Belatacept-versus cyclosporine-based immunosuppression in renal transplant recipients with pre-existing diabetes

Pancreatic β-cell mitophagy as an adaptive response to metabolic stress and the underlying mechanism that involves lysosomal Ca2+ release

Mitophagy is an excellent example of selective autophagy that eliminates damaged or dysfunctional mitochondria, and it is crucial for the maintenance of mitochondrial integrity and function. The critical roles of autophagy in pancreatic β-cell structure and function have been clearly shown. Furthermore, morphological abnormalities and decreased function of mitochondria have been observed in autophagy-deficient β-cells, suggesting the importance of β-cell mitophagy. However, the role of authentic mitophagy in β-cell function has not been clearly demonstrated, as mice with pancreatic β-cell-specific disruption of Parkin, one of the most important players in mitophagy, did not exhibit apparent abnormalities in β-cell function or glucose homeostasis. Instead, the role of mitophagy in pancreatic β-cells has been investigated using β-cell-specific Tfeb-knockout mice (TfebΔβ-cell mice); Tfeb is a master regulator of lysosomal biogenesis or autophagy gene expression and participates in mitophagy. TfebΔβ-cell mice were unable to adaptively increase mitophagy or mitochondrial complex activity in response to high-fat diet (HFD)-induced metabolic stress. Consequently, TfebΔβ-cell mice exhibited impaired β-cell responses and further exacerbated metabolic deterioration after HFD feeding. TFEB was activated by mitochondrial or metabolic stress-induced lysosomal Ca2+ release, which led to calcineurin activation and mitophagy. After lysosomal Ca2+ release, depleted lysosomal Ca2+ stores were replenished by ER Ca2+ through ER→lysosomal Ca2+ refilling, which supplemented the low lysosomal Ca2+ capacity. The importance of mitophagy in β-cell function was also demonstrated in mice that developed β-cell dysfunction and glucose intolerance after treatment with a calcineurin inhibitor that hampered TFEB activation and mitophagy.

Assessment of Renal Transplant Perfusion by Contrast-Enhanced Ultrasound after Switch from Calcineurin Inhibitor to Belatacept: A Pilot Study

Calcineurin inhibitors (CNIs) have improved short-term kidney allograft survival but are nephrotoxic and vasoconstrictive. Vasoconstriction is potentially reversible after switching from CNIs to belatacept. The kidney allograft shows optimal requirements for dynamic perfusion imaging using contrast-enhanced ultrasound (CEUS). We performed standardized CEUS in patients after switching from CNIs to belatacept for clinical indication to study the suitability of CEUS, in order to assess the effects of CNI cessation on kidney allograft perfusion. Eleven kidney transplant patients were enrolled from February 2020 until November 2020. Demographic, clinical, and laboratory parameters, as well as perfusion imaging, were assessed at baseline and 6 months after switching immunosuppression. Quantification of perfusion imaging on CEUS was performed using a post-processing software tool on uncompressed DICOM cine loops. After CNI cessation, estimated glomerular filtration rate increased by 4.8 mL/min/1.73 m² (16%). Despite good quality of fit and comparable regions of interest in baseline and follow-up CEUS examinations, quantification of perfusion imaging showed a slightly improved cortical perfusion without reaching statistical significance after CNI cessation. This is the first study that systematically investigates the suitability of CEUS to detect changes of microvascular perfusion in kidney transplant recipients in vivo. No significant differences could be detected in perfusion measurements before and after CNI cessation.

pre-existing diabetes and PTDM in kidney transplant recipients: how to handle immunosuppression

INTRODUCTION

Preexisting diabetes (PD) and post-transplant diabetes mellitus (PTDM) are common and severe comorbidities posttransplantation. The immunosuppressive regimens are modifiable risk factors.

