Tacrolimus vs. cyclosporine A as primary immunosuppression in pediatric renal transplantation: a NAPRTCS study

Data mining and safety analysis of traditional immunosuppressive drugs: a pharmacovigilance investigation based on the FAERS database

OBJECTIVE

The purpose of this study aimed to explore the new and serious adverse events(AEs) of Tacrolimus(FK506), cyclosporine(CsA), azathioprine(AZA), mycophenolate mofetil(MMF), cyclophosphamide(CTX) and methotrexate(MTX), which have not been concerned.

METHODS

The FAERS data from January 2016 and December 2022 were selected for disproportionality analysis to discover the potential risks of traditional immunosuppressive drugs.

RESULTS

Compared with CsA, FK506 has more frequent transplant rejection, and is more related to renal impairment, COVID-19, cytomegalovirus infection and aspergillus infection. However, CsA has a high infection-related fatality rate. In addition, we also found some serious and rare AE in other drugs which were rarely reported in previous studies. For example, AZA is closely related to hepatosplenic T-cell lymphoma with high fatality rate and MTX is strongly related to hypofibrinogenemia.

CONCLUSION

The AEs report on this study confirmed that the results were basically consistent with the previous studies, but there were also some important safety signals that were inconsistent with or not mentioned in previous published studies.

EXPERT OPINION

The opinion section discusses some of the limitations and shortcomings, proposing the areas where more effort should be invested in order to improve the safety of immunosuppressive drugs.

Comparison of tacrolimus vs. cyclosporine in pediatric hematopoietic stem cell transplantation for thalassemia

OBJECTIVES

Graft-versus-host disease (GvHD) is one of the leading causes of morbidity and mortality in patients undergoing allogeneic HSCT, and effective prevention of GvHD is critical for the success of the HSCT procedure. Calcineurin inhibitors (CNI) have been used for decades as the backbone of GvHD prophylaxis. In this study, the efficacy and safety of Cyclosporine A (CsA) and tacrolimus (TCR) were compared in pediatric HSCT for thalassemia.

MATERIALS AND METHODS

This is a retrospective analysis of 129 pediatric patients who underwent HSCT with the diagnosis of thalassemia at Medicalpark Göztepe and Antalya Hospitals between January 2017 and December 2020.

RESULTS

Despite the GvHD prophylaxis, grade II-IV acute GvHD developed in 29 patients. Of these patients, 12 had only gut, 10 had only skin, 6 had combined gut and skin, and one had only liver GvHD. Fifteen of these 29 patients were in the CsA group, and 14 of them were in the TCR group. There was no significant difference between the groups in terms of acute GvHD occurrence, GvHD stage, or involvement sites. In terms of CNI-related toxicity, neurotoxicity in 15 (CsA n = 9, TCR n = 6) and nephrotoxicity in 18 (CsA n = 4, TCR n = 14) patients were observed. While there was no difference between the two groups in terms of neurotoxicity, more nephrotoxicity developed in patients using TCR (p = .013). There was no significant difference between the groups in terms of engraftment syndrome, veno-occlusive disease, CMV reactivation, PRES, or graft rejection.

CONCLUSION

Regarding GvHD, there was no difference in efficacy between TCR and CsA usage. Patients taking TCR experienced noticeably higher nephrotoxicity in terms of adverse effects. This difference should be considered according to the patient's clinical situation while choosing a CNI.

Induction and maintenance immunosuppression in pediatric kidney transplantation-Advances and controversies

Advances in immunosuppression have improved graft survival in pediatric kidney transplant recipients; however, treatment-related toxicities need to be balanced against the possibility of graft rejection. Several immunosuppressive agents are available for use in transplant recipients; however, the optimal combinations of agents remain unclear, resulting in variations in institutional protocols. Lymphocyte-depleting antibodies, specifically ATG, are the most common induction agent used for pediatric kidney transplantation in the US. Basiliximab may be used for induction in immunologically low-risk children; however, pediatric data are scarce. CNIs and antiproliferative agents (mostly Tac and mycophenolate in recent years) constitute the backbone of maintenance immunosuppression. Steroid-avoidance maintenance regimens remain controversial. Belatacept and mTOR inhibitors are used in children under specific circumstances such as non-adherence or CNI toxicity. This article reviews the indications, mechanism of action, efficacy, dosing, and side effect profiles of various immunosuppressive agents available for pediatric kidney transplantation.

Acute rejection in pediatric renal transplantation: Retrospective study of epidemiology, risk factors, and impact on renal function

AR is a major relevant and challenging topic in pediatric kidney transplantation. Our objective was to evaluate cumulative incidence of AR in pediatric kidney transplant patient, risk factors for this outcome, and impact on allograft function and survival. A retrospective cohort including pediatric patients that underwent kidney transplantation between 2011 and 2015 was designed. Risk factors for AR were tested by competing risk analysis. To estimate its impact, graft survival and difference in GFR were evaluated. Two hundred thirty patients were included. As a whole, the incidence of AR episodes was 0.16 (95% CI = 0.12-0.20) per person-year of follow-up. And cumulative incidence of AR was 23% in 1 year and 39% in 5 years. Risk factors for AR were number of MM (SHR 1.36 CI 1.14-1.63 P = .001); ISS with CSA, PRED, and AZA (SHR 2.22 CI 1.14-4.33 P = .018); DGF (SHR 2.49 CI 1.57-3.93 P < .001); CMV infection (SHR 5.52 CI 2.27-11.0 P < .001); and poor adherence (SHR 2.28 CI 1.70-4.66 P < .001). Death-censored graft survival in 1 and 5 years was 92.5% and 72.1%. Risk factors for graft loss were number of MM (HR 1.51 CI 1.07-2.13 P = .01), >12 years (HR 2.66 CI 1.07-6.59 P = .03), and PRA 1%-50% (HR 2.67 CI 1.24-5.73 P = .01). Although occurrence of AR did not influence 5-year graft survival, it negatively impacted GFR. AR was frequent in patients assessed and associated with number of MM, ISS regimen, DGF, CMV infection, and poor adherence, and had deleterious effect on GFR.

Temporal Changes in the Impact of HLA Mismatching Among Pediatric Kidney Transplant Recipients

BACKGROUND

Allocation for pediatric deceased-donor kidney transplantation (pDDKT) in the United States now de-emphasizes HLA matching to improve equality in access to transplantation, but other national systems still consider HLA matching due to concerns about graft survival. We hypothesized that the impact of HLA mismatching has decreased over time due to advances including improved immunosuppression.

METHODS

Using Scientific Registry of Transplant Recipient data, we analyzed whether the association between the number of HLA mismatches and outcomes of first-time pDDKTs changed between 2 eras: 1995 to 2004 (N = 2854) and 2005 to 2014 (N = 4643).

RESULTS

Between eras, the median number of mismatches increased from 4 to 5 (P < 0.001). Overall graft failure risk was higher among HLA-mismatched versus HLA-matched transplants (adjusted hazard ratio 1.211.431.69 for 3-6 versus 0-2 mismatches; P < 0.001), and this association was similar pre-2005 and post-2005 (Pinteraction = 0.5). Median panel-reactive antibody change at relisting increased from 79 to 85 (P = 0.01), but the association between number of HLA mismatches and panel-reactive antibody change was similar between eras (Pinteraction = 0.6).

CONCLUSIONS

Our finding that increased HLA mismatching continues to impact graft survival, with 43% higher risk of graft failure, highlights the tradeoff between transplant access equity and outcomes and calls into question the deemphasis on HLA matching in pDDKT allocation in the United States.

