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.
UGT; Transplantation; Toxicity; Rejection; Mycophenolic acid; Pharmacogenetics
Immunosuppressants require therapeutic drug monitoring because of their narrow therapeutic index and significant inter-individual variability in blood concentrations. This variability can be because of factors like drug-nutrient interactions, drug-disease interactions, renal-insufficiency, inflammation and infection, gender, age, polymorphism and liver mass. Drug monitoring is widely practiced especially for cyclosporine, tacrolimus, sirolimus and mycophenolic acid.
Therapeutic monitoring of immunosuppressive therapy with cyclosporine is a critical requirement because of intra- and inter-patient variability of drug absorption, narrow therapeutic window and drug induced nephrotoxicity.
Mycophenolic acid (MPA)
Some reasons for therapeutic drug monitoring of MPA during post-transplant period include: relationship between MPA pharmacokinetic parameters and clinical outcomes, Inter-patient pharmacokinetic variability for MPA despite fixed MMF doses, alternations of MPA pharmacokinetics during the first months after transplantation, drug- drug interaction and influence of kidney function on MPA pharmacokinetic.
A recent review of the pharmacokinetics of sirolimus suggested a therapeutic range of 5 to 10 μg l−1 in whole blood. However, the only consensus guidelines published on the therapeutic monitoring of sirolimus concluded that there was not enough information available about the clinical use of the drug to make recommendations.
Sudies have shown, in kidney and liver transplant patients, significant associations of low tacrolimus concentrations with rejection and of high concentrations with nephrotoxicity. Although the feasibility of a limited sampling scheme to predict AUC has been demonstrated, as yet, trough, or pre-dose, whole blood concentration monitoring is still the method of choice.
Cyclosporine; Mycophenolic acid; Sirolimus; Tacrolimus; Therapeutic drug monitoring
The goal of this study was to determine the role of the Organic Anion Transporting Polypeptides, OATP1A2, OATP1B1 and OATP1B3 and their genetic variants in the pharmacokinetics of the immunosuppressive drug mycophenolate mofetil (MMF). Using OATP-transfected HEK cells, we measured the uptake of mycophenolic acid (MPA) and its glucuronide (MPAG). MPAG, but not MPA, significantly accumulated in cells expressing OATP1B3 or OATP1B1 (p<0.05). MPA and MPAG pharmacokinetics were significantly influenced by the OATP1B3 polymorphism, 334T>G/699G>A, in 70 renal transplant patients co-treated with tacrolimus or sirolimus but not in 115 patients co-treated with cyclosporine. The decrease in MPA dose-normalized exposure and concomitant increase in the MPAG/MPA metabolic ratio are consistent with reduced enterohepatic cycling in patients carrying the OATP1B3 334G-699A haplotype. Further studies demonstrated that this variant of OATP1B3 exhibited a reduced Vmax in transfected HEK cells, providing functional support of our clinical findings.
Cell Line; Genetic Variation; genetics; Humans; Mycophenolic Acid; pharmacokinetics; Organic Anion Transporters; genetics; physiology; Peptides; genetics; physiology; Polymorphism, Genetic; genetics; immunosuppressive agents; transplantation; transporters; pharmacogenetics; mycophenolic acid.
Although immunosuppressive treatments and therapeutic drug monitoring have significantly contributed to the increased success of thoracic transplantation, there is currently no consensus on the best immunosuppressive strategies. Maintenance therapy typically consists of a triple-drug regimen including corticosteroids, a calcineurin inhibitor (cyclosporine or tacrolimus) and either a purine synthesis antagonist (mycophenolate mofetil or azathioprine) or a mTOR inhibitor (sirolimus or everolimus). The incidence of acute and chronic rejection and of mortality after thoracic transplantation is still high compared to other types of solid organ transplantation. The high allogeneicity and immunogenicity of the lungs justify the use of higher doses of immunosuppressants, putting lung transplant recipients at a higher risk for drug-induced toxicities. All immunosuppressants are characterized by a large intra- and inter-individual variability of their pharmacokinetics and by a narrow therapeutic index. It is essential to know their pharmacokinetic properties and to use them for treatment individualization through therapeutic drug monitoring (TDM) in order to improve treatment outcome. Unlike the kidneys and the liver, the heart and the lungs are not directly involved in drug metabolism and elimination, which may be the cause of pharmacokinetic differences between patients from all these transplant groups.