AREAS COVERED

We reviewed Pubmed and Cochrane database and we summarize the mechanisms and impacts of available immunosuppressive treatments on the risk of PD and PTDM. We also assess the possible management of these drugs to improve glycemic parameters while considering risks inherent in transplantation.

EXPERT OPINION

PD i) increases the risk of sepsis, ii) is an independent risk factor for infection-related mortality, and iii) increases acute rejection risk. Regarding PTDM development i) immunosuppressive strategies without corticosteroids significantly reduce the risk but the price may be a higher incidence of rejection; ii) minimization or rapid withdrawal of steroids are two valuable approaches; iii) the diabetogenic role of calcineurin inhibitors(CNIs) is also well-described and is more important for tacrolimus than for cyclosporine. Reducing tacrolimus-exposure may improve glycemic parameters but also has a higher risk of rejection. PTDM risk is higher in patients that receive sirolimus compared to mycophenolate mofetil. Finally, conversion from CNIs to belatacept may offer the best benefits to PTDM-recipients in terms of glycemic parameters, graft and patient-outcomes.

Conversion From Belatacept to Another Immunosuppressive Regimen in Maintenance Kidney-Transplantation Patients

Introduction

During the coronavirus disease 2019 (Covid-19) pandemic, several physicians have questioned pursuing belatacept in kidney-transplant patients in order to reduce the risk of nosocomial transmission during the monthly infusion. The effect of the conversion from belatacept to another immunosuppressive regimen is underreported. The aim of the present retrospective study was to assess the effect on kidney function and the clinical outcome of the conversion from belatacept to another regimen.

Methods

We have identified 44 maintenance kidney transplantation patients from five French kidney transplantation centers who were converted from belatacept to another regimen either because of a complication (n = 28) or another reason (patients’ request or belatacept shortage, n = 13). The follow-up after the conversion from belatacept was 27.5 ± 25.3 months.

Results

Overall, mean estimated glomerular filtration rate (eGFR) decreased from 44.2 ± 16 ml/min per 1.73 m² at conversion from belatacept to 35.7 ± 18.4 ml/min per 1.73 m² at last follow-up (P = 0.0002). eGFR significantly decreased in patients who had been given belatacept at transplantation as well as in those who had been converted to belatacept earlier. The decrease was less significant in patients who had stopped belatacept without having experienced any complications. Finally, eGFR decreased more severely in patients who were converted to calcineurin inhibitors (CNIs), compared to those who received mammalian target of rapamycin inhibitor (mTORi). Few patients also developed diabetes and hypertension.

Conclusions

Thus, transplantation physicians should avoid stopping belatacept when not clinically required.

Metabolic Disorders with Kidney Transplant

Metabolic disorders are highly prevalent in kidney transplant candidates and recipients and can adversely affect post-transplant graft outcomes. Management of diabetes, hyperparathyroidism, and obesity presents distinct opportunities to optimize patients both before and after transplant as well as the ability to track objective data over time to assess a patient's ability to partner effectively with the health care team and adhere to complex treatment regimens. Optimization of these particular disorders can most dramatically decrease the risk of surgical and cardiovascular complications post-transplant. Approximately 60% of nondiabetic patients experience hyperglycemia in the immediate post-transplant phase. Multiple risk factors have been identified related to development of new onset diabetes after transplant, and it is estimated that upward of 7%-30% of patients will develop new onset diabetes within the first year post-transplant. There are a number of medications studied in the kidney transplant population for diabetes management, and recent data and the risks and benefits of each regimen should be optimized. Secondary hyperparathyroidism occurs in most patients with CKD and can persist after kidney transplant in up to 66% of patients, despite an initial decrease in parathyroid hormone levels. Parathyroidectomy and medical management are the options for treatment of secondary hyperparathyroidism, but there is no randomized, controlled trial providing clear recommendations for optimal management, and patient-specific factors should be considered. Obesity is the most common metabolic disorder affecting the transplant population in both the pre- and post-transplant phases of care. Not only does obesity have associations and interactions with comorbid illnesses, such as diabetes, dyslipidemia, and cardiovascular disease, all of which increase morbidity and mortality post-transplant, but it also is intimately inter-related with access to transplantation for patients with kidney failure. We review these metabolic disorders and their management, including data in patients with kidney transplants.

