Abstract: BACKGROUND: To better define subpopulations in which achieving adequate mycophenolic acid (MPA) concentrations quickly would be important, a post hoc exploratory analysis on the fixed-dose concentration-controlled database was performed, comparing high- versus low-risk renal transplant patients. METHODS: Renal transplant patients were treated with mycophenolate mofetil, corticosteroids, and cyclosporine A or tacrolimus. Patients were defined as "high risk" if they had one or more of the following characteristics: delayed graft function, second or third transplantation, panel reactive antibodies >15%, four or more human leukocyte antigen mismatches, or were of black race. RESULTS: A total of 549 patients (61%) were classified as high risk, of whom 284 were on cyclosporine A treatment and 265 on tacrolimus. In high-risk patients, the difference in rejection incidence was 14.3% in the MPA-area under the concentration (AUC) less than 30 mg hr/L vs. 7.8% in the MPA-AUC more than or equal to 30 mg hr/L groups (P=0.025) during the first month after transplantation; whereas, in low-risk patients, there were similar rejection rates (5.7% vs. 4.5%). In the subgroup of high-risk tacrolimus-treated patients, the difference in acute rejection incidence in the first month between patients with MPA-AUC0-12 less than or more than or equal to 30 mg hr/L was most pronounced: 16 of 67 patients (23.9%) vs. 18 of 173 patients (10.4%); P=0.012. CONCLUSIONS: The incidence of acute rejection is higher in high-risk patients if MPA-AUC0-12 is below 30 mg hr/L. In contrast, a difference in acute rejection incidence in low-risk patients with MPA-AUC0-12 less than or more than or equal to 30 mg hr/L was not observed. This supports the use of a higher mycophenolate mofetil starting dose in selected patient populations early after transplantation.
Abstract: BACKGROUND AND OBJECTIVES: Adequate early mycophenolic acid (MPA) exposure is an important determinant for effective rejection prophylaxis. This pharmacokinetic study investigated whether an intensified dosing regimen of enteric-coated mycophenolate sodium (EC-MPS) could achieve higher mycophenolic acid (MPA) exposure early after transplantation versus a standard dosing regimen. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: De novo kidney transplant recipients (n = 75) who were treated with basiliximab induction and cyclosporine were randomly assigned to receive EC-MPS as either standard dosing (1440 mg/d; n = 37) or intensified dosing (days 0 through 14: 2880 mg/d; days 15 through 42: 2160 mg/d; followed by 1440 mg/d; n = 38). Full 12-hour pharmacokinetic and pharmacodynamic profiles were taken at six time points during the first 3 months. Exploratory analysis of inosine monophosphate dehydrogenase (IMPDH) activity was also performed for better understanding of the pharmacokinetic-pharmacodynamic relationship between MPA exposure and IMPDH activity in the early posttransplantation period. Preliminary efficacy parameters, safety, and tolerability were assessed. RESULTS: Exposure to MPA was significantly higher on days 3 and 10 after transplantation in the intensified versus standard EC-MPS group, with 52.9 versus 22.2% (P < 0.05) of patients reaching MPA exposure >40 mg/h per L in the first week. The intensified regimen resulted in significantly lower IMPDH activity on day 3 after transplantation, and the overall safety was comparable for both groups. CONCLUSIONS: These pharmacokinetic and safety data support further research on the hypothesis that early adequate MPA exposure could improve clinical outcome.
Abstract: BACKGROUND: Early and long-term use of cyclosporine A (CsA) leads to increased risks of renal toxicity. We hypothesized that administration of daclizumab in combination with mycophenolate mofetil (MMF) allows a relevant reduction in the dose of CsA. METHODS: We carried out a 3-year, prospective, randomized, controlled clinical multi-centre trial in 156 patients. The patients were randomized to standard treatment (CsA, MMF, steroids) or to high-dose daclizumab (first dose: 2 mg/kg), in combination with low-dose CsA, MMF and steroids. We maintained the mean CsA levels of daclizumab patients at 57% of standard patients (132 versus 216 ng/ml) on Day 7 post-transplant, and 84% by 6 months. RESULTS: Primary outcome, creatinine clearance (with imputation of informative dropouts) at 12 months, was significantly better in daclizumab-treated (34 +/- 17) than standard patients (29 +/- 17; P = 0.028, two sided). Only 5 cases of BPAR were recorded in the daclizumab compared to 22 in the standard group (P = 0.0016). Daclizumab patients had 91% event-free survival after 1 year compared to 66% in standard patients (P = 0.00017). CONCLUSION: We demonstrate here that high-dose daclizumab in combination with lower CsA levels in adult renal transplant recipients is as or more effective than standard regimen (CsA, MMF, steroids) and may result in better outcomes at 12 months post-transplant with no increase in adverse reactions.
Abstract: BACKGROUND: Laparoscopic live donor nephrectomy is the preferred method of kidney donation in high-volume US transplant centers, but for small transplant programs the question of the minimal case load per year necessary to reach the quality standards is open. PATIENTS AND METHODS: From 1996 to 2007 we performed 130 live kidney donations including 93 laparoscopic donor nephrectomies followed by transplantation in a community hospital with an average case load of 10 laparoscopic cases per year. We compared the results after 37 open and 93 laparoscopic live donor operations with respect to operating time, conversion rate, complications, and recipients' outcome. RESULTS: There were no significant differences in terms of safe outcome of donor patients after open or laparoscopic donor nephrectomy. The mean operating time was significantly shorter (p < 0.001) in the open group (125 min, OG) than in the laparoscopic group (150 min, LG). Mean hospital stay was significantly shorter (p < 0.001) in LG (6.8 days) versus OG (9.7 days). The conversion rate was 3.2% in the LG. Postoperative complication of donors consisted of temporary nerve irritation (two patients) and retroperitoneal hematoma (one patient) in the LG, and wound infection followed by hernia formation (one patient) and ileus 1 year after organ donation (one patient) in the OG. Safe outcome of the recipients after open (RaOD) or laparoscopic donation (RaLD) was similar. Uneventful transplantation occurred in 94.6% of the RaOD and in 92.5% of the RaLD. One kidney was lost due to renal vein thrombosis (RaLD). Mean postoperative creatinine after 4 weeks showed no difference between RaOD (1.6 mg/dl) and RaLD (1.7 mg/dl). CONCLUSION: Approximately ten cases per year may be enough to ensure safety and quality of laparoscopic live donor nephrectomy.