TDM is mandatory for most immunosuppressants, and has become an integral part of immunosuppressive drug therapy. It is usually based on trough concentrations (C0) monitoring, but other TDM tools include the area under the concentration-time curve over the dosing interval (AUC0-12) or over the first 4 hours post-dose (AUC0-4), as well as other single concentration-time points, such as the concentration 2 hours after dosing (C2). Given the peculiarities of thoracic transplantation, a review of the pharmacokinetics and TDM of the main immunosuppressants used in thoracic transplantation is presented in this article. Even more so than in other solid organ transplant populations, their pharmacokinetics is characterized by wide inter- and intra-individual variability in thoracic transplant recipients. The pharmacokinetics of cyclosporine in heart and lung transplant recipients has been explored in a number of studies, but less is known about that of mycophenolate and tacrolimus in these populations, while there are also hardly any studies on the pharmacokinetics of sirolimus and everolimus. Given the increased use of these molecules in thoracic transplant recipients, their pharmacokinetics deserves to be explored more in depth. There is very little data, some of which is conflicting, on the practices and outcomes of the TDM of immunosuppressants after thoracic transplantation. The development of sophisticated TDM tools dedicated to thoracic transplantation are awaited, in order to evaluate accurately and precisely patients’ exposure to drugs in general and in particular, to immunosuppre ssants. Finally, large cohort TDM studies definitely need to be conducted in thoracic transplant patients, in order to identify the most predictive exposure indices, and their target values, and to validate the clinical usefulness of improved TDM in these conditions.
Calcineurin; antagonists & inhibitors; Cyclosporine; pharmacokinetics; therapeutic use; Drug Monitoring; Heart Transplantation; Heart-Lung Transplantation; Humans; Immunosuppressive Agents; pharmacokinetics; therapeutic use; Lung Transplantation; Pediatrics; Tacrolimus; pharmacokinetics; therapeutic use
In this study a new principle of measurement in LC-MS/MS (liquid chromatography mass spectrometry) for determination of the immunosuppressive drugs sirolimus, everolimus, tacrolimus, and cyclosporin A has been introduced by using the Cs+ ion as the product ion in the multiple reaction monitoring mode (MRM).
Separation of the immunosuppressive agents was achieved using a phenyl-hexyl-RP column together with a ternary gradient elution profile, consisting of water, methanol and acetonitrile combined with 0.1% v/v formic acid and 0.1 mmol/l Cs+.
Quantification was performed using cyclosporin D, ascomycin and 32-desmethoxy-rapamycin as internal standards.
The inter-run precision of this new method, expressed as the coefficient of variation, was 2.57% for sirolimus, 2.11% for everolimus, 2.31% for tacrolimus and 2.11% for cyclosporin A.
immunosuppressive drugs; LC-MS/MS; Cs+ adducts
The aim of the study was to analyse the influence of renal impairment on the pharmacokinetic parameters (PK) of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) in renal transplant recipients.
Material and methods
The study included 43 adult patients during the maintenance period (> 6 months) following renal transplantation, treated with mycophenolate mofetil (MMF), calcineurin inhibitors (CNI) (tacrolimus or cyclosporine) and steroids. The study compared patients with normal renal function (n = 17; creatinine clearance (Ccr) > 60 ml/min) and with renal impairment (n = 26; Ccr < 60 ml/min). Areas under the 4-h curve (AUC0-4 h) of MPA and MPAG were determined using a validated HPLC method.
The renal impairment group showed significantly increased AUC0-4 h and pre-dose (C0) for MPAG compared to patients with normal renal function and increased MPA C0. However, there was no significant difference in MPA AUC0-4 h between patients with renal impairment and patients with normal renal function. In multivariate analysis some MPA and MPAG PK parameters were correlated with sex, CNI co-administered and body weight.
Although MPAG is an inactive metabolite, its accumulation in patients with renal impairment can be unfavourable. The results of our study indicate that solely MPA C0 determination in patients receiving MMF may be insufficient in clinical practice because of great inter-patient variability of this PK parameter caused mainly by enterohepatic recirculation.
kidney transplantation; immunosuppressive agents; mycophenolate mofetil metabolites; pharmacokinetics; renal impairment
Background & objectives:
The immunosuppressants administered to renal transplant subjects are usually monitored therapeutically to prevent graft rejection and drug toxicity. Mycophenolic acid (MPA) is an immunosuppressant. The present prospective study was undertaken to establish the utility of plasma level monitoring of MPA and to correlate it with clinical outcomes in renal transplant receipients.
MPA plasma level at 2, 4 and 9 h and the area under concentration-time curve (AUC) were estimated using high performance liquid chromatography in 24 renal transplant recipients receiving immunosuppressant MPA plus tacrolimus and steroid.
There was wide inter-individual variation in MPA plasma level and the AUC. The incidences of gastrointestinal adverse drug events (diarrhoea and acidity) were significantly more in the high MPA AUC patients. Though biopsy proven acute rejection was not found, of the six subjects with lower MPA AUC (<30 mg.h/l), three were clinically diagnosed to develop tacrolimus nephrotoxicity. The Gastrointestinal Symptom Rating Scale (GSRS) and Gastrointestinal Quality of Life Index (GIQLI) scores represented better health related quality of life in lower MPA AUC than in the higher MPA AUC (>60 mg.h/l).
Interpretation & conclusions:
The present findings suggest the MPA AUC of 30 - 60 mg.h/l in the maintenance stage of renal transplant patients to have optimum clinical benefit and relegated adverse events profile indicating the usefulness of AUC of MPA with limited sampling strategy in optimizing its use.
