High Rejection Rate during Calcineurin Inhibitor-Free and Early Steroid Withdrawal Immunosuppression in Renal Transplantation

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.

Effect of sirolimus on malignancy and survival after kidney transplantation: systematic review and meta-analysis of individual patient data

OBJECTIVE

To examine risk of malignancy and death in patients with kidney transplant who receive the immunosuppressive drug sirolimus.

DESIGN

Systematic review and meta-analysis of individual patient data.

DATA SOURCES

Medline, Embase, and the Cochrane Central Register of Controlled Trials from inception to March 2013.

ELIGIBILITY

Randomized controlled trials comparing immunosuppressive regimens with and without sirolimus in recipients of kidney or combined pancreatic and renal transplant for which the author was willing to provide individual patient level data. Two reviewers independently screened titles/abstracts and full text reports of potentially eligible trials to identify studies for inclusion. All eligible trials reported data on malignancy or survival.

RESULTS

The search yielded 2365 unique citations. Patient level data were available from 5876 patients from 21 randomized trials. Sirolimus was associated with a 40% reduction in the risk of malignancy (adjusted hazard ratio 0.60, 95% confidence interval 0.39 to 0.93) and a 56% reduction in the risk of non-melanoma skin cancer (0.44, 0.30 to 0.63) compared with controls. The most pronounced effect was seen in patients who converted to sirolimus from an established immunosuppressive regimen, resulting in a reduction in risk of malignancy (0.34, 0.28 to 0.41), non-melanoma skin cancer (0.32, 0.24 to 0.42), and other cancers (0.52, 0.38 to 0.69). Sirolimus was associated with an increased risk of death (1.43, 1.21 to 1.71) compared with controls.

CONCLUSIONS

Sirolimus was associated with a reduction in the risk of malignancy and non-melanoma skin cancer in transplant recipients. The benefit was most pronounced in patients who converted from an established immunosuppressive regimen to sirolimus. Given the risk of mortality, however, the use of this drug does not seem warranted for most patients with kidney transplant. Further research is needed to determine if different populations, such as those at high risk of cancer, might benefit from sirolimus.

Risk of serious opportunistic infections after solid organ transplantation: interleukin-2 receptor antagonists versus polyclonal antibodies. A meta-analysis

BACKGROUND

We aimed to evaluate and quantify the risk of serious opportunistic infections after induction with polyclonal antibodies versus IL-2 receptor antagonists (IL-2RAs) in randomized clinical trials.

METHODS

PRISMA guidelines were followed and random-effects models were performed.

RESULTS

70 randomized clinical trials (10,106 patients) were selected: 36 polyclonal antibodies (n = 3377), and 34 IL-2RAs (n = 6729). Compared to controls, polyclonal antibodies showed higher risk of serious opportunistic infections (OR: 1.93, 95% CI: 1.34-2.80; p < 0.0001); IL-2RAs were associated with lower risk of serious opportunistic infections (OR: 0.80, 95% CI: 0.68-0.94; p = 0.009). Polyclonal antibodies were associated with higher risk of bacterial (OR: 1.58, 95% CI: 1.00-2.50; p = 0.049) and viral infections (OR: 2.37, 95% CI: 1.60-3.49; p < 0.0001), while IL-2RAs were associated with lower risk of cytomegalovirus (CMV) disease (OR: 0.73, 95% CI: 0.56-0.97; p = 0.032). Adjusted indirect comparison: compared to polyclonal antibodies, IL-2RAs were associated with lower risk of serious opportunistic infections (OR: 0.41, 95% CI: 0.34-0.49; p < 0.0001), bacterial infections (OR: 0.51, 95% CI: 0.39-0.67; p < 0.0001) and CMV disease (OR: 0.58, 95% CI: 0.34-0.98; p = 0.043). Results remained consistent across allografts.

CONCLUSION

The risk of serious opportunistic infections, bacterial infections and CMV disease were all significantly decreased with IL-2RAs compared to polyclonal antibodies.

Maintenance immunosuppression in renal transplantation

The need to maintain allograft recipients on immunosuppression is nearly universal. Immunosuppressive agents used in organ transplantation target one or more steps of the host alloimmune response, specifically processes related to CD4-positive T lymphocytes. Calcineurin-inhibitor based steroid-containing regimens have been the mainstay of maintenance immunosuppression over the last two decades. Newer agents have shown efficacy in this role in recent trials with comparable allograft and patient outcomes. These agents have permitted calcineurin-inhibitor minimization and steroid-sparing strategies in selected groups of patients.