Immunosuppressants in Organ Transplantation

The goal of immunosuppressive therapy post-transplantation in pediatric renal transplant recipients is to prevent acute and chronic rejection while minimizing drug side effects. Most therapies alter immune response mechanisms but are not immunologically specific, and a careful balance is required to find the dose that prevents rejection of the graft while minimizing the risks of overimmunosuppression leading to infection and cancer. While this chapter because of space constraints focuses on immunosuppressive therapy in pediatric renal transplant recipients, many aspects can be applied on pediatric recipients of other solid organ transplants such as the liver and heart. The major maintenance immunosuppressive agents currently used in various combination regimens are tacrolimus, cyclosporine, mycophenolate mofetil, azathioprine, everolimus, sirolimus, and glucocorticoids (steroids). Although data from adult renal transplantation trials are used to help guide management decisions in pediatric patients, immunosuppressive therapy in pediatric renal transplant recipients often must be modified because of the unique dosage requirements and clinical effects of these agents in children, including their impact on growth and development. The optimal immunosuppressive therapy post-transplant is not established. The goal remains to find the best combination of immunosuppressive agents that optimizes allograft survival by preventing acute rejection while limiting drug toxicities.

Clinical aspects of tacrolimus use in paediatric renal transplant recipients

The calcineurin inhibitor tacrolimus, cornerstone of most immunosuppressive regimens, is a drug with a narrow therapeutic window: underexposure can lead to allograft rejection and overexposure can result in an increased incidence of infections, toxicity and malignancies. Tacrolimus is metabolised in the liver and intestine by the cytochrome P450 3A (CYP3A) isoforms CYP3A4 and CYP3A5. This review focusses on the clinical aspects of tacrolimus pharmacodynamics, such as efficacy and toxicity. Factors affecting tacrolimus pharmacokinetics, including pharmacogenetics and the rationale for routine CYP3A5*1/*3 genotyping in prospective paediatric renal transplant recipients, are also reviewed. Therapeutic drug monitoring, including pre-dose concentrations and pharmacokinetic profiles with the available "reference values", are discussed. Factors contributing to high intra-patient variability in tacrolimus exposure and its impact on clinical outcome are also reviewed. Lastly, suggestions for future research and clinical perspectives are discussed.

Immunosuppressive therapy for kidney transplantation in children and adolescents: systematic review and economic evaluation

BACKGROUND

End-stage renal disease is a long-term irreversible decline in kidney function requiring kidney transplantation, haemodialysis or peritoneal dialysis. The preferred option is kidney transplantation followed by induction and maintenance immunosuppressive therapy to reduce the risk of kidney rejection and prolong graft survival.

OBJECTIVES

To systematically review and update the evidence for the clinical effectiveness and cost-effectiveness of basiliximab (BAS) (Simulect,(®) Novartis Pharmaceuticals) and rabbit antihuman thymocyte immunoglobulin (Thymoglobuline,(®) Sanofi) as induction therapy and immediate-release tacrolimus [Adoport(®) (Sandoz); Capexion(®) (Mylan); Modigraf(®) (Astellas Pharma); Perixis(®) (Accord Healthcare); Prograf(®) (Astellas Pharma); Tacni(®) (Teva); Vivadex(®) (Dexcel Pharma)], prolonged-release tacrolimus (Advagraf,(®) Astellas Pharma); belatacept (BEL) (Nulojix,(®) Bristol-Myers Squibb), mycophenolate mofetil (MMF) [Arzip(®) (Zentiva), CellCept(®) (Roche Products), Myfenax(®) (Teva), generic MMF is manufactured by Accord Healthcare, Actavis, Arrow Pharmaceuticals, Dr Reddy's Laboratories, Mylan, Sandoz and Wockhardt], mycophenolate sodium, sirolimus (Rapamune,(®) Pfizer) and everolimus (Certican,(®) Novartis Pharmaceuticals) as maintenance therapy in children and adolescents undergoing renal transplantation.

DATA SOURCES

Clinical effectiveness searches were conducted to 7 January 2015 in MEDLINE (via Ovid), EMBASE (via Ovid), Cochrane Central Register of Controlled Trials (via Wiley Online Library) and Web of Science [via Institute for Scientific Information (ISI)], Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects and Health Technology Assessment (HTA) (The Cochrane Library via Wiley Online Library) and Health Management Information Consortium (via Ovid). Cost-effectiveness searches were conducted to 15 January 2015 using a costs or economic literature search filter in MEDLINE (via Ovid), EMBASE (via Ovid), NHS Economic Evaluation Databases (via Wiley Online Library), Web of Science (via ISI), Health Economic Evaluations Database (via Wiley Online Library) and EconLit (via EBSCOhost).

REVIEW METHODS

Titles and abstracts were screened according to predefined inclusion criteria, as were full texts of identified studies. Included studies were extracted and quality appraised. Data were meta-analysed when appropriate. A new discrete time state transition economic model (semi-Markov) was developed; graft function, and incidences of acute rejection and new-onset diabetes mellitus were used to extrapolate graft survival. Recipients were assumed to be in one of three health states: functioning graft, graft loss or death.

RESULTS

Three randomised controlled trials (RCTs) and four non-RCTs were included. The RCTs only evaluated BAS and tacrolimus (TAC). No statistically significant differences in key outcomes were found between BAS and placebo/no induction. Statistically significantly higher graft function (p < 0.01) and less biopsy-proven acute rejection (odds ratio 0.29, 95% confidence interval 0.15 to 0.57) was found between TAC and ciclosporin (CSA). Only one cost-effectiveness study was identified, which informed NICE guidance TA99. BAS [with TAC and azathioprine (AZA)] was predicted to be cost-effective at £20,000-30,000 per quality-adjusted life year (QALY) versus no induction (BAS was dominant). BAS (with CSA and MMF) was not predicted to be cost-effective at £20,000-30,000 per QALY versus no induction (BAS was dominated). TAC (with AZA) was predicted to be cost-effective at £20,000-30,000 per QALY versus CSA (TAC was dominant). A model based on adult evidence suggests that at a cost-effectiveness threshold of £20,000-30,000 per QALY, BAS and TAC are cost-effective in all considered combinations; MMF was also cost-effective with CSA but not TAC.

LIMITATIONS

The RCT evidence is very limited; analyses comparing all interventions need to rely on adult evidence.

CONCLUSIONS

TAC is likely to be cost-effective (vs. CSA, in combination with AZA) at £20,000-30,000 per QALY. Analysis based on one RCT found BAS to be dominant, but analysis based on another RCT found BAS to be dominated. BAS plus TAC and AZA was predicted to be cost-effective at £20,000-30,000 per QALY when all regimens were compared using extrapolated adult evidence. High-quality primary effectiveness research is needed. The UK Renal Registry could form the basis for a prospective primary study.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013544.

FUNDING

The National Institute for Health Research HTA programme.

Cutaneous Malignancies in Pediatric Solid Organ Transplant Recipients

Pediatric organ transplant recipients (POTRs) are at risk of developing malignancies due to a combination of immunosuppression, impaired DNA damage repair, and infection with oncogenic viruses. The most commonly developed malignancies in this population are skin cancers, which include nonmelanoma skin cancer, melanoma, Kaposi's sarcoma, and anogenital carcinoma. The literature shows that skin cancers account for 13% to 55% of all cancers that occur after transplantation. Given the increasing number and life expectancy of POTRs, prevention and management of skin cancer in these patients is essential, but there is a substantial knowledge gap in our understanding of the differences in skin cancer development, prevention, and management between POTRs and adult organ transplant recipients (AOTRs), for whom more data are available. Substantial differences have been observed in the patterns of malignancy development between POTRs and AOTRs, and data specific to pediatric populations are needed. The objective of this review is to provide updated information on posttransplantation skin cancer development in POTRs, including epidemiologic research on transplant patients and disease development, medication management, surveillance, and education efforts.