Adverse drug events; area under the curve (AUC); health related quality of life; mycophenolic acid (MPA); renal transplant
Lung transplantation is a recognised treatment for patients with end stage pulmonary disease. Transplant recipients receive life-long administration of immunosuppressive drugs that target T cell mediated graft rejection. However little is known of the impact on NK cells, which have the potential to be alloreactive in response to HLA-mismatched ligands on the lung allograft and in doing so, may impact negatively on allograft survival. NK cells from 20 healthy controls were assessed in response to Cyclosporine A, Mycophenolic acid (MPA; active form of Mycophenolate mofetil) and Prednisolone at a range of concentrations. The impact of these clinically used immunosuppressive drugs on cytotoxicity (measured by CD107a expression), IFN-γ production and CFSE proliferation was assessed in response to various stimuli including MHC class-I negative cell lines, IL-2/IL-12 cytokines and PMA/Ionomycin. Treatment with MPA and Prednisolone revealed significantly reduced CD107a expression in response to cell line stimulation. In comparison, addition of MPA and Cyclosporine A displayed reduced CD107a expression and IFN-γ production following PMA/Ionomycin stimulation. Diminished proliferation was observed in response to treatment with each drug. Additional functional inhibitors (LY294002, PD98059, Rottlerin, Rapamycin) were used to elucidate intracellular pathways of NK cell activation in response to stimulation with K562 or PMA-I. CD107a expression was significantly decreased with the addition of PD98059 following K562 stimulation. Similarly, CD107a expression significantly decreased following PMA-I stimulation with the addition of LY294002, PD98059 and Rottlerin. Ten lung transplant patients, not receiving immunosuppressive drugs pre-transplant, were assessed for longitudinal changes post-transplant in relation to the administration of immunosuppressive drugs. Individual patient dynamics revealed different longitudinal patterns of NK cell function post-transplantation. These results provide mechanistic insights into pathways of NK cell activation and show commonly administered transplant immunosuppression agents and clinical rejection/infection events have differential effects on NK cell function that may impact the immune response following lung transplantation.
Mycophenolic acid (MPA) is widely used as part of immunosuppressive regimens following allograft transplantation. The large pharmacokinetic (PK) and pharmacodynamic (PD) variability and narrow therapeutic range of MPA provide a potential for therapeutic drug monitoring. The objective of this pilot study was to investigate the MPA PK and PD relation in combination with belatacept (2nd generation CTLA4-Ig) or cyclosporine (CsA).
Seven renal allograft recipients were randomized to either belatacept (n = 4) or cyclosporine (n = 3) based immunosuppression. Samples for MPA PK and PD evaluations were collected predose and at 1, 2 and 13 weeks posttransplant. Plasma concentrations of MPA were determined by HPLC-UV. Activity of inosine monophosphate dehydrogenase (IMPDH) and the expressions of two IMPDH isoforms were measured in CD4+ cells by HPLC-UV and real-time reverse-transcription PCR, respectively. Subsets of T cells were characterized by flow cytometry.
The MPA exposure tended to be higher among belatacept patients than in CsA patients at week 1 (P = 0.057). Further, MPA concentrations (AUC0–9 h and C0) increased with time in both groups and were higher at week 13 than at week 2 (P = 0.031, n = 6). In contrast to the postdose reductions of IMPDH activity observed early posttransplant, IMPDH activity within both treatment groups was elevated throughout the dosing interval at week 13. Transient postdose increments were also observed for IMPDH1 expression, starting at week 1. Higher MPA exposure was associated with larger elevations of IMPDH1 (r = 0.81, P = 0.023, n = 7 for MPA and IMPDH1 AUC0–9 h at week 1). The maximum IMPDH1 expression was 52 (13–177)% higher at week 13 compared to week 1 (P = 0.031, n = 6). One patient showed lower MPA exposure with time and did neither display elevations of IMPDH activity nor IMPDH1 expression. No difference was observed in T cell subsets between treatment groups.
The significant influence of MPA on IMPDH1 expression, possibly mediated through reduced guanine nucleotide levels, could explain the elevations of IMPDH activity within dosing intervals at week 13. The present regulation of IMPDH in CD4+ cells should be considered when interpreting measurements of IMPDH inhibition.
Pharmacokinetic monitoring has been insufficiently studied in paediatric solid organ transplantation, especially because some agents are relatively new to paediatric use, are of new formulation modification or are being used in combinations not previously well studied. The choice of immunosuppressive drugs after paediatric renal transplantation is increasing. Cyclosporine A (CyA), tacrolimus and mycophenolate mofetil (MMF) use has become routine. While pharmacokinetic monitoring of CyA and tacrolimus is routine, few paediatric data on tacrolimus pharmacokinetics exist, and, for MMF, pharmacokinetic monitoring is performed in only a few Canadian centres. The aim of the present article is to provide guidelines for the use of these three drugs by using a large number of full pharmacokinetic profiles in children.
One hundred forty-nine full pharmacokinetic 10-point profiles on cyclosporine microemulsion, 103 on the classic cyclosporine, 118 on tacrolimus and 114 on MMF were retrospectively analyzed. All pharmacokinetic profiles were obtained from paediatric renal transplant patients in steady state.