Abstract: BACKGROUND: The choice of immunosuppression regimen is of paramount importance for outcomes and cost of renal transplantation. We compared the cost-effectiveness of triple immunosuppressive regimens in Germany. METHODS: A strong micro-simulation model was built comparing regimens based on cyclosporine, everolimus, sirolimus, and tacrolimus. Mean cost per patient, incremental cost per life year gained, and incremental cost per additional year with functioning graft were assessed from the perspective of the German statutory health insurance (SHI) after 2 and 10 years. RESULTS: Over the 2-year period, the model predicted mean total costs per patient of 26,732, 29,352, 33,415, and 49,978 euro for sirolimus, cyclosporine, everolimus, and tacrolimus, respectively. Focusing on the cost per life year gained, the sirolimus-based regimen compared favorably with those based on everolimus and tacrolimus. The incremental cost-effectiveness ratio (ICER) of cyclosporine versus sirolimus is 524,000 euro per life year gained. Regarding the cost per year with functioning graft gained, sirolimus dominated cyclosporine and everolimus, while the ICER for tacrolimus compared to sirolimus amounts to 1,788,154 euro. Over the 10-year time frame, mean total costs per patient were 100,758, 108,300, 120,316, and 183,802 euro for sirolimus, cyclosporine, everolimus, and tacrolimus, respectively. With regard to life years gained, sirolimus dominated both cyclosporine and everolimus. The ICER of tacrolimus versus sirolimus was 1,766,894 euro. Considering the years with functioning graft gained, sirolimus dominated cyclosporine and everolimus, while the ICER for tacrolimus compared to sirolimus amounted to 1,339,419 euro. CONCLUSIONS: Over both the 2-year and the 10-year time horizon, sirolimus-based immunosuppression represents a cost-effective option in renal transplantation in Germany.
Abstract: BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a slowly progressive hereditary disorder that usually leads to end-stage renal disease. Although the underlying gene mutations were identified several years ago, efficacious therapy to curtail cyst growth and prevent renal failure is not available. Experimental and observational studies suggest that the mammalian target of rapamycin (mTOR) pathway plays a critical role in cyst growth. METHODS: In this 2-year, double-blind trial, we randomly assigned 433 patients with ADPKD to receive either placebo or the mTOR inhibitor everolimus. The primary outcome was the change in total kidney volume, as measured on magnetic resonance imaging, at 12 and 24 months. RESULTS: Total kidney volume increased between baseline and 1 year by 102 ml in the everolimus group, versus 157 ml in the placebo group (P=0.02) and between baseline and 2 years by 230 ml and 301 ml, respectively (P=0.06). Cyst volume increased by 76 ml in the everolimus group and 98 ml in the placebo group after 1 year (P=0.27) and by 181 ml and 215 ml, respectively, after 2 years (P=0.28). Parenchymal volume increased by 26 ml in the everolimus group and 62 ml in the placebo group after 1 year (P=0.003) and by 56 ml and 93 ml, respectively, after 2 years (P=0.11). The mean decrement in the estimated glomerular filtration rate after 24 months was 8.9 ml per minute per 1.73 m2 of body-surface area in the everolimus group versus 7.7 ml per minute in the placebo group (P=0.15). Drug-specific adverse events were more common in the everolimus group; the rate of infection was similar in the two groups. CONCLUSIONS: Within the 2-year study period,as compared with placebo, everolimus slowed the increase in total kidney volume of patients with ADPKD but did not slow the progression of renal impairment [corrected]. (Funded by Novartis; EudraCT number, 2006-001485-16; ClinicalTrials.gov number, NCT00414440.)
Abstract: Dose reduction and discontinuation of mycophenolate mofetil (MMF) therapy because of gastrointestinal complications has been associated with increased risk of acute rejection episodes and graft loss. Enteric-coated mycophenolate sodium (EC-MPS) delays release of mycophenolic acid (MPA), and was designed to reduce MPA-related gastrointestinal adverse events. Data comparing the efficacy of EC-MPS vs MMF in de novo renal transplant (RTx) recipients from large prospective studies are limited. Therefore, a pooled data analysis was performed based on 1891 de novo RTx recipients receiving EC-MPS (n = 1289) or MMF (n = 602) plus cyclosporine and steroid therapy in 4 prospective multicenter studies with similar entry criteria. In all trials, the initial dose of EC-MPS was 1440 mg/d, and of MMF was 2000 mg/d; both dosages deliver equimolar amounts of MPA. Induction therapy was permitted in 2 studies per center practice. Multivariate logistic regression analysis was performed, adjusting other potential explanatory variables including recipient age, sex, and race/ethnicity; induction therapy; and diabetes mellitus at baseline. In addition, propensity scores were used to explain potential bias. Mean (SD) MPA dose (EC-MPS dosage was converted to MMF equivalent) during months 0 to 12 was similar: EC-MPS, 1820 (370) mg/d, vs MMF, 1860 (290) mg/d. However, at univariate and multivariate analyses, the rates of treatment failure, biopsy-proved acute rejection episodes, and graft loss were significantly lower with EC-MPS compared with MMF at month 12. In conclusion, this pooled analysis documents a substantial improvement in efficacy in de novo RTx recipients receiving EC-MPS vs MMF with concomitant cyclosporine and steroid therapy.
