Comparison of sirolimus-based calcineurin inhibitor-sparing and calcineurin inhibitor-free regimens in cadaveric renal transplantation

Mammalian Target of Rapamycin Inhibitors and Wound Healing Complications in Kidney Transplantation: Old Myths and New Realities

Mammalian target of rapamycin inhibitors (mTOR-I) lacks nephrotoxicity, has antineoplastic effects, and reduces viral infections in kidney transplant recipients. Earlier studies reported a significant incidence of wound healing complications and lymphocele. This resulted in the uncomfortable willingness of transplant clinicians to use these agents in the immediate posttransplant period. As evidence and experience evolved over time, much useful information became available about the optimal use of these agents. Understandably, mTOR-I effects wound healing through their antiproliferative properties. However, there are a lot of other immunological and nonimmunological factors which can also contribute to wound healing complications. These risk factors include obesity, uremia, increasing age, diabetes, smoking, alcoholism, and protein-energy malnutrition. Except for age, the rest of all these risk factors are modifiable. At the same time, mycophenolic acid derivatives, steroids, and antithymocyte globulin (ATG) have also been implicated in wound healing complications. A lot has been learnt about the optimal dose of mTOR-I and their trough levels, its combinations with other immunosuppressive medications, and patients' profile, enabling clinicians to use these agents appropriately for maximum benefits. Recent randomized control trials have further increased the confidence of clinicians to use these agents in immediate posttransplant periods.

Target of rapamycin inhibitors (TOR-I; sirolimus and everolimus) for primary immunosuppression in kidney transplant recipients

BACKGROUND

Kidney transplantation is the therapy of choice for many patients with end-stage kidney disease (ESKD) with an improvement in survival rates and satisfactory short term graft survival. However, there has been little improvement in long-term survival. The place of target of rapamycin inhibitors (TOR-I) (sirolimus, everolimus), which have different modes of action from other commonly used immunosuppressive agents, in kidney transplantation remains uncertain. This is an update of a review first published in 2006.

OBJECTIVES

To evaluate the short and long-term benefits and harms of TOR-I (sirolimus and everolimus) when used in primary immunosuppressive regimens for kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 20 September 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs in which drug regimens, containing TOR-I commenced within seven days of transplant, were compared to alternative drug regimens, were included without age restriction, dosage or language of report.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed study eligibility, risk of bias, and extracted data. Results were reported as risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) with 95% CI for continuous outcomes. Statistical analyses were performed using the random-effects model. The certainty of the evidence was assessed using GRADE MAIN RESULTS: Seventy studies (17,462 randomised participants) were included; eight studies included two comparisons to provide 78 comparisons. Outcomes were reported at six months to three years post transplant. Risk of bias was judged to be low for sequence generation in 25 studies, for allocation concealment in 23 studies, performance bias in four studies, detection bias in 65 studies, attrition bias in 45 studies, selective reporting bias in 48 studies, and for other potential bias in three studies. Risk of bias was judged to be at high risk of bias for sequence generation in two studies, allocation concealment in two studies, performance bias in 61 studies, detection bias in one study, attrition bias in four studies, for selective reporting bias in 11 studies and for other potential risk of bias in 46 studies. Compared with CNI and antimetabolite, TOR-I with antimetabolite probably makes little or no difference to death (RR 1.31, 95% CI 0.87 to 1.98; 19 studies) or malignancies (RR 0.86, 95% CI 0.50 to 1.48; 10 studies); probably increases graft loss censored for death (RR 1.32, 95% CI 0.96 to 1.81; 15 studies), biopsy-proven acute rejection (RR 1.60, 95% CI 1.25 to 2.04; 15 studies), need to change treatment (RR 2.42, 95% CI 1.88 to 3.11; 14 studies) and wound complications (RR 2.56, 95% CI 1.94 to 3.36; 12 studies) (moderate certainty evidence); but reduces CMV infection (RR 0.43, 95% CI 0.29 to 0.63; 13 studies) (high certainty evidence). Compared with antimetabolites and CNI, TOR-I with CNI probably makes little or no difference to death (RR 1.06, 95% CI 0.84 to 1.33; 31 studies), graft loss censored for death (RR 1.09, 95% CI 0.82 to 1.45; 26 studies), biopsy-proven acute rejection (RR 0.95, 95% CI 0.81 to 1.12; 24 studies); and malignancies (RR 0.83, 95% CI 0.64 to 1.07; 17 studies); probably increases the need to change treatment (RR 1.56, 95% CI 1.28 to 1.90; 25 studies), and wound complications (RR 1.56, 95% CI 1.28 to 1.91; 17 studies); but probably reduces CMV infection (RR 0.44, 95% CI 0.34 to 0.58; 25 studies) (moderate certainty evidence). Lower dose TOR-I and standard dose CNI compared with higher dose TOR-I and reduced dose CNI probably makes little or no difference to death (RR 1.07, 95% CI 0.64 to 1.78; 9 studies), graft loss censored for death (RR 1.09, 95% CI 0.54 to 2.20; 8 studies), biopsy-proven acute rejection (RR 0.87, 95% CI 0.67 to 1.13; 8 studies), and CMV infection (RR 1.42, 95% CI 0.78 to 2.60; 5 studies) (moderate certainty evidence); and may make little or no difference to wound complications (RR 0.95, 95% CI 0.53 to 1.71; 3 studies), malignancies (RR 1.04, 95% CI 0.36 to 3.04; 7 studies), and the need to change treatments (RR 1.18, 95% CI 0.58 to 2.42; 5 studies) (low certainty evidence). Lower dose of TOR-I compared with higher doses probably makes little or no difference to death (RR 0.84, 95% CI 0.67 to 1.06; 13 studies), graft loss censored for death (RR 0.92, 95% CI 0.71 to 1.19; 12 studies), biopsy-proven acute rejection (RR 1.26, 95% CI 1.10 to 1.43; 11 studies), CMV infection (RR 0.87, 95% CI 0.63 to 1.21; 9 studies), wound complications (RR 0.92, 95% CI 0.66 to 1.29; 7 studies), and malignancy (RR 0.84, 95% CI 0.54 to 1.32; 10 studies) (moderate certainty evidence); and may make little or no difference to the need to change treatments (RR 0.91, 95% CI 0.78 to 1.05; 10 studies) (low certainty evidence). It is uncertain whether sirolimus and everolimus differ in their effects on kidney function and lipid levels because the certainty of the evidence is very low based on a single small study with only three months of follow-up.

AUTHORS' CONCLUSIONS

In studies with follow-up to three years, TOR-I with an antimetabolite increases the risk of graft loss and acute rejection compared with CNI and an antimetabolite. TOR-I with CNI potentially offers an alternative to an antimetabolite with CNI as rates of graft loss and acute rejection are similar between interventions and TOR-I regimens are associated with a reduced risk of CMV infections. Wound complications and the need to change immunosuppressive medications are higher with TOR-I regimens. While further new studies are not required, longer-term follow-up data from participants in existing methodologically robust RCTs are needed to determine how useful immunosuppressive regimens, which include TOR-I, are in maintaining kidney transplant function and survival beyond three years.

