De novo donor-specific antibodies in belatacept-treated vs cyclosporine-treated kidney-transplant recipients: Post hoc analyses of the randomized phase III BENEFIT and BENEFIT-EXT studies.

Donor-specific antibodies (DSAs) are associated with an increased risk of antibody-mediated rejection and graft failure. In BENEFIT and BENEFIT-EXT, kidney-transplant recipients were randomized to receive belatacept more intense (MI)-based, belatacept less intense (LI)-based, or cyclosporine-based immunosuppression for up to 7 years (84 months). The presence/absence of HLA-specific antibodies was determined at baseline, at months 6, 12, 24, 36, 48, 60, and 84, and at the time of clinically suspected episodes of acute rejection, using solid-phase flow-cytometry screening. Samples from anti-HLA-positive patients were further tested with a single-antigen bead assay to determine antibody specificities, presence/absence of DSAs, and mean fluorescence intensity (MFI) of any DSAs present. In BENEFIT, de novo DSAs developed in 1.4%, 3.5%, and 12.1% of belatacept MI-treated, belatacept LI-treated, and cyclosporine-treated patients, respectively. The corresponding values in BENEFIT-EXT were 3.8%, 1.1%, and 11.2%. Per Kaplan-Meier analysis, de novo DSA incidence was significantly lower in belatacept-treated vs cyclosporine-treated patients over 7 years in both studies (P < .01). In patients who developed de novo DSAs, belatacept-based immunosuppression was associated with numerically lower MFI vs cyclosporine-based immunosuppression. Although derived post hoc, these data suggest that belatacept-based immunosuppression suppresses de novo DSA development more effectively than cyclosporine-based immunosuppression.

Posttransplant reduction in preexisting donor-specific antibody levels after belatacept- versus cyclosporine-based immunosuppression: Post hoc analyses of BENEFIT and BENEFIT-EXT.

BENEFIT and BENEFIT-EXT were phase III studies of cytotoxic T-cell crossmatch-negative kidney transplant recipients randomized to belatacept more intense (MI)-based, belatacept less intense (LI)-based, or cyclosporine-based immunosuppression. Following study completion, presence/absence of HLA-specific antibodies was determined centrally via solid-phase flow cytometry screening. Stored sera from anti-HLA-positive patients were further tested with a single-antigen bead assay to determine antibody specificities, presence/absence of donor-specific antibodies (DSAs), and mean fluorescent intensity (MFI) of any DSAs present. The effect of belatacept-based and cyclosporine-based immunosuppression on MFI was explored post hoc in patients with preexisting DSAs enrolled to BENEFIT and BENEFIT-EXT. In BENEFIT, preexisting DSAs were detected in 4.6%, 4.9%, and 6.3% of belatacept MI-treated, belatacept LI-treated, and cyclosporine-treated patients, respectively. The corresponding values in BENEFIT-EXT were 6.0%, 5.7%, and 9.2%. In both studies, most preexisting DSAs were of class I specificity. Over the first 24 months posttransplant, a greater proportion of preexisting DSAs in belatacept-treated versus cyclosporine-treated patients exhibited decreases or no change in MFI. MFI decline was more apparent with belatacept MI-based versus belatacept LI-based immunosuppression in both studies and more pronounced in BENEFIT-EXT versus BENEFIT. Although derived post hoc, these data suggest that belatacept-based immunosuppression decreases preexisting DSAs more effectively than cyclosporine-based immunosuppression.

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.

Ten-year outcomes in a randomized phase II study of kidney transplant recipients administered belatacept 4-weekly or 8-weekly.

In the phase II IM103-100 study, kidney transplant recipients were first randomized to belatacept more-intensive-based (n = 74), belatacept less-intensive-based (n = 71), or cyclosporine-based (n = 73) immunosuppression. At 3-6 months posttransplant, belatacept-treated patients were re-randomized to receive belatacept every 4 weeks (4-weekly, n = 62) or every 8 weeks (8-weekly, n = 60). Patients initially randomized to cyclosporine continued to receive cyclosporine-based immunosuppression. Cumulative rates of biopsy-proven acute rejection (BPAR) from first randomization to year 10 were 22.8%, 37.0%, and 25.8% for belatacept more-intensive, belatacept less-intensive, and cyclosporine, respectively (belatacept more-intensive vs cyclosporine: hazard ratio [HR] = 0.95; 95% confidence interval [CI] 0.47-1.92; P = .89; belatacept less-intensive vs cyclosporine: HR = 1.61; 95% CI 0.85-3.05; P = .15). Cumulative BPAR rates from second randomization to year 10 for belatacept 4-weekly, belatacept 8-weekly, and cyclosporine were 11.1%, 21.9%, and 13.9%, respectively (belatacept 4-weekly vs cyclosporine: HR = 1.06, 95% CI 0.35-3.17, P = .92; belatacept 8-weekly vs cyclosporine: HR = 2.00, 95% CI 0.75-5.35, P = .17). Renal function trends were estimated using a repeated-measures model. Estimated mean GFR values at year 10 for belatacept 4-weekly, belatacept 8-weekly, and cyclosporine were 67.0, 68.7, and 42.7 mL/min per 1.73 m2 , respectively (P<.001 for overall treatment effect). Although not statistically significant, rates of BPAR were 2-fold higher in patients administered belatacept every 8 weeks vs every 4 weeks.