For pharmacokinetic monitoring of the classic cyclosporine formulation, evaluation of the trough levels suffices to estimate the area under the curve (AUC). For microemulsified cyclosporine, the trough levels do not provide a useful tool, and blood concentrations at 2 or 3 h (C2 or C3) after intake should be measured instead. Tacrolimus trough levels sufficiently estimate the AUC, but measuring the C4 yields the best prediction of the AUC. Nonetheless, C2 also provides a superior tool than the trough levels. Tacrolimus and CyA AUCs change substantially over time after renal transplantation. There is only a poor correlation between the trough level and the AUC for mycophenolic acid (MPA). No single time point provides a surrogate marker of the AUC. At least three time points are required to accurately estimate the AUC, and C1, C2 and C6 serve as the best markers. The article also describes the interaction between MPA and differing concomitant immunosuppression, as well as the variation of the MPA AUC with differing concentrations of cyclosporine.
Pharmacokinetic monitoring of these three drugs is mandatory in paediatric renal transplantation because it is impossible to predict the drug interactions and blood levels from a given dose. Target AUCs for a given time point after transplantation remain to be established.
Area under the curve; Cyclosporine; Mycophenolate mofetil; Mycophenolic acid; Pharmacokinetics; Tacrolimus
Prospective data are lacking concerning the effect of reduced mycophenolic acid (MPA) dosing on efficacy and the influence of concomitant tacrolimus exposure. The Mycophenolic Renal Transplant (MORE) Registry is a prospective, observational study of de novo kidney transplant patients receiving MPA therapy under routine management. The effect of MPA dose reduction, interruption, or discontinuation (dose changes) was assessed in 870 tacrolimus-treated patients: 375 (43.1%) reduced tacrolimus (≤7 ng/mL at baseline) and 495 (56.9%) standard tacrolimus (>7 ng/mL); enteric-coated mycophenolate sodium 589 (67.7%) and mycophenolate mofetil 281 (32.3%). During baseline to month 1, months 1–3, months 3–6, and months 6–12, 9.3% (78/838), 16.6% (132/794), 20.7% (145/701), and 13.1% (70/535) patients, respectively, required MPA dose changes. These patients experienced an increased risk of biopsy-proven acute rejection at one yr with tacrolimus exposure either included in the model (hazard ratio [HR] 2.60, 95% CI 1.28–5.29, p = 0.008) or excluded (HR 2.58, 95% CI 1.28–5.23, p = 0.008). MPA dose changes were significantly associated with one yr graft failure when tacrolimus exposure was included (HR 2.23; 95% CI 1.01–4.89, p = 0.047) but not when tacrolimus exposure was excluded (HR 2.16; 95% CI 0.99–4.79; p = 0.054). These results suggest that reducing or discontinuing MPA can adversely affect graft outcomes regardless of tacrolimus trough levels.
cellcept; EC-MPS; kidney transplantation; mycophenolate mofetil; mycophenolate; myfortic; outcomes; tacrolimus
Successful clinical islet allotransplantation requires control of both allo- and auto-immunity by using immunosuppressant drugs which have a number of side effects. The development of the autoimmune condition alopecia areata following successful islet transplantation is therefore unexpected. Three cases of alopecia affecting female islet transplant recipients are described. In all cases, alopecia developed approximately 7 years after initial transplant. All had received daclizumab, sirolimus and tacrolimus with their initial transplants, but all were receiving a combination of tacrolimus and mycophenolate mofetil at the time alopecia developed. Two subjects had received thymoglobulin for a subsequent islet infusion and prior to the onset of alopecia. The progression of alopecia has been halted or reversed in all cases. Tacrolimus has been continued in 2 cases (one as monotherapy) while cyclosporine was used in place of tacrolimus in the third case. These three cases represent a crude incidence of <2.5% over 5 years compared with a prevalence of alopecia in islet transplant candidates (pre-transplant) of <1%. Although alopecia might be expected in a proportion of individuals with type 1 diabetes, the risk may be increased after islet transplantation, and may be associated with the use of anti-TNF drugs, lymphodepleting antibodies or higher dose tacrolimus.
Mycophenolic acid (MPA) is commonly used to treat patients with solid organ transplants during maintenance immunosuppressive therapy. Response to MPA varies widely, both for efficacy and drug-induced toxicity. A portion of this variation can be explained by pharmacokinetic and pharmacodynamic factors, including genetic variation in MPA-metabolizing UDP-glucuronyltransferase isoforms and the MPA targets, inosine monophosphate dehydrogenase 1 and 2. However, much of the variation in MPA response presently remains unexplained. We set out to determine whether there might be additional genes that modify response to MPA by performing a genome-wide association study between basal gene mRNA expression profiles and an MPA cytotoxicity phenotype using a 271 human lymphoblastoid cell line model system to identify and functionally validate genes that might contribute to variation in MPA response. Our association study identified 41 gene expression probe sets, corresponding to 35 genes, that were associated with MPA cytotoxicity as a drug response phenotype (p < 1 × 10−6). Follow-up siRNA-mediated knockdown-based functional validation identified four of these candidate genes, C17orf108, CYBRD1, NASP, and RRM2, whose knockdown shifted the MPA cytotoxicity curves in the direction predicted by the association analysis. These studies have identified novel candidate genes that may contribute to variation in response to MPA therapy and, as a result, may help make it possible to move toward more highly individualized MPA-based immunosuppressive therapy.