Clinical research in pediatric organ transplantation

Solid organ transplantation has greatly improved survival in children with end-stage disease, becoming one of the main treatment options in this population. Nonetheless, there are significant challenges associated with validating and optimizing the effects of these interventions in clinical trials. Therefore, we reviewed the main issues related to conducting clinical transplantation research in children. We divided these challenges into three different categories: (i) challenges related to surgical techniques and anesthetic procedures, (ii) challenges related to post-transplant care and (iii) challenges specific to a particular population group and disease type. Some of the observed burdens for clinical research in this field are related to the limitations of conducting studies with a placebo or sham procedure, determining the standard of care for a control group, low prevalence of cases, ethical concerns related to use of a placebo control group and lack of generalizability from animal studies and clinical trials conducted in adult populations. To overcome some of these barriers, it is necessary to utilize alternative clinical trial designs, such as observational studies or non-inferiority trials, and to develop multicenter collaborations to increase the recruitment rate. In conclusion, the lack of robust data related to pediatric transplantation remains problematic, and further clinical trials are needed to develop more efficacious and safer treatments.

Prevalence of renal dysfunction in tacrolimus-treated pediatric transplant recipients: a systematic review

Renal dysfunction after non-renal transplantation in adult tacrolimus-treated transplant patients is well documented. Little is known about its prevalence in children. Age-related changes in both disposition and effect of tacrolimus as well as renal function may preclude extrapolation of adult data to children. To systematically review the literature on renal dysfunction in non-renal pediatric transplant recipients treated with tacrolimus. PubMed/Medline, Embase, and Google were searched from their inception until April 19, 2012, with the search terms "tacrolimus," "renal function," "transplantation," and "children." Eighteen of 385 retrieved papers were considered relevant. Twelve dealt with liver, four with heart transplant, one with heart and lung transplant, and one with intestinal recipients. Reported prevalences of mild and severe chronic kidney disease ranged from 0% to 39% and 0% to 71.4%, respectively, for liver, and from 22.7% to 40% and 6.8% to 46%, respectively, for heart and/or lung transplant recipients. Ranges remained wide after adjusting for follow-up time and disease severity. Possible explanations are inclusion bias and definitions used for renal dysfunction. A considerable proportion of pediatric non-renal transplant patients who receive tacrolimus-based immunosuppression, appear to suffer from chronic kidney disease. This conclusion warrants further research into the real risk, its risk factors, and individualization of immunosuppressant therapy.

Intra-patient variability in tacrolimus trough concentrations and renal function decline in pediatric renal transplant recipients

High intra-patient variability in TCL exposure is a risk factor for allograft loss and late acute rejection. We hypothesized that a higher intra-patient variability leads to a faster decline in GFR in pediatric renal transplant patients and that adolescents have a higher intra-patient variability due to poorer adherence. We included 69 children aged 3.5-18 yr who had undergone renal transplantation between April 1996 and May 2009 in two pediatric nephrology centers in the Netherlands. We analyzed TCL trough concentrations over a period of one yr and calculated TCL trough concentrations variability using VC. We investigated the correlation between the TCL trough concentrations variability and the decline in estimated GFR over four yr. The median intra-patient variability in TCL concentrations was 30.1% (range 8.6-77.6) and the mean GFR slope -3.8 mL/min/1.73 m(2) /yr. The VC correlated neither with the GFR slope, nor with the patients' age. However, children with late acute rejection had higher VC (p = 0.045). We were unable to provide evidence that a high variability in TCL exposure leads to a faster decline in renal function, although children with late acute rejection have a higher variability in TCL exposure. Adolescents do not have a higher intra-patient variability in TCL trough concentrations than younger children.

Long-term outcome of deceased donor renal transplantation in pediatric recipients: a single-center experience from a developing country

RTx is best treatment for children with ESRD. Data scarcity on DDRTx outcome in children prompted us to review our experience. This study was undertaken to evaluate patient/graft survival, function vis-a-vis SCr, rejection episodes, and mortality in DDRTx performed in 37 children between 1998 and 2011. The most common recipient diseases leading to ESRD were congenital anomalies of kidney and urinary tract (48.6%) and chronic glomerulonephritis (18.9%). Mean recipient age was 13.8 ± 3.1 yr; 67.5% (n = 25) were men. Mean donor age was 38.8 ± 18.6 yr; 48.5% (n = 18) were men. Mean dialysis duration pre-transplantation was 15.5 ± 3.5 months. All recipients received r-ATG, and triple immunosuppression. Over a mean follow-up of 3.93 ± 3.5 yr, patient and graft survival rates were 72.9% (n = 27) and 83.7% (n = 31), respectively, with a mean SCr of 1.1 mg/dL; 21.6% (n = 8) of patients had acute rejection episodes; 24.3% (n = 9) of patients had DGF. A total of 27% (n = 10) patients died, mainly owing to infections (n = 6) and cardiovascular disease (n = 3). DDRTx is a viable option for children and achieves acceptable graft function with patient/graft survival over long-term follow-up, encouraging use of this approach.

Pediatric renal transplantation in the jordanian population: the clinical outcome measures during long-term follow-up period

INTRODUCTION

Recently, many international studies have suggested that pediatric patients from diverse ethnic origins confront unique challenges for transplantation. Data concerning the efficacy and safety of transplantation for various pediatric renal transplant populations remains limited and are often confounded by immunosuppressive protocols. In one study, we aimed to evaluate the short- and long-term outcomes of renal transplants in Jordanian children in comparison with groups of different nationalities.

METHODS

We retrospectively retrieved data for 34 Jordanian children who received kidney transplants from living donors between January 2003 and January 2009. Subsequently, we continued to follow-up with these selected patients at scheduled clinic visits to prospectively collect long-term data for a period of approximately 22 months±15 months.

RESULTS

The patients included in this study ranged between 4 years and 19 years of age. The male/female ratio was 0.79. Glumerulonephritis (35.3%) was the most common cause of end-stage renal disease in the sample of this study; 23.5% had received a preemptive transplant. All patients also received triple immunosuppressive therapy, consisting of tacrolimus (TAC), prednisolone, and mycophenolate mofetil (n=26) or azathioprine (n=8). Furthermore, the rate of acute rejection episodes was lower in the sample of this study than the average rate of many previous studies. The patients' survival rate at 1 year, 2 years and 3 years posttransplant was nearly 100%. The corresponding graft survivals were 97.1%, 94.12% and 91.2% respectively. Beyond three years, one female patient died postgraft loss. This graft loss was mainly attributed to recurrent glomerulonephritis. Strikingly, the prevalence of posttransplant diabetes (PTD) and hypertension was higher than reported international figures. Other adverse events, such as infections, were manageable.

CONCLUSION

The average result of pediatric renal transplantation in Jordan is more successful than the average results of this procedure in many developed countries, especially in terms of early graft function, acute rejection episodes as well as long-term patient and graft survivals. However, additional studies are needed to better characterize pharmacokinetic of TAC and to fully understand those factors that lead to an increased probability of developing conditions like PTD and hypertension.

[Immunosuppressive treatment]

Immunosuppressive treatment following renal transplantation includes induction therapy during the initial period when the risk of rejection is higher. Depleting anti-lymphocyte antibodies are indicated mostly in patients who developped anti-HLA antibodies and following a second graft. Anti-IL2 receptor antibodies may be used in non-responders. After the first month, maintenance therapy mostly consists in the association of several immunosuppressants, mainly corticosteroids, an antimetabolic agent (azathioprine or mycophenolate mofetil) and a calcineurin inhibitor (cyclosporine or tacrolimus). Side effects associated with these treatments led to the development of new immunosuppressive protocols, with the reduction or withdrawal of corticosteroids treatment due to its deleterious effects on statural growth, and decreased doses of anti-calcineurin agents to reduce their nephrotoxic effect. These therapeutic options are possible in patients at low immunological risk.