Abstract: Renal transplant recipients show an increased risk of cardiovascular disease compared with a nontransplant population. Herein we have shown an analysis of a randomized controlled trial wherein 525 patients receiving a first or second (9.7%) renal allograft from a deceased (89.1%), a living-related (7.8%), or a living-unrelated donor (3.1%) received sirolimus (SRL), cyclosporine (CsA), and steroids (ST) at the time of transplantation with randomization at 3 months after transplantation of 430 eligible patients to continue on SRL-CsA-ST or to have CsA withdrawn with increased SRL trough targets (SRL-ST group). Graft survival, patient survival, and renal function at 5 years were analyzed by average fasting total cholesterol (<or=200 or >200 mg/dL) and triglyceride (<or=240 or >240 mg/dL) subgroups. At 5 years, total, high-density lipoprotein (HDL), and low-density lipoprotein [LDL] cholesterol and triglyceride values were similar between the groups. Statins ( approximately 80% of patients of both groups) were most effective to lower cholesterol ( approximately 50 mg/dL; P < .001; both groups), and fibrates ( approximately 25% of patients of both groups) were most effective to decrease triglycerides ( approximately 100 mg/dL; P < .001; both groups). Renal function and blood pressure were significantly better with SRL-ST. Hypercholesterolemia and hypertriglyceridemia were associated with reduced graft survival, patient survival, and calculated GFR, but the only significant difference was lower graft survival among SRL-CsA-ST patients with hypertriglyceridemia. Cardiovascular-related deaths were reported in 3.7% and 2.8% of patients in the SRL-CsA-ST and SRL-ST groups, respectively. In conclusion, when compared with continuous SRL-CsA-ST, CsA withdrawal at 3 months followed by SRL-ST significantly improved glomerular filtration rate (GFR) and blood pressure without a further increase in lipid parameters or an incidence of untoward effects from hyperlipidemia, despite a 2-fold higher SRL exposure.
Abstract: Chronic allograft nephropathy (CAN) leads to the majority of late graft loss following renal transplantation. Detection of CAN is often too late to permit early intervention and successful management. Most current strategies for managing CAN rely on minimizing or eliminating calcineurin inhibitors (CNIs) once CAN has become established. The proliferation signal inhibitors everolimus and sirolimus have potent immunosuppressive and antiproliferative actions, with the potential to alter the natural history of CAN by reducing CNI exposure whilst avoiding acute rejection. Whilst data will be forthcoming from a number of clinical trials investigating this potential, we discuss early detection of CAN and the rationale for a role for this class of agent.
Abstract: INTRODUCTION: In contrast to the USA, laparoscopic donor nephrectomy is rarely practised in German transplant centres. Safety concerns and difficulties with the learning curve of this advanced laparoscopic procedure are the main obstacles to the establishment of this operation. PATIENTS AND METHODS: From 1998-2005, we performed laparoscopic kidney procurement in 50 live kidney donors on an intention to treat basis harvesting a total of 29 left and 21 right kidneys for transplantation. RESULTS: Negative adverse effects on the donor side were temporary nerve irritation (2 patients) and postoperative retroperitoneal hematoma. Reasons to convert to open nephrectomy were bleeding (2 patients) and adhesions (1 patient). On the recipient side, one kidney was lost due to renal vein thrombosis. Three patients required short-time dialysis after transplantation. All other kidney transplants worked without any problems. CONCLUSION: Laparoscopic donor nephrectomy is a safe procedure and has been established as the method of choice for live kidney donation in our hospital.
Abstract: Transplantation offers a unique opportunity to demonstrate the complementary roles of randomized controlled trials and outcome research. The surgery and collaboration necessary for the transplant procedure makes randomization and blinding difficult. Because essentially every recipient is included in a transplant registry, sampling bias is minimized. Regulatory agencies generally do not consider outcomes research when assessing efficacy of new drugs or medical interventions. This workgroup summary examines the suitability of outcomes research to complement results of randomized controlled trials and related issues: efficacy versus effectiveness, internal versus external validity, data types, limitations, and analysis methodologies. Many advances in outcomes research have been pioneered in transplantation. A case is made for regulatory and reimbursement authorities to use outcomes research when making efficacy, effectiveness, and coverage decisions in transplantation.
Abstract: New classes of agents have sequentially increased the specificity of post-transplant immunosuppression, leading to profound improvements in success rates after renal transplantation. The next era will focus on increased long-term survival rates through optimal use of existing agents and the rational development of drugs based on prior identification of specific immunologic targets. Conventionally, long-term outcomes after kidney transplantation have been assessed by surrogate markers, notably acute rejection, but graft-threatening complications such as development of new-onset diabetes mellitus and polyomavirus nephropathy must be addressed if long-term survival rates are to be improved. Mycophenolic acid therapy must be administered optimally to ensure that adequate exposure is achieved in the immediate post-transplant period and, subsequently, by avoiding underdosing due to gastrointestinal events. Chronic allograft nephropathy remains a major concern, and protocol-led, reliable monitoring strategies are essential to enable early intervention, for example, through introduction of proliferation signal inhibitor therapy with concomitant calcineurin inhibitor reduction or withdrawal. The range of immunosuppressive regimens now available and in development, together with improved assessment of patients' risk profiles for immunologic events and comorbid disease, offers the opportunity for further individualization of immunosuppression after renal transplantation.
