC-MPS (720 mg twice a day) or vice versa, both in combination with cyclosporine. The median MPA predose level was approximately 30% higher when patients received EC-MPS (2.40 microg/mL; range, 0.49-39.30 microg/mL) compared with MMF (1.83 microg/mL; range

Mycophenolic acid (MPA) is a relatively new immuno-suppressive drug, used since the nineties for theprevention of rejection in kidney transplantation.MPA has not only proved effective in preventingrejection, being even superior to azathioprine, but alsoseems to cause less adverse effects than otherimmunosuppressive drugs [1]. Because of these favour-able experiences with MPA in renal transplantation,the drug is currently used in patients with liver, lungand bone marrow transplantation as well. Given itsfavourable profile, MPA has also been used inautoimmune diseases. Following many cases andopen series on the successful use of MPA, mostly inthe form of mycophenolate mofetil (MMF), in renal,rheumatological, gastrointestinal, ophthalmological,dermatological and neurological autoimmune diseases,the first controlled studies have been published or areunderway.MPA is the active metabolite of the two currentlyavailable formulations: mycophenolate mofetil (MMF,Cellcept ) and the slow release formulation enteric-coated mycophenolate sodium (EC-MPS, Myfortic ).The mode of action and the pharmacokinetics of MPAare elegantly described by Allison [2]. In short, MPA isa non-alkylating drug that suppresses the immuneresponse by inhibiting the proliferation of activatedlymphocytes. MPA blocks the enzyme inosine mono-phosphate dehydrogenase (IMPDH), which is essentialfor the de novo synthesis of the purine guanine, andthereby inhibits lymphocytes from proliferating. Whilelymphocytes depend completely on IMPDH forsynthesis of guanine, most other human cells useother pathways for this synthesis, and are therefore notor less affected by the anti-proliferative effect of MPA.In addition, MPA has anti-fibrotic effects, as reviewedby Eugui [3].Following oral ingestion, both MMF and EC-MPSare resorbed and hydrolysed to MPA, which isconjugated in the liver into inactive mycophenolicacid glucuronide before being almost completelycleared by the kidney. Altered pharmacokinetics inpatients with renal insufficiency might explain theincreased rate of adverse effects, which can bemanaged by decreasing the dose of MMF [4]. MPAis not substantially cleared by peritoneal or haemodial-ysis [4].We hereby review the clinical experience with MPAin the treatment of renal diseases.

Mycophenolic acid (MPA), a reversible inhibitor of inosine 5''-monophosphate dehydrogenase (IMPDH), selectively inhibits T- and B-cell proliferation. MPA exposure correlates inversely with the risk of acute rejection. Mycophenolate mofetil (CellCept; MMF) is an immediate-release formulation of MPA that is absorbed in the stomach and small intestine. Enteric-coated mycophenolate sodium (myfortic; EC-MPS) delays MPA release until the small intestine. There are some indications that EC-MPS may be associated with improved gastrointestinal (GI) toxicity. It is widely believed that systemic MPA exposure determines the extent of GI toxicity. However, intestinal cells absorb purines locally from the gut lumen via passive diffusion and a specific transport mechanism. It seems likely that local, rather than systemic, MPA exposure is responsible for GI events. Acyl-MPAG, a toxic metabolite of MPA, may be produced by GI cells contributing to MPA-related gut toxicity, suggesting that measures to alter the rate or location of MPA absorption could be beneficial. Lastly, the release of N-(2-hydroxyethyl)morpholine following deestification of MMF may have local irritative effects on gastric mucosal cells. Research which more closely focuses on the local gut pathobiology of MPA-containing drugs may provide a much clearer understanding of the dose-limiting toxicity of this drug class.

