Early elimination of cyclosporine in kidney transplant recipients receiving sirolimus prevents progression of chronic pathologic allograft lesions

Calcineurin inhibitor withdrawal or tapering for kidney transplant recipients

BACKGROUND

Calcineurin inhibitors (CNI) can reduce acute transplant rejection and immediate graft loss but are associated with significant adverse effects such as hypertension and nephrotoxicity which may contribute to chronic rejection. CNI toxicity has led to numerous studies investigating CNI withdrawal and tapering strategies. Despite this, uncertainty remains about minimisation or withdrawal of CNI.

OBJECTIVES

This review aimed to look at the benefits and harms of CNI tapering or withdrawal in terms of graft function and loss, incidence of acute rejection episodes, treatment-related side effects (hypertension, hyperlipidaemia) and death.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 11 October 2016 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) where drug regimens containing CNI were compared to alternative drug regimens (CNI withdrawal, tapering or low dose) in the post-transplant period were included, without age or dosage restriction.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for eligibility, risk of bias, and extracted data. Results were expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 83 studies that involved 16,156 participants. Most were open-label studies; less than 30% of studies reported randomisation method and allocation concealment. Studies were analysed as intent-to-treat in 60% and all pre-specified outcomes were reported in 54 studies. The attrition and reporting bias were unclear in the remainder of the studies as factors used to judge bias were reported inconsistently. We also noted that 50% (47 studies) of studies were funded by the pharmaceutical industry.We classified studies into four groups: CNI withdrawal or avoidance with or without substitution with mammalian target of rapamycin inhibitors (mTOR-I); and low dose CNI with or without mTOR-I. The withdrawal groups were further stratified as avoidance and withdrawal subgroups for major outcomes.CNI withdrawal may lead to rejection (RR 2.54, 95% CI 1.56 to 4.12; moderate certainty evidence), may make little or no difference to death (RR 1.09, 95% CI 0.96 to 1.24; moderate certainty), and probably slightly reduces graft loss (RR 0.85, 95% CI 0.74 to 0.98; low quality evidence). Hypertension was probably reduced in the CNI withdrawal group (RR 0.82, 95% CI 0.71 to 0.95; low certainty), while CNI withdrawal may make little or no difference to malignancy (RR 1.10, 95% CI 0.93 to 1.30; low certainty), and probably makes little or no difference to cytomegalovirus (CMV) (RR 0.87, 95% CI 0.52 to 1.45; low certainty)CNI avoidance may result in increased acute rejection (RR 2.16, 95% CI 0.85 to 5.49; low certainty) but little or no difference in graft loss (RR 0.96, 95% CI 0.79 to 1.16; low certainty). Late CNI withdrawal increased acute rejection (RR 3.21, 95% CI 1.59 to 6.48; moderate certainty) but probably reduced graft loss (RR 0.84, 95% CI 0.72 to 0.97, low certainty).Results were similar when CNI avoidance or withdrawal was combined with the introduction of mTOR-I; acute rejection was probably increased (RR 1.43; 95% CI 1.15 to 1.78; moderate certainty) and there was probably little or no difference in death (RR 0.96; 95% CI 0.69 to 1.36, moderate certainty). mTOR-I substitution may make little or no difference to graft loss (RR 0.94, 95% CI 0.75 to 1.19; low certainty), probably makes little of no difference to hypertension (RR 0.86, 95% CI 0.64 to 1.15; moderate), and probably reduced the risk of cytomegalovirus (CMV) (RR 0.60, 95% CI 0.44 to 0.82; moderate certainty) and malignancy (RR 0.69, 95% CI 0.47 to 1.00; low certainty). Lymphoceles were increased with mTOR-I substitution (RR 1.45, 95% CI 0.95 to 2.21; low certainty).Low dose CNI combined with mTOR-I probably increased glomerular filtration rate (GFR) (MD 6.24 mL/min, 95% CI 3.28 to 9.119; moderate certainty), reduced graft loss (RR 0.75, 95% CI 0.55 to 1.02; moderate certainty), and made little or no difference to acute rejection (RR 1.13 ; 95% CI 0.91 to 1.40; moderate certainty). Hypertension was decreased (RR 0.98, 95% CI 0.80 to 1.20; low certainty) as was CMV (RR 0.41, 95% CI 0.16 to 1.06; low certainty). Low dose CNI plus mTOR-I makes probably makes little of no difference to malignancy (RR 1.22, 95% CI 0.42 to 3.53; low certainty) and may make little of no difference to death (RR 1.16, 95% CI 0.71 to 1.90; moderate certainty).