Immunosuppressive therapy for kidney transplantation in adults: a systematic review and economic model

BACKGROUND

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

OBJECTIVES

To review and update the evidence for the clinical effectiveness and cost-effectiveness of basiliximab (BAS) (Simulect(®), Novartis Pharmaceuticals UK Ltd) and rabbit anti-human thymocyte immunoglobulin (rATG) (Thymoglobulin(®), Sanofi) as induction therapy, and immediate-release tacrolimus (TAC) (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), mycophenolate sodium (MPS) (Myfortic(®), Novartis Pharmaceuticals UK Ltd), sirolimus (SRL) (Rapamune(®), Pfizer) and everolimus (EVL) (Certican(®), Novartis) as maintenance therapy in adult renal transplantation.

METHODS

Clinical effectiveness searches were conducted until 18 November 2014 in MEDLINE (via Ovid), EMBASE (via Ovid), Cochrane Central Register of Controlled Trials (via Wiley Online Library) and Web of Science (via ISI), Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects and Health Technology Assessment (The Cochrane Library via Wiley Online Library) and Health Management Information Consortium (via Ovid). Cost-effectiveness searches were conducted until 18 November 2014 using a costs or economic literature search filter in MEDLINE (via Ovid), EMBASE (via Ovid), NHS Economic Evaluation Database (via Wiley Online Library), Web of Science (via ISI), Health Economic Evaluations Database (via Wiley Online Library) and the American Economic Association's electronic bibliography (via EconLit, EBSCOhost). Included studies were selected according to predefined methods and criteria. A random-effects model was used to analyse clinical effectiveness data (odds ratios for binary data and mean differences for continuous data). Network meta-analyses were undertaken within a Bayesian framework. A new discrete time-state transition economic model (semi-Markov) was developed, with acute rejection, graft function (GRF) and new-onset diabetes mellitus used to extrapolate graft survival. Recipients were assumed to be in one of three health states: functioning graft, graft loss or death.

RESULTS

Eighty-nine randomised controlled trials (RCTs), of variable quality, were included. For induction therapy, no treatment appeared more effective than another in reducing graft loss or mortality. Compared with placebo/no induction, rATG and BAS appeared more effective in reducing biopsy-proven acute rejection (BPAR) and BAS appeared more effective at improving GRF. For maintenance therapy, no treatment was better for all outcomes and no treatment appeared most effective at reducing graft loss. BEL + MMF appeared more effective than TAC + MMF and SRL + MMF at reducing mortality. MMF + CSA (ciclosporin), TAC + MMF, SRL + TAC, TAC + AZA (azathioprine) and EVL + CSA appeared more effective than CSA + AZA and EVL + MPS at reducing BPAR. SRL + AZA, TAC + AZA, TAC + MMF and BEL + MMF appeared to improve GRF compared with CSA + AZA and MMF + CSA. In the base-case deterministic and probabilistic analyses, BAS, MMF and TAC were predicted to be cost-effective at £20,000 and £30,000 per quality-adjusted life-year (QALY). When comparing all regimens, only BAS + TAC + MMF was cost-effective at £20,000 and £30,000 per QALY.

LIMITATIONS

For included trials, there was substantial methodological heterogeneity, few trials reported follow-up beyond 1 year, and there were insufficient data to perform subgroup analysis. Treatment discontinuation and switching were not modelled.

FUTURE WORK

High-quality, better-reported, longer-term RCTs are needed. Ideally, these would be sufficiently powered for subgroup analysis and include health-related quality of life as an outcome.

CONCLUSION

Only a regimen of BAS induction followed by maintenance with TAC and MMF is likely to be cost-effective at £20,000-30,000 per QALY.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013189.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

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.

Kidney Fibrosis: Origins and Interventions

All causes of renal allograft injury, when severe and/or sustained, can result in chronic histological damage of which interstitial fibrosis and tubular atrophy are dominant features. Unless a specific disease process can be identified, what drives interstitial fibrosis and tubular atrophy progression in individual patients is often unclear. In general, clinicopathological factors known to predict and drive allograft fibrosis include graft quality, inflammation (whether "nonspecific" or related to a specific diagnosis), infections, such as polyomavirus-associated nephropathy, calcineurin inhibitors (CNI), and genetic factors. The incidence and severity of chronic histological damage have decreased substantially over the last 3 decades, but it is difficult to disentangle what effects individual innovations (eg, better matching and preservation techniques, lower CNI dosing, BK viremia screening) may have had. There is little evidence that CNI-sparing/minimization strategies, steroid minimization or renin-angiotensin-aldosterone system blockade result in better preservation of intermediate-term histology. Treatment of subclinical rejections has only proven beneficial to histological and functional outcome in studies in which the rate of subclinical rejection in the first 3 months was greater than 10% to 15%. Potential novel antifibrotic strategies include antagonists of transforming growth factor-β, connective tissue growth factor, several tyrosine kinase ligands (epidermal growth factor, platelet-derived growth factor, vascular endothelial growth factor), endothelin and inhibitors of chemotaxis. Although many of these drugs are mainly being developed and marketed for oncological indications and diseases, such as idiopathic pulmonary fibrosis, a number may hold promise in the treatment of diabetic nephropathy, which could eventually lead to applications in renal transplantation.

Systematic Review on Role of Mammalian Target of Rapamycin Inhibitors as an Alternative to Calcineurin Inhibitors in Renal Transplant: Challenges and Window to Excel

OBJECTIVES

This review focuses on the current limited evidence of graft function and graft survival in various immunosuppressive regimens involving mammalian target of rapamycin inhibitors with or without calcineurin inhibitors.

MATERIALS AND METHODS

We evaluated the current literature for describing the role of mammalian target of rapamycin inhibitors as an alternative to calcineurin inhibitors by searching the PubMed, EMBASE, Cochrane, Crossref, and Scopus databases using medical subject heading terms.

RESULTS

Our detailed analyses of all relevant literature showed use of mammalian target of rapamycin inhibitor-based de novo regimens, early calcineurin inhibitor withdrawal with subsequent introduction of mammalian target of rapamycin inhibitor-based regimens, and late conversion from a calcineurin inhibitor-based regimen to mammalian target of rapamycin inhibitor-based regimens. Notably, early calcineurin inhibitor withdrawal with subsequent introduction of mammalian target of rapamycin inhibitor-based regimen seemed to be a more practical and realistic approach toward immunosuppressive treatment of renal transplant recipients. However, in view of the high rejection rate observed in these studies, it is advisable not to offer these regimens to patients with moderate to high immunologic risk.