Improved Glucose Tolerance in a Kidney Transplant Recipient With Type 2 Diabetes Mellitus After Switching From Tacrolimus To Belatacept: A Case Report and Review of Potential Mechanisms

Supplemental digital content is available in the text.

The introduction of immunosuppressant belatacept, an inhibitor of the CD28-80/86 pathway, has improved 1-year outcomes in kidney transplant recipients with preexistent diabetes mellitus and has also reduced the risk of posttransplant diabetes mellitus. So far, no studies have compared a tacrolimus-based with a belatacept-based immunosuppressive regimen with regard to improving glucose tolerance after kidney transplantation. Here, we present the case of a 54-year-old man with type 2 diabetes mellitus who was converted from belatacept to tacrolimus 1 year after a successful kidney transplantation. Thereafter, he quickly developed severe hyperglycemia, and administration of insulin was needed to improve metabolic control. Six months after this episode, he was converted back to belatacept because of nausea, diarrhea, and hyperglycemia. After switching back to belatacept and within 4 days after stopping tacrolimus glucose tolerance improved and insulin therapy could be discontinued. Although belatacept is considered less diabetogenic than tacrolimus, the rapid improvement of glucose tolerance after switching to belatacept is remarkable. In this article, the potential mechanisms of this observation are discussed.

Successful Treatment of T Cell-Mediated Acute Rejection with Delayed CTLA4-Ig in Mice

Clinical observations that kidney transplant recipients receiving belatacept who experienced T cell-mediated acute rejection can be successfully treated and subsequently maintained on belatacept-based immunosuppression suggest that belatacept is able to control memory T cells. We recently reported that treatment with CTLA4-Ig from day 6 posttransplantation successfully rescues allografts from acute rejection in a BALB/c to C57BL/6 heart transplant model, in part, by abolishing B cell germinal centers and reducing alloantibody titers. Here, we show that CTLA4-Ig is additionally able to inhibit established T cell responses independently of B cells. CTLA4-Ig inhibited the in vivo cytolytic activity of donor-specific CD8⁺ T cells, and the production of IFNγ by graft-infiltrating T cells. Delayed CTLA4-Ig treatment did not reduce the numbers of graft-infiltrating T cells nor prevented the accumulation of antigen-experienced donor-specific memory T cells in the spleen. Nevertheless, delayed CTLA4-Ig treatment successfully maintained long-term graft acceptance in the majority of recipients that had experienced a rejection crisis, and enabled the acceptance of secondary BALB/c heart grafts transplanted 30 days after the first transplantation. In summary, we conclude that delayed CTLA4-Ig treatment is able to partially halt ongoing T cell-mediated acute rejection. These findings extend the functional efficacy of CTLA4-Ig therapy to effector T cells and provide an explanation for why CTLA4-Ig-based immunosuppression in the clinic successfully maintains long-term graft survival after T cell-mediated rejection.

Belatacept Conversion in an HIV-Positive Kidney Transplant Recipient With Prolonged Delayed Graft Function

We report an HIV-positive renal transplant recipient with delayed graft function who was converted from tacrolimus to belatacept in an attempt to improve renal function. The patient had kidney biopsies at 4 and 8 weeks posttransplant that revealed acute tubular necrosis and mild fibrosis. After 14 weeks of delayed function, belatacept was initiated and tacrolimus was weaned off. Shortly after discontinuing tacrolimus, renal function began to improve. The patient was able to discontinue dialysis 21 weeks posttransplant. HIV viral load was undetectable at last follow-up. To our knowledge, this is the first report of belatacept use in a patient with HIV.