Pharmacogenetics in immunosuppressants: impact on dose requirement of calcineurin inhibitors in renal and liver pediatric transplant recipients

PURPOSE OF REVIEW

Calcineurin inhibitors (CNI) are the mainstay immunosuppressive therapy in pediatric solid organ transplantation. These drugs have narrow therapeutic window, and continuous therapeutic drug monitoring is required to keep blood levels within the therapeutic range. Personalization of immunosuppressive therapy according to the genetic profile may provide a way to optimize drug dosing from the first day of transplantation. In this review, we will highlight the recent pharmacogenetic studies of CNIs in pediatric renal and liver transplantation.

RECENT FINDINGS

CNIs are metabolized by CYP3A4 and CYP3A5. In the intestine, the absorption of these drugs is limited by the P-glycoprotein efflux transporter. Most of the pediatric studies showed an association between CYP3A5 genetic variation and CNI dosing. Carriers of the wild-type allele (CYP3A5*1) required higher doses of CNIs as compared with individuals homozygous to the variant CYP3A5*3 allele. CYP3A4 and ABCB1 (encoding P-glycoprotein) genetic variations did not show an association with CNI dosing.

SUMMARY

The pharmacogenetics of CNIs has been widely investigated in adults, little is known about this field in the pediatric groups. Prospective studies are needed to elucidate the effect of genetic variations on CNI drug dosing and to investigate their impact on short and long-term clinical outcome.

Characteristics of long-term immunosuppressive therapy in Chinese pediatric renal transplant patients: a single-center experience

We performed this study to investigate the trend and characteristics of various immunosuppressive regimens as well as their efficacy and safety for long-term survival of Chinese pediatric renal allograft recipients.

METHODS

Thirty-four patients who underwent kidney transplantation between January 1985 and July 2002 had >/=5 years follow up. We retrospectively reviewed the baseline characteristics, patient and kidney survival rates, renal function, immunosuppressive regimens, drug levels, and adverse effects of immunosuppressive medications.

RESULTS

The 1-, 3-, and 5-year recipient versus graft survival rates were 100% and 97.1%; 91.2% and 88.2%; 85.3% and 82.4%, respectively. The proportions of patients treated with cyclosporine- or tacrolimus-based immunosuppressive regimen at these times were 48.5%/51.5%; 60.0%/40.0%; and 53.6/46.4%. There were no significant differences in the dosages and drug levels after 1 year (P > .05). The proportions of azathioprine versus mycophenolate mofetil adjunctive therapy were 21.3/78.8%; 23.3%/70%; and 32.1%/60.7%, respectively. Forty percent of the surviving recipients developed complications, including hypertension, hyperlipidemia, gingival hyperplasia, hirsutism, liver dysfunction, herpes zoster, diabetes mellitus or cataracts.

CONCLUSIONS

Cyclosporine or tacrolimus, plus mycophenolate mofetil or azathioprine, and prednisone triple therapies showed promising long-term results with similar efficacy and safety in pediatric renal recipients. Periodic drug level monitoring is required to facilitate individualization of immunosuppressive regimens. Drug doses and levels differed markedly from non-Chinese patients because of the ethnic discrepancy.

Variables affecting estimated glomerular filtration rate after renal transplantation in children: a NAPRTCS data analysis

Short-term graft survival has improved in renal transplants without significant effect on long-term graft survival. As GFR decline precedes graft loss, an understanding of variables affecting eGFR after TX may help improve graft survival. NAPRTCS data were analyzed to assess effects of donor, recipient, and other variables on Schwartz eGFR after transplantation. For 8438 children with a functioning graft at day 30, data were censored for children dying with a functioning graft, and those with <3 yr follow-up. Multivariate linear regression and repeated measures analyses identified factors related to eGFR at day 30 after TX and during follow-up. Young, female, non-black, children without ATN and acute rejection in the first 30 days, TX after 1995, those with better eGFR at day 30, and receiving tacrolimus had better long-term eGFR. Transplant from ideal (6-35 yr) donors had best short-term eGFR, young donors (<5 yr) had lower eGFR and poor graft survival. After one yr, eGFR improved in surviving grafts of young donors and matched ideal donors. Acute rejection, BP medications, and hospitalizations in prior six months had negative association with subsequent eGFR. Regardless of variables, eGFR deteriorated with time. Slope of eGFR decline has not changed in the recent era indicating the need for innovative therapies.

Treatment strategies to minimize or prevent chronic allograft dysfunction in pediatric renal transplant recipients: an overview

Long-term allograft survival poses a major problem in pediatric renal transplantation, with allograft nephropathy being the principal cause of graft failure after the first post-transplant year. The mechanisms of nephron loss resulting in graft dysfunction are multiple, comprising both immunologic factors such as acute and chronic antibody- or T-cell-mediated rejection and non-immunologic components. The latter include peri-transplant injuries and renovascular lesions (renal artery stenosis, thrombosis) as well as cardiovascular risk factors such as arterial hypertension and hyperlipidemia. Another relevant issue leading to progressive nephron loss and declining kidney transplant function is acute and chronic nephrotoxicity induced by the calcineurin inhibitors (CNIs) ciclosporin (cyclosporine microemulsion) and tacrolimus. Furthermore, the presence of an abnormal lower urinary tract as well as bacterial (recurrent pyelonephritis) and viral (cytomegalovirus [CMV], polyomavirus [BK virus; BKV]) infections are crucial factors involved in the incidence of chronic allograft dysfunction and graft failure. Renovascular lesions and lower urinary tract obstruction are typical indicators for surgical intervention. The aim of treatment in pediatric patients with renal failure secondary to a dysfunctional lower urinary tract is to create a sterile, continent, and nonrefluxive reservoir. Surgical techniques such as bladder augmentation and the introduction of intermittent catheterization and anticholinergic therapy have significantly improved graft outcome. Arterial hypertension, another factor responsible for graft function deterioration in pediatric renal transplant recipients, is controlled preferably by the use of angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor antagonists, which are known to possess nephroprotective properties in addition to their potent antihypertensive effects. Although treatment of subclinical rejection with augmented immunosuppression has been associated with better graft survival, an increase of the immunosuppressive level to avoid subclinical rejection should be weighed against the risk of infection. The majority of viral infections affecting kidney allografts are caused by CMV and BKV. Antiviral CMV prophylaxis or pre-emptive therapy with ganciclovir has been shown to have beneficial effects in the pediatric renal transplant population. Treatment of BKV-induced nephropathy is based on reduction of the immunosuppressant therapy, although specific antiviral agents such as cidofovir and leflunomide are known to inhibit BKV. However, cidofovir itself is nephrotoxic and should therefore be administered cautiously to pediatric renal transplant patients. Since CNIs are likewise known for their nephrotoxic effects, especially with long-term use, alteration of the immunosuppressant regimen is necessary in case of deteriorating graft function due to CNI-induced histopathologic changes. Complete CNI avoidance seems inappropriate because, in this situation in pediatric renal transplant recipients, other relatively potent immunosuppressant agents such as lymphocyte-depleting antibodies, which are frequently accompanied by a higher incidence of infections, are needed for rejection prophylaxis. CNI withdrawal and switching of the immunosuppressant regimen from CNI therapy to sirolimus may be an option for some pediatric renal transplant patients with less advanced graft function deterioration. Nevertheless, potential adverse events such as aggravation of proteinuria, hyperlipidemia, myelosuppression, and hypergonadotropic hypogonadism have to be considered, and controlled studies are lacking. At present, an immunosuppressant maintenance therapy composed of low-dose tacrolimus or ciclosporin (CNI minimization) and mycophenolate mofetil with low-dose corticosteroids appears to be the most promising strategy to adopt in pediatric renal transplant recipients at low or normal immunologic risk.