High incidence of rejection episodes and poor tolerance of sirolimus in a protocol with early steroid withdrawal and calcineurin inhibitor-free maintenance therapy in renal transplantation: experiences of a randomized prospective single-center study

Immunosuppressive maintenance therapy after kidney transplantation leads to various undesired side effects such as calcineurin inhibitor (CNI)-associated nephrotoxicity or elevated cardiovascular risk due to posttransplantation diabetes and hypertension. These effects show negative impacts on long-term allograft function as well as patient morbidity and mortality. Therefore, we used an immunosuppressive regimen with early corticosteroid withdrawal (ESW), maintenance therapy containing tacrolimus, sirolimus (SRL), and mycophenolate sodium for 3 months followed by a prospective randomized trial comparing a CNI free versus a low-dose CNI therapy. The primary endpoint was 6-month graft function. Among 75 patients, ESW was performed after 4 days in 65 patients. Over the following 3 months before randomization to CNI-free maintenance therapy, we experienced a high number (25%) of SRL discontinuations due to adverse events, including leukopenia, anemia, arthritis, and pneumonitis. In addition there were significantly more allograft rejection episodes in the CNI-free group (P = .017) during the study period leading to a switch from SRL to a CNI. Despite the higher rate of rejection episodes in the CNI-free groups, glomerular filtration rates (GFR) at 6 months were comparable between the study groups (P = .25). After 1 year only 9.2% (6/65) of all patients treated with SRL remained on this drug. Conclusion, there was an unacceptably high rate of SRL intolerance using an ESW and CNI-free immunosuppressive regimen combined with a significantly higher rate of rejection episodes.

Immunosuppressive regimen and interstitial fibrosis and tubules atrophy at 12 months postrenal transplant

BACKGROUND AND OBJECTIVES

Chronic renal transplant dysfunction is histopathologically characterized by interstitial fibrosis and tubular atrophy. This study investigated the relative contribution of baseline donor, recipient, and transplant characteristics to interstitial fibrosis and tubular atrophy score at month 12 after renal transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective study includes all 109 consecutive recipients with adequate implantation and month 12 biopsies transplanted between April of 2003 and February of 2007. Immunosuppression regimen was tacrolimus and steroids (10 days) plus either sirolimus or mycophenolate mofetil.

RESULTS

Average interstitial fibrosis and tubular atrophy score increased from 0.70 to 1.65 (P<0.001). In an adjusted multiple linear regression analysis, interstitial fibrosis and tubular atrophy score at month 12 was significantly related to donor type (donors after cardiac death versus living donor had interstitial fibrosis and tubular atrophy score+0.41, 95% confidence interval=0.05-0.76, P=0.02), baseline interstitial fibrosis and tubular atrophy, and immunosuppression regimen. Because of interaction between the latter two variables (P=0.002), results are given separately: recipients with a baseline interstitial fibrosis and tubular atrophy score of zero had a 0.60 higher score at month 12 (95% confidence interval=0.09-1.10, P=0.02) when mycophenolate mofetil-treated, whereas recipients with a baseline interstitial fibrosis and tubular atrophy score more than zero had a 0.38 higher score at month 12 (95% confidence interval=0.01-0.74, P=0.04) when sirolimus-treated. A higher score at month 12 correlated with a lower estimated GFR (ρ=-0.45, P<0.001).

CONCLUSIONS

These findings suggest that histologic assessment of a preimplantation biopsy may guide choice of immunosuppresion to maximize transplant survival and its interaction with type of immunosuppression.

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.

Early loss of peritubular capillaries after kidney transplantation

Inflammation, interstitial fibrosis (IF), and tubular atrophy (TA) precede chronic transplant dysfunction, which is a major cause of renal allograft loss. There is an association between IF/TA and loss of peritubular capillaries (PTCs) in advanced renal disease, but whether PTC loss occurs in an early stage of chronic transplant dysfunction is unknown. Here, we studied PTC number, IF/TA, inflammation, and renal function in 48 patients who underwent protocol biopsies. Compared with before transplantation, there was a statistically significant loss of PTCs by 3 months after transplantation. Fewer PTCs in the 3-month biopsy correlated with high IF/TA and inflammation scores and predicted lower renal function at 1 year. Predictors of PTC loss during the first 3 months after transplantation included donor type, rejection, donor age, and the number of PTCs at the time of implantation. In conclusion, PTC loss occurs during the first 3 months after renal transplantation, associates with increased IF and TA, and predicts reduced renal function.

Use of kidney function end points in kidney transplant trials: a systematic review

BACKGROUND

Clinical trials in kidney transplantation are beginning to include markers of kidney function as end points now that traditional outcomes, such as acute rejection, become increasingly rare events. The frequency and type of kidney function end points used are unknown.

STUDY DESIGN

Systematic review.

SETTING & POPULATION

Randomized controlled trials in adult kidney transplant recipients reported in 5 major general medical journals and 5 major subspecialty journals in nephrology and transplantation between January 2003 and November 2008.