AUTHORS' CONCLUSIONS

CNI avoidance increased acute rejection and CNI withdrawal increases acute rejection but reduced graft loss at least over the short-term. Low dose CNI with induction regimens reduced acute rejection and graft loss with no major adverse events, also in the short-term. The use of mTOR-I reduced CMV infections but increased the risk of acute rejection. These conclusions must be tempered by the lack of long-term data in most of the studies, particularly with regards to chronic antibody-mediated rejection, and the suboptimal methodological quality of the included studies.

Chronic Allograft Nephropathy: Pathogenesis and Management of an Important Posttransplant Complication

Chronic allograft nephropathy is a devastating complication of kidney transplantation that is responsible for a significant proportion of graft loss. This complication is characterized by a progressive decline in kidney function, which is not attributable to a specific cause. Many risk factors exist for the development of chronic allograft nephropathy, including donor-, recipient-, and transplant-related factors (eg, use of calcineurin inhibitors and acute rejection episodes), as well as comorbid conditions such as hypertension and hyperlipidemia. There is no definitive treatment for this complication; management has focused on minimization or withdrawal of calcineurin inhibitors in conjunction with addition of sirolimus or mycophenolate mofetil. Alterations in the immunosuppressive regimen must be done cautiously, as precipitating acute rejection will cause further damage to the allograft. Optimal control of blood pressure, particularly with the use of agents such as angiotensin II receptor blockers, in conjunction with management of dyslipidemia may be effective concurrent therapies in patients with chronic allograft nephropathy.

Pharmacokinetics and Long-Term Safety and Tolerability of Everolimus in Renal Transplant Recipients Converted From Cyclosporine

BACKGROUND

Conversion from cyclosporine (CsA) to everolimus (EVR) in kidney transplant recipients receiving mycophenolate sodium (MPS) and corticosteroids has been used to reduce CsA associated toxicities. Nevertheless, exposures produced by the initial EVR dose, the steady state pharmacokinetic and long-term safety and tolerability have not been explored in detail.

METHODS

Twenty-four stable kidney transplant recipients receiving CSA, MPS, and corticosteroids were converted from CSA to EVR. The initial EVR dose was 3 mg BID. Weekly monitoring of EVR blood concentrations was followed by a full 12 hour pharmacokinetic profile 28 days after conversion. Therapeutic drug monitoring, safety, and tolerability were analyzed during 5 years of follow-up.

RESULTS

The study population was relatively young (mean of 42 years) with a predominance of males (62%) and White (67%) recipients of kidneys from living (54%) or deceased (46%) donors. Mean time of the conversion was 61 months after transplantation. In the first 7 patients, the initial EVR dose of 3 mg BID resulted in mean EVR trough blood concentration of 14.7 ± 3.7 ng/mL at day 7. The initial EVR dose was then reduced to 2 mg BID for the following 17 patients. Four weeks after conversion, mean EVR dose was 1.7 ± 0.5 mg BID (7 patients were receiving 1 mg BID and 17 were receiving 2 mg BID) resulting in mean EVR trough blood concentration of 4.0 ± 1.4 ng/mL. Whereas mean maximum concentration (13.4 ± 2.8 versus 22.9 ± 7.4 ng/mL, P = 0.003) and mean apparent clearance (232 ± 79 versus 366 ± 173 mL/min, P = 0.016) were higher, mean area under the curve (78.2 ± 22.1 versus 102.5 ± 38.5 ng.h/mL, P = 0.067) and mean C0 (3.7 ± 1.3 versus 4.1 ± 1.5 ng/mL, P = 0.852) were no different comparing patients receiving 1 mg and 2 mg EVR BID. Mean inter-subject variability of area under the curve, trough concentration, and maximum concentration was 38%, 36%, and 38%. EVR treatment was discontinued in 29% of patients due to proteinuria (N = 2), pneumonia (N = 2), dyslipidemia (N = 2), and anemia (N = 1) and MPS dose was reduced in 58% of patients.