Mycophenolic acid; mycophenolate; immunosuppression; pharmacogenomics; cell line model system; C17orf108; CYPRD1; NASP; RRM2
The description more than 30 years ago of the role of de novo purine synthesis in T and B lymphocytes clonal proliferation opened the possibility for selective immunosuppression by targeting specific enzymatic pathways. Mycophenolic acid (MPA) blocks the key enzyme inosine monophosphate dehydrogenase and the production of guanosine nucleotides required for DNA synthesis. Two MPA formulations are currently used in clinical transplantation as part of the maintenance immunosuppressive regimen. Mycophenolate mofetil (MMF) was the first MPA agent to be approved for the prevention of acute rejection following renal transplantation, in combination with cyclosporine and steroids. Enteric-coated mycophenolate sodium (EC-MPS) is an alternative MPA formulation available in clinical transplantation. In this review, we will discuss the clinical trials that have evaluated the efficacy and safety of MPA in adult kidney transplantation for the prevention of acute rejection and their use in new combination regimens aiming at minimizing calcineurin inhibitor toxicity and chronic allograft nephropathy. We will also discuss MPA pharmacokinetics and the rationale for therapeutic drug monitoring in optimizing the balance between efficacy and safety in individual patients.
kidney transplantation; immunosuppression; mycophenolic acid; mycophenolate mofetil; enteric-coated mycophenolate sodium; acute rejection; chronic allograft nephropathy
Skin is the most immunogenic component of a vascularized composite allograft (VCA) and is the primary trigger and target of rejection.
The skin is directly accessible for visual monitoring of acute rejection (AR) and for directed biopsy, timely therapeutic intervention, and management of AR.
Logically, antirejection drugs, biologics, or other agents delivered locally to the VCA may reduce the need for systemic immunosuppression with its adverse effects.
Topical FK 506 (tacrolimus) and steroids have been used in clinical VCA as an adjunct to systemic therapy with unclear beneficial effects. However, there are no commercially available topical formulations for other widely used systemic immunosuppressive drugs such as mycophenolic acid, sirolimus, and everolimus. Investigating the site-specific therapeutic effects and efficacy of systemically active agents may enable optimizing the dosing, frequency, and duration of overall immunosuppression in VCA with minimization or elimination of long-term drug-related toxicity.
Only a few randomized clinical trials have been performed so far in heart transplant recipients, mainly because of the relatively small number of heart transplants performed worldwide each year. The main focus of the few controlled trials that have been completed has been the prevention and treatment of heart allograft rejection. In the area of pharmacologic immunosuppression, both biological agents and drugs have been the subject of investigation. Among the biological agents, chimeric monoclonal antibodies directed against the interleukin (IL)-2 receptor, which have been found to be safe and effective in renal transplant recipients, are now undergoing the test of controlled trials in heart transplant recipients. Immunosuppressive drugs that have been studied in controlled trials include calcineurin inhibitors (such as the microemulsion formulation of cyclosporine and tacrolimus) and inhibitors of purine synthesis, such as mycophenolate mofetil. Non-pharmacologic prophylactic immunosuppression with photopheresis has also been tested in a prospective, multicenter, randomized trial. New immunosuppressive regimens, such as mycophenolate mofetil combined with a monoclonal antibody against the IL-2 receptor, are being tested with the aim to reduce or eliminate calcineurin inhibitors or corticosteroids. Although clinical approaches to the induction of tolerance have undergone preliminary clinical evaluation, the ability to induce tolerance to an allograft in humans remains an elusive goal.
heart transplantation; immunosuppression; monoclonal antibodies; rejection; tolerance
Background & objectives:
Kidney transplantation is the best option for patients with end-stage renal disease (ESRD) failure. Prolonged use of immunosuppressive drugs often causes opportunistic infections and malignancies of skin and mucosae, but due to lack of a careful dermatological screening in several transplantation centers the diagnosis and the treatment of dermatological lesions in kidney transplant patients are underestimated. In addition after the introduction of interleukin (IL)-2 -receptor antagonists (basiliximab/daclizumab), mTOR inhibitors and mycophenolate mofetil (MMF)/mycophenolic acid (MPA) in new immunosuppressive protocols only a few studies have analyzed the skin and mucosal lesions in kidney transplant patients. This study was undertaken to evaluate the cutaneous and mucosal diseases after kidney transplantation, and to investigate the association between these and different immunosuppressive protocols and/or demographic features.
A retrospective analysis was done using medical records of kidney transplantation between 2000 and 2009 at the Transplant Unit of Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. The study included 183 patients (M 57.3%, F 42.7%) aged 51.5±11.8 yr) with transplant age 52.3±34.9 months. Induction therapy was basiliximab and steroids based; maintenance therapy included combination-regimes from cyclosporine, tacrolimus, steroids, mycophenolate mofetil (MM), mycophenolic acid (MPA), rapamycin, everolimus. Anti-rejection therapy was steroid and/or thymoglobulines based. Diagnosis of cutaneous disease was made through examination of skin, mucous membranes, nails and hair evaluation. Skin biopsies, specific cultures and serological tests were done when required.
