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

Delayed initiation or reduced initial dose of calcineurin-inhibitors for kidney transplant recipients at high risk of delayed graft function

BACKGROUND

Kidney transplantation is the preferred therapy for many patients with kidney failure. Delayed graft function (DGF) is more common in donors after cardiac death (DCD), especially those with older age, longer cold ischemia time, or higher creatinine levels. Currently, there is no agreement on the optimal immunosuppressive approach for patients at increased risk of DGF. Strategies include delaying the introduction of calcineurin inhibitors (CNI) or using an initial low dose of CNI.

OBJECTIVES

To evaluate the benefits and harms of delayed initiation of CNI or reduced CNI dose as initial immunosuppression therapy for kidney transplant recipients at high risk of DGF.

SEARCH METHODS

The Cochrane Kidney and Transplant Register of Studies was searched up to 11 December 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs evaluating delayed versus early initiation of CNI or reduced versus standard initial dose of CNI in kidney transplant recipients at high risk of DGF.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed study eligibility, and two assessed the risk of bias, certainty of evidence, extracted the data, and performed the analysis. Results were reported as risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes and as mean difference (MD) with 95% CI for continuous outcomes. Statistical analysis was performed using the random-effects model. Risk of bias was assessed with the Cochrane risk of bias assessment tool 1.0, and the certainty of the evidence according to the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) methods, which are presented in the summary of findings tables.

MAIN RESULTS

We included 12 studies (2230 randomised participants). All studies were performed in Europe. Around 60% of the participants were males, reflecting the expected proportion in the population on kidney replacement therapy in Europe. Most studies had insufficient information to judge adequate random sequence generation and, or allocation concealment. All studies were unblinded, and judged as high risk of bias for DGF if the definition was based on need for dialysis, and for acute rejection if the diagnosis did not require a biopsy. Overall, the level of certainty was low, and reasons to downgrade were mainly due to risk of bias and imprecision. Delayed versus early initiation of CNI There may be little or no difference in DGF between the groups (6 studies, 905 recipients: RR 0.92, 95% CI 0.76 to 1.12; low certainty evidence) or in acute rejection (8 studies, 1295 recipients: RR 1.02, 95% CI 0.75 to 1.40; low certainty evidence). Delaying the initiation of CNI probably makes little or no difference to eGFR (6 studies, 851 recipients: MD -0.81 mL/min, 95% CI -3.33 to 1.72; moderate certainty evidence). Delaying the initiation of CNI may make little or no difference to graft loss censored for death (8 studies, 1295 recipients: RR 1.58, 95% CI 0.68 to 3.65; very low certainty evidence) or to all-cause death (8 studies, 907 recipients: RR 1.08, 95% CI 0.54 to 2.14; very low certainty evidence) although the evidence is very uncertain. There is probably little or no difference in all infections between the groups (6 studies, 1226 recipients: RR 1.10, 95% CI 0.97 to 1.25; moderate certainty evidence). Low versus standard initial dose of CNI There may be little or no difference to DGF between the groups (5 studies, 983 recipients: RR 1.16, 95% CI 0.90 to 1.50; low certainty evidence) or in acute rejection (5 studies, 947 recipients: RR 0.83, 95% CI 0.52 to 1.30; low certainty evidence). Starting CNI at a lower dose may make little or no difference to eGFR (5 studies, 935 recipients: MD 4.06 mL/min, 95% CI -1.36 to 9.48, low certainty evidence). Starting CNI at a lower dose may make little or no difference to graft loss censored for death, although the evidence is very uncertain (5 studies, 983 recipients: RR 1.05, 95% CI 0.64 to 1.71; very low certainty evidence), or to all-cause death (4 studies, 521 recipients: RR 1.01, 95% CI 0.41 to 2.47; low certainty evidence). There is probably little or no difference in all infections between the groups (4 studies, 828 recipients: RR 0.87, 95% CI 0.71 to 1.07; moderate certainty evidence).

AUTHORS' CONCLUSIONS

There may be little or no difference in DGF or acute rejection when delaying the start of CNI or when starting it at a lower dose in kidney transplant recipients at high risk of DGF. The available data are of low certainty.