Immunosuppression for kidney transplantation: Where are we now and where are we going?

Advances in immunosuppression have propelled kidney transplantation from a scientific curiosity to the optimal treatment for patients with end stage kidney disease. Declining rates of acute rejection have led to improvements in short term kidney transplant survival, culminating in incrementally better long term patient and allograft outcomes. Contextualized around established immune-suppressing drug targets, this review summarizes the history of the clinical science and highlights the pivotal trials that have led to present-day treatment standards at the level of both individual agents and multidrug regimens for kidney recipients. Finally, recently approved and emerging therapies are discussed, with an emphasis on challenges faced by clinicians managing this increasingly complex patient population.

Belatacept for the prophylaxis of organ rejection in kidney transplant patients: an evidence-based review of its place in therapy

Background

Belatacept is a novel immunosuppressive therapy designed to improve clinical outcomes associated with kidney transplant recipients while minimizing use of calcineurin inhibitors (CNIs).

Methods

We searched for clinical trials related to administration of belatacept to kidney transplant patients compared to various immunosuppression regimens, as well as for studies that utilized data from belatacept trials to validate new surrogate measures. The purpose of this review is to consolidate the published evidence of belatacept’s effectiveness and safety in renal transplant recipients to better elucidate its place in clinical practice.

Results

Analysis of the results from the Belatacept Evaluation of Nephroprotection and Effi-cacy as First-Line Immunosuppressive Trial (BENEFIT) study, a de novo trial that compared cyclosporine (CsA)-based therapy to belatacept-based therapy in standard criteria donors, found a significant difference in mean estimated glomerular filtration rate (eGFR) of 13–15 mL/min/1.73 m² and 23–27 mL/min/1.73 m² at 1 year and 7 years, respectively. The BENEFIT-EXT study was similarly designed with the exception that it included extended criteria donors. Renal function improved significantly for the more intensive belatacept group in all years of the BENEFIT-EXT study; however, it was not significant in the less intensive group until 5 years after transplant. Belatacept regimens resulted in lower blood pressure, cholesterol levels, and incidence of new-onset diabetes after transplant compared to CsA-based regimens. Results from conversion of CNIs to belatacept therapy, dual therapy of belatacept with sirolimus, and belatacept with corticosteroid avoidance therapy are also included in this article.

Conclusion

The evidence reviewed in this article suggests that belatacept is an effective alternative in kidney transplant recipients. Compared to CNI-based therapy, belatacept-based therapy results in superior renal function and similar rates of allograft survival. In terms of safety, belatacept was shown to have lower incidence of hypertension, hyperlipidemia, and diabetes; however, incidence of posttransplantation lymphoproliferative disorder and the cost of belatacept may hinder use of this medication.

A safety evaluation of belatacept for the treatment of kidney transplant

INTRODUCTION

Improving long-term survival in kidney transplantation is one of the main goals in modern immunosuppressive research. Current standard immunosuppression based in a combination of calcineurin inhibitors (CNI) and antiproliferatives, with or without steroids, has improved short-term graft survival. In the last decade, belatacept has been evaluated as a CNI free option regimen addressing better kidney transplant outcomes.

AREAS COVERED

This paper reviewed the indications, mechanisms of action, pharmacology and published trials using belatacept in different clinical situations. The main objective was to evaluate the safety of this immunosuppressive drug.

EXPERT OPINION

Kidney transplant patients receiving belatacept demonstrated improvement in renal function, less chronic allograft nephropathy, a more favorable metabolic profile and lower donor-specific antibody formation compared with cyclosporine. Based on the published data and on our personal experience, we have good expectations on belatacept use in the future. If these characteristics will translate in sustained better renal function, less chronic kidney disease-related complications and lower cardiovascular risk, improving patient and graft survival and quality of life, is still to be assessed with longer term follow-up and a larger number of exposed patients.