Skin and mucosal diseases were reported in 173 (95.7%) of patients; 88 (50.81%) showed viral lesions; 92 (53.01%) immunosuppression-related lesions; 28 (16.39%) benign tumours; 26 (15.3%) precancers /neoplastic lesions; 24 (14.21%) mycosis; 16 (9.29%) cutaneous xerosis, 15 (8.74%) dermatitis, while absence of cutaneous disease was evident only in 8 (4.37%) cases. An association between drug side effects and anti-rejection treatment (P≤0.01) and/or calcineurin-inhibitors (CNI) exposure (P≤0.01) was found. Longer exposure to immunosuppressive drugs (>60 months) was associated with pre-malignancy and malignancy lesions.
Interpretation & conclusions:
Cutaneous diseases are frequent in kidney transplanted patients. Continuous skin monitoring is necessary to make an early diagnosis and to start appropriate treatment.
Anti-rejection treatment; benign tumour; end-stage renal disease; immunosuppression; kidney transplant; skin lesions
Only a minority of islet transplant recipients maintain insulin independence at 5 years under the Edmonton protocol of immunosuppression. New immunosuppressive strategies are required in order to improve long term outcomes.
Materials and Methods
Three subjects with unstable type 1 DM underwent islet transplantation with alemtuzumab induction and sirolimus-tacrolimus maintenance for three months then sirolimus-mycophenolic acid maintenance thereafter. Follow-up was >2 years. Comparison was with sixteen historical subjects transplanted under the Miami version of the Edmonton protocol.
Insulin independence was achieved in 2/3 alemtuzumab and 14/16 historical subjects. Those who did not achieve insulin independence only received a single islet infusion. Insulin independence rates remained unchanged in the Alemtuzumab group, but decreased from 14/16 (88%) to 6/16 (38%) in the Historical group over two years. Insulin requirements increased in the Historical group while remaining stable in the Alemtuzumab group. Comparison of functional measures at 3 months suggested better engraftment with alemtuzumab (NS). Further comparison of Alemtuzumab versus Historical groups, up to 24 months, demonstrated significantly better: Mixed Meal Stimulation Index (24 months 1.0±0.08 n=3 vs 0.5±0.06 pmol/mL n=6, p<0.01), Mixed Meal peak C-peptide (24 months 5.0±0.5 n=3 vs 3.1±0.3 nmol/mL n=6, p<0.05), HbA1c (24 months 5.4±0.15 n=3 vs 6.3±0.12pmol/mL n=10, p<0.01).
Administration of alemtuzumab was well tolerated. There was no increased incidence of infections in alemtuzumab subjects despite profound, prolonged lymphocyte depletion.
Islet transplantation with alemtuzumab induction was well tolerated and resulted in improved short and long term outcomes. Further investigation is underway for validation.
There is evidence that renal transplant recipients have accelerated atherosclerosis manifest by increased cardiovascular morbidity and mortality. The high incidence of atherosclerosis is, in part, related to increased arterial stiffness, vascular dysfunction, elevated oxidative stress and inflammation associated with immunosuppressive therapy. The dietary supplement astaxanthin has shown promise as an antioxidant and anti-inflammatory therapeutic agent in cardiovascular disease. The aim of this trial is to investigate the effects of astaxanthin supplementation on arterial stiffness, oxidative stress and inflammation in renal transplant patients.
Method and Design
This is a randomised, placebo controlled clinical trial. A total of 66 renal transplant recipients will be enrolled and allocated to receive either 12 mg/day of astaxanthin or an identical placebo for one-year. Patients will be stratified into four groups according to the type of immunosuppressant therapy they receive: 1) cyclosporine, 2) sirolimus, 3) tacrolimus or 4) prednisolone+/-azathioprine, mycophenolate mofetil or mycophenolate sodium. Primary outcome measures will be changes in 1) arterial stiffness measured by aortic pulse wave velocity (PWV), 2) oxidative stress assessed by plasma isoprostanes and 3) inflammation by plasma pentraxin 3. Secondary outcomes will include changes in vascular function assessed using the brachial artery reactivity (BAR) technique, carotid artery intimal medial thickness (CIMT), augmentation index (AIx), left ventricular afterload and additional measures of oxidative stress and inflammation. Patients will undergo these measures at baseline, six and 12 months.
The results of this study will help determine the efficacy of astaxanthin on vascular structure, oxidative stress and inflammation in renal transplant patients. This may lead to a larger intervention trial assessing cardiovascular morbidity and mortality.