Abstract: BACKGROUND: Laparoscopic live donor nephrectomy has become the new gold standard for kidney procurement in many high-volume transplant centres worldwide, but it is often limited to left-sided donor kidneys. Concerns about adequate anatomical renal vessel length and sufficient surgical exposure are the main obstacles to the use of the laparoscopic approach for right kidney live donors as well. MATERIAL AND METHODS: From 1998 to 2006 we performed laparoscopic kidney procurement in 73 live kidney donors on an intention-to-treat basis, harvesting a total of 48 left (LKG) and 25 right kidneys (RKG) for transplantation. We compared these two groups with respect to operating time, conversion rate, complications, hospital stay, and recipient outcome. RESULTS: There were no differences in outcome of donor patients after left (D-LKG) or right laparoscopic donor nephrectomy (D-RKG). Operating time was 160 min in D-RKG versus 164 min in D-LKG. Warm ischemia was below 150 s in both groups. Hospital stay was 7.0 (D-RKG) versus 6.7 days (D-LKG). Negative events on the donor site were one temporary nerve irritation in each group and one postoperative retroperitoneal hematoma in the left kidney group. Reasons to convert to open nephrectomy were bleeding in two patients in the left kidney group and adhesions in one patient in the right kidney group. The outcome of the recipients after left (R-LKG) or right kidney (R-RKG) transplantation was similar. One kidney was lost due to renal vein thrombosis (R-LKG). Postoperative ureter complications occurred in one patient of each group. One patient of the R-RKG and two patients of the R-LKG required lymphocele fenestration. All other kidney transplants worked without problems. CONCLUSION: Laparoscopic donor nephrectomy is a safe procedure and has been established as the method of choice for live kidney donation in our clinic. Laparoscopic procurement of right and left kidneys can be performed with comparable quality and outcome for donors and recipients.
Abstract: The aim of this study was to determine whether plasma concentrations of the acyl (AcMPAG) and phenolic (MPAG) glucuronide metabolites of mycophenolic acid (MPA) were related to diarrhoea in renal transplant patients on mycophenolate mofetil (MMF) with cyclosporine (CsA) or tacrolimus (TCL). Blood samples (0, 30, 120 min) were taken at days 3, 10, week 4, months 3, 6 and 12 for determination of MPA, MPAG and AcMPAG. MPA-AUC was estimated using validated algorithms. Two hour AUCs were calculated for MPAG and AcMPAG. Immunosuppressive therapy consisted of CsA/MMF (n= 110) and of TCL/MMF (n= 180). In 70/290 (24%) patients 86 episodes of diarrhoea were recorded during 12 months. Significantly more patients on TCL (31.1%) suffered from diarrhea compared to CsA (12.7%). MMF dose, MPA-AUC and the 2 h AUCs of MPAG and AcMPAG did not differ between patients with and without diarrhoea. Plasma AcMPAG and MPAG concentrations were substantially higher in patients on CsA compared with TCL, while MPA-AUC was lower in the former group. These data support the concept that CsA inhibits the biliary excretion of MPAG and AcMPAG, thereby potentially reducing the risk of intestinal injury through enterohepatic recycling of MPA and its metabolites.
Abstract: BACKGROUND: Mycophenolic acid (MPA) pharmacokinetics using the mycophenolate mofetil (MMF) formulation are known to differ between patients receiving tacrolimus or cyclosporine, but only limited data exist concerning concomitant use of tacrolimus and enteric-coated mycophenolate sodium (EC-MPS). METHODS: In this six-month, multicenter, open-label, single-arm trial, 63 maintenance renal transplant patients receiving tacrolimus were converted from mycophenolate mofetil (MMF) to EC-MPS. RESULTS: MPA concentration-time profiles in 21 patients showed that MPA exposure was similar with MMF or EC-MPS (mean area under the curve 39.9+/-11.6 microg x h/mL versus 43.7+/-17.4 microg x h/mL at day 14 post-conversion). Median time to peak concentration was 0.5 hr with MMF and 1.5 hr with EC-MPS. Inosine monophosphate dehydrogenase (IMPDH) activity was almost identical: area under the enzyme activity time curve (AEC) was 124.2+/-32.0 nmol x h/mg prot/h with MMF and 130.3+/-36.6 nmol x h/mg prot/h with EC-MPS at 14 days post-conversion; average daytime IMPDH activity was 10.3+/-2.7 nmol/h/mg protein and 10.9+/-2.7 nmol/h/mg protein, respectively. Maximal daytime inhibition of IMPDH activity was 67% with MMF and 62% with EC-MPS at day 14. One patient (1.6%) experienced mild biopsy-proven acute rejection. No graft losses or deaths occurred. Renal function remained stable (mean calculated creatinine clearance 70.6+/-26.8 mL/min with MMF and 68.8+/-25.4 mL/min six months post-conversion). Adverse events or infections with a suspected relation to EC-MPS occurred in 12 patients (19%). Four patients discontinued EC-MPS due to adverse events or infections. CONCLUSIONS: MMF and EC-MPS are associated with similar MPA exposure and equivalent pharmacodynamic effect. Conversion of tacrolimus-treated maintenance renal transplant patients from MMF to EC-MPS is safe and well-tolerated and does not compromise therapeutic efficacy.
Abstract: 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.
Abstract: Acute rejection episodes are now as low as 5-20% in the first year after renal transplantation; however, graft half-life has remained almost unchanged in the last decade. This statistic is mainly attributable to the side effects of immunosuppression, with loss of allografts due to the chronic allograft nephropathy that is a consequence of calcineurin inhibitor toxicity or hypertension. Patient death due to cardiovascular events, infections and malignancy also contribute to allograft loss. The introduction of the inhibitors of the mammalian target of rapamycin sirolimus and everolimus in renal transplantation has increased the repertoire of immunosuppressive protocols substantially. They have a different mode of action and a different side effect profile (i.e. lower nephrotoxicity, less hypertension and less neoplastic potential) than the calcineurin inhibitors. The inhibitors of the mammalian target of rapamycin therefore provide an especially promising alternative for the maintenance immunosuppression after renal transplantation. This overview provides a summary of the current literature on inhibitors of the mammalian target of rapamycin, with a special focus on sirolimus.