CONCLUSIONS

The present evidences suggest that treatment with mammalian target of rapamycin inhibitors allows early and substantial calcineurin inhibitor minimization. The mammalian target of rapamycin inhibitors everolimus and sirolimus are preferred due to their complementary mechanisms of action and favorable nephrotoxicity profile, which have opened the way for calcineurin inhibitor reduction/withdrawal in the early posttransplant period.

Protocol Biopsies: Utility and Limitations

As both T cell and antibody-mediated rejection can have a subclinical phase, protocol biopsies provide an early opportunity to intervene before the onset of clinical allograft dysfunction. Protocol biopsies are usually done after reperfusion to establish baseline, between 3 and 6 months to identify subclinical rejection, and at 6-12 months to assess chronicity and persistent inflammation that have prognostic implication. Treatment of both subclinical T cell and antibody-mediated rejection prevents progression of rejection and development of interstitial fibrosis/tubular atrophy or transplant glomerulopathy. Although subclinical rejection has become less frequent in low-risk patients on triple immunosuppression containing tacrolimus, protocol biopsies may still be useful in selected population. Protocol biopsies are more likely to benefit patients at higher risk for rejection, including those who are highly sensitized, transplanted across donor-specific antibody barriers, or on calcineurin inhibitor/corticosteroids sparing regimens. Interstitial fibrosis on protocol biopsies, especially in conjunction with persistent inflammation, predicts lower allograft survival.

Calcineurin Inhibitor Minimization, Conversion, Withdrawal, and Avoidance Strategies in Renal Transplantation: A Systematic Review and Meta-Analysis

Despite their clinical efficacy, concerns about calcineurin inhibitor (CNI) toxicity make alternative regimens that reduce CNI exposure attractive for renal transplant recipients. In this systematic review and meta-analysis, we assessed four CNI immunosuppression strategies (minimization, conversion, withdrawal, and avoidance) designed to reduce CNI exposure and assessed the impact of each on patient and allograft survival, acute rejection and renal function. We evaluated 92 comparisons from 88 randomized controlled trials and found moderate- to high-strength evidence suggesting that minimization strategies result in better clinical outcomes compared with standard-dose regimens; moderate-strength evidence indicating that conversion to a mammalian target of rapamycin inhibitor or belatacept was associated with improved renal function but increased rejection risk; and moderate- to high-strength evidence suggesting planned CNI withdrawal could result in improved renal function despite an association with increased rejection risk. The evidence base for avoidance studies was insufficient to draw meaningful conclusions. The applicability of the review is limited by the large number of studies examining cyclosporine-based strategies and low-risk populations. Additional research is needed with tacrolimus-based regimens and higher risk populations. Moreover, research is necessary to clarify the effect of induction and adjunctive agents in alternative immunosuppression strategies and should include more comprehensive and consistent reporting of patient-centered outcomes.

A randomized, prospective comparison of transition to sirolimus-based CNI-minimization or withdrawal in African American kidney transplant recipients

BACKGROUND

There is a lack of conclusive evidence to suggest if calcineurin inhibitor (CNI) withdrawal or minimization with sirolimus is the best strategy for African Americans.

METHODS

This was a randomized, prospective, open-label, pilot study comparing the two mammalian target of rapamycin (mTOR) transition strategies in adult African Americans between six and 24 wk post-transplant. The primary outcome was a comparison of the eGFR at one yr after conversion.

RESULTS

Forty patients were randomized and analyzed in an intent-to-treat fashion. Median day of transition was day 96 (withdrawal) and 68 (minimization). Patients in the CNI-withdrawal group (n = 23) had significantly higher eGFR at one yr compared to the CNI-minimization group (n = 17, 73 vs. 56 mL/min, p = 0.03), as well as a significantly larger increase in eGFR from baseline (12 vs. 5 mL/min, p = 0.03). There were no differences in infections, acute rejection, death, or graft loss. Both regimens were constrained by disproportionately high discontinuation rates despite modest toxicity profiles.

CONCLUSION

In spite of considerable withdrawal rate across both study arms, African American kidney transplant recipients who underwent early transition to a sirolimus-based CNI-withdrawal regimen had significantly better graft function at one yr compared to those transitioned to a sirolimus-based CNI-minimization regimen. Clinicaltrials.gov identifier: NCT01005706.

Sirolimus-Based Immunosuppressive Regimens in Renal Transplantation: A Systemic Review

Sirolimus (SRL)-based immunosuppressive regimens have been used for preventing rejection after kidney transplantation. This review analyzes their merits and demerits compared with other conventional regimes from the aspects of acute rejection rate, graft function, as well as patient/graft survival rates. In general, SRL is mostly recommended to be used as conversion therapy from calcineurin inhibitor (CNI) after kidney transplantation in most studies. Minimization or withdrawal of cyclosporine A (CsA) could also be considered when it was combined with SRL. SRL can replace mycophenolate mofetil (MMF), and the CNI dose should be reduced appropriately in this setting. Quadruple maintenance regimens containing SRL need future study to clarify their superiority. De novo use of low-dose CNI combined with SRL has no apparent merits and thus is not recommended. De novo use of standard-dose CNI combined with SRL followed by maintenance, de novo use of CNI-free regimens, as well as SRL use in delayed graft function (DGF) patients who spare antibody induction and postpone CNI administration should also be avoided. SRL supports steroids withdrawal after kidney transplantation, and SRL combined with tacrolimus is recommended in this setting. Loading dose is recommended when initiating SRL treatment and its trough blood level should be routinely monitored.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

A comparative, randomized trial of concentration-controlled sirolimus combined with reduced-dose tacrolimus or standard-dose tacrolimus in renal allograft recipients

BACKGROUND

The clinical safety and efficacy of sirolimus plus reduced-dose tacrolimus was evaluated in de novo renal allograft recipients enrolled in a comparative, open-label study.

METHODS

One hundred twenty-eight renal allograft recipients were randomly assigned (1:1) to receive reduced-dose tacrolimus plus sirolimus (rTAC) or standard-dose tacrolimus and sirolimus (sTAC) for 6 months. The primary efficacy endpoint was calculated creatinine clearance values at 6 months.

RESULTS

Demographic variables were similar between groups. At 6 months, mean (± standard deviation) calculated creatinine clearance was significantly improved in the rTAC group (63.8 vs 52.7 mL/min, P = .005), although mean serum creatinine values were not significantly different. Patient survival (95.2% and 96.9%) and graft survival (93.7% and 98.5%) were similar between the rTAC and sTAC groups, respectively. Acute rejection rates were 17.5% with rTAC and 7.7% with sTAC (P = .095).

CONCLUSIONS

The rTAC regimen provided effective immunosuppression and was associated with improved creatinine clearance. Adequate immunosuppressant exposure must be achieved in the early postoperative period to minimize the risk of acute rejection.