CONCLUSIONS

The initial 3 mg BID dose produced high EVR trough blood concentrations. The 2 mg BID dose appears to be the appropriate initial dose to provide therapeutic concentrations but still requires initial intensive therapeutic monitoring to achieve and maintain blood concentrations within the therapeutic target concentration. The combination of EVR and full dose MPS has limited long-term tolerability and safety.

Switching to sirolimus in renal transplant recipients with hepatitis C virus: a safe option

INTRODUCTION

The presence of hepatitis C virus (HCV) in renal transplant recipients is an independent risk factor for death and graft failure. Chronic allograft nephropathy (CAN) favored by the use of calcineurin inhibitors (CNI) is one of the main causes of graft loss, whereas sirolimus (SRL) has proven to maintain better graft function with lower rates of CAN.

OBJECTIVES AND METHODS

We developed a protocol to evaluate the safety of SRL in transplant recipients with respect to HCV. We studied 5 patients (3 men) of mean age 52 +/- 9.2 years with HCV who had not received antiviral treatment. The viral genotypes were 1b in 4 cases and 2a/2c in 1 case. Basic immunosuppression was mycophenolate mofetil (MMF) and corticosteroids in all patients, cyclosporine (CsA) in 4 cases, and tacrolimus (Tac) in 1 case. Before the switch, a renal biopsy was performed and viral replication and cryoglobulins determined.

RESULTS

Biopsy provided a diagnosis of CAN in 1 case, CNI toxicity-associated CAN in 2 cases, CNI toxicity in 1 case, and no renal damage in the remaining case. We observed a nonsignificant decrease in the number (log) of viral copies with a stabilization of renal function but with a slight to moderate increase in proteinuria.

CONCLUSIONS

The switch seemed to be safe with no increase in viral copies. Graft renal function remained stable with increased proteinuria that must be supervised, even though it did not reach statistical significance.

The challenge of renal function in heart transplant children

Renal dysfunction may occur after pediatric heart transplantation and impacts on long-term prognosis. This study aims to review the incidence and mechanisms of chronic nephropathy following heart transplantation, and suggest therapeutic directions. The proportion of pediatric heart-transplant recipients with impaired renal function varies from 22 to 57%, and end-stage renal failure from 3 to 10%, depending on the method used for estimating the glomerular filtration rate. The pathophysiology of renal dysfunction is in part due to calcineurin inhibitor-induced renal vasoconstriction, through activation of the intrarenal renin-angiotensin system, TGF-beta1 upregulation and TGF-beta1 gene polymorphisms. Overproduction of angiotensin II, associated with angiotensin-converting-enzyme genotype, might be associated with poor prognosis and pharmacological factor gene polymorphisms, and may contribute to variation of calcineurine inhibitor exposure in the kidney. Strategies to prevent renal dysfunction include reducing calcineurine inhibitor exposure or delaying calcineurine inhibitor administration from the early post-transplant period. Calcium channel blockers and angiotensin-converting-enzyme inhibitors, blockade of angiotensin II, or anti-TGF-beta1 antibodies might limit nephrotoxicity. No accurate marker can predict the potential of renal lesions to develop. Lowering calcineurine inhibitors levels with immunosuppressive agents that are either less nephrotoxic or non-nephrotoxic should be formally studied. Of high interest is the impact of genetic polymorphism on the development of renal dysfunction.

Stable graft function after reduction of calcineurin inhibitor dosage in paediatric kidney transplant patients

BACKGROUND

Chronic calcineurin inhibitor (CNI) toxicity contributes to the development and progression of chronic allograft nephropathy (CAN), which is still the major cause of transplant dysfunction and graft loss. Reduction in dosage of CNI may delay the development of CAN, leading to longer graft survival.

METHODS

Therefore, 19 paediatric kidney transplant patients under immunosuppressive therapy with CNI (12/19 ciclosporin A, CSA, 7/19 tacrolimus, Tac), mycophenolat mofetil and some patients on steroids were included in a prospective study. Over a period of 9 months CNI dosage was stepwise reduced from CSA trough levels of 100-150 ng/ml to 50-70 ng/ml and Tac trough levels of 5-8 ng/ml to 2-3 ng/ml, respectively.

RESULTS

Glomerular filtration rate was stabilized in patients after CSA and Tac reduction. One borderline rejection occurred in a patient prior to reduction of Tac. In patients on CSA, one interstitial cellular rejection (BANFF IA) was noted. Reduction of CNI had no significant effects on blood pressure, lipid status and the infection frequency.