Belatacept prophylaxis against organ rejection in adult kidney-transplant recipients

End-stage renal disease is a major health problem worldwide, with kidney transplantation being the treatment of choice. Calcineurin inhibitors are still the cornerstone of immunosuppressive therapy. However, they have well-known nephrotoxic affects and increase the risk of cardiovascular disease and cancer. In contrast, belatacept is a biological immunosuppressive agent that inhibits the T-cell co-stimulation. It is approved by the US Food and Drug Administration and the European Medicine Agency for use in adult kidney-transplant recipients to prevent acute rejection. Developmental studies show that belatacept is as efficient as calcineurin inhibitors at preventing acute rejection. In addition, kidney function is better and cardiovascular risk factors are reduced in patients given belatacept. Herein, the authors review the published evidence concerning the efficacy and safety of belatacept and discuss its potential specific indications.

The need for minimization strategies: current problems of immunosuppression

New immunosuppressants and the better use of immunosuppressant combination therapy have led to significant improvements in renal allograft outcomes over the last decades. Yet, despite dramatic reduction in rejection rates and improvement in 1-year graft survival, long-term graft attrition rates remained rather constant. Current immunosuppressant combinations are frequently leading to overimmunosuppression and are increasing cardiovascular risk. Importantly, calcineurin inhibitors are nephrotoxic, contribute to cardiovascular risk and chronic allograft dysfunction. Furthermore, immunosuppressant-associated toxicities aggravate immune-mediated nephron injury and side effects lead to nonadherence, an identified important reason for late acute and chronic antibody-mediated rejections. The frequent development of a chronic humoral response indicates rather insufficient immunosuppression of current combinations than simple under-immunosuppression. While there is no evidence that increasing immunosuppressive doses will improve outcomes or reduce de novo HLA-antibody formation, there is clear evidence that adequate minimization strategies will reduce side effect burden. Because of low rejection risk, but frequent side effects, drug minimization is particularly relevant for the many maintenance patients. In summary, new therapeutic strategies need to be developed from adequately powered clinical trials for reduction of the many side effects of immunosuppressants. Such evidence-based and time-dependent immunosuppressive minimization strategies are needed to achieve better long-term outcomes in the future.

Belatacept for kidney transplant recipients

BACKGROUND

Most people who receive a kidney transplant die from either cardiovascular disease or cancer before their transplant fails. The most common reason for someone with a kidney transplant to lose the function of their transplanted kidney necessitating return to dialysis is chronic kidney transplant scarring. Immunosuppressant drugs have side effects that increase risks of cardiovascular disease, cancer and chronic kidney transplant scarring. Belatacept may provide sufficient immunosuppression while avoiding unwanted side effects of other immunosuppressant drugs. However, high rates of post-transplant lymphoproliferative disease (PTLD) have been reported when belatacept is used in particular kidney transplant recipients at high dosage.

OBJECTIVES

1) Compare the relative efficacy of belatacept versus any other primary immunosuppression regimen for preventing acute rejection, maintaining kidney transplant function, and preventing death. 2) Compare the incidence of several adverse events: PTLD; other malignancies; chronic transplant kidney scarring (IF/TA); infections; change in blood pressure, lipid and blood sugar control. 3) Assess any variation in effects by study, intervention and recipient characteristics, including: differences in pre-transplant Epstein Barr virus serostatus; belatacept dosage; and donor-category (living, standard criteria deceased, or extended criteria deceased).

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 1 September 2014 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCT) that compared belatacept versus any other immunosuppression regimen in kidney transplant recipients were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data for study quality and transplant outcomes and synthesized results using random effects meta-analysis, expressed as risk ratios (RR) and mean differences (MD), both with 95% confidence intervals (CI).  Subgroup analyses and univariate meta-regression were used to investigate potential heterogeneity.