Strategies for the management of adverse events associated with mTOR inhibitors

Mammalian target of rapamycin (mTOR) inhibitors are used as potent immunosuppressive agents in solid-organ transplant recipients (everolimus and sirolimus) and as antineoplastic therapies for various cancers (eg, advanced renal cell carcinoma; everolimus, temsirolimus, ridaforolimus). Relevant literature, obtained from specific PubMed searches, was reviewed to evaluate the incidence and mechanistic features of specific adverse events (AEs) associated with mTOR inhibitor treatment, and to present strategies to effectively manage these events. The AEs examined in this review include stomatitis and other cutaneous AEs, wound-healing complications (eg, lymphocele, incisional hernia), diabetes/hyperglycemia, dyslipidemia, proteinuria, nephrotoxicity, delayed graft function, pneumonitis, anemia, hypertension, gonadal dysfunction, and ovarian toxicity. Strategies for selecting appropriate patients for mTOR inhibitor therapy and minimizing the risks of AEs are discussed, along with best practices for identifying and managing side effects. mTOR inhibitors are promising therapeutic options in immunosuppression and oncology; most AEs can be effectively detected and managed or reversed with careful monitoring and appropriate interventions.

Obesity and metabolic syndrome in kidney transplantation

The epidemic of obesity and metabolic syndrome (MS) contributes to the rapid growth of chronic kidney disease (CKD) and end-stage renal disease (ESRD). There is a reverse epidemiology, known as the "obesity paradox," in ESRD patients receiving maintenance dialysis. Obese patients are routinely referred for kidney transplant, and they have more surgical and medical complications than non-obese patients. However, compared to dialysis, kidney transplant provides a survival benefit for obese patients. After kidney transplant, obese patients tend to gain more body weight, and non-obese patients can develop new-onset obesity/MS. Obesity/MS is not only associated with serious morbidities, but also compromises the long-term graft and patient survival. The immunosuppressive drugs commonly used as maintenance therapy, including corticosteroids, calcineurin inhibitors and mammalian target-of-rapamycin inhibitors, contribute to obesity/MS. Development of novel immunosuppressive drugs free of metabolic adverse effects is needed, so that the full potential and benefits of kidney transplantation can be realized.

Impact of calcineurin-inhibitor conversion to mTOR inhibitor on renal allograft function in a prednisone-free regimen

Traditionally, chronic calcineurin inhibitor (CNI) nephrotoxicity has been considered to be one of the main nonimmune mechanisms causing chronic renal allograft dysfunction. CNI minimization and withdrawal strategies have yielded inconsistent results. Few studies address the feasibility of CNI elimination in a prednisone-free regimen. We report a prospective, randomized trial in 200 patients evaluating the impact on renal function and incidence of acute rejection after conversion from tacrolimus (Tac) to sirolimus (SRL). Patients with recent (<3 months) acute rejection episodes or with >0.5 g/day of proteinuria were excluded. All were induced with alemtuzumab, underwent rapid steroid elimination and were maintained on mycophenolate mofetil and Tac. At 12 months posttransplant, patients were randomized 2:1 to SRL (n = 123) or maintained on Tac (n = 64). Mean follow-up was 41.1 ± 15.8 months in the SRL group and 40.7 ± 14.4 months in the Tac group. Biopsy-proven acute rejection at 24 months postrandomization was similar between the groups. Patient survival, graft survival and estimated GFR were also not statistically different. Our study demonstrates that in a prednisone-free immunosuppressive regimen, conversion from Tac to SRL at 12 months posttransplantation is not associated with increased rates of acute rejection and graft loss. However, despite CNI elimination, renal allograft function is equally maintained in both groups.

Is it time to give up with calcineurin inhibitors in kidney transplantation?

Calcineurin inhibitors (CNIs) represent today a cornerstone for the maintenance immunosuppressive treatment in solid organ transplantation. Nevertheless, several attempts have been made either to minimize their dosage or to avoid CNIs at all because these drugs have the severe side effect of chronic nephrotoxicity. This issue represents a frontier for renal transplantation. The principal problem is to understanding whether the poor outcome over the long-term may be ascribed to CNIs nephrotoxicity or to the inability of these drugs to control the acute and chronic rejection B cells mediated. The authors analyze extensively all the international trials attempting to withdraw, minimize or avoid the use of CNIs. Few trials undertaken in low risk patients with an early conversion from CNIs to proliferation signal inhibitors were successful, but the vast majority of trials failed to improve CNIs side effects. To date the use of a new drug, a co-stimulation blocker, seems promising in avoiding CNIs with similar efficacy, better glomerular filtration rate and an improved metabolic profile. Moreover the use of this drug is not associated with the development of donor-specific anti-human leukocyte antigen antibodies. This point has a particular relevance, because the failure of CNIs to realize good outcomes in renal transplantation has recently ascribed to their inability to control the acute and chronic rejections B-cell mediated. This paper analyzes all the recent studies that have been done on this issue that represents the real frontier that should be overcome to realize better results over the long-term after transplantation.

An evaluation of sirolimus in renal transplantation

INTRODUCTION

Sirolimus is a powerful antiproliferative immunosuppressive drug approved for the prevention of kidney allograft rejection. By its unique mechanism of action, sirolimus provides a multitude of clinical potential and has been used effectively in different drug combinations. Extensive experience has been gained regarding the best timing of its application, side effect profile and potential benefits and limitations compared with other immunosuppressive drugs.

AREAS COVERED

The authors evaluate the recent experience with sirolimus in kidney transplantation. Pivotal randomized controlled trials were used to provide an overview with special attention to pharmacokinetic and dynamic aspects of sirolimus, its current clinical use as well as perspectives for its future role.

EXPERT OPINION

Sirolimus enriches the possibilities of immunosuppressive therapies after renal transplantation. Beneficial effects toward kidney function by allowing CNI sparing, lower incidence of malignancies and less viral infections have been suggested. Sirolimus should be used cautiously in de novo patients for reasons of wound healing. An early conversion to a sirolimus-based CNI-free regimen has shown promising results, whereas late conversion is more challenging. Finally, sirolimus-associated side effects are causing tolerability concerns and frequent discontinuations. Future research should aim to better define the therapeutic window and those patients most likely to benefit.

Mycophenolate mofetil and FK506 have different effects on kidney allograft fibrosis in rats that underwent chronic allograft nephropathy

Background

Tacrolimus (FK506) is associated with renal fibrosis in long-term use. Mycophenolatemofetil (MMF) can also inhibit or attenuate the progression of renal fibrosis. This study aimed to determine the different effects of FK506 and MMF on fibrosis-associated genes in the kidney in rats that underwent chronic allograft nephropathy (CAN).