Monitoring kidney function and renal disease in children following transplant

This article reviews the currently available tools for measuring glomerular filtration rate (GFR) and early detection of chronic kidney disease in pediatric transplant recipients. GFR measurement remains the mainstay to detect renal dysfunction. Inulin clearance formed the earlier gold standard method to measure GFR. In current clinical practice, it has been replaced by nuclear medicine techniques (51Cr EDTA and 99Tc DTPA isotope clearance studies). GFR estimation based on surrogate markers allows more frequent GFR monitoring in a clinical setting. Serum creatinine has a low sensitivity to detect early renal dysfunction and its muscle mass dependency hampers its clinical utility. The Schwartz formula accounts for age-dependent muscle changes in children, but requires center-specific constants. Cystatin C offers the advantage of a constant production and a higher sensitivity in diagnosing renal dysfunction. Microalbuminuria has been an established screening tool in diabetic renal disease. It offers the advantage of detecting underlying renal damage even before a decrease in GFR. Its diagnostic value in other conditions needs evaluation. Hypertension is known to accelerate the progression of chronic kidney disease. A 24-h ambulatory blood pressure is a useful tool to diagnose hypertension, to quantify blood pressure load and to characterize nocturnal blood pressure dipping. GFR scans, serum creatinine and cystatin C form the cornerstone of currently used tools to evaluate kidney dysfunction.

Multicenter trial of everolimus in pediatric renal transplant recipients: results at three year

There are few prospective clinical trials of mTOR inhibitors (or proliferation signal inhibitors) combined with CNI inhibitors in de novo pediatric renal transplantation. Results reported here are from a multicenter, open-label study in de novo pediatric renal transplant patients (<or=16 yr), in which patients received everolimus with cyclosporine and corticosteroids for one yr, then entered an extension study for a further two yr. Nineteen patients completed the one-yr study, of whom three discontinued study medication. Fifteen of the remaining 16 patients entered the extension study, eight of whom were aged <10 yr (Group 1) and seven were aged 10-16 yr (Group 2). Mean daily dose of everolimus during the first 36 months was 1.53 mg/m(2) BSA. Biopsy-proven acute rejection occurred in three patients in Group 2 and in one patient in Group 1. Biopsy-proven chronic allograft rejection was reported in four patients (two in each age group). Graft survival at one yr was 100%; one patient in Group 2 lost their graft subsequently during the extension. For patients entering the extension, patient survival at three yr was 100%. There were three cases of viral infection, including one case of cytomegalovirus infection. At three yr, mean total cholesterol was 5.5 +/- 0.8 mm/L (213 +/- 31 mg/dL) and four patients received statin therapy. Mean serum creatinine at 36 months was 96 +/- 36 microm/L (1.1 +/- 0.4 mg/dL). This is the first long-term prospective study to demonstrate that a regimen of everolimus, cyclosporine, and corticosteroids provides good efficacy, tolerability, and safety in de novo pediatric renal transplant patients.

How to monitor renal function in pediatric solid organ transplant recipients

The aim is to review the tools for early detection of renal dysfunction after pediatric solid organ transplantation. Currently, the most widely used marker for detection of renal dysfunction involves measurement of GFR. Inulin clearance forms the "gold standard" method for measuring GFR; however, nuclear medicine methods ((51)Cr EDTA and (99)Tc DTPA isotope clearance studies) have replaced inulin clearance. The measurement of serum creatinine has a low sensitivity for the early detection of renal damage. The Schwartz formula using patient height and serum creatinine requires center-specific constants and has limitations associated with creatinine determination. These limitations may be overcome using a cystatin C-based GFR estimation. In diabetic nephropathy, and more recently in hemolytic uremic syndrome, microalbuminuria has been established as a useful screening tool for renal damage, while its predictive value in the transplantation setting needs to be established. All transplant recipients should be screened for hypertension. Early referral for ambulatory 24-h blood pressure monitoring and involvement of pediatric nephrologists should be considered. All pediatric solid organ transplant recipients receiving CNI should be screened regularly for high blood pressure and early evidence of renal damage using either GFR scans or cystatin C-based GFR estimations.

Hypertension in children with chronic kidney disease: pathophysiology and management

Arterial hypertension is very common in children with all stages of chronic kidney disease (CKD). While fluid overload and activation of the renin-angiotensin system have long been recognized as crucial pathophysiological pathways, sympathetic hyperactivation, endothelial dysfunction and chronic hyperparathyroidism have more recently been identified as important factors contributing to CKD-associated hypertension. Moreover, several drugs commonly administered in CKD, such as erythropoietin, glucocorticoids and cyclosporine A, independently raise blood pressure in a dose-dependent fashion. Because of the deleterious consequences of hypertension on the progression of renal disease and cardiovascular outcomes, an active screening approach should be adapted in patients with all stages of CKD. Before one starts antihypertensive treatment, non-pharmacological options should be explored. In hemodialysis patients a low salt diet, low dialysate sodium and stricter dialysis towards dry weight can often achieve adequate blood pressure control. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers are first-line therapy for patients with proteinuria, due to their additional anti-proteinuric properties. Diuretics are a useful alternative for non-proteinuric patients or as an add-on to renin-angiotensin system blockade. Multiple drug therapy is often needed to maintain blood pressure below the 90th percentile target, but adequate blood pressure control is essential for better renal and cardiovascular long-term outcomes.

The long-term outcomes of pediatric kidney transplantation: a single-centre experience in China

To explore the long-term outcomes of paediatric kidney transplantation and the effects of renal allograft on growth, education, employment, marriage and procreation. Twenty-seven children with ESRD received the renal allograft from 1985 to 2001. The patient and kidney survival rate, renal function, growth and employment, etc., were reviewed retrospectively. The average follow-up period was 10.3 +/- 4.4 yr. The one-, three-, five- and 10-yr graft survival rates were 96.3%, 88.9%, 81.5% and 66.7%, respectively, and the corresponding patient survival rates were 100%, 92.6%, 85.2% and 68.8%. The body weight gain was 4-10 kg in one-yr post-operative and the height increased 0-2 cm for girls and 2-5 cm for boys. A total of 44.4% of the recipients accomplished their education above junior high school. The employment rate was 46.2% in males, and 57.2% in females. Twelve patients were married. Non-adherence occurred in 30% of the recipients. Forty percent of the surviving recipients developed complications. Seven patients died. More attention should be paid to non-adherence of medications and more supports from the society are required to improve the life quality of paediatric recipients, especially in employment and education.

25 years of live related renal transplantation in children: The Buenos Aires experience

The number of pediatric patients with end stage renal disease (ESRD) has been steadily growing during the last 10 years all over the world, because of the improvement of medical and surgical treatment of severe urologic malformations and congenital and acquired nephrological disorders. Kidney transplantation (Tx) with a live related donor continues to be the gold standard therapy to treat ESRD in children because of the best final results, the chronic lack of cadaveric donors and the frequent possibility of young patients to have parents or relatives as a source of a potential graft donor.Nowadays almost every pediatric patient can be dialyzed and transplanted, even early in life, if he or she has the possibility of a live related donor. Improvements in pediatric anesthesiology and intensive care have also been very important, in reducing the morbidity and mortality related to Tx procedures.Here we report our experience with Tx for the last 25 years, specially our long experience of live related donor transplantation in children and adolescents with emphasis on technical issues in small children and pediatric patients with severe urologic malformations and bladder dysfunction. We'll make special considerations on the improvement in short and long follow-up with the actual prevention and treatment of graft rejection, due to the new immunosuppressive agents and protocols.