Renal transplant patients prescribed mycophenolate mofetil (MMF) may require treatment for tuberculosis with a regimen including the tuberculocidal drug rifampicin. MMF is an ester prodrug which is rapidly hydrolysed to the active compound, mycophenolic acid (MPA). Therapeutic drug monitoring of mycophenolate involves the measurement of MPA area under the curve (MPA-AUC0-12). Rifampicin is known to increase the metabolism and decrease enterohepatic recirculation of mycophenolic acid, (MPA). When MPA is monitored after the discontinuation of rifampicin, an important factor is the time required for the MPA area under the curve to return to the pre-rifampicin value. At present this is not known. This report describes one such renal allograft patient, on long term MMF and prescribed rifampicin by a local physician. As expected there was a clinically significant decrease in MPA-AUC0-12 Three weeks after rifampicin was discontinued the MPA-AUC0-12 was still only 65% of the pre-rifampicin value and only 55% of the steady state MPA-AUC0-12 measured six months later.
Mycophenolate; rifampicin; interaction; renal transplantation
As proton pump inhibitors share CYP3A4 enzyme with tacrolimus for their hepatic elimination, they potentially affect its pharmacokinetics, most prominently in patients with CYP2C19 or CYP3A5 gene mutations. Our aim was to investigate the impact of omeprazole on tacrolimus pharmacokinetics in CYP3A5 non-expressors, kidney transplant recipients.
Twelve patients (five males/seven females) were observed for 175 ± 92.05 days. Omeprazole (20 mg pos) was administrated for 75.83 ± 45.17 days. Immunosuppressant regimen consisted of tacrolimus (n = 12), methylprednisolone (n = 10), mycophenolate mofetil (n = 11), azathioprine (n = 1), and everolimus (n = 2). Patient’s body weight, coadministered drugs, and tacrolimus trough levels were monitored. Aspartate and alanine aminotransferase, γ-glutamyltransferase, and bilirubin were used for evaluating hepatic function. Tacrolimus kinetics were estimated with daily dose, concentration, dose adjusted concentration, and volume of distribution with and without coadministration of omeprazole. CYP3A5 genotyping was performed with PCR followed by restriction fragment length polymorphism analysis. Statistical analysis was performed with Prism 4 software (GraphPad Software, Inc).
No statistically significant difference was observed in tacrolimus kinetics and hepatic function during coadministration of omeprazole.
Our results let us propose that there is no need for more frequent therapeutic drug monitoring of tacrolimus when coadministrated with omeprazole in CYP3A5 nonexpressors, though prospective studies with more patients and longer observation period are needed to confirm these findings.
CYP3A5; omeprazole; renal transplantation; tacrolimus
Mycophenolic acid (MPA) is used as an immunosuppressant after organ transplantation and for the treatment of immune diseases. There is increasing evidence that therapeutic drug monitoring and plasma concentration-guided dose adjustments are beneficial for patients to maintain immunosuppressive efficacy and to avoid toxicity. The major MPA metabolite that can be found in high concentrations in plasma is MPA glucuronide (MPAG). A metabolite usually present at lower concentrations, MPA acyl-glucuronide (AcMPAG), has been implicated in some of the adverse effects of MPA.
We developed and validated an automated high-throughput ultra-high performance chromatography-tandem mass spectrometry (U-HPLC-MS/MS) assay using liquid-handling robotic extraction for the quantification of MPA, MPAG, and AcMPAG in human EDTA plasma and urine.
The ranges of reliable response were 0.097 (lower limit of quantitation) to 200 μg/mL for MPA and MPAG and 0.156– 10 μg/mL for AcMPAG in human urine and plasma. The inter-day accuracies were 94.3–104.4%, 93.8–105.0% and 94.4–104.7% for MPA, MPAG and AcMPAG, respectively. Inter-day precisions were 0.7–7.8%, 0.9–6.9% and 1.6–8.6% for MPA, MPAG and AcMPAG. No matrix interferences, ion suppression/enhancement and carry-over were detected. The total assay run time was 2.3 min.
The assay met all predefined acceptance criteria and the quantification of MPA was successfully cross-validated with an LC-MS/MS assay routinely used for clinical therapeutic drug monitoring. The assay has proven to be robust and reliable during the measurement of samples from several pharmacokinetics trials.
Mycophenolic Acid; Mycophenolic Acid Glucuronide; Mycophenolic Acid Acyl-Glucuronide; U-HPLC-MS/MS; immunosuppressant
Allogeneic hematopoietic cell transplantation (HCT) using reduced intensity conditioning (RIC) regimens is a potentially curative treatment for patients (patients) with myelofibrosis (MF), as we (1) and others have reported. Non-relapse mortality (NRM) from Graft vs. Host Disease (GVHD) and other complications has limited the success of this approach. As part of an ongoing prospective research study at City of Hope, a combination of tacrolimus/sirolimus +/− methotrexate (MTX) for GVHD prophylaxis has become the standard treatment for our allogeneic HCT patients. In this report, we present results for 23 consecutive patients, including extended follow up for 9 patients previously reported who received cyclosporine (CSA)/mycophenolate (MMF) +/− MTX, and the current series of 14 patients who received tacrolimus/sirolimus +/− MTX, and evaluate the impact of the GVHD prophylaxis regimen on the outcomes. Median follow up for alive patients was 29.0 months (9.5–97.0). The estimated 2 yr overall survival (OS) for the CSA/MMF cohort was 55.6 % (confidence interval 36.0, 71.3), and for the tacrolimus/sirolimus cohort it was 92.9% (63.3, 98.8) (p=0.047). The probability of grade III or IV acute GVHD was 60% for the CSA/MMF patients, and 10% for the tacrolimus/sirolimus group (p=0.0102). No significant differences were seen for grade II to IV acute GVHD in the two groups. We conclude that the combination of tacrolimus/sirolimus +/− MTX for GVHD prophylaxis in the setting of RIC HCT for MF appears to reduce the incidence of severe acute GVHD and NRM, and leads to improved OS compared to CSA/MMF +/− MTX.