Methods

Fisher (F344) kidneys were orthotopically transplanted into Lewis rat recipients. All recipients were given Cyclosporin A (CsA) 10 mg/kg^-1.d^-1 × 10 day and were then randomly divided into three oral treatment groups (n = 9 in each group): (1) the vehicle group was given vehicle orally; (2) the FK506 group was given 0.15 mg/kg^-1.d^-1 FK506; and (3) the MMF group was given 20 mg/kg^-1.d^-1 MMF. At 4, 8, and 12 weeks post-transplantation, serum creatinine (SCr), collagen deposition, Connective tissue growth factor (CTGF), alpha smooth muscle actin (α-SMA) and E-cadherin expressions were determined and hematoxylin-eosin (HE) and Periodic acid-Schiff (PAS) stains were performed.

Results

Renal function progressively deteriorated and showed typical CAN morphology in the vehicle and FK506 groups, while SCr and inflammatory infiltration (Banff score) showed a significant decrease in the MMF group after 8 weeks post-transplantation compared with those in the other groups (p < 0.05). Furthermore, expression levels of CTGF and α-SMA in the MMF group were significantly reduced, and the down-regulated expression of E-cadherin was abated (p < 0.05).

Conclusions

MMF showed favorable effects on renal interstitial fibrosis, thus efficiently retarding the progression of CAN.

Adult dual kidney transplantations obtained from marginal donors: two case reports

Organ shortage has led us to use grafts from expanded criteria donors (ECD). Dual kidney transplantation (DKT) using organs from an ECD, which are not acceptable for single kidney transplantation (KT), may overcome the insufficient functioning nephron mass. We performed DKTs in two recipients, the first DKT to be reported from Korea. In case 1, the donor was a 36-year-old man with hypertension. The cause of his brain death was intracranial hemorrhage. He had no known underlying renal disease; his serum creatinine level was 4.2 mg/dL. Despite the relatively young age of the donor, a biopsy revealed mild interstitial fibrosis and tubular atrophy with moderate arteriolar narrowing. The recipient's postoperative course was uneventful over the 69-month follow-up; her last serum creatinine was 1.3 mg/dL. In case 2, the 80-year-old male donor with a history of hypertension had a normal creatinine. The donor biopsy revealed mild glomerular sclerosis, tubular atrophy, and interstitial fibrosis with moderate arteriolar narrowing. The recipient had undergone a previous KT 14 years previously on the right side of the abdomen, but had resumed dialysis 2 years previously due to chronic allograft nephropathy. There was no delayed graft function. At month 4 posttransplantation, lymphoceles were treated by fenestration. At 6-month follow-up, her creatinine was 1.0 mg/dL. In our experience with these two cases, DKT with ECD kidney grafts seemed to be a successful strategy to avoid poor graft outcomes and overcome the donor organ shortage. Further studies including histological criteria for DKT, should be performed to determine the safest means to utilize ECD grafts.

Immunosuppression in the era of biological agents

Immunosuppression is the mayor mechanism to prevent allograft rejection and to induce tolerance. Since the first solid organ transplant, the development of safe and effective immunosuppressive regimens was a constant over the last decades. A lot of immunosuppressants have been discovered, and today the immunosuppressive agents are classified in two broad groups: Xenobiotic immunosuppressants and biological immunosuppressants. Xenobiotics, like corticoids and calcineurin and mTOR inhibitors, mainly interfere with the intracellular molecular mechanisms of the various types of cells involved in the immune response and generally these immunosuppressants are used early on in the transplantation process to prevent rejection as well as in long-term maintenance therapy. On the other hand, target molecules of biological immunosuppressants are on the surface of these immunological cells and normally in clinical immunosuppressive protocols have been used as auxiliary agents of xenobiotics to prevent rejection as well as in the treatment of acute rejection. However, these xenobiotics and biological agents have multiple side effects; that is why there has been a search for new drugs to minimise these side effects and to improve patients' quality of life. In this way, new biological agents have been proposed as maintenance immunosuppressive agents. The majority of these new immunosuppressive agents are polyclonal or monoclonal antibodies and recently the so-called fusion proteins may be the start of a new era of biological immunosuppression for maintenance regimens.

Is cellular senescence important in pediatric kidney disease?

Somatic cellular senescence (SCS) describes the limited ability of cells to divide. Normally, SCS is associated with physiological aging, but evidence suggests that it may play a role in disease progression, even in young patients. Stressors such as acute injury or chronic inflammation may induce SCS, which in turn exhausts organ regenerative potential. This review summarizes what is known about SCS in the kidney with aging and disease. As most patients with chronic kidney disease (CKD) also develop cardiovascular complications, a second focus of this review deals with the role of SCS in cardiovascular disease. Also, as SCS seems to accelerate CKD and cardiovascular disease progression, developing strategies for new treatment options that overcome SCS or protect a patient from it represents an exciting challenge.

Meta-analysis of calcineurin-inhibitor-sparing regimens in kidney transplantation

Calcineurin-inhibitor-sparing strategies in kidney transplantation may spare patients the adverse effects of these drugs, but the efficacy of these strategies is unknown. Here, we conduct a meta-analysis to assess outcomes associated with reducing calcineurin inhibitor exposure from the time of transplantation. We search Medline, Embase, and Cochrane Register of Controlled Trials for randomized controlled trials published between 1966 and 2010 that compared de novo calcineurin-inhibitor-sparing regimens to calcineurin-inhibitor-based regimens. In this analysis, we include 56 studies comprising data from 11337 renal transplant recipients. Use of the contemporary agents belatacept or tofacitinib, in combination with mycophenolate, decreased the odds of overall graft failure (OR 0.61; 95% CI 0.39-0.96; P = 0.03). Similarly, minimization of calcineurin inhibitors in combination with various induction and adjunctive agents reduces the odds of graft failure (OR 0.73; 95% CI 0.58-0.92; P = 0.009). Conversely, the use of inhibitors of mammalian target of rapamycin (mTOR), in combination with mycophenolate, increases the odds of graft failure (OR 1.43; 95% CI 1.08-1.90; P = 0.01). Calcineurin-inhibitor-sparing strategies are associated with less delayed graft function (OR 0.89; 95% CI 0.80-0.98; P = 0.02), improved graft function, and less new-onset diabetes. The more contemporary protocols did not seem to increase rates of acute rejection. In conclusion, this meta-analysis suggests that reducing exposure to calcineurin inhibitors immediately after kidney transplantation may improve clinical outcomes.

The histology of solitary renal allografts at 1 and 5 years after transplantation

Previous studies suggest that the majority of renal allografts are affected by progressive, severe chronic histologic injury, yet studies using current protocols are lacking. The goal of this study was to examine the prevalence and progression of histologic changes using protocol allograft biopsies at 1 and 5 years after solitary kidney transplantation in patients transplanted between 1998 and 2004. Chronic histologic changes generally were mild at both 1 and 5 years and were similar in deceased and living donor kidneys. The overall prevalence of moderate or severe fibrosis was 13% (60/447) at 1 year and 17% (60/343) at 5 years. In a subgroup of 296 patients who underwent both 1- and 5-year biopsies, mild fibrosis present at 1 year progressed to more severe forms at 5 years in 23% of allografts. The prevalence of moderate or severe arteriolar hyalinosis was similar in tacrolimus and calcineurin inhibitor-free immunosuppression. These results in the recent era of transplantation demonstrate fewer, less severe and less progressive chronic histologic changes in the first 5 years after transplantation than previously reported.

