Increasing the Use of Kidneys From Unconventional and High‐Risk Deceased Donors

In this paper, we have reviewed the literature and report on kidney donors that are currently used at relatively low rates. Kidneys from donors with acute kidney injury (AKI) seem to have outcomes equivalent to those from donors without AKI, provided one can rule out significant cortical necrosis. Kidneys from donors with preexisting diabetes or hypertension may have marginally lower aggregate survival but still provide patients with a significant benefit over remaining on the wait list. The Kidney Donor Profile Index derives only an aggregate association with survival with a very modest C statistic; therefore, the data indicated that this index should not be the sole reason to discard a kidney, except perhaps in patients with extremely low estimated posttransplant survival scores. It is important to note that the Scientific Registry of Transplant Recipients models of risk adjustment should allay concerns regarding regulatory issues for observed outcomes falling below expectations. The successful utilization of kidneys from donation after cardiac death over the past decade shows how expanding our thinking can translate into more patients benefiting from transplantation. Given the growing number of patients on the wait list, broadening our approach to kidney acceptance could have an important impact on the population with end‐stage renal disease. Many lives could be prolonged by carefully considering use of kidneys that are often discarded.     

Long‐Term Outcomes in Belatacept‐ Versus Cyclosporine‐Treated Recipients of Extended Criteria Donor Kidneys: Final Results From BENEFIT‐EXT,a Phase III Randomized Study

In the Belatacept Evaluation of Nephroprotection and Efficacy as First‐Line Immunosuppression Trial–Extended Criteria Donors (BENEFIT‐EXT), extended criteria donor kidney recipients were randomized to receive belatacept‐based (more intense [MI] or less intense [LI]) or cyclosporine‐based immunosuppression. In prior analyses, belatacept was associated with significantly better renal function compared with cyclosporine. In this prospective analysis of the intent‐to‐treat population, efficacy and safety were compared across regimens at 7 years after transplant. Overall, 128 of 184 belatacept MI–treated, 138 of 175 belatacept LI–treated and 108 of 184 cyclosporine‐treated patients contributed data to these analyses. Hazard ratios (HRs) comparing time to death or graft loss were 0.915 (95% confidence interval [CI] 0.625–1.339; p = 0.65) for belatacept MI versus cyclosporine and 0.927 (95% CI 0.634–1.356; p = 0.70) for belatacept LI versus cyclosporine. Mean estimated GFR (eGFR) plus or minus standard error at 7 years was 53.9 ± 1.9, 54.2 ± 1.9, and 35.3 ± 2.0 mL/min per 1.73 m² for belatacept MI, belatacept LI and cyclosporine, respectively (p < 0.001 for overall treatment effect). HRs comparing freedom from death, graft loss or eGFR <20 mL/min per 1.73 m² were 0.754 (95% CI 0.536–1.061; p = 0.10) for belatacept MI versus cyclosporine and 0.706 (95% CI 0.499–0.998; p = 0.05) for belatacept LI versus cyclosporine. Acute rejection rates and safety profiles of belatacept‐ and cyclosporine‐based treatment were similar. De novo donor‐specific antibody incidence was lower for belatacept (p ≤ 0.0001). Relative to cyclosporine, belatacept was associated with similar death and graft loss and improved renal function at 7 years after transplant and had a safety profile consistent with previous reports.     

Belatacept Combined With Transient Calcineurin Inhibitor Therapy Prevents Rejection and Promotes Improved Long‐Term Renal Allograft Function