Contributions of the Transplant Registry: The 2006 Annual Report of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS)

This summary of the NAPRTCS 2006 Annual Report of the Transplant Registry highlights the significant impact the registry has had in advancing knowledge in pediatric renal transplantation worldwide. This cooperative group has collected clinical information on children undergoing a renal transplantation since 1987 and now includes over 150 participating medical centers in the USA, Canada, Mexico, and Costa Rica. Currently, the NAPRTCS transplant registry includes information on 9837 renal transplants in 8990 patients (NAPRTCS 2006 Annual Report). Since the first data analysis in 1989, NAPRTCS reports have documented marked improvements in outcome after renal transplantation in addition to identifying factors associated with both favorable and poor outcomes. The registry has served to document and influence practice patterns, clinical outcomes, and changing trends in renal transplantation.

Current issues in pediatric transplantation

Pediatric solid organ transplantation is so successful that >80% of children will survive to become teenagers and adults. Therefore, it is essential that these children maintain a good quality life, free of significant long-term side effects. While intensive immunosuppressive regimens (containing CsA, tacrolimus, MMF, and steroids) effectively reduce acute or chronic rejection, they can produce long-term side effects including viral infection, renal dysfunction, hypertension, and stunting. The development of effective methods of diagnosis, prevention, and treatment of CMV means that this is no longer a significant cause of mortality, but morbidity remains high. In contrast, infection rates of EBV remain high in EBV-negative pre-transplant patients. However, pre-emptive reduction of immunosuppression or treatment with rituximab or adoptive T-cell therapy is effective in preventing/treating post-transplant lymphoproliferative disease. Recent protocols have concentrated on reducing CsA immunosuppression, to prevent unacceptable cosmetic effects, and to reduce the hypertension, hyperlipidemia, and nephrotoxicity. Both CsA and tacrolimus cause a 30% reduction in renal function, with 4-5% of patients developing severe chronic renal failure. The use of IL-2 inhibitors for induction therapy with low-dose calcineurin inhibitors, in combination with renal-sparing drugs such as MMF or sirolimus for maintenance immunosuppression, should prevent significant renal dysfunction in the future. The concept of steroid-free immunosuppression with IL-2 inhibitors, tacrolimus, and MMF is an attractive option, which may reduce stunting and renal dysfunction. However, these regimens may be associated with the increased development of de-novo autoimmune hepatitis in 2-3% of children. The most important challenge to long-term survival in transplanted children is the management of non-adherence and other adolescent issues, particularly when transferring to adult units, as this is the time when many successful transplant survivors lose their grafts.

Mycophenolate mofetil in organ transplantation: focus on metabolism, safety and tolerability

Mycophenolate mofetil (MMF) received its first approval for the prevention of renal allograft rejection in 1995 and has now become the most frequently used antiproliferative agent in maintenance immunosuppressive therapy for kidney, pancreas, liver and heart transplantation. In addition, its use for the treatment of autoimmune diseases steadily increases. This review focuses on the miscellaneous pharmacodynamic properties of the drug, its pharmacokinetics in healthy subjects, recipients of different organ transplants and combination therapy with other pharmaceuticals, as well as its safety profile. The immunosuppressive activity of MMF is thought to derive mainly from the potent and selective inhibition of purine synthesis in both T and B lymphocytes. In contrast to other immunosuppressants on the market, it is metabolised primarily by glucuronidation and lacks nephrotoxicity, cardiovascular toxicity or diabetogenic potential, thus making it a suitable candidate for combination regimens. The most important side effects under MMF include gastrointestinal disorders, of which the underlying mechanisms are not yet fully understood, but seem to be complex and related to both effects of mycophenolic acid and its acyl glucuronide, as well as to decreased -immunity due to general immunosuppression after transplantation.

Kidney transplantation in small children with live related donors: 20 years of experience

OBJECTIVES

Kidney transplantation (Tx) with a live related donor is the best option available for the treatment of end-stage renal disease at any age. Modern dialysis has allowed many very young and small children to receive a renal transplant with good results in spite of the limitations of space and the size of the adult kidney. Here, we report our experience with renal Tx with live related donors in this complex group of pediatric patients.

MATERIAL AND METHODS

From 1978 to 2004 a kidney transplantation was performed in 211 pediatric patients. Of this group, 23 patients between 1 and 10 years of age (16 males and seven females) of less than 17 kg (8.9-16.9 kg) received their first live related donor transplantation between 1985 and 2004. Renal insufficiency was secondary to nephropathy in 11 patients, infravesical obstruction in six and renal dysplasia or renal infarcts in six.

RESULTS

Patient and graft survival was 100% and 95.6% with an average follow up of 89.6 months (6-231). There were no vascular or urological complications. Urinary infection in five (21.7%) and acute rejection in three (13%) were the most common complications. One patient has returned to dialysis 11 years after Tx.

CONCLUSIONS

Young pediatric patients with a low body weight did not suffer a higher percentage of postoperative surgical complications, and the follow-up results are similar to those in older patients. A complex urological malformation has not prevented a living related Tx. These results encourage us to perform this procedure more frequently in younger patients when a live donor is available.

A prospective, randomized, multicenter trial of tacrolimus-based therapy with or without basiliximab in pediatric renal transplantation

In a 6-month, multicenter, randomized, controlled, open-label, parallel-group trial, we investigated the efficacy and safety of adding basiliximab to a standard tacrolimus-based regimen in pediatric renal transplant recipients. Patients < 18 years received tacrolimus/azathioprine/steroids (TAS, n = 93) or tacrolimus/azathioprine/steroids/basiliximab (TAS + B, n = 99). Target tacrolimus levels were 10-20 ng/mL between days 0-21 and 5-15 ng/mL thereafter. Steroid dosing was identical in both groups. Basiliximab was administered at 10 mg (patients < 40 kg) or 20 mg (patients > or = 40 kg) within 4 h of reperfusion; the same dose was repeated on day 4. Biopsy-proven acute rejection rates were 20.4% (TAS) and 19.2% (TAS + B); steroid-resistant acute rejection rates were 3.2% and 3.0%, respectively. Patient survival was 100%; graft survival rates were 95% in both arms. The nature and incidence of adverse events were similar in both arms except toxic nephropathy and abdominal pain, which were significantly higher in the TAS + B arm (14.1% vs. 4.3%; p = 0.03 and 11.1% vs. 2.2%; p = 0.02; respectively). Median serum creatinine concentrations at 6 months were 86 micromol/L in the TAS and 91 micromol/L in the TAS + B arm; glomerular filtration rate was 79.4 and 77.6 (mL/min/1.73 m2), respectively. Adding basiliximab to a tacrolimus-based regimen is safe in pediatric patients, but does not improve clinical efficacy.