Abstract: Increasing success in renal transplantation and longer patient survival has meant that post-transplant malignancies are having an increasing impact on long-term graft and patient survival. Choice of the immunosuppressive agents provides one of the controllable risk factors for the development of malignancies in this population. Calcineurin inhibitors (CNIs) are associated with an increased incidence of cancers, whereas the proliferation signal inhibitors (PSIs), everolimus and sirolimus have demonstrated anti-oncogenic effects in pre-clinical models and are currently being investigated as anti-cancer agents in clinical trials. There is increasing evidence demonstrating a lower incidence of post-transplant malignancies in renal transplant recipients receiving PSI-based immunosuppression compared with those receiving CNIs. Conversion from CNIs to PSIs has been shown to lead to the regression of Kaposi's sarcoma in renal transplant recipients and is now part of accepted standard care for this tumour in this setting. The anti-cancer properties of PSI-based regimens have the potential to combine the dual benefits of immunosuppression without the use of CNIs and the direct anti-oncogenic effects through their inhibition of the mammalian target of rapamycin (mTOR) signalling pathway. In the absence of formal clinical trial evidence on the best way to use PSIs in this setting, a workshop was held to provide practical guidance on immunosuppressive strategies in the context of malignancy, given the current state of knowledge.
Abstract: While advances in immunosuppressive therapy have allowed dramatic improvements in the control of acute allograft rejection, there is still a need to improve long-term graft and patient survival rates following renal and heart transplantation. Among the recognized threats to long-term organ survival are chronic allograft dysfunction in the form of chronic allograft nephropathy and cardiac allograft vasculopathy, with long-term patient morbidity and mortality further compromised by higher than normal rates of posttransplant cardiovascular disease, infection, and malignancy. A growing body of evidence finds that the selection and dosing of immunosuppressive therapies can have great influence on long-term transplantation outcomes. Early evidence suggests that the proliferation signal inhibitors (PSIs), everolimus and sirolimus, might offer effective immunosuppressive activity together with antiproliferative effects that may address some of the unmet needs in the long-term therapeutic management of the posttransplant patient. This review summarizes the emerging evidence for employing PSI-based immunosuppression to seek a balance between the goals of maximizing graft and patient survival, while minimizing the risks of adverse events and long-term complications. Based on the proceedings of an international gathering of nephrologists, cardiologists and surgeons at the inaugural PSI Forum meeting "Proliferation signal inhibitors in transplantation: questions at the cutting edge," this paper aims to provide both an evidence base and practical guidance for transplant physicians seeking to optimize their use of PSI treatment and highlights avenues of ongoing research into the clinical potential of this class of immunosuppressive therapy.
Abstract: Enteric-coated mycophenolate sodium is an advanced formulation delivering mycophenolic acid (MPA), designed to improve MPA-related upper gastrointestinal adverse events by delaying MPA release until the small intestine. OBJECTIVE: Two studies were undertaken to identify the absolute bioavailability and dose-proportionality of enteric-coated mycophenolate sodium in stable renal transplant patients receiving cyclosporine. METHODS: Study 1: The mean MPA AUC(0-t) was shown to be greater after MPA infusion than after oral enteric-coated mycophenolate sodium (42.1 vs. 28.9 microg x h/ml). Mean absolute bioavailability was 0.71 +/- 0.21 (SD). Study 2: The AUC(0-t) and C(max) for MPA were proportional to the dose of enteric-coated mycophenolate sodium, similarly mean AUC(0-infinity) and C(max) for MPA glucuronide were proportional to dose administered. RESULTS AND CONCLUSIONS: In patients receiving cyclosporine the absolute bioavailability of MPA provided by enteric-coated mycophenolate sodium is equivalent to that provided by mycophenolate mofetil when administered in combination with cyclosporine, and exhibits dose-proportionality. Enteric-coated mycophenolate sodium was well tolerated from 180 - 2,160 mg with no serious adverse events reported.
Abstract: BACKGROUND: The benefit of converting renal transplant recipients with gastrointestinal (GI) complaints from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) has not been evaluated using patient-reported outcomes. METHODS: A multicenter, open-label, prospective study was undertaken in MMF-treated renal transplant patients. Patients experiencing GI complaints were converted to equimolar EC-MPS (Cohort A). Patients without GI complaints remained on MMF (Cohort B). At baseline and Visit 2 (4-6 weeks postbaseline), patients completed the Gastrointestinal Symptom Rating Scale (GSRS), Gastrointestinal Quality of Life Index (GIQLI) and Psychological General Well-being Index (PGWBI). At Visit 2, patients and physicians completed the Overall Treatment Effect (OTE) scale for GI symptoms. Additionally, patients completed the OTE for health-related quality of life (HRQoL). Minimal important difference (MID) was calculated for GSRS and GIQLI based on patients' and physicians' OTE evaluation. RESULTS: Of 328 patients enrolled (i.e. the intent-to-treat and safety populations), 278 formed the per-protocol population (Cohort A, n=177; Cohort B, n=101). At baseline, Cohort A had significantly worse scores on all GSRS, GIQLI and PGWBI subscales compared to Cohort B (all P<0.0001). All GSRS, GIQLI and PGWBI subscale scores improved significantly in Cohort A between baseline and Visit 2 (all P<0.0001). Mean improvements in all GSRS subscales and most GIQLI subscores exceeded the calculated MID. GSRS, GIQLI and PGWBI subscales remained stable in Cohort B. CONCLUSION: This first exploratory study indicates that converting patients with mild, moderate or severe GI complaints from MMF to EC-MPS significantly reduces GI-related symptom burden and improves patient functioning and well-being.