Belatacept, a T cell costimulation blocker, demonstrated superior renal function, lower cardiovascular risk, and improved graft and patient survival in renal transplant recipients. Despite the potential benefits, adoption of belatacept has been limited in part due to concerns regarding higher rates and grades of acute rejection in clinical trials. Since July 2011, we have utilized belatacept‐based immunosuppression regimens in clinical practice. In this retrospective analysis of 745 patients undergoing renal transplantation at our center, we compared patients treated with belatacept (n = 535) with a historical cohort receiving a tacrolimus‐based protocol (n = 205). Patient and graft survival were equivalent for all groups. An increased rate of acute rejection was observed in an initial cohort treated with a protocol similar to the low‐intensity regimen from the BENEFIT trial versus the historical tacrolimus group (50.5% vs. 20.5%). The addition of a transient course of tacrolimus reduced rejection rates to acceptable levels (16%). Treatment with belatacept was associated with superior estimated GFR (belatacept 63.8 mL/min vs. tacrolimus 46.2 mL/min at 4 years, p < 0.0001). There were no differences in serious infections including rates of cytomegalovirus or BK viremia. We describe the development of a costimulatory blockade‐based strategy that ultimately allows renal transplant recipients to achieve calcineurin inhibitor–free immunosuppression.     

Early Conversion From Calcineurin Inhibitor‐ to Everolimus‐Based Therapy Following Kidney Transplantation: Results of the Randomized ELEVATE Trial

In a 24‐month, multicenter, open‐label, randomized trial, 715 de novo kidney transplant recipients were randomized at 10–14 weeks to convert to everolimus (n = 359) or remain on standard calcineurin inhibitor (CNI) therapy (n = 356; 231 tacrolimus; 125 cyclosporine), all with mycophenolic acid and steroids. The primary endpoint, change in estimated glomerular filtration rate (eGFR) from randomization to month 12, was similar for everolimus versus CNI: mean (standard error) 0.3(1.5) mL/min/1.73² versus ?1.5(1.5) mL/min/1.73² (p = 0.116). Biopsy‐proven acute rejection (BPAR) at month 12 was more frequent under everolimus versus CNI overall (9.7% vs. 4.8%, p = 0.014) and versus tacrolimus‐treated patients (2.6%, p < 0.001) but similar to cyclosporine‐treated patients (8.8%, p = 0.755). Reporting on de novo donor‐specific antibodies (DSA) was limited but suggested more frequent anti‐HLA Class I DSA under everolimus. Change in left ventricular mass index was similar. Discontinuation due to adverse events was more frequent with everolimus (23.6%) versus CNI (8.4%). In conclusion, conversion to everolimus at 10–14 weeks posttransplant was associated with renal function similar to that with standard therapy overall. Rates of BPAR were low in all groups, but lower with tacrolimus than everolimus.     

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.     

Transplanting Kidneys from Deceased Donors With Severe Acute Kidney Injury

Our aim was to determine outcomes with transplanting kidneys from deceased donors with acute kidney injury, defined as a donor with terminal serum creatinine ≥2.0 mg/dL, or a donor requiring acute renal replacement therapy. We included all patients who received deceased donor kidney transplant from June 2004 to October 2013. There were 162 AKI donor transplant recipients (21% of deceased donor transplants): 139 in the standard criteria donor (SCD) and 23 in the expanded criteria donor (ECD) cohort. 71% of the AKI donors had stage 3 (severe AKI), based on acute kidney injury network (AKIN) staging. Protocol biopsies were done at 1, 4, and 12 months posttransplant. One and four month formalin‐fixed paraffin embedded (FFPE) biopsies from 48 patients (24 AKI donors, 24 non‐AKI) underwent global gene expression profiling using DNA microarrays (96 arrays). DGF was more common in the AKI group but eGFR, graft survival at 1 year and proportion with IF/TA>2 at 1 year were similar for the two groups. At 1 month, there were 898 differentially expressed genes in the AKI group (p‐value <0.005; FDR <10%), but by 4 months there were no differences. Transplanting selected kidneys from deceased donors with AKI is safe and has excellent outcomes.     