Myelofibrosis; reduced intensity conditioning; allogeneic transplantation; tacrolimus/sirolimus
The rate of mycophenolic acid (MPA) absorption after oral administration of mycophenolate mofetil (MMF) is delayed in patients with diabetes. Cyclosporine (CsA) decreases MPA exposure by inhibiting enterohepatic recirculation of MPA/MPA glucuronide, and tacrolimus (TRL) may alter the rate and extent of MPA absorption due to its prokinetic properties especially in patients with diabetic gastroparesis. This study evaluated the effect of changing from CsA to TRL on pharmacokinetics of MPA in stable renal transplant recipients with long-standing diabetes. Eight patients were switched from a stable dose of CsA to TRL while taking MMF 1 g twice daily. The 12-hour steady-state total plasma concentration–time profiles of MPA and MPA glucuronide were obtained after oral administration of MMF on 2 occasions: first while taking CsA and second after changing to TRL. Pharmacokinetic parameters of MPA were calculated by the noncompartmental method. Changing from CsA to TRL resulted in significantly increased MPA exposure (area under the concentration–time curve from 0 to 12 hours, AUC0–12) by 46 ± 32% (P = 0.012) and MPA predose concentration (C0) by 121 ± 67% (P = 0.008). The magnitude of change in MPA exposure did not correlate well with MPA-C0 or CsA trough concentration. Switching to TRL had minimal impact on peak concentration of MPA (15.0 ± 6.9 mg/L with CsA versus 16.1 ± 9.7 mg/L with TRL, P = 0.773) and time to reach the peak concentration (1.0 ± 0.4 hours with CsA versus 1.2 ± 0.8 hours with TRL, P = 0.461). Highly variable and unpredictable changes in MPA exposure among renal transplant patients with diabetes do not support a strategy of preemptively adjusting MMF dose when switching calcineurin inhibitors in this population.
mycophenolic acid; pharmacokinetics; diabetes; cyclosporine; tacrolimus
AIM: To evaluate the prophylaxis of chronic kidney disease (CKD) after liver transplantation (LT) with low-dose calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF).
METHODS: From March 1999 to December 2009, a total of 572 patients (478 males and 94 females) underwent LT enrolled in the study. Initial immunosuppression was by triple-drug regimens that included a CNI, MMF, and prednisone. The initial dose of CNI was 0.05-0.10 mg/kg per day for tacrolimus (TAC) and 5-10 mg/kg per d for cyclosporine A (CSA) respectively, and was gradually reduced based on a stable graft function. The serum trough level of CNI was 6-8 ng/mL for TAC and 120-150 ng/mL for CSA 3-mo post-operation, 4-6 ng/mL for TAC and 80-120 ng/mL for CSA 1-year after transplantation was expected with stable liver function. MMF was personalized between 1.0-1.5 g/d. Glomerular filtration rate (GFR) was estimated by an abbreviated Modification of Diet in Renal Disease formula. Risk factors of CKD were examined by univariate and multivariate logistic regression.
RESULTS: With a definition of GFR < 60 mL/min per 1.73 m2, the incidence of CKD was 17.3% 5-year after LT. There were 68.3% (293 of 429 cases) patients managed to control their TAC trough concentrations within 8 ng/mL and 58.0% (83 of 143 cases) patients’ CSA trough concentrations within 150 ng/mL. Of the 450 recipients followed-up over 1 year, 55.5% (183 of 330 cases) of which were treated with TAC had a trough concentration ≤ 6 ng/mL while 65.8% (79 of 120 cases) of which were treated with CSA had a concentration ≤ 120 ng/mL. The incidence of CKD in the groups of lower CNI trough concentrations was significantly lower than the groups with CNI concentrations above the ideal range. Patients with CKD had much higher CNI trough concentrations than that of patients without CKD. MMF was adopted in 359 patients (62.8%). Patients administrated with MMF had a relatively low CNI trough concentrations but with no significant difference. The graft function remained stable during follow-up. No difference was found between different groups of CNI trough concentrations. Pre-LT renal dysfunction, ages, acute kidney injury, high blood trough concentrations of CNI in 3 mo (TAC > 8 ng/mL, CSA > 150 ng/mL) and hypertension after operation were associated with CKD progression, while male gender and adoption of MMF were protection factors.
CONCLUSION: Low dose of CNI combined with MMF managed to prevent CKD after LT with stable graft function.
Liver transplantation; Chronic kidney disease; Calcineurin inhibitor; Mycophenolate mofetil; Risk factor