CONCLUSIONS

In paediatric kidney transplant patients, reduction of CNI down to low trough levels stabilizes renal function. However, the risk of acute rejection episodes may be increased. Therefore, further studies based on protocol biopsies within a randomized trial are warranted.

Mycophenolate mofetil introduction stabilizes and subsequent cyclosporine A reduction slightly improves kidney function in pediatric renal transplant patients: a retrospective analysis

Chronic allograft nephropathy (CAN) is the major cause of late graft loss. Among others, chronic calcineurin inhibitor toxicity (CNI) contributes to the development of CAN. Therefore, reduction in CNI dosage may delay the development of CAN, leading to longer graft survival. It was the aim of the present retrospective analysis to investigate the effect of mycophenolate mofetil (MMF) addition with subsequent cyclosporine A (CSA) reduction on renal function in pediatric kidney allograft recipients. Seventeen patients (aged 8.3-17.6 yr) with monotherapy with CSA and progressive loss of renal function at a median of 3.4 yr after kidney transplantation were enrolled. After at least three months of MMF treatment, CSA dosage was stepwise reduced to trough levels of 100, 80, and 60 ng/mL. In all patients, introduction of MMF prevented a further decrease of glomerular filtration rate (GFR). The mean GFR 12 months before study enrollment was 96.1+/-24.5 and 71.0+/-21.0 mL/min/1.73 m2 at start of MMF. After introduction of MMF and unchanged CSA dosage GFR was stabilized to 71.1+/-23.8 mL/min/1.73 m2. After CSA reduction to trough levels of 60 ng/mL, GFR was slightly ameliorated up to 76.3+/-24.1 mL/min/1.73 m2. Within the follow-up period, one borderline rejection occurred in a patient in whom the CSA trough level was 60 ng/mL since seven months. In pediatric kidney allograft recipients with progressive loss of renal function reduction of CSA after introduction of MMF may stabilize and even slightly ameliorate renal function.

Sirolimus: the evidence for clinical pharmacokinetic monitoring

This review seeks to apply a decision-making algorithm to establish whether clinical pharmacokinetic monitoring (CPM) of sirolimus (rapamycin) in solid organ transplantation is indicated in specific patient populations. The need for CPM of sirolimus, although a regulatory requirement in Europe, has not yet been firmly established in North America and other parts of the world. Sirolimus has demonstrated immunosuppressive efficacy in renal, pancreatic islet cell, liver and heart transplant recipients. The pharmacological response of immunosuppressive therapy with sirolimus cannot be readily evaluated; however, a relationship between trough blood sirolimus concentrations, area under the plasma concentration-time curve (AUC) and the incidence of rejection has been proposed. Furthermore, sirolimus can be measured in whole blood by several assays--high-performance liquid chromatography with detection by tandem mass spectrometry, or with ultraviolet detection, radioreceptor assay or microparticle enzyme immunoassay. Both experimental animal and clinical data suggest that adverse events and their associated severity are correlated with blood concentrations. To prevent rejection and minimise toxicity, a therapeutic range of 4-12 microg/L (measured via chromatographic assays) is recommended when sirolimus is used in conjunction with ciclosporin. If ciclosporin therapy is discontinued, a target trough range of 12-20 microg/L is recommended. Sirolimus pharmacokinetics display large inter- and intrapatient variability, which may change in specific patient populations due to disease states or concurrent immunosuppressants or other interacting drugs. Due to the long half-life of sirolimus, dosage adjustments would ideally be based on trough levels obtained more than 5-7 days after initiation of therapy or dosage change. Once the initial dose titration is complete, monitoring sirolimus trough concentrations weekly for the first month and every 2 weeks for the second month appears to be appropriate. After the first 2 months of dose titration, routine CPM of sirolimus is not necessary in all patients, but may be warranted to achieve target concentrations in certain populations of patients, but the frequency of further monitoring remains to be determined and should be individualised.