Abstract: Conversion from mycophenolate mofetil (MMF, CellCept) to enteric-coated mycophenolate sodium (EC-MPS, myfortic) is safe and effective in renal transplant patients treated with the standard dose of 2 g MMF. In this 6-month, international, multicenter, open-label, single-arm trial, a large cohort of maintenance renal transplant patients receiving different doses of MMF were converted under normal clinical conditions to equimolar doses of EC-MPS. Mean calculated creatinine clearance remained stable from the time of study entry (59.6 +/- 19.7 mL/min) to the end of the study (58.3 +/- 19.8 mL/min). Adverse events were reported by 152 patients (67%), with gastrointestinal complications being observed in 45 patients (20%). Thirty-three patients (15%) experienced adverse events or infections with a suspected relation to EC-MPS, including one case of anemia and two cases of leukopenia. Eleven patients (4.9%) required a reduction in EC-MPS dose and seven patients (3.1%) permanently discontinued EC-MPS owing to adverse events. At month 6 after conversion, five patients (2.2%) experienced biopsy-proven acute rejection. There were no graft losses or deaths. These data support earlier findings that stable maintenance renal transplant patients receiving MMF with cyclosporine with or without corticosteroids can be converted to EC-MPS with no compromise in efficacy and tolerability, and no adverse effect on renal function.
Abstract: Mycophenolate mofetil (MMF) has conventionally been administered at a fixed dose without routinely monitoring blood levels of mycophenolic acid (MPA), the active metabolite. The contribution of therapeutic drug monitoring (TDM) during MMF therapy remains controversial. A literature review was performed to explore the usefulness of TDM for MPA in solid organ transplantation. In addition, emphasis was placed on the potential clinical benefits and limitations of TDM for MPA. Available studies have limitations and report conflicting results. Although early after transplantation MPA area under the curve might have predictive value for the risk of acute rejection, predose levels appear less reliable. With regard to MPA toxicity, most studies showed no correlation between MPA pharmacokinetics and adverse effects. TDM is hampered by several factors such as the considerable intra-subject variability of MPA pharmacokinetics and the increasing number of different drug combinations. Proposed target ranges are restricted to the early posttransplant period when MMF is used in combination with cyclosporine. The current review of the literature indicates no clear support for a substantial clinical benefit of TDM and more data from prospective randomized trials are needed.
Abstract: BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive chronic disorder of the lower respiratory tract. The main clinical feature is a progressive shortness of breath, particularly on exercise. An overproduction and deposition of collagen and a proliferation of mesenchymal cells are the histopathologic characteristics. Rapamycin is an immunosuppressive agent with antiproliferative effects on mesenchymal cells including fibroblasts. It was this rationale that prompted the authors to administer rapamycin in a case of rapidly progressive IPF. CASE REPORT: In a 73-year-old female with a 2-month history of IPF, treatment with steroids and interferon gamma-1b did not improve the detrimental clinical course. Treatment with rapamycin was started; subsequently, clinical condition and objective findings improved markedly within weeks. She is now under treatment for 18 months. CONCLUSION: The authors presume that partial remission is related to rapamycin which may be effective in blocking the progressive fibrosis and increased collagen synthesis thought to be pathophysiologically relevant in this disease. Further studies have to show whether rapamycin may be a treatment option in idiopathic pulmonary fibrosis.
Abstract: Mycophenolic acid (MPA), the active moiety of mycophenolate mofetil (MMF), is routinely used as an adjunct immunosuppressant therapy in renal transplantation. Although highly effective, MMF therapy is associated with significant gastrointestinal adverse effects. Enteric-coated mycophenolate sodium (EC-MPS) is an advanced formulation delivering MPA. The enteric coat dissolves at pH > 5 allowing for MPA delivery in the small intestine. A single-center, open-label, randomized, three-way crossover study of 24 stable Caucasian renal transplant patients receiving cyclosporine-based immunosuppression, compared the relative bioavailability of two EC-MPS doses (640 and 720 mg) with MMF (1000 mg). Both EC-MPS doses delivered bioequivalent mean MPA exposure (AUC(0-infinity)) compared with 1000 mg MMF: 60.7 microg h/mL for 640 mg EC-MPS, 66.5 microg h/mL for 720 mg EC-MPS, and 63.7 microg h/mL for 1000 mg MMF. Median t(max) was significantly delayed for both EC-MPS doses compared with MMF (2.0 h vs. 0.75 h, respectively; p < 0.01), consistent with a functional enteric coating of EC-MPS. Furthermore, both EC-MPS doses were bioequivalent to 1000 mg MMF for AUC and C(max) for mycophenolic acid glucuronide. All three treatments were well tolerated. The EC-MPS 720 mg dose most closely approximated the MPA exposure of 1000 mg MMF and was selected for subsequent phase III studies.
Abstract: This ongoing multicenter prospective observational study was undertaken in de novo renal allograft recipients managed with cyclosporine (CsA) trough (C0) and 2-hour postdose (C2) level monitoring at defined times so as to assess the risk for an acute rejection episode or allograft dysfunction. The renal transplant recipients (n = 159) were enrolled at 11 German centers. The 6-month posttransplant data from 138 patients were evaluable for this interim analysis. Mean C2 levels (ng/mL), which were measured by liquid chromatography-tandem mass spectrometry at a central laboratory, were: days 3 to 5: 873.1 +/- 391.9; days 7 to 10: 939.1 +/- 422.8; days 14 to 28: 1116.3 +/- 497.6; 3 months: 905.0 +/- 316.8; and after 6 months: 787.0 +/- 276.5. To identify patients at higher risk for acute rejection or allograft dysfunction, we calculated the relative CsA absorption capacity (C2 [ng/mL]/morning dose [mg/kg]; CsA-Abs), yielding mean values on days 3 to 5: 284.4 +/- 115.1; days 7 to 10: 306.7 +/- 134.8; days 14 to 28: 382.5 +/- 164.7; month 3: 501.5 +/- 168.8; month 6: 512.7 +/- 176.5. Three groups were distinguished by CsA-Abs at days 7 to 10: low absorbers (CsA-Abs < 200), normal absorbers (CsA-Abs 200 to 350), and high absorbers (CsA-Abs > 350). A between-group comparison of absorption level at 6 months posttransplant revealed the incidences of biopsy-proven acute rejection and Cockcroft-Gault formula-based mean glomerular filtration rates of 23.8% and 54.7 +/- 19.0 mL/min, 22.6% and 59.5 +/- 20.7 mL/min, and 17.6% and 67.7 +/- 23.5, respectively. In conclusion, mean C2 levels >1000 ng/mL are attained within 2 to 4 weeks, with CsA-Abs increasing continuously over the first 6 posttransplant months. High CsA absorbers show a propensity toward good allograft function and lower acute rejection rates at 6 months after renal transplantation.