Lessons Learned: Early Termination of a Randomized Trial of Calcineurin Inhibitor and Corticosteroid Avoidance Using Belatacept

The intent of this National Institutes of Health–sponsored study was to compare a belatacept‐based immunosuppressive regimen with a maintenance regimen of tacrolimus and mycophenolate. Nineteen primary, Epstein–Barr virus–immune renal transplant recipients with a negative cross‐match were randomized to one of three groups. All patient groups received perioperative steroids and maintenance mycophenolate mofetil. Patients in groups 1 and 2 were induced with alemtuzumab and maintained on tacrolimus or belatacept, respectively. Patients in group 3 were induced with basiliximab, received 3 mo of tacrolimus, and maintained on belatacept. There was one death with a functioning allograft due to endocarditis (group 1). There were three graft losses due to vascular thrombosis (all group 2) and one graft loss due to glomerular disease (group 1). Biopsy‐proven acute cellular rejection was more frequent in the belatacept‐treated groups, with 10 treated episodes in seven participants compared with one episode in group 1; however, estimated GFR was similar between groups at week 52. There were no episodes of posttransplant lymphoproliferative disorder or opportunistic infections in any group. Protocol enrollment was halted prematurely because of a high rate of serious adverse events. Such negative outcomes pose challenges to clinical investigators, who ultimately must weigh the risks and benefits in randomized trials.     

Early Macrophage Infiltration and Sustained Inflammation in Kidneys From Deceased Donors Are Associated With Long‐Term Renal Function

Kidney transplants from living donors (LDs) have a better outcome than those from deceased donors (DDs). Different factors have been suggested to justify the different outcome. In this study, we analyzed the infiltration and phenotype of monocytes/macrophages and the expression of inflammatory and fibrotic markers in renal biopsy specimens from 94 kidney recipients (60 DDs and 34 LDs) at baseline and 4 months after transplantation. We evaluated their association with medium‐ and long‐term renal function. At baseline, inflammatory gene expression was higher in DDs than in LDs. These results were confirmed by the high number of CD68‐positive cells in DD kidneys, which correlated negatively with long‐term renal function. Expression of the fibrotic markers vimentin, fibronectin, and α–smooth muscle actin was more elevated in biopsy specimens from DDs at 4 months than in those from LDs. Gene expression of inflammatory and fibrotic markers at 4 months and difference between 4 months and baseline correlated negatively with medium‐ and long‐term renal function in DDs. Multivariate analysis point to transforming growth factor‐β1 as the best predictor of long‐term renal function in DDs. We conclude that early macrophage infiltration, sustained inflammation, and transforming growth factor‐β1 expression, at least for the first 4 months, contribute significantly to the difference in DD and LD transplant outcome.     

Donor Hemodynamics as a Predictor of Outcomes After Kidney Transplantation From Donors After Cardiac Death

Donation after cardiac death is an important source of transplantable organs, but evidence suggests donor warm ischemia contributes to inferior outcomes. Attempts to predict recipient outcome using donor hemodynamic measurements have not yielded statistically significant results. We evaluated novel measures of donor hemodynamics as predictors of delayed graft function and graft failure in a cohort of 1050 kidneys from 566 donors. Hemodynamics were described using regression line slopes, areas under the curve, and time beyond thresholds for systolic blood pressure, oxygen saturation, and shock index (heart rate divided by systolic blood pressure). A logistic generalized estimation equation model showed that area under the curve for systolic blood pressure was predictive of delayed graft function (above median: odds ratio 1.42, 95% confidence interval [CI] 1.06–1.90). Multivariable Cox regression demonstrated that slope of oxygen saturation during the first 10 minutes after extubation was associated with graft failure (below median: hazard ratio 1.30, 95% CI 1.03–1.64), with 5‐year graft survival of 70.0% (95%CI 64.5%–74.8%) for donors above the median versus 61.4% (95%CI 55.5%–66.7%) for those below the median. Among older donors, increased shock index slope was associated with increased hazard of graft failure. Validation of these findings is necessary to determine the utility of characterizing donor warm ischemia to predict recipient outcome.     