Rabbit antithymocyte globulin (thymoglobulin): 25 years and new frontiers in solid organ transplantation and haematology

The more than 25 years of clinical experience with rabbit antithymocyte globulin (rATG), specifically Thymoglobulin, has transformed immunosuppression in solid organ transplantation and haematology. The utility of rATG has evolved from the treatment of allograft rejection and graft-versus-host disease to the prevention of various complications that limit the success of solid organ and stem cell transplantation. Today, rATG is being successfully incorporated into novel therapeutic regimens that seek to reduce overall toxicity and improve long-term outcomes. Clinical trials have demonstrated the efficacy and safety of rATG in recipients of various types of solid organ allografts, recipients of allogeneic stem cell transplants who are conditioned with both conventional and nonconventional regimens, and patients with aplastic anaemia. Over time, clinicians have learnt how to better balance the benefits and risks associated with rATG. Advances in the understanding of the multifaceted mechanism of action will guide research into new therapeutic areas and future applications.

[Proliferation signal inhibitors: what therapeutic protocols are followed in 2009?]

Proliferation signal inhibitors (PSI) have been used in France for kidney transplants for some ten years. They provide a certain number of long-term benefits for kidney function in transplant patients due to their anti-proliferation and anti-tumour properties and absence of nephrotoxicity. Their use has been evaluated in therapeutic regimens aimed at reducing the nephrotoxicity associated with calcineurin inhibitors (CNI). Strategies based on minimizing the use of CNIs and therapy switches between 3 and 6 months have shown promising results, especially in terms of prevention of deterioration of kidney function. The best time to make the switch has not yet been defined with certainty, but predictors of success, preservation of good kidney function and absence of proteinuria have been established. Aside from cases of demonstrated CNI toxicity, a history or onset of de novo cancer is a situation in which this type of regimen can be considered.

Potential differences in kidney allograft outcomes between ethnicities when converting to sirolimus base immunosuppression

OBJECTIVE

The aim of this study was to determine whether ethnicity impacts graft outcomes in kidney transplant patients converted to sirolimus (SRL) and maintained on either calcineurin inhibitors (CI) or mycophenolate mofetil (MMF) with steroids.

METHODS

This study analyzed kidney transplants converted to SRL and transplanted between July 1991 and April 2007. Patients were divided into 4 groups: group 1: African-Americans converted to SRL + CI; group 2: non-African-Americans converted to SRL + CI; group 3: African-Americans converted to SRL + MMF; group 4: non-African-Americans converted to SRL + MMF.

RESULTS

A total of 242 patients was included. Demographics, baseline immunosuppression, and reason for SRL conversion were similar among groups. Patients converted to SRL + CI regimens had significantly higher rates of acute rejection before SRL conversion, but equal rates after conversion. Development of proteinuria was similar across groups. African-American patients converted to SRL + MMF tended to have poorer outcomes compared with African-American patients converted to SRL + CI. Non-African-American patients converted to SRL + MMF tended to have better graft outcomes compared with non-African-American patients converted to SRL + CI.

CONCLUSIONS

African-Americans converted to SRL may benefit from continued CI, whereas non-African-Americans converted to SRL seem to have better outcomes with MMF. Further prospective studies are warranted to confirm these findings.

Interstitial fibrosis quantification in renal transplant recipients randomized to continue cyclosporine or convert to sirolimus

Conversion from cyclosporine (CsA) to sirolimus at week 12 after kidney transplantation is associated with a significant improvement in renal function. The aim of this analysis was to investigate the effect of this conversion on interstitial fibrosis (IF), a hallmark of chronic allograft injury, in patients taking part in the CONCEPT trial. This multicenter, prospective, trial included 193 renal recipients randomized at week 12 to switch from CsA to sirolimus or to continue CsA, with mycophenolate mofetil. Routine biopsy with automated, quantified assessment of IF by a program of color segmentation was performed at 1 year in 121 patients. At 1 year, renal function was significantly improved in the conversion group as assessed by estimated GFR (MDRD) and measured GFR. Biopsy results, however, showed no between-group difference in percentage of IF. Calculated GFR at 1 year was significantly associated with the percentage of IF (p = 0.004, R(2)= 0.07). By multivariate analysis diabetic patients had more fibrosis than non-diabetic patients. In conclusion, although kidney transplant patients converted from CsA to sirolimus showed significant improvement in renal function, we found no difference of IF on 1-year biopsies.

Multicentric outcome analysis of sirolimus-based immunosuppression in 252 liver transplant recipients

SUMMARY

The use of sirolimus (SRL) in orthotopic liver transplantation (OLT) has been controversial after experimental data suggested an increased risk of hepatic artery thrombosis (HAT). To assess the safety and efficacy of SRL as de novo immunosuppression in OLT recipients. Outcomes of 252 OLT patients who received SRL were compared with outcomes of 291 OLT recipients who received calcineurin inhibitor in a retrospective study. Primary outcomes of this study were: patient- and graft survivals, vascular, biliary, wound complications and rejection rates. Secondary outcomes were: postoperative infection rate, bone marrow and renal function and changes of lipid levels. Patient- and graft survivals, rejection and infection rates were similar. In the SRL group, HAT occurred in 1.2%, biliary complications in 19.4%, and incisional hernias in 9.1%. In the control group the incidence of HAT was 5.8% (P = 0.004), biliary complications 18.5% (P = NS) and incisional hernias 7.2% (P = NS). Patients on SRL experienced significantly higher levels of serum triglycerides but fewer acute cellular rejections. Bone marrow and renal functions were similar in both the groups. Our findings would suggest that SRL is safe and effective for very selected OLT recipients. Randomized controlled trials are necessary to confirm our results.

Sirolimus in kidney transplantation indications and practical guidelines: de novo sirolimus-based therapy without calcineurin inhibitors

A de novo calcineurin inhibitor avoidance regimen based on sirolimus has been successfully used worldwide; demonstrating improved renal function from 1 to 5 years. This includes use of an induction antibody followed by sirolimus, mycophenolate mofetil, and steroids. This combination has a somewhat different side effect profile and wider experience has revealed that the use of de novo sirolimus requires careful therapeutic drug level monitoring, especially the first 6 months posttransplant. Experience has also demonstrated that delaying the introduction of sirolimus in patients considered at high risk for early mammalian target of rapamycin associated complications will optimize these results. For such recipients, the initial use of a calcineurin inhibitor drug for 2 to 4 months is preferred, followed by conversion to sirolimus. The late withdrawal of steroids may be possible, but awaits further evaluation in randomized controlled trials.