Abstract: The introduction of mycophenolate mofetil (MMF) represented a major advance in transplant medicine, although optimal use may be limited by gastrointestinal (GI) side-effects. An enteric-coated formulation of mycophenolate sodium (EC-MPS; myfortic) has been developed with the aim of improving the upper GI tolerability of mycophenolic acid. Therapeutic equivalence of EC-MPS (720 mg b.i.d.) and MMF (1000 mg MMF b.i.d.), with concomitant cyclosporine microemulsion (Neoral) and corticosteroids, was assessed in 423 de novo kidney transplant patients recruited to a 12-month, double-blind study. Efficacy failure (biopsy-proven acute rejection [BPAR], graft loss, death or loss to follow up) at 6 months (EC-MPS 25.8% vs. MMF 26.2%; 95% CI: [-8.7, +8.0]) demonstrated therapeutic equivalence. At 12 months, the incidence of BPAR, graft loss or death was 26.3% and 28.1%, and of BPAR alone was 22.5% and 24.3% for EC-MPS and MMF, respectively. Among those with BPAR, the incidence of severe acute rejection was 2.1% with EC-MPS and 9.8% with MMF (p=ns). The safety profile and incidence of GI adverse events were similar for both groups. Within 12 months, 15.0% of EC-MPS patients and 19.5% of MMF patients required dose changes for GI adverse events (p=ns). Enteric-coated-MPS 720 mg b.i.d. is therapeutically equivalent to MMF 1000 mg b.i.d. with a comparable safety profile.
Abstract: Mycophenolate mofetil (MMF), in combination with cyclosporine and corticosteroids, improves long-term graft survival in renal transplant recipients. However, optimal MMF therapy may be limited by gastrointestinal (GI) intolerance, which may result in the need for MMF dose reduction, interruption, or discontinuation, leading to increased risk of acute rejection. Enteric-coated mycophenolate sodium (EC-MPS) is a new formulation delivering mycophenolic acid developed with the aim of improving upper GI tolerability. A large prospective, open-label, multicenter program (myPROMS: myfortic PROspective Multicenter Study) is underway to determine the efficacy and safety of EC-MPS, in combination with cyclosporine microemulsion (CsA; Neoral) in a large population of de novo and maintenance renal transplant recipients. myPROMS consists of one global protocol with 14 subprotocols. Each subprotocol is designed to address further specific objectives, such as specific patient populations, steroid regimens, and various CsA C2 targets. The preliminary data summarized here are from two subprotocols, which investigated the benefits of converting maintenance renal transplant patients receiving MMF to EC-MPS. The 3-month interim analyses suggest that the conversion from MMF to EC-MPS is well tolerated in maintenance renal transplant recipients.
Abstract: BACKGROUND: Increased frequency of acute rejection episodes is the best predictor for the development of an chonic rejection process in kidney transplantation. An effective antirejection therapy is critical to prevent transplant failure due to chronic rejection. OBJECTIVE: The relationship between acute and chronic rejection is determined by the number of rejection episodes, clinical and histological grading, timing, residual function and individual problems of donor and recipient. THERAPY: Standard immunosuppression with calcineurin inhibitors such as cyclosporine or tacrolimus and antiproliferative substances such as azathioprine or mycophenolatemofetile have to be intensified when an acute rejection episode occurs. For maximal immunosuppression antibody preparations such as ATG and OKT3 in combination with with a short course of steroid pulse therapy are available. CONCLUSION: In this review we summarize the clinical implications and therapeutic consequences of the relationship between acute and chronic rejection. The acute rejection episode has still a great impact on long-term graft outcome which may only be improved by a prompt treatment of initial acute rejection episodes.
Abstract: HISTORY AND FINDINGS: Ten days after a complication-free operation for early gastric cancer a 61-year old man had a seizure and acute renal failure. INVESTIGATIONS: A percutaneous renal biopsy was performed to find the cause of the renal failure, which at times required several sessions of haemodialysis. TREATMENT AND COURSE: The seizure was thought to have been due to cerebrovascular deposits of oxalate crystals (renocerebral oxalosis). Parenteral xylitol had been given postoperatively, as a glucose substitute (total dose 1560g), together with other routine drugs. Primary oxalosis and other causes of secondary oxalosis had been excluded. CONCLUSION: Xylitol should not be used parenterally as a glucose substitute (banned in the USA).