SELECTION CRITERIA

Inclusion of at least one kidney function end point at least 1 month posttransplant.

RESULTS

133 (79%) of 169 randomized trials identified used a kidney function end point. Of these, 37 (28%) used one or more measures of kidney function as the primary end point, and 81 (61%), as a secondary end point. For the primary end point, 21 (57%) trials used a creatinine-based estimated glomerular filtration rate (eGFR), 18 (49%) used serum creatinine level, and 7 (19%) used measured GFR. Overall, eGFR was an end point in 81 (61%) trials, and measured GFR, in 12 (9%) trials.

LIMITATIONS

This review is limited by the poor quality of the included trials, with many not defining either primary or secondary end points.

CONCLUSIONS

Measures of kidney function are used commonly as surrogate end points in kidney transplant trials, with eGFR becoming more frequently used over time. Further data are needed to properly validate these surrogate end points and fully understand their limitations when designing and interpreting randomized trials.

{beta}-Cell secretory capacity and demand in recipients of islet, pancreas, and kidney transplants

CONTEXT

beta-Cell secretory capacity, a measure of functional beta-cell mass, is often impaired in islet transplant recipients, likely because of a low engrafted beta-cell mass, although calcineurin inhibitor toxicity is often cited as the explanation.

OBJECTIVE

We sought to determine whether use of the calcineurin inhibitor tacrolimus was associated with reduced beta-cell secretory capacity or with increased beta-cell secretory demand independent of engrafted islet mass.

DESIGN AND PARTICIPANTS

We compared metabolic measures in five intraportal islet recipients vs. 10 normal controls and in seven portally-drained pancreas-kidney and eight nondiabetic kidney recipients vs. nine kidney donor controls. All transplant groups received comparable exposure to tacrolimus, and each transplant group was matched for kidney function to its respective control group.

INTERVENTION AND MAIN OUTCOME MEASURES

All participants underwent glucose-potentiated arginine testing where acute insulin responses to arginine (5 g) were determined under fasting (AIR(arg)), 230 mg/dl (AIR(pot)), and 340 mg/dl (AIR(max)) clamp conditions, and AIR(max) gives the beta-cell secretory capacity. Insulin sensitivity (M/I) and proinsulin secretory ratios (PISRs) were assessed to determine whether tacrolimus increased beta-cell secretory demand.

RESULTS

Insulin responses were significantly lower than normal in the islet group for AIR(arg) (P < 0.05), AIR(pot) (P < 0.01), and AIR(max) (P < 0.01), whereas responses in the pancreas-kidney and kidney transplant groups were not different than in the kidney donor group. M/I and PISRs were not different in any of the transplant vs. control groups.

CONCLUSIONS

Impaired beta-cell secretory capacity in islet transplantation is best explained by a low engrafted beta-cell mass and not by a deleterious effect of tacrolimus.

Interleukin 2 receptor antagonists for kidney transplant recipients

BACKGROUND

Interleukin 2 receptor antagonists (IL2Ra) are used as induction therapy for prophylaxis against acute rejection in kidney transplant recipients. Use of IL2Ra has increased steadily since their introduction, but the proportion of new transplant recipients receiving IL2Ra differs around the globe, with 27% of new kidney transplant recipients in the United States, and 70% in Australasia receiving IL2Ra in 2007.

OBJECTIVES

To systematically identify and summarise the effects of using an IL2Ra, as an addition to standard therapy, or as an alternative to another immunosuppressive induction strategy.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE to identify new records, and authors of included reports were contacted for clarification where necessary.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in all languages comparing IL2Ra to placebo, no treatment, other IL2Ra or other antibody therapy.

DATA COLLECTION AND ANALYSIS

Data was extracted and assessed independently by two authors, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 71 studies (306 reports, 10,537 participants). Where IL2Ra were compared with placebo (32 studies; 5,784 patients) graft loss including death with a functioning graft was reduced by 25% at six months (16 studies: RR 0.75, 95% CI 0.58 to 0.98) and one year (24 studies: RR 0.75, 95% CI 0.62 to 0.90), but not beyond this. At one year biopsy-proven acute rejection was reduced by 28% (14 studies: RR 0.72, 95% CI 0.64 to 0.81), and there was a 19% reduction in CMV disease (13 studies: RR 0.81, 95% CI 0.68 to 0.97). There was a 64% reduction in early malignancy within six months (8 studies: RR 0.36, 95% CI 0.15 to 0.86), and creatinine was lower (7 studies: MD -8.18 micromol/L 95% CI -14.28 to -2.09) but these differences were not sustained.When IL2Ra were compared to ATG (16 studies, 2211 participants), there was no difference in graft loss at any time point, or for acute rejection diagnosed clinically, but the was benefit of ATG therapy over IL2Ra for biopsy-proven acute rejection at one year (8 studies:, RR 1.30 95% CI 1.01 to 1.67), but at the cost of a 75% increase in malignancy (7 studies: RR 0.25 95% CI 0.07 to 0.87) and a 32% increase in CMV disease (13 studies: RR 0.68 95% CI 0.50 to 0.93). Serum creatinine was significantly lower for IL2Ra treated patients at six months (4 studies: MD -11.20 micromol/L 95% CI -19.94 to -2.09). ATG patients experienced significantly more fever, cytokine release syndrome and other adverse reactions to drug administration and more leucopenia but not thrombocytopenia. There were no significant differences in outcomes according to cyclosporine or tacrolimus use, azathioprine or mycophenolate, or to the study populations baseline risk for acute rejection. There was no evidence that effects were different according to whether equine or rabbit ATG was used.