Efficacy and Safety Outcomes of Extended Criteria Donor Kidneys by Subtype: Subgroup Analysis of BENEFIT‐EXT at 7 Years After Transplant

The phase III Belatacept Evaluation of Nephroprotection and Efficacy as First‐Line Immunosuppression Trial–Extended Criteria Donors Trial (BENEFIT‐EXT) study compared more or less intensive belatacept‐based immunosuppression with cyclosporine (CsA)–based immunosuppression in recipients of extended criteria donor kidneys. In this post hoc analysis, patient outcomes were assessed according to donor kidney subtype. In total, 68.9% of patients received an expanded criteria donor kidney (United Network for Organ Sharing definition), 10.1% received a donation after cardiac death kidney, and 21.0% received a kidney with an anticipated cold ischemic time ≥24 h. Over 7 years, time to death or graft loss was similar between belatacept‐ and CsA‐based immunosuppression, regardless of donor kidney subtype. In all three donor kidney cohorts, estimated mean GFR increased over months 1–84 for belatacept‐based treatment but declined for CsA‐based treatment. The estimated differences in GFR significantly favored each belatacept‐based regimen versus the CsA‐based regimen in the three subgroups (p < 0.0001 for overall treatment effect). No differences in the safety profile of belatacept were observed by donor kidney subtype.     

Belatacept during pregnancy in renal transplant recipients: Two case reports

Impaired fertility is common among patients with chronic organ failure, including end‐stage renal disease (ESRD). Women of childbearing age undergoing transplantation may experience rapid return of fertility. Pregnancy posttransplant presents numerous risks for the patient, fetus, and allograft. Maternal risks include hypertension and preeclampsia. Allograft risks include acute rejection and failure of the organ, and fetal risks include miscarriage, birth defects from immunosuppressants, premature delivery, and low birth weight. Belatacept, a selective T cell costimulation blocker, was approved for use in kidney transplant recipients in the United States in 2011. Little is known about the safety of belatacept during pregnancy in humans. We describe 2 cases of successful pregnancy and delivery with the use of belatacept‐based immunosuppression. The Transplant Pregnancy Registry International (TPR) is a voluntary registry for transplant recipients who have had pregnancies or fathered a pregnancy posttransplant. To date, these 2 cases are the only known exposures to belatacept that have been reported to the TPR. 1     

Prolonged Ischemic Time,Delayed Graft Function,and Graft and Patient Outcomes in Live Donor Kidney Transplant Recipients

The association between prolonged cold ischemic time (CIT) and graft and patient outcomes in live donor kidney transplant recipients remains unclear. The aims of this study were to examine the association of CIT with delayed graft function and graft loss in live donor kidney transplant recipients and those who participated in the Australian Paired Kidney Exchange program using data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) registry. Of 3717 live donor transplant recipients between 1997 and 2012 who were followed for a median of 6.6 years (25 977 person‐years), 224 (25%) experienced CIT >4–8 h. Donor age was an effect modifier between CIT and graft outcomes. In recipients who received kidneys from older donors aged >50 years, every hour of increase in CIT was associated with adjusted odds of 1.28 (95% confidence interval [CI] 1.07–1.53, p = 0.007) for delayed graft function, whereas CIT >4–8 h was associated with adjusted hazards of 1.93 (95% CI 1.21–3.09, p = 0.006) and 1.91 (95% CI 1.05–3.49, p = 0.035) for overall and death‐censored graft loss, respectively, compared with CIT of 1–2 h. Attempts to reduce CIT in live donor kidney transplants involving older donor kidneys may lead to improvement of graft outcomes.     

The Kidney Donor Profile Index (KDPI) of Marginal Donors Allocated by Standardized Pretransplant Donor Biopsy Assessment: Distribution and Association With Graft Outcomes

Pretransplant donor biopsy (PTDB)‐based marginal donor allocation systems to single or dual renal transplantation could increase the use of organs with Kidney Donor Profile Index (KDPI) in the highest range (e.g. >80 or >90), whose discard rate approximates 50% in the United States. To test this hypothesis, we retrospectively calculated the KDPI and analyzed the outcomes of 442 marginal kidney transplants (340 single transplants: 278 with a PTDB Remuzzi score <4 [median KDPI: 87; interquartile range (IQR): 78–94] and 62 with a score = 4 [median KDPI: 87; IQR: 76–93]; 102 dual transplants [median KDPI: 93; IQR: 86–96]) and 248 single standard transplant controls (median KDPI: 36; IQR: 18–51). PTDB‐based allocation of marginal grafts led to a limited discard rate of 15% for kidneys with KDPI of 80–90 and of 37% for kidneys with a KDPI of 91–100. Although 1‐year estimated GFRs were significantly lower in recipients of marginal kidneys (?9.3, ?17.9 and ?18.8 mL/min, for dual transplants, single kidneys with PTDB score <4 and =4, respectively; p < 0.001), graft survival (median follow‐up 3.3 years) was similar between marginal and standard kidney transplants (hazard ratio: 1.20 [95% confidence interval: 0.80–1.79; p = 0.38]). In conclusion, PTDB‐based allocation allows the safe transplantation of kidneys with KDPI in the highest range that may otherwise be discarded.