Safety and efficacy of a calcineurin inhibitor avoidance regimen in pediatric renal transplantation

Thirty-four children were entered into a pilot trial of calcineurin inhibitor avoidance after living-donor kidney transplantation, the CN-01 study. Patients were treated with anti-CD25 mAb, prednisone, mycophenolate mofetil, and sirolimus. Twenty patients were maintained on the protocol for up to 3 yr of follow-up. One enrolled patient did not receive the transplant because of a donor problem, eight terminated because of one or more rejection episodes, four terminated because of adverse events, and one was lost to follow-up. Two grafts were lost, one as a result of chronic rejection and the other as a result of posttransplantation lymphoproliferative disorder. There were no deaths. The 6- and 12-mo acute rejection rates were 21.8 and 31.5%, respectively. GFR were stable throughout the course of the study, with a slight downward trend by 6 mo after transplantation followed by a slight upward trend to a mean of 70 ml/min thereafter. Early surveillance graft biopsies frequently showed focal interstitial mononuclear cellular infiltrates without overt vasculitis or tubulitis, but these infiltrates disappeared without treatment. Anti-HLA class I and II antibodies were detected in three patients before transplantation, and all three had acute rejections, including the two patients who lost their grafts. De novo anti-HLA Ab production occurred in only one patient after transplantation. There were two episodes of Epstein Barr virus-related posttransplantation lymphoproliferative disorder, one of which developed after the patient had been terminated from the study. It is concluded that calcineurin inhibitor-free immunosuppression can be safe and effective in pediatric living-donor renal transplantation. However, further modifications that are designed to lessen early rejection rates and decrease complications should be tested before this approach is used routinely.

Complete avoidance of calcineurin inhibitors in renal transplantation: a randomized trial comparing sirolimus and tacrolimus

Calcineurin inhibitors have decreased acute rejection and improved early renal allograft survival, but their use has been implicated in the development of chronic nephrotoxicity. We performed a prospective, randomized trial in kidney transplantation comparing sirolimus-MMF-prednisone to tacrolimus-MMF-prednisone. Eighty-one patients in the sirolimus group and 84 patients in the tacrolimus group were enrolled (mean follow-up = 33 months; range 13-47 months). At 1 year, patient survival was similar in the groups (98% with sirolimus, 96% with tacrolimus; p = 0.42) as was graft survival (94% sirolimus vs. 92% tacrolimus, p = 0.95). The incidence of clinical acute rejection was 10% in the tacrolimus group and 13% in the sirolimus group (p = 0.58). There was no difference in mean GFR measured by iothalamate clearance between the tacrolimus and sirolimus groups at 1 year (61 +/- 19 mL/min vs. 63 +/- 18 mL/min, p = 0.57) or 2 years (61 +/- 17 mL/min vs. 61 +/- 19 mL/min, p = 0.84). At 1 year, chronicity using the Banff schema showed no difference in interstitial, tubular or glomerular changes, but fewer chronic vascular changes in the sirolimus group. This study shows that a CNI-free regimen using sirolimus-MMF-prednisone produces similar acute rejection rates, graft survival and renal function 1-2 years after transplantation compared to tacrolimus-MMF-prednisone.

Unexpectedly high prevalence of pretransplant abnormal glucose tolerance in pediatric kidney transplant recipients

Several studies suggested that the incidence of new-onset diabetes following pediatric kidney transplantation has increased markedly in recent years, with reported incidence of up to 20%. However, limited information is available regarding the incidence and features of pretransplant status of abnormal glucose tolerance in pediatric kidney transplant recipients. We assessed the risk of 55 non-diabetic pediatric transplant recipients developing PTDM by performing OGTT prior to transplantation. For post-transplant immunosuppression, each patient received either a CsA- or a TAC-based regimen. However, recipients who had abnormal glucose tolerance in the pretransplant OGTT were allocated to the CsA-based regimen. The mean age of the patients was 9.7 +/- 5.4 yr while mean BMI was 16.5 +/- 3.3 kg/m2. FPG level before transplantation was within the normal limit in all patients, while the mean HbA1C value was 4.5. However, 18 of the 55 patients (32.7%) had abnormal glucose tolerance in the pretransplant OGTT, 13 (23.6%) had impaired glucose tolerance, and 5 (9.4%) had DM. PTDM developed in two patients on the TAC-based regimen with these patients having normal glucose tolerance prior to the transplant. In contrast, the 18 patients with abnormal glucose tolerance did not develop PTDM under CsA-based immunosuppression. Our results demonstrated an unexpectedly high prevalence of abnormal glucose tolerance in pretransplant OGTT even in a pediatric population. We believe that modification of post-transplant immunosuppression by the identification of high-risk patients using the pretransplant OGTT may minimize the development of new onset of PTDM.

Potential cardiovascular risk factors in paediatric renal transplant recipients

Cyclosporin (CsA) therapy is associated with side effects such as hypertension, hyperlipidemia and nephrotoxicity. Tacrolimus (Tac) has been shown to be more favourable in this respect. We retrospectively analysed office blood pressure (BP), serum total cholesterol (TC) and fasting glucose levels, and estimated graft function profiles in paediatric (n =56) and young adult (n =14) renal transplant recipients whose maintenance immunosuppressive regimen was based upon CsA (n =38) or Tac (n =32) given with mycophenolate mofetil and corticosteroids. The analysis was performed at four different time-points: at 1, 6, 12, and 24 months post-transplant, respectively. Baseline characteristics were comparable between treatment groups. Differences for both systolic and diastolic BP, and graft function between treatment groups became significant from month 1 and throughout the 2-year period. Values (mean +/- SD) for CsA-treated and Tac-treated recipients at 2 years were 118.8+/-11.1 / 74.6+/-7.4 mmHg vs 109.3+/-11.2 / 67.2+/-7.8 mmHg for systolic and diastolic BP, respectively, p <0.005/0.005; and 72.0+/-18.5 ml/min vs 84.0+/-22.4 ml/min per 1.73 m(2) for graft function, respectively, p <0.01. Office hypertension, defined as the use of antihypertensive medication at month 24, was significantly associated with CsA-therapy (chi(2), p <0.01). TC levels became significantly lower at months 6, 12, and 24 in the Tac group compared with the CsA group. Hypercholesterolemia, defined as TC>or=200 mg/dl, was significantly associated with CsA-based immunosuppressive regimen at months 6, 12, and 24 post-transplant (chi(2), p <0.05, p <0.001, and p <0.01, respectively). Although Tac therapy was associated with higher glucose levels, no recipient developed post-transplant diabetes mellitus. The number of recipients who experienced acute rejections was comparable in both groups. In conclusion, Tac-based immunosuppressive therapy was found to be associated with more favourable potential risk-factor profiles for cardiovascular disease and better graft function at 2 years post-transplant compared with CsA-therapy.

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.

Mycophenolate mofetil suspension in pediatric renal transplantation: three-year data from the tricontinental trial

Mycophenolate mofetil (MMF) is widely used to prevent acute rejection in adult solid organ transplant recipients, but data in children and adolescents are scarce. This prospective, multicenter, open-labeled, single-arm study investigated the efficacy and safety of an MMF-based immunosuppressive regimen in 100 pediatric renal transplant recipients over a 3-yr period of time. Three age groups were formed (<6 yr, n = 33; 6 to <12 yr, n = 34; 12-18 yr, n = 33). Basic immunosuppression consisted of MMF (600 mg/m(2) b.i.d), cyclosporin A microemulsion and corticosteroids. Seventy-three percent of patients were given anti-lymphocyte antibody induction therapy, of whom 74% received anti-thymocyte globulin. Patient and graft survival 3 yr after transplantation amounted to 98 and 95%, respectively. Twenty-five percent of all patients suffered a biopsy-proven acute rejection episode in the first 6 month post-transplant. Children undergoing induction therapy exhibited a numerically lower rejection rate (21 vs. 37%, p = 0.11). Three years after transplantation, the acute rejection rate added up to 30% (26% with induction therapy vs. 41% without induction therapy, p = 0.21). The number of patients with acute rejection was lowest in the youngest age group (18%), in comparison with 39% in the 6 to <12 yr and 33% in the 12-18 yr age group, respectively. For the entire patient population, the rate of patients who withdrew prematurely because of adverse events was low (12%). The present study shows that MMF therapy in pediatric renal transplant recipients leads to an excellent patient and graft survival 3 yr post-transplant with an acceptable safety profile.