Immunosuppressive agents in solid organ transplantation: Mechanisms of action and therapeutic efficacy

Effective immunosuppression is an essential pre-requisite for successful organ transplantation and improvements in outcome after transplantation have to a large extent been dependent on developments in immunosuppressive therapy. Here we provide an overview of the different immunosuppressive agents currently used in solid organ transplantation. A historical perspective on the development of immunosuppression for organ transplantation is followed by a review of the individual agents, with a focus on their mechanism of action and efficacy. Steroids, anti-proliferative agents (azathioprine and mycophenolate), calcineurin inhibitors (cyclosporine and tacrolimus) and TOR inhibitors (sirolimus and everolimus) are discussed along with both polyclonal and monoclonal antibody preparations. Many of the key clinical trials that underpin current clinical usage of these agents are described and side-effects of the different agents are highlighted. Finally, a number of newer agents still in various stages of clinical development are briefly considered.

What we CAN do about chronic allograft nephropathy: Role of immunosuppressive modulations

Given the potency of modern immunosuppressive agents, kidney transplantation across alloantingen barriers is a routine phenomenon with excellent 1-year graft survival in most centers. However, the improvement in 1-year graft survival has not been matched by improvements in long-term graft function and chronic allograft nephropathy (CAN) remains the second commonest cause of graft attrition over time. Calcineurin inhibitors, namely cyclosporine A (CyA) and tacrolimus, have been implicated as causal agents in the development of the fibrotic processes that are the hallmarks of CAN. Many studies have, therefore, concentrated on the improvement of long term graft function through the modulation of immunosuppressive therapy. It is the purpose of this review to describe and appraise the available evidence for the prevention and management of CAN through modulation of immunosuppressive agents.

Calcineurin inhibitor withdrawal from sirolimus-based therapy in kidney transplantation: a systematic review of randomized trials

Calcineurin inhibitor (CNI) withdrawal has been used as a strategy to improve renal allograft function, however, it also carries risk of acute rejection. We conducted a systematic review of randomized trials that involved CNI withdrawal from a sirolimus-based immunosuppressive regimen. The search strategy yielded six trials (n = 1047 patients) reported in eight publications. CNI withdrawal from sirolimus-based therapy, was associated with an increased risk of acute rejection (risk difference, 6%; 95% CI 2-10%, p = 0.002) but a higher creatinine clearance (mean difference, 7.49 mL/min; 95% CI 5.08-9.89 mL/min, p < 0.00001) at 1 year compared to continued CNI and sirolimus therapy. Graft loss (relative risk, 0.87; 95% CI 0.46-1.64, p = 0.66) and death (relative risk, 0.88; CI 0.40-1.96, p = 0.76) were similar in both groups at 1 year. Hypertension was significantly reduced in the CNI withdrawal group (relative risk, 0.56; 95% CI 0.40-0.78, p = 0.0006). CNI withdrawal from sirolimus-based therapy is associated with an increased risk of acute rejection in the short term with a significant improvement in renal function and a reduction in hypertension. Longer follow-up is needed to determine if these changes will result in a significant improvement in patient and graft survival.

Cyclosporine renal dysfunction

Cyclosporine (CsA), introduced as an immunosuppressive agent in the 1980s, quickly become the first-line treatment in organ transplantation. However, these improvements were associated with an increased incidence of renal dysfunction. CsA causes histopathological changes in renal transplants that are often difficult to distinguish from other processes, especially chronic allograft nephropathy. Enhanced angiotensin II, transforming growth factor-beta, and vascular endothelial growth factor expression together with down-regulation of nitric oxide synthesis may play roles in chronic CsA nephropathy. Efforts have recently focused upon protocols that minimize the risk of CsA nephrotoxicity while preserving low rates of acute rejection. Four types of CsA-sparing studies have emerged from recent clinical experience: (1) conversion studies in which a nonnephrotoxic drug is substituted to allow CsA reduction, (2) minimal CsA exposure studies in which reduced CsA doses are combined with nonnephrotoxic drugs, (3) withdrawal studies in which CsA is completely discontinued at some time after transplantation, and (4) CsA-free studies in which the drug is completely avoided from the time of transplantation. Monitoring of CsA immunosuppression according to C2 blood levels, which better correlate with the area under the time-concentration curve than trough concentrations, should reduce the risk for toxicity; however, the most appropriate target range has not yet been clearly established. Because of interindividual differences in CsA absorption and susceptibility to renal dysfunction, the current therapeutic drug monitoring should be supplemented with pharmacogenetic information on genetic variability of relevant genes for pharmacokinetic parameters and therapeutic targets. This approach may guide choices for immunosuppressants for particular patients, with low toxicity. Thus, despite of 20 years of its history, CsA renal dysfunction remains an important clinical challenge.