Mycophenolate mofetil: safety and efficacy in the prophylaxis of acute kidney transplantation rejection

Mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), is an inhibitor of inosine monophosphate dehydrogenase (IMPDH). It preferentially inhibits denovo pathway of guanosine nucleotide synthesis in T and B-lymphocytes and prevents their proliferation, thereby suppresses both cell mediated and humoral immune responses. Clinical trials in kidney transplant recipients have shown the efficacy of MMF in reducing the incidence and severity of acute rejection episodes. It also improves long term graft function as well as graft and patient survival in kidney transplant recipients. MMF is useful as a component of toxicity sparing regimens to reduce or avoid exposure of steroids or calcineurin inhibitor (CNI). Enteric-coated mycophenolate sodium (EC-MPS) can be used as an alternative immunosuppressive agent in kidney transplant recipients with efficacy and safety profile similar to MMF.

[Immunosuppressive strategies and chronic graft dysfunction in kidney transplantation]

Chronic graft dysfunction is a major cause of return to dialysis. In the majority of cases, it is correlated with histological signs of cellular and/or humoral rejection, the nephrotoxicity of anticalcineurins, or nonspecific lesions of interstitial fibrosis and tubular atrophy. Although the incidence of acute rejection has considerably decreased, renal toxicity of the calcineurin inhibitors remains problematic. In cases of established nephrotoxicity, the use of non-nephrotoxic immunosuppressors such as mycophenolic acid or the proliferation signal inhibitors makes it possible to reduce or even stop the anticalcineurins. In prevention of anticalcineurin nephrotoxicity, many attempts to minimize or wean patients from them have shown that improvement in renal function is only obtained at the cost of an increase in the incidence of acute rejection. This makes it necessary to select patients who may benefit from anticalcineurin-sparing treatment, based on clinical, histological, and biological markers. Finally, long-term follow-up is also fundamental in order to validate the positive impact on renal function of this strategy in terms of graft survival.

Risk factors and consequences of delayed graft function in deceased donor renal transplant patients receiving antithymocyte globulin induction

BACKGROUND

Induction rabbit antithymocyte globulin (rATG) is largely used in renal allograft recipients at risk for delayed graft function (DGF) and immunologic rejection. The purpose of our study was to characterize risk factors and outcomes associated with DGF when it occurs in recipients undergoing routine rATG induction.

METHODS

We retrospectively reviewed our experience in a predominantly high-risk population receiving modern immunosuppressive regimens.

RESULTS

Of 231 deceased-donor transplants, high-risk characteristics included African American race (68%), retransplants (12%), peak panel reactive antibody of atleast 20% (19%), expanded criteria donor kidney (15%), and cold ischemia time exceeding 24 hr (27%). DGF occurred in 29% of patients. rATG was continued to a dose of 7.3 mg/kg in DGF patients and 5 mg/kg in non-DGF patients (P<0.0001). Risk factors for DGF were recipient body mass index greater than 30 kg/m(2) (odds ratio [OR]=1.5, P=0.02), female donor/male recipient pairings (OR=1.5, P=0.033), sirolimus use (OR=1.7, P=0.003), and donor creatinine more than 1.5 mg/dL (OR=1.6, P=0.016). One-year patient survival (99% non-DGF, 91% DGF; P=0.001) and acute rejection incidence through 36 months (11% non-DGF, 22.4% DGF; P=0.025) differed between groups. DGF patients experienced a higher rejection rate during the second and third years posttransplant. Death-censored graft survival was similar throughout 36 months.

CONCLUSION

In kidney transplantation with routine rATG induction, DGF was related to size and gender, donor creatinine, and immunosuppressive protocol. Despite low first-year rejection rates, DGF was associated with inferior patient survival. Importantly, patients with DGF continued to be at risk for rejection beyond the first year. Donor and recipient selection impacts short-term outcomes, and induction alone may not confer a long-term advantage without further modification of baseline therapy.

Long-term efficacy and safety of a calcineurin inhibitor-free regimen in live-donor renal transplant recipients

Calcineurin inhibitor (CNI) nephrotoxicity is a major concern after renal transplantation. To investigate the safety and efficacy of a CNI-free immunosuppressive regimen, 132 live-donor renal transplant recipients were included in a prospective, randomized controlled trial. All patients received induction therapy with basiliximab and steroids. The patients were randomized to a maintenance immunosuppression regimen that included steroids, sirolimus, and either low-dose tacrolimus or mycophenolate mofetil (MMF). Over a mean follow-up period of approximately 5 yr, patient and graft survival did not significantly differ between the two maintenance regimens. Patient survival was 93.8% and 98.5% in the tacrolimus/sirolimus and MMF/sirolimus groups, respectively, and graft survival was 83% and 88%, respectively. However, the MMF/sirolimus group had significantly better renal function, calculated by Cockcroft-Gault, from the second year post-transplant until the last follow-up. In addition, this group was less likely to require a change in their primary immunosuppression regimen than the tacrolimus/sirolimus group (20.8% versus 53.8%, P = 0.001). The safety profile was similar between groups. In summary, after long-term follow-up, a CNI-free maintenance regimen consisting of sirolimus, MMF, and steroids was both safe and efficacious among low to moderate immunologic risk renal transplant recipients.

Calcineurin inhibitor-sparing regimens in solid organ transplantation: focus on improving renal function and nephrotoxicity

BACKGROUND

The calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, have had a revolutionary effect on the overall success of renal transplantation through reduction in early immunologic injury and acute rejection rates. However, the CNIs have a significant adverse impact on renal function and cardiovascular disease, and extended long-term graft survival has not been achieved. The recognition of these effects sparked interest in CNI-sparing strategies. Strategies to limit CNI exposure include CNI minimization, avoidance, and withdrawal. We sought to review the impact of CNI-sparing strategies in kidney, liver, and heart transplantation.

MATERIALS AND METHODS

A PubMed search 1966 to August 2006 was conducted to identify relevant research articles, and the references of these articles as well as the authors' personal files were reviewed.

RESULTS

Calcineurin inhibitor minimization using mycophenolate mofetil or sirolimus may be associated with a modest increase in creatinine clearance (CrCl) and a decrease in serum creatinine (SCr) in the short term. Despite improvement in CrCl or SCr, CNI nephrotoxicity and chronic allograft nephrotoxicity are progressive over time when CNI exposure is maintained. In kidney transplantation, the tubulo-interstitial and glomerular damage are irreversible. Mycophenolate mofetil may improve renal outcomes during CNI minimization more than sirolimus, and antibody induction may be effective to limit CNI exposure, but longer-term follow-up data are required. Use of sirolimus with mycophenolate mofetil or azathioprine to avoid CNI exposure de novo has improved glomerular filtration rate for at least two yr in most studies in kidney transplantation; however, experience is limited in liver and heart transplantation, and reports of delayed graft function and wound healing with sirolimus may have dampened enthusiasm for de novo use. Late CNI withdrawal has achieved variable results, possibly because withdrawal was attempted after the kidney damage was too extensive. Early CNI withdrawal, prior to significant graft damage, has generally improved CrCl and markers of fibrosis and decreased chronic allograft lesions, a finding also observed with sirolimus in most CNI avoidance studies. Successful withdrawal appears to be more effective than CNI minimization.