Differential Impact of Delayed Graft Function in Deceased Donor Renal Transplant Recipients With and Without Donor-specific HLA-antibodies

BACKGROUND

Delayed graft function (DGF) and pretransplant donor-specific HLA-antibodies (DSA) are both regarded as risk factors for rejection and lower graft survival. However, the combined impact of DGF and DSA has not been studied in detail.

METHODS

We investigated 375 deceased donor kidney transplantations, which had DSA assignment by single-antigen bead technology and which had surveillance biopsies at 3 of 6 months. Median follow-up time was 6.1 years.

RESULTS

DGF occurred in 137 of 375 patients (37%), and DSA were present in 85 of 375 patients (23%). The incidence of DGF was similar in DSA-positive (DSApos)-patients and DSA-negative (DSAneg)-patients (40% versus 36%; P = 0.45). In DSAneg-patients, 5-year graft survival was not different with/without DGF (81% versus 83%; P = 0.48). By contrast, in DSApos-patients, 5-year graft survival was significantly lower with DGF (64% versus 79%; P = 0.01). Moreover, DSApos-patients with DGF had a higher 1-year incidence of subclinical rejection, which were mostly antibody-mediated or mixed rejection phenotypes. Graft loss due to rejection was significantly more frequent in DSApos-patients with DGF (5/34; 15%) compared to DSApos-patients without DGF (2/51; 4%), and DSAneg-patients with/without DGF (3/103; 3% and 4/187; 2%, respectively) (P = 0.005). In a multivariate Cox model, DSA with DGF was an independent predictor for graft (hazard ratio = 2.84 [95% confidence interval, 1.54-5.06]; P = 0.001) and death-censored graft loss (hazard ratio = 4.65 [95% confidence interval, 1.83-11.51]; P = 0.002).

CONCLUSIONS

DGF has a much more detrimental impact in DSApos-patients than in DSAneg-patients, which is likely related to a higher incidence of antibody-mediated rejection. If possible, the combined risks of DGF and DSA should be avoided.

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.

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.

Metabolic consequences of modern immunosuppressive agents in solid organ transplantation

Among other factors, sophistication of immunosuppressive (IS) regimen accounts for the remarkable success attained in the short- and medium-term solid organ transplant (SOT) survival. The use of steroids, mycophenolate mofetil and calcineurin inhibitors (CNI) have led to annual renal graft survival rates exceeding 90% in the last six decades. On the other hand, attrition rates of the allograft beyond the first year have remained unchanged. In addition, there is a persistent high cardiovascular (CV) mortality rate among transplant recipients with functioning grafts. These shortcomings are in part due to the metabolic effects of steroids, CNI and sirolimus (SRL), all of which are implicated in hypertension, new onset diabetes after transplant (NODAT), and dyslipidemia. In a bid to reduce the required amount of harmful maintenance agents, T-cell-depleting antibodies are increasingly used for induction therapy. The downsides to their use are greater incidence of opportunistic viral infections and malignancy. On the other hand, inadequate immunosuppression causes recurrent rejection episodes and therefore early-onset chronic allograft dysfunction. In addition to the adverse metabolic effects of the steroid rescue needed in these settings, the generated proinflammatory milieu may promote accelerated atherosclerotic disorders, thus setting up a vicious cycle. The recent availability of newer agent, belatacept holds a promise in reducing the incidence of metabolic disorders and hopefully its long-term CV consequences. Although therapeutic drug monitoring as applied to CNI may be helpful, pharmacodynamic tools are needed to promote a customized selection of IS agents that offer the most benefit to an individual without jeopardizing the allograft survival.

Molecular pathways and therapies in autosomal-dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease (ADPKD) is the most prevalent inherited renal disease, characterized by multiple cysts that can eventually lead to kidney failure. Studies investigating the role of primary cilia and polycystins have significantly advanced our understanding of the pathogenesis of PKD. This review will present clinical and basic aspects of ADPKD, review current concepts of PKD pathogenesis, evaluate potential therapeutic targets, and highlight challenges for future clinical studies.

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.