AUTHORS' CONCLUSIONS

Given a 38% risk of rejection, per 100 recipients compared with no treatment, nine recipients would need treatment with IL2Ra to prevent one recipient having rejection, 42 to prevent one graft loss, and 38 to prevent one having CMV disease over the first year post-transplantation. Compared with ATG treatment, ATG may prevent some experiencing acute rejection, but 16 recipients would need IL2Ra to prevent one having CMV, but 58 would need IL2Ra to prevent one having malignancy. There are no apparent differences between basiliximab and daclizumab. IL2Ra are as effective as other antibody therapies and with significantly fewer side effects.

Efficacy on renal function of early conversion from cyclosporine to sirolimus 3 months after renal transplantation: concept study

Sirolimus (SRL) allows to minimize the use of cyclosporine (CsA), but de novo administration after transplantation is associated with various complications. We report a prospective, open-label, multicenter randomized study to evaluate conversion from a CsA-based regimen to a SRL-based regimen 3 months after transplantation. One hundred ninety-two of a total of 237 patients were eligible at 3 months to be converted to SRL (n = 95) or to continue CsA (n = 97). All patients were also given mycophenolate mofetil (MMF) and oral steroids, planned to be discontinued at month 8. The primary endpoint, the clearance estimated according to Cockcroft and Gault at week 52, was significantly better in the SRL group (68.9 vs. 64.4 mL/min, p = 0.017). Patient and graft survival were not statistically different. The incidence of acute rejection episodes, mainly occurring after withdrawal of steroids, was numerically but not statistically higher in the SRL group (17% vs. 8%, p = 0.071). Sixteen patients discontinued SRL, mainly for adverse events (n = 11), and seven patients discontinued CsA for renal failure or acute rejection. Significantly, more patients in the SRL group reported aphthous, diarrhea, acne and high triglyceride levels. Conversion CsA to SRL 3 months after transplantation combined with MMF is associated with improvement in renal function.

Intermediate-term outcomes with early steroid withdrawal in African-American renal transplant recipients undergoing surveillance biopsy

BACKGROUND

There is a paucity of data regarding the use of early corticosteroid withdrawal (ESW) in African-American renal allograft recipients, and very few reports with >or=1 year follow-up in all patients.

METHODS

We examined the outcomes of 57 African-American renal allograft recipients with minimum follow-up 12 months who did not receive maintenance steroids after day 4 posttransplant. All patients received thymoglobulin induction, mycophenolate mofetil, and initial tacrolimus (n = 48) or sirolimus (n = 9).

RESULTS

Patient and graft survival were 98% and 96% at 1 year, and 95% and 89% over the entire follow-up period (mean, 23 +/- 8 months). Incidence of acute rejection and cytomegalovirus infection were 18% and 7%, respectively, with mean serum creatinine 1.6 +/- 0.5 and 1.7 +/- 0.9 mg/dL at 6 and 12 months. Of patients with functioning grafts, 84% remained steroid free at 1 year, of which 11 (24%) were also calcineurin inhibitor free. Twenty-seven patients underwent surveillance biopsy at 1 month and 28 at 12 months, with 15 surveyed at both time points. There were significant increases in only 2 of the 6 1997 Banff chronic allograft nephropathy (CAN) category scores in this subgroup, with all mean values remaining <1 (mild in severity) at 1 year. Overall, from 82% to 96% of the 12-month scores were <or=1 in all categories for 28 patients; only 3 patients (11%) had interstitial fibrosis and tubular atrophy scores at least moderate in severity. We did not observe any cases of subclinical acute rejection.

CONCLUSIONS

Our findings suggest that ESW in African-American renal allograft recipients with multiple high-risk factors can produce excellent intermediate-term antirejection and graft functional outcomes with minimal development of CAN at 12 months. Our results will need to be verified in larger numbers of patients with longer follow-up.