MAIN RESULTS

We included five studies that compared belatacept and calcineurin inhibitors (CNI) that reported data from a total of 1535 kidney transplant recipients. Of the five studies, three (478 participants) compared belatacept and cyclosporin and two (43 recipients) compared belatacept and tacrolimus. Co-interventions included basiliximab (4 studies, 1434 recipients); anti-thymocyte globulin (1 study, 89 recipients); alemtuzumab (1 study, 12 recipients); mycophenolate mofetil (MMF, 5 studies, 1509 recipients); sirolimus (1 study, 26 recipients) and prednisone (5 studies, 1535 recipients).Up to three years following transplant, belatacept and CNI-treated recipients were at similar risk of dying (4 studies, 1516 recipients: RR 0.75, 95% CI 0.39 to 1.44), losing their kidney transplant and returning to dialysis (4 studies, 1516 recipients: RR 0.91, 95% CI 0.61 to 1.38), and having an episode of acute rejection (4 studies, 1516 recipients: RR 1.56, 95% CI 0.85 to 2.86). Belatacept-treated kidney transplant recipients were 28% less likely to have chronic kidney scarring (3 studies, 1360 recipients: RR 0.72, 95% CI 0.55 to 0.94) and also had better graft function (measured glomerular filtration rate (GFR) (3 studies 1083 recipients): 10.89 mL/min/1.73 m², 95% CI 4.01 to 17.77; estimated GFR (4 studies, 1083 recipients): MD 9.96 mL/min/1.73 m², 95% CI 3.28 to 16.64) than CNI-treated recipients. Blood pressure was lower (systolic (2 studies, 658 recipients): MD -7.51 mm Hg, 95% CI -10.57 to -4.46; diastolic (2 studies, 658 recipients): MD -3.07 mm Hg, 95% CI -4.83 to -1.31, lipid profile was better (non-HDL (3 studies 1101 recipients): MD -12.25 mg/dL, 95% CI -17.93 to -6.57; triglycerides (3 studies 1101 recipients): MD -24.09 mg/dL, 95% CI -44.55 to -3.64), and incidence of new-onset diabetes after transplant was reduced by 39% (4 studies (1049 recipients): RR 0.61, 95% CI 0.40 to 0.93) among belatacept-treated versus CNI-treated recipients.Risk of PTLD was similar in belatacept and CNI-treated recipients (4 studies, 1516 recipients: RR 2.79, 95% CI 0.61 to 12.66) and was no different among recipients who received different belatacept dosages (high versus low dosage: ratio of risk ratios (RRR) 1.06, 95% CI 0.11 to 9.80, test of difference = 0.96) or among those who were Epstein Barr virus seronegative compared with those who were seropositive before their kidney transplant (seronegative versus seropositive; RRR 1.49, 95% CI 0.15 to 14.76, test for difference = 0.73).The belatacept dose used (high versus low), type of donor kidney the recipient received (extended versus standard criteria) and whether the kidney transplant recipient received tacrolimus or cyclosporin made no difference to kidney transplant survival, incidence of acute rejection or estimated GFR. Selective outcome reporting meant that data for some key subgroup comparisons were sparse and that estimates of the effect of treatment in these groups of recipients remain imprecise.

AUTHORS' CONCLUSIONS

There is no evidence of any difference in the effectiveness of belatacept and CNI in preventing acute rejection, graft loss and death, but treatment with belatacept is associated with less chronic kidney scarring and better kidney transplant function. Treatment with belatacept is also associated with better blood pressure and lipid profile and a lower incidence of diabetes versus treatment with a CNI. Important side effects (particularly PTLD) remain poorly reported and so the relative benefits and harms of using belatacept remain unclear. Whether short-term advantages of treatment with belatacept are maintained over the medium- to long-term or translate into better cardiovascular outcomes or longer kidney transplant survival with function remains unclear. Longer-term, fully reported and published studies comparing belatacept versus tacrolimus are needed to help clinicians decide which patients might benefit most from using belatacept.