Abstract: Potential differences in the acute effect of cyclosporin on renal function when dosed orally as the current market formulation or following a milligram-to-milligram conversion to a new microemulsion formulation were investigated in 14 stable kidney transplant patients. The study consisted of three sequential periods of 2 weeks duration each. Patients entered (period I) and completed (period III) the investigation with the market formulation and received the microemulsion formulation in period II; individualized cyclosporin doses remained unchanged throughout the study. Over one steady-state dosing interval at the end of each study period, whole blood cyclosporin pharmacokinetic profiles were assessed in parallel with endogenous creatinine clearances over sequential 1- to 2-h intervals. The rate and extent of cyclosporin absorption were significantly greater (P < 0.01) from the microemulsion formulation with average increases of 73% in peak concentration and 44% in area under the curve compared to the market formulation. Sequential creatinine clearances exhibited a transient decrease with the nadir occurring on average between 4 and 6 h post dose followed by a rapid return to baseline. Specifically in period I on the market formulation, clearances decreased from a baseline of 71.7 +/- 20.6 to a minimum of 51.1 +/- 17.9 ml/min per 1.73 m2 (similar values in period III) and from 76.8 +/- 24.8 to 53.5 +/- 17.5 ml/min 1.73 m2 in period II on the microemulsion. Neither the baseline nor minimum clearances were significantly different among the study periods.(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract: A concentration-guided study was designed to maintain adequate immunosuppression and avoid excessive drug exposure while determining steady-state relative bioavailability of two cyclosporine G (CyG) oral formulations in stable renal transplant patients. In period I (week 1), 26 patients taking cyclosporine A (CyA)-based immunosuppressive regimens entered the study. Doses were titrated to maintain trough concentrations within a predefined range, as measured by fluorescence polarization immunoassay (FPIA). Patients were given an oral solution of CyG in period II (weeks 2-3), and a microemulsion capsule formulation of CyG in period III (weeks 4-5), with dose titration as necessary to achieve trough concentrations in a predefined range, as measured by FPIA. Full pharmacokinetic profiles were obtained on the last day of each study period. Treatment with CyA was reinitiated in period IV (week 6) at the same doses as at study entry. All blood samples were analyzed at the conclusion of the study using CyG- and CyA-specific high-performance liquid chromatography (HPLC). When changing from oral solution to capsule for CyG, an average 19% dose reduction was necessary to compensate for the elevated trough concentrations resulting from the increased bioavailability of the capsule formulation. The concentration-guided strategy was successful in avoiding over-exposure, and resulted in comparable values for area under the concentration-time curve (AUC) for both formulations of CyG. Dose normalization of the pharmacokinetic parameters subsequently allowed calculation of the relative bioavailability. Specifically, a faster rate and greater extent of CyG absorption from the capsule than the oral solution were manifested as a slightly earlier time to peak concentration (tmax), an average 44% increase in the maximum concentration (Cmax), and an average 29% increase in AUC. This experience demonstrated that a concentration-guided trial design allowed a drug development question for a compound with a narrow therapeutic index to be addressed safely and directly in the target patient population.
Abstract: A new microemulsion formulation of cyclosporine (Sandimmune Neoral) was compared to the commercially available formulation (Sandimmune) in 11 stable renal transplant patients with regard to the consistency in cyclosporine pharmacokinetics between a daytime fasting, and a nighttime nonfasting administration. Daily cyclosporine doses were individualized and administered in equal, divided doses every 12 h as soft gelatin capsules; doses were kept constant throughout the study. Serial blood samples were obtained over a 24-h period (two consecutive dosing intervals) at steady-state for each formulation, and cyclosporine concentrations were determined in whole blood by a specific radioimmunoassay method. Within-formulation consistency in pharmacokinetic parameters between the daytime and nighttime administrations was assessed in terms of bioequivalence criteria. Following the mg-to-mg conversion from the commercial to the microemulsion formulation, area under the curve (AUC) was increased on average by 30% due to absorption-related pharmacokinetic differences, while trough concentrations remained in the therapeutic range. Within each formulation, AUC was bioequivalent when comparing the daytime fasting to the nighttime nonfasting administration. For the commercial formulation, however, there was considerable variation in absorption rate, dampening of peak-trough fluctuation, and elevation of trough concentration following the nighttime nonfasting dose. By contrast, the microemulsion exhibited a more stable concentration-time profile over the two dosing intervals, with bioequivalence in peak-trough fluctuation and trough concentrations. Hence, the steady-state pharmacokinetics of cyclosporine from the microemulsion formulation exhibit greater within-day consistency compared to the commercial formulation in stable renal allograft recipients.
Abstract: In a prospective randomized trial 50 renal transplant patients (group A) received a sequential course of 14 days conventional immunosuppression (Lymphocytoglobulin (ALG), azathioprine, steroids) and cyclosporin and steroids thereafter, while 50 patients (group B) received the conventional immunosuppression for 7 days followed by cyclosporin and steroids. In the latter group ALG was tolerated for the whole period while in the first group conversion from conventional to cyclosporin A therapy had to be performed after a mean of 11 days, due to ALG intolerance. Actual patient survival rates 1 year posttransplant were 100% in both groups and graft survival rates 96% in group A and 86% in group B (P less than 0.05). There was a mean dialysis frequency per patient of 0.7 +/- 2.0 in group A and 1.8 +/- 3.4 in group B (P = 0.064). Serum creatinine 1 year posttransplant was 1.8 +/- 0.8 mg/dl in group A and 2.2 +/- 1.4 in group B. A total of 58 patients had a serum creatinine of less than 2 mg/dl at the time of conversion to cyclosporin. These patients had a significantly better graft survival rate (98.3%) and serum creatinine 1 year posttransplant (1.6 +/- 0.5 mg/dl) than the 40 patients with a serum creatinine of more than 2 mg/dl at the time of conversion (85%; 2.4 +/- 1.4 mg/dl), indicating that a delayed onset of cyclosporin therapy might benefit the kidney in the immediate posttransplant period when it is susceptible to nephrotoxicity due to the damage from hypothermic storage.
Abstract: The effectiveness of preventing cytomegalovirus (CMV) infections by administering CMV hyperimmunoglobulin was evaluated in a prospective randomized trial. The patients in the treatment group (n = 50) had intravenous infusions of 2 ml/kg bodyweight of CMV-Polyglobin at three-week intervals, up to day 105 after kidney transplantation. The 50 patients in the control group received no infusions. There was no significant difference between the treatment and control groups in transplant survival or patients survival rates. But the number of symptomatic CMV infections was higher in the control (n = 11) than the treatment group (n = 5). There were also significantly fewer symptomatic herpes-simplex infections in the treatment (n = 6) than in the control group (n = 25). It is concluded from these results that prophylaxis with CMV hyperimmunoglobulin should be undertaken either selectively or for shorter periods than those chosen for the reported trial.