This review aims to provide an extensive overview of the literature on the clinical pharmacokinetics of mycophenolate in solid organ transplantation and a briefer summary of current pharmacodynamic information. Strategies are suggested for further optimisation of mycophenolate therapy and areas where additional research is warranted are highlighted. Mycophenolate has gained widespread acceptance as the antimetabolite immunosuppressant of choice in organ transplant regimens. Mycophenolic acid (MPA) is the active drug moiety. Currently, two mycophenolate compounds are available, mycophenolate mofetil and enteric-coated (EC) mycophenolate sodium. MPA is a potent, selective and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), leading to eventual arrest of T- and B-lymphocyte proliferation. Mycophenolate mofetil and EC-mycophenolate sodium are essentially completely hydrolysed to MPA by esterases in the gut wall, blood, liver and tissue. Oral bioavailability of MPA, subsequent to mycophenolate mofetil administration, ranges from 80.7% to 94%. EC-mycophenolate sodium has an absolute bioavailability of MPA of approximately 72%. MPA binds 97–99% to serum albumin in patients with normal renal and liver function. It is metabolised in the liver, gastrointestinal tract and kidney by uridine diphosphate gluconosyltransferases (UGTs). 7-O-MPA-glucuronide (MPAG) is the major metabolite of MPA. MPAG is usually present in the plasma at 20- to 100-fold higher concentrations than MPA, but it is not pharmacologically active. At least three minor metabolites are also formed, of which an acyl-glucuronide has pharmacological potency comparable to MPA. MPAG is excreted into the urine via active tubular secretion and into the bile by multi-drug resistance protein 2 (MRP-2). MPAG is de-conjugated back to MPA by gut bacteria and then reabsorbed in the colon. Mycophenolate mofetil and EC-mycophenolate sodium display linear pharmacokinetics. Following mycophenolate mofetil administration, MPA maximum concentration usually occurs in 1–2 hours. EC-mycophenolate sodium exhibits a median lag time in absorption of MPA from 0.25 to 1.25 hours. A secondary peak in the concentration-time profile of MPA, due to enterohepatic recirculation, often appears 6–12 hours after dosing. This contributes approximately 40% to the area under the plasma concentration-time curve (AUC). The mean elimination half-life of MPA ranges from 9 to 17 hours. MPA displays large between- and within-subject pharmacokinetic variability. Dose-normalised MPA AUC can vary more than 10-fold. Total MPA concentrations should be interpreted with caution in patients with severe renal impairment, liver disease and hypoalbuminaemia. In such individuals, MPA and MPAG plasma protein binding may be altered, changing the fraction of free MPA available. Apparent oral clearance (CL/F) of total MPA appears to increase in proportion to the increased free fraction, with a reduction in total MPA AUC. However, there may be little change in the MPA free concentration. Ciclosporin inhibits biliary excretion of MPAG by MRP-2, reducing enterohepatic recirculation of MPA. Exposure to MPA when mycophenolate mofetil is given in combination with ciclosporin is approximately 30–40% lower than when given alone or with tacrolimus or sirolimus. High dosages of corticosteroids may induce expression of UGT, reducing exposure to MPA. Other co-medications can interfere with the absorption, enterohepatic recycling and metabolism of mycophenolate. Most pharmacokinetic investigations of MPA have involved mycophenolate mofetil rather than EC-mycophenolate sodium therapy. In population pharmacokinetic studies, MPA CL/F in adults ranges from 14.1 to 34.9 L/h (ciclosporin co-therapy) and from 11.9 to 25.4 L/h (tacrolimus co-therapy). Patient bodyweight, serum albumin concentration and immunosuppressant co-therapy have a significant influence on CL/F. The majority of pharmacodynamic data on MPA have been obtained in patients receiving mycophenolate mofetil therapy in the first year after kidney transplantation. Low MPA AUC is associated with increased incidence of biopsy-proven acute rejection. Gastrointestinal adverse events may be dose related. Leukopenia and anaemia have been associated with high MPA AUC, trough concentration and metabolite concentrations in some, but not all, studies. High free MPA exposure has been identified as a risk factor for leukopenia in some investigations. Targeting a total MPA AUC from 0 to 12 hours (AUC12) of 30–60 mg ∙ hr/L is likely to minimise the risk of acute rejection and may reduce toxicity. IMPDH monitoring is in the early experimental stage. Individualisation of mycophenolate therapy should lead to improved patient outcomes. MPA AUC12 appears to be the most useful exposure measure for such individualisation. Limited sampling strategies and Bayesian forecasting are practical means of estimating MPA AUC12 without full concentration-time profiling. Target concentration intervention may be particularly useful in the first few months post-transplant and prior to major changes in anti-rejection therapy. In patients with impaired renal or hepatic function or hypoalbuminaemia, free drug measurement could be valuable in further interpretation of MPA exposure.

Purpose The increased tolerability of enteric-coated mycophenolate sodium (EC-MPS), compared to mycophenolate mofetil, among kidney transplant recipients has the potential to facilitate cyclosporine (CsA) minimization. Therefore, a prospective trial to determine the optimum EC-MPS dose in CsA-based immunosuppression regimens is necessary. Materials and Methods A comparative, parallel, randomized, open-label study was performed for 140 patients from four centers to compare the efficacy and tolerability of low dose CsA with standard dose EC-MPS (the investigational group) versus standard dose CsA with low dose EC-MPS (the control group) for six months in de novo kidney transplant recipients. Graft function, the incidence of efficacy failure [biopsy-confirmed acute rejection (BCAR), death, graft loss, loss to follow-up], and adverse events were compared. Results The mean estimated glomerular filtration rate (eGFR) of the investigational group at six months post-transplantation was non-inferior to that of the control group (confidence interval between 57.3 mL/min/1.73m2 and 67.4 mL/min/1.73 m2, p0.05) in the incidence of discontinuations and serious adverse events (SAE) between the groups. Conclusion CsA minimization using a standard dose of EC-MPS kept the incidence of acute rejection and additional risks as low as conventional immunosuppression and provided therapeutic equivalence in terms of renal graft function and safety issues.