Conversion from tacrolimus to belatacept to prevent the progression of chronic kidney disease in pancreas transplantation: case report of two patients

Belatacept is a novel immunosuppressive agent that may be used as an alternative to calcineurin inhibitors (CNI) in immunosuppression (IS) regimens. We report two cases of pancreas transplant that were switched from tacrolimus (TAC) to belatacept. Case 1: 38-year-old female with pancreas transplant alone maintained on TAC-based IS regimen whose serum creatinine (SCr) slowly deteriorated from 0.6 mg/dL at baseline to 2.2 mg/dL, 16 months posttransplant. A native kidney biopsy performed showed CNI toxicity. The patient was started on belatacept and TAC was eliminated. Case 2: 49-year-old female with simultaneous pancreas-kidney transplant, maintained on TAC-based regimen where the SCr worsened over an initial 3-month period from a baseline of 1.0 to 3.0 mg/dL. Belatacept was started and TAC was lowered. Due to persistent graft dysfunction and kidney transplant biopsy still showing changes consistent with CNI toxicity, the TAC was then discontinued. At >1 year postbelatacept and off TAC follow-up, kidney function as measured by SCr remains stable at 1.0±0.2 mg/dL in both recipients. Neither patient developed rejection following the switch, and pancreas allograft function remains stable in both recipients.

Tolerance--is it worth it?

We are entering an exciting time in the study of immunologic tolerance. Several cellular and molecular strategies have been developed that show promise in nonhuman transplant models and these approaches are just now appearing in clinical trials. Tolerance strategies that prevent immune rejection and obviate the need for immunosuppressive medications (with inherent risk of cancer, infection, and organ toxicity) would improve both graft and patient survival. Each tolerance protocol brings its own set of associated risks. As the results of these trials become available, we must continue to evaluate their successes and failures. The balance of these outcomes will help us answer the question: "Tolerance-Is it worth it?"

Novel immunosuppressive agents in kidney transplantation

Excellent outcomes have been achieved in the field of renal transplantation. A significant reduction in acute rejection has been attained at many renal transplant centers using contemporary immunosuppressive, consisting of an induction agent, a calcineurin inhibitor, an antiproliferative agent plus or minus a corticosteroid. Despite improvements with these regimens, chronic allograft injury and adverse events still persist. The perfect immunosuppressive regimen would limit or eliminate calcineurin inhibitors and/or corticosteroid toxicity while providing enhanced allograft outcomes. Potential improvements to the calcineurin inhibitor class include a prolonged release tacrolimus formulation and voclosporin, a cyclosporine analog. Belatacept has shown promise as an agent to replace calcineurin inhibitors. A novel, fully-human anti-CD40 monoclonal antibody, ASKP1240, is currently enrolling patients in phase 2 trials with calcineurin minimization and avoidance regimens. Another future goal of transplant immunosuppression is effective and safe treatment of allograft rejection. Novel treatments for antibody mediated rejection include bortezomib and eculizumab. Several investigational agents are no longer being pursed in transplantation including the induction agents, efalizumab and alefacept, and maintenance agents, sotrastaurin and tofacitinib. The purpose of this review is to consolidate the published evidence of the effectiveness and safety of investigational immunosuppressive agents in renal transplant recipients.

Corticosteroid and calcineurin inhibitor sparing regimens in kidney transplantation

Chronic kidney disease is a major public health problem that is associated with increased risks of kidney disease progression, cardiovascular disease and death. Kidney transplantation remains the renal replacement therapy of choice for patients with end-stage kidney disease. Despite impressive strides in short-term allograft survival, there has been little improvement in long-term kidney graft survival, and rates of death with a functioning allograft remain high. Long-term safety profiles of existing immunosuppressive regimens point to a need for continued search for alternative agents. This overview discusses emerging evidence on a few promising therapeutic approaches, juxtaposes conflicting findings and highlights remaining knowledge gaps.