     

ASP2409, A Next‐Generation CTLA4‐Ig,Versus Belatacept in Renal Allograft Survival in Cynomolgus Monkeys

Belatacept is the first costimulatory blockade agent approved for maintenance immunosuppression in kidney transplant recipients. Clinical results have indicated that belatacept is associated with superior renal function and improved metabolic profile; however, higher incidence of acute rejection and posttransplant lymphoproliferative disorder are the shortcomings of this agent. In this study, ASP2409, a new cytotoxic T‐lymphocyte associated protein 4‐immunoglobulin possessing 14‐fold higher in vitro CD86 binding affinity than belatacept, was tested for renal allograft survival in cynomolgus monkeys. ASP2409 monotherapy dose‐dependently prolonged renal allograft survival. Low‐dose ASP2409 in combination with a subtherapeutic dose of tacrolimus showed much longer median survival time than monotherapy. Similar allograft survival results were observed in regimens based on high‐dose ASP2409, belatacept, and therapeutic‐dose tacrolimus. The results of renal allograft histopathology with high‐dose ASP2409‐based regimens were not inferior to the belatacept‐based regimen. Moreover, higher frequencies of FoxP3‐positive regulatory T cells in renal allografts were observed in ASP2409‐ and belatacept‐based regimens compared with tacrolimus‐based regimens. No serious side effects related to ASP2409 administration were found during the study. These data suggest that ASP2409 is a promising candidate for calcineurin inhibitor‐sparing or ‐avoidance regimens.     

Survival Benefit From Kidney Transplantation Using Kidneys From Deceased Donors Aged ≥75 Years: A Time‐Dependent Analysis

Patients with end‐stage renal disease have longer survival after kidney transplantation than they would by remaining on dialysis; however, outcome with kidneys from donors aged ≥75 years and the survival of recipients of these organs compared with their dialysis counterparts with the same probability of obtaining an organ is unknown. In a longitudinal mortality study, 2040 patients on dialysis were placed on a waiting list, and 389 of them received a first transplant from a deceased donor aged ≥75 years. The adjusted risk of death and survival were calculated by non–proportional hazards analysis with being transplanted as a time‐dependent effect. Projected years of life since placement on the waiting list was almost twofold higher for transplanted patients. Nonproportional adjusted risk of death after transplantation was 0.44 (95% confidence interval [CI] 0.61–0.32; p < 0.001) in comparison with those that remained on dialysis. Stratifying by age, adjusted hazard ratios for death were 0.17 (95% CI 0.47–0.06; p = 0.001) for those aged <65 years, 0.56 (95% CI 0.92–0.34; p = 0.022) for those aged 65–69 years and 0.82 (95% CI 1.28–0.52; p = 0.389) for those aged ≥70 years. Although kidney transplantation from elderly deceased donors is associated with reduced graft survival, transplanted patients have lower mortality than those remaining on dialysis.     

Postdepletion Lymphocyte Reconstitution During Belatacept and Rapamycin Treatment in Kidney Transplant Recipients