CONCLUSIONS

Calcineurin inhibitors are associated with significant nephrotoxicity and chronic kidney damage. Minimization is associated with a modest increase in renal function, but persistent damage is observed on biopsies as long as the CNIs are continued. Avoidance is hampered by lack of experience and possible sirolimus-induced side effects. CNI withdrawal may be the best option by delivering CNIs during the early period of immunologic graft injury and then converting them to less nephrotoxic agents before significant renal damage occurs.

Kidney transplantation with sirolimus and mycophenolate mofetil-based immunosuppression: 5-year results of a randomized prospective trial compared to calcineurin inhibitor drugs

BACKGROUND

We report the 5-year outcomes from a randomized prospective trial in primary adult renal allograft recipients, designed to evaluate calcineurin inhibitor (CNI)-free immunosuppression on kidney transplant function.

METHODS

Sixty-one patients were randomized to either sirolimus (n=31) or cyclosporine (n=30) after basiliximab induction and mycophenolate mofetil (MMF) with steroids. Sirolimus was concentration controlled at 10-12 ng/mL for at least 6 months.

RESULTS

After 5 years, sirolimus-MMF-steroids compared to cyclosporine-MMF-steroids provides similar patient survival (87.1 vs. 90%, P=0.681), acute rejection rates (12.9 vs. 23.3%, P=0.22), total cholesterol (209.1 vs. 204.3 mg/dL, P=0.973), urine protein/creatinine ratios (0.398 vs. 0.478 mg/dL, P=0.72), and overall medical and surgical morbidity (P=NS). Although unadjusted patient survival was similar, sirolimus based CNI-free patients had longer death censored graft survival (96.4 vs. 76.7%, P=0.0265), higher glomerular filtration rate (GFR) by the abbreviated Modified Diet in Renal Disease (66.7 vs. 50.7 cc/min, P=0.0075), and fewer graft losses from chronic allograft nephropathy. The Banff chronic scores at two years were strong predictors of 5-year GFR. At 5 years, there were six de novo (three solid organ, three skin) cancers in the CNI group and only two de novo (one skin, one leukemia, no solid organ) cancers in the sirolimus group (P=NS).

CONCLUSIONS

This study of low to moderate risk patients demonstrates that excellent 5-year kidney transplant outcomes can be achieved without CNI drugs, when therapeutic drug monitoring of sirolimus is employed. The application of CNI drug avoidance protocols to high-risk recipients (retransplants, highly sensitized, etc.), extrarenal allograft recipients, or alternative drug regimens such as steroid or MMF elimination should be subjected to controlled trials.

Non-heart beating organ donation: overview and future perspectives

New indications for organ transplantation combined with a stagnating number of available donor grafts have severely lengthened the waiting list for almost all types of transplantations. This has led to a renewed interest in non-heart beating (NHB) donation, as a possible solution to bridge the gap between supply and demand. In this review, we present an overview of current NHB donation practice, outcome, existing problems and future perspectives. We focus on possible improvements in donor management, recipient care and new methods of organ preservation that may be better suited for these marginal organs. Successful institution of NHB protocols depends on adapting current transplantation practice at all levels, which is one of the greatest challenges for researchers and professionals in this interesting re-emerging field.

Use of sirolimus in solid organ transplantation

Sirolimus is a mammalian target of rapamycin (mTOR) inhibitor that inhibits cell cycle progression and has proven to be a potent immunosuppressive agent for use in solid organ transplant recipients. The drug was initially studied as an adjunct to ciclosporin (cyclosporine) to prevent acute rejection in kidney transplant recipients. Subsequent studies have shown efficacy when combined with a variety of other immunosuppressive agents. The most common adverse effects of sirolimus are hyperlipidaemia and myelosuppression. The drug has unique antiatherogenic and antineoplastic properties, and may promote immunological tolerance and reduce the incidence of chronic allograft nephropathy. Although sirolimus is relatively non-nephrotoxic when administered as monotherapy, it pharmacodynamically enhances the toxicity of calcineurin inhibitors. Ironically, the drug has been used to facilitate calcineurin inhibitor-free protocols designed to preserve renal function after solid organ transplantation. Whether sirolimus can be used safely over the long term with low doses of calcineurin inhibitors requires further study. The use of sirolimus as a corticosteroid-sparing agent also remains to be proven in controlled trials. Postmarketing studies have revealed a number of unforeseen adverse effects including impaired wound healing and possibly proteinuria, oedema, pneumonitis and thrombotic microangiopathy. Overall, sirolimus is a powerful agent when used judiciously with other available immunosuppressants. As is true for all immunosuppressive drugs available for treatment of solid organ transplant recipients, the efficacy of the drug must be balanced against its considerable adverse effects.

Calcineurin inhibitor-free immunosuppression in dual kidney transplantation from elderly donors

BACKGROUND

Kidneys from expanded-criteria donors may be particularly susceptible to calcineurin inhibitor (CI)-mediated vasoconstriction and nephrotoxicity. In the early post-transplant phase, using CI may prolong ischemic injury and, in the long term, chronic CI nephrotoxicity is an even greater concern. To avoid the acute and chronic consequences of CI in kidneys from marginal donors, CI-free protocols have been introduced for maintenance immunosuppressive therapy. A CI-free protocol of anti-thymocyte globulin (ATG) induction, sirolimus, mycophenolate mofetil (MMF) and steroids has been adopted at our center in recipients of dual kidney transplantation (DKT) from elderly donors (EDs).

METHODS

Dual kidney transplantations performed since April 2003 on CI-free immunosuppression (group 1 = 31) were compared with earlier DKTs in recipients treated with CI-based therapy (group 2 = 25), retrospectively analyzing patient and graft survival, surgical and medical complications, rejection episodes and renal function.

RESULTS

No deaths occurred after a mean follow-up of 10.1 +/- 7.6 (group 1) and 48.2 +/- 17.4 months (group 2). Graft loss occurred in one patient in group 1 (bilateral renal vein thrombosis) and in three patients in group 2 (one primary non-function [PNF], one chronic rejection, one Kaposi's sarcoma). The incidence of acute rejection was 19% in group 1 and 16% in group 2. Delayed graft function (DGF) was recorded in 16% and 48%, respectively. Renal function was better in group 1, with a mean S-Cr of 135 +/- 48 vs. 210 +/- 141 micromol/L at one month and 116 +/- 30 vs. 149 +/- 49 micromol/L at six months.

CONCLUSIONS

After DKT from EDs, a CI-free immunosuppressive regimen including ATG induction, sirolimus, MMF and steroids affords excellent results, with a lower DGF rate and a better renal function.