Conversion From Cyclosporine Microemulsion to Tacrolimus-Based Immunoprophylaxis Improves Cholesterol Profile in Heart Transplant Recipients With Treated but Persistent Dyslipidemia: The Canadian Multicentre Randomized Trial of Tacrolimus vs Cyclosporine Microemulsion

BACKGROUND

Tacrolimus improves lipid profile in renal and liver transplant recipients. The impact of conversion from cyclosporine microemulsion (Neoral) to tacrolimus (Prograf) in a large randomized study of stable heart transplant recipients with treated but persistent mild dyslipidemia is reported.

METHODS

One hundred twenty-nine long-term (>or=12 months) cyclosporine microemulsion-treated heart transplant recipients with low-density lipoprotein cholesterol >2.5 mmol/liter and/or a total cholesterol/high-density lipoprotein cholesterol ratio >4 were recruited for the study. Complete lipid profile was assessed before (baseline) and after 6 months of treatment with either cyclosporine microemulsion maintenance (n=64) or tacrolimus conversion (n=65).

RESULTS

At 6 months, tacrolimus-converted patients exhibited a greater decrease in total cholesterol (from 5.51 +/- 0.16 to 4.88 +/- 1.22 mmol/liter [tacrolimus], vs 5.61 +/- 1.36 to 5.38 +/- 0.87 mmol/liter [cyclosporine]; p = 0.0078). This decrease in cholesterol was caused largely by a decrease in low-density lipoprotein cholesterol (-0.41 +/- 0.54 [tacrolimus] vs -0.13 +/- 0.55 [cyclosporine]; p=0.0018). There were no changes in high-density lipoprotein cholesterol and triglyceride levels, but apolipoprotein B therapy was reduced in tacrolimus-converted vs cyclosporine-maintained patients (p=0.0003). By 6 months, 23.7% of tacrolimus- vs 6.7% of cyclosporine-treated patients met the target lipid levels for high-risk patients (p=0.0094). Conversion from cyclosporine to tacrolimus resulted in decreases in blood urea nitrogen, creatinine, and uric acid without any changes in glucose, HbA(1C), and insulin levels.

CONCLUSIONS

Conversion from cyclosporine microemulsion- to tacrolimus-based immunoprophylaxis resulted in decreased cholesterol, apolipoprotein B, urea, creatinine, and uric acid without any clinically evident perturbation of glucose metabolism in stable heart transplant recipients with treated but persistent mild dyslipidemia.

Successful Treatment of 115 Pediatric Renal Transplant Recipients With Tacrolimus-Based Immunosuppressive Therapy: A 7-Year Multicenter Study in Japan

The safety and efficacy of tacrolimus (Tac)-based immunosuppressive treatments were studied in 115 pediatric renal transplant recipients (mean follow-up period, approximately 20 months). The acute rejection rate was 22.7% 6 months after transplantation and the steroid-resistant acute rejection rate was 6.4%. The 5-year patient and graft survival rates were 98.6% and 95.9%, respectively. Major adverse effects included infection, ie, cytomegalovirus (CMV) antigenemia (41.7%), renal dysfunction (29.6%), and impaired glucose tolerance (20.9%). The incidences of these adverse events were significantly decreased among patients who had undergone transplantation after March 2000 (n = 43), namely, 30.2%, 18.6%, and 11.6%, respectively.

Effect of age, ethnicity, and glucocorticoid use on tacrolimus pharmacokinetics in pediatric renal transplant patients

Tacrolimus has become an effective alternative to cyclosporine as a component of primary immunosuppression in pediatric renal transplant patients, but the information on the pharmacokinetic characteristics of tacrolimus in young patients is still limited. The primary objective of this study was to determine the effect of patient age, ethnicity, and concurrent steroid administration on tacrolimus pharmacokinetics in pediatric renal transplant patients. The study population consisted of 30 pediatric patients, age 1.5-18.6 yr, who received a kidney transplant between July 1999 and February 2004. After twice daily dosing was stabilized based on clinical judgment, at least 5 days postoperatively, tacrolimus levels were drawn prior to, and 1, 2, 4, 8, and 12 h after the morning dose. The mean dose of tacrolimus was 0.12 mg/kg/dose. Mean trough level was 11.9 +/- 5.0 ng/mL. Mean area under the curve (AUC) was 192 +/- 84 with a range of 78-360 h x (ng/mL). The correlation between trough level and AUC was only fair (r = 0.74); later time points correlated better with AUC, and an excellent correlation (r = 0.96) was obtained between the mean of trough and 2-h level (C(2)) and AUC. There was a negative correlation between age and dose per body weight (r = -0.68). African-American patients had marginally lower drug exposure with similar dosing. Three age groups (<5, 5-12, and >12 yr) were compared with respect to dosing and AUC. Despite similar AUC in all three groups, the mean dose per kg required to achieve the AUC was 2.7- and 1.9-fold higher in the <5 and 5-12-yr groups, respectively, compared with the >12-yr group. Nine of the 30 patients were on a totally steroid-free regimen. Their tacrolimus dose and trough levels were similar to those of steroid-exposed patients, but their mean AUC was 41% higher. Our results show an inverse correlation between age and required tacrolimus dose, wide interindividual variation, and greater exposure with steroid-free regimen despite no change in trough level.

What is the calcineurin inhibitor of choice for pediatric renal transplantation?

Cyclosporine microemulsion (CyA) and tacrolimus (Tac) are the principal immunosuppressants prescribed for adult and pediatric renal transplantation. In the majority of patients, these calcineurin inhibitors have been used in combination with other immunosuppressive drugs, such as azathioprine or mycophenolate mofetil (MMF). In this review we will address the question of what calcineurin inhibitor we should use in an individual pediatric renal transplant patient. Well-designed randomized studies in children showed no difference in short-term patient and graft survival with cyclosporine microemulsion and tacrolimus. However Tac is significantly more effective than CyA microemulsion in preventing acute rejection after renal transplantation in a pediatric population when used in conjunction with azathioprine and corticosteroids. This difference disappears when calcineurin inhibitors are used in combination with MMF as both Tac and CyA produce similar rejection rates and graft survival. However, Tac is associated with improved graft function at 1 and 2 yr post-transplant. Adverse events of hypomagnesaemia and diarrhea seem to be higher in Tac group whereas hypertrichosis, flu syndrome and gum hyperplasia occurs more frequently in the CyA group. The incidence of post-transplant diabetes mellitus was almost identical between Tac and CyA treated patients. The recommendation drawn from the available data is that both CyA and Tac can be used safely and effectively in children. However Tac may be preferable to CyA because of steroid sparing effect and less hirsutism. We recommend that cyclosporine should be chosen when patients experience Tac-related adverse events. Nevertheless, the best calcineurin inhibitor should be decided on individual patients according to variable risk factors, such as risk of rejection in sensitized patient or delayed graft function. The possibility of adverse events should also be considered.

A DECADE OF PROGRESS IN KIDNEY TRANSPLANTATION

Kidney transplantation has become the treatment of choice for patients with end-stage renal disease because of better surgical techniques and the availability of more powerful immunosuppressive drugs. Regimens of immunosuppression should combine both short-term outcomes and predictors of long-term safety and survival. The value of tacrolimus for immunosuppression protocols lies in its ability to reduce the immunologic risk to the allograft and its excellent safety profile. Outcomes for kidney-transplant recipients can be further optimized by individualizing therapy to address each patient's risk profile.