Belatacept for prevention of acute rejection in adult patients who have had a kidney transplant: an update

In June 2011, the US Food and Drug Administration approved belatacept for the prophylaxis of organ rejection in adult kidney transplant recipients. This review discusses the use of belatacept for the prevention of acute rejection as part of a maintenance immunosuppression regimen. Belatacept is a selective costimulation blocker designed to provide effective immunosuppression while avoiding the toxicities associated with calcineurin inhibitors. Phase III trial data have demonstrated that belatacept is noninferior to cyclosporine in 1-year patient and allograft survival. Three-year data demonstrate an ongoing improvement in mean measured glomerular filtration rate in belatacept-treated versus cyclosporine-treated patients. However, the rate of acute rejection was higher in belatacept-treated patients compared with cyclosporine. Specifically, there was a higher incidence of Banff type II rejections in patients treated with belatacept. Despite the higher Banff grade, rejections on belatacept were not associated with other factors associated with poor outcomes, such as the development of donor-specific antibodies or reduced estimated glomerular filtration rate. One safety issue that must be considered when using belatacept is the potential for increased risk of post-transplant lymphoproliferative disease. There were more cases of post-transplant lymphoproliferative disease in belatacept-treated patients, especially in recipients seronegative for Epstein–Barr virus or patients treated with lymphocyte-depleting agents. Therefore, belatacept can be recommended for use in Epstein–Barr virus antibody-positive recipients.

CD28 family and chronic rejection: "to belatacept...And beyond!"

Kidneys are one of the most frequently transplanted human organs. Immunosuppressive agents may prevent or reverse most acute rejection episodes; however, the graft may still succumb to chronic rejection. The immunological response involved in the chronic rejection process depends on both innate and adaptive immune response. T lymphocytes have a pivotal role in chronic rejection in adaptive immune response. Meanwhile, we aim to present a general overview on the state-of-the-art knowledge of the strategies used for manipulating the lymphocyte activation mechanisms involved in allografts, with emphasis on T-lymphocyte costimulatory and coinhibitory molecules of the B7-CD28 superfamily. A deeper understanding of the structure and function of these molecules improves both the knowledge of the immune system itself and their potential action as rejection inducers or tolerance promoters. In this context, the central role played by CD28 family, especially the relationship between CD28 and CTLA-4, becomes an interesting target for the development of immune-based therapies aiming to increase the survival rate of allografts and to decrease autoimmune phenomena. Good results obtained by the recent development of abatacept and belatacept with potential clinical use aroused better expectations concerning the outcome of transplanted patients.

Belatacept : a new biological agent for maintenance immunosuppression in kidney transplantation

INTRODUCTION

Over the past decades, calcineurin inhibitors (CNIs) have become the cornerstone of transplant immunosuppression. CNIs can exert negative effects on chronic allograft function along with cardiovascular (CV) and metabolic adverse effects. Belatacept , a selective co-stimulation blocker of T cells, is the first US FDA (06/2011) and EMEA (06/2011) approved biologic agent for maintenance immunosuppression in renal transplantation.

AREAS COVERED

The authors critically reviewed the literature over the last few years comparing belatacept with current standard of maintenance immunosuppression including CNIs in kidney transplantation.

EXPERT OPINION

Despite the increased incidence and severity of acute rejection with belatacept in Phase II and III studies, a better preservation of GFR and reduced incidence of chronic allograft nephropathy was observed as compared with CNIs. Patient and graft survivals were similar over 3- and 5-year follow-up post-transplantation. Incidence of adverse events were similar between the groups, but the risk of post-transplant lymphoproliferative disorder, predominantly involving CNS, was higher in Epstein-Barr virus seronegative recipients on belatacept, especially with a more intensive regimen. CV and metabolic end points were more favorable in belatacept versus CNI groups with similar incidences of diabetes after transplantation. Belatacept seems to be a promising drug for the future, but long-term outcomes are awaited.