Belatacept is used to prevent allograft rejection but fails to do so in a sizable minority of patients due to inadequate control of costimulation‐resistant T cells. In this study, we report control of costimulation‐resistant rejection when belatacept was combined with perioperative alemtuzumab‐mediated lymphocyte depletion and rapamycin. To assess the means by which the alemtuzumab, belatacept and rapamycin (ABR) regimen controls belatacept‐resistant rejection, we studied 20 ABR‐treated patients and characterized peripheral lymphocyte phenotype and functional responses to donor, third‐party and viral antigens using flow cytometry, intracellular cytokine staining and carboxyfluorescein succinimidyl ester–based lymphocyte proliferation. Compared with conventional immunosuppression in 10 patients, lymphocyte depletion evoked substantial homeostatic lymphocyte activation balanced by regulatory T and B cell phenotypes. The reconstituted T cell repertoire was enriched for CD28⁺ naïve cells, notably diminished in belatacept‐resistant CD28^? memory subsets and depleted of polyfunctional donor‐specific T cells but able to respond to third‐party and latent herpes viruses. B cell responses were similarly favorable, without alloantibody development and a reduction in memory subsets—changes not seen in conventionally treated patients. The ABR regimen uniquely altered the immune profile, producing a repertoire enriched for CD28⁺ T cells, hyporesponsive to donor alloantigen and competent in its protective immune capabilities. The resulting repertoire was permissive for control of rejection with belatacept monotherapy.

     

Three‐Year Outcomes From BENEFIT‐EXT: A Phase III Study of Belatacept Versus Cyclosporine in Recipients of Extended Criteria Donor Kidneys

Recipients of extended‐criteria donor (ECD) kidneys have poorer long‐term outcomes compared to standard‐criteria donor kidney recipients. We report 3‐year outcomes from a randomized, phase III study in recipients of de novo ECD kidneys (n = 543) assigned (1:1:1) to either a more intensive (MI) or less intensive (LI) belatacept regimen, or cyclosporine. Three hundred twenty‐three patients completed treatment by year 3. Patient survival with a functioning graft was comparable between groups (80% in MI, 82% in LI, 80% in cyclosporine). Mean calculated GFR (cGFR) was 11 mL/min higher in belatacept‐treated versus cyclosporine‐treated patients (42.7 in MI, 42.2 in LI, 31.5 mL/min in cyclosporine). More cyclosporine‐treated patients (44%) progressed to GFR <30 mL/min (chronic kidney disease [CKD] stage 4/5) than belatacept‐treated patients (27–30%). Acute rejection rates were similar between groups. Posttransplant lymphoproliferative disorder (PTLD) occurrence was higher in belatacept‐treated patients (two in MI, three in LI), most of which occurred during the first 18 months; four additional cases (3 in LI, 1 in cyclosporine) occurred after 3 years. Tuberculosis was reported in two MI, four LI and no cyclosporine patients. In conclusion, at 3 years after transplantation, immunosuppression with belatacept resulted in similar patient survival, graft survival and acute rejection, with better renal function compared with cyclosporine. As previously reported, PTLD and tuberculosis were the principal safety findings associated with belatacept in this study population.     

Th‐17 Alloimmune Responses in Renal Allograft Biopsies From Recipients of Kidney Transplants Using Extended Criteria Donors During Acute T Cell–Mediated Rejection

Although renal transplantation using expanded criteria donors has become a common practice, immune responses related to immunosenescence in those kidney allografts have not been studied yet in humans. We performed a retrospective molecular analysis of the T cell immune response in 43 kidney biopsies from patients with acute T cell–mediated rejection including 25 from recipients engrafted with a kidney from expanded criteria donor and 18 from recipients grafted with optimal kidney allograft. The clinical, transplant and acute T cell–mediated rejection characteristics of both groups were similar at baseline. The expression of RORγt, Il‐17 and T‐bet mRNA was significantly higher in the elderly than in the optimal group (p = 0.02, p = 0.036, and p = 0.01, respectively). Foxp3 mRNA levels were significantly higher in elderly patients experiencing successful acute T cell–mediated rejection reversal (p = 0.03). The presence of IL‐17 mRNA was strongly associated with nonsuccessful reversal in elderly patients (p = 0.008). Patients with mRNA IL17 expression detection and low mRNA Foxp3 expression experienced significantly more treatment failure (87.5%) than patients with no mRNA IL17 expression and/or high mRNA Foxp3 expression (26.7%; p = 0.017). Our study suggests that the Th17 pathway is involved in pathogenesis and prognosis of acute T cell–mediated rejection in recipients of expanded criteria allograft.