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.

Pulsatile pump decreases risk of delayed graft function in kidneys donated after cardiac death.

Organ storage techniques have been under scrutiny to determine the best preservation method, particularly in donation after cardiac death (DCD) kidneys. Conflicting literature on the benefit of pulsatile perfusion (PP) over cold storage (CS) warrants further investigation. We analyzed the risk of developing delayed graft function (DGF) in recipients of DCD and donation after brain death (DBD) kidneys undergoing PP or CS. We stratified on basis of cold ischemic time (CIT) to determine the interaction of preservation techniques, CIT and DCD kidneys on developing DGF. Of 54 136 recipients, 4923 received DCD kidneys of which 3330 (67%) underwent PP. Of 49 213 DBD recipients, 7531 (15%) underwent PP. DCD had a higher risk of DGF versus DBD (adjusted odds ratio, AOR 3.2; 3.0-3.5). PP kidneys had less DGF (AOR 0.59; 0.56-0.63) compared to CS. Interaction models of method by donor type referenced to PP/DBD revealed CS/DBD kidneys had higher DGF (AOR 1.8; 1.7-1.9), whereas CS/DCD kidneys had the highest risk of DGF (AOR 5.01; 4.43-5.67). Even though suggestive for a benefit of PP on DGF, this retrospective analysis cannot address whether this is an intrinsic effect of PP or is associated with the logistics of PP such as discard of DCD kidneys based on pump parameters.

Associations between EBV serostatus and organ transplant type in PTLD risk: an analysis of the SRTR National Registry Data in the United States.

In a prior multiorgan transplant database study, recipient Epstein-Barr virus (EBV) seronegativity was not associated with increased risk for posttransplant lymphoproliferative disorders (PTLD) in liver transplants (LTX), at variance with prior single center reports and with data from kidney and heart transplants (KTX and HTX). The Scientific Registry of Transplant Recipients (SRTR) in the United States is the only other registry with data on the required variables for comparison.Our study set comprised 112 756 KTX (580 PTLDs; 0.51%), 13 937 HTX (140 PTLDs; 1.0%) and 40 437 LTX (383 PTLDs; 0.95%) performed January 2003 onward. The unadjusted hazard ratio (HR) for PTLD if recipient EBV seronegative was 5.005 for KTX, 6.528 for HTX and 2.615 for LTX (p < 0.001 for all). In models adjusted for multiple covariates, the adjusted HR was 3.583 (p < 0.001) for KTX, 4.037 (p < 0.001) for HTX, 1.479 (p = 0.03) for LTX. Interaction models using EBV seropositive KTX as reference group showed significantly higher risk for all other EBV seronegative organ transplant groups and also for EBV seropositive LTX (AHR 2.053, p < 0.0001).Recipient EBV seronegativity is still significantly associated with risk for PTLD in LTX, though less so because of higher baseline risk in the EBV seropositive LTX group.

Blood transfusions in organ transplant patients: mechanisms of sensitization and implications for prevention.

Sensitization by previous pregnancies or transplants is considered unavoidable, but it is transfusions given to these patients that leads most often to broad sensitization. Both leukocytes and red cells carry a significant HLA antigen load, and residual leukocytes and/or red cell HLA may explain why leukocyte-reduced units are unable to prevent sensitization to any significant degree. Prevention of sensitization will require a more active effort to avoid blood transfusions, whenever possible. When transfusions are required, there is evidence that the use of HLA-matched blood or immunosuppression in selected situations may reduce sensitization, even in patients previously exposed to alloantigens. These additional measures are not logistically straightforward or devoid of risks and need to be confirmed by rigorous studies. However, remaining as passive observers when patients become broadly sensitized should no longer be considered an acceptable alternative for potential transplant recipients.

Solid organ allograft survival improvement in the United States: the long-term does not mirror the dramatic short-term success.

Organ survival in the short-term period post-transplant has improved dramatically over the past few decades. Whether this has translated to a long-term survival benefit remains unclear. This study quantifies the progression of nonrenal solid organ transplant outcomes from 1989 to 2009 in liver, lung, heart, intestine and pancreas transplants. Long-term graft survival was analyzed using data on adult solid organ transplant recipients from the UNOS/SRTR database and is reported as organ half-life and yearly attrition rates. Liver, lung, heart, intestine and pancreas half-lives have improved from 5.8 to 8.5, 1.7 to 5.2, 8.8 to 11, 2.1 to 3.6 and 10.5 to 16.7 years, respectively. Long-term attrition rates have not shown the same consistent improvement, with the yearly attrition rate 5-10 years post-transplant for liver, lung, heart and pancreas changing from 4.7 to 4.3, 10.9 to 10.1, 6.4 to 5.1 and 3.3 to 4.2, respectively. Attrition rates for intestine and pancreas transplantation alone display more variability due to smaller sample size but exhibit similar trends of improved first-year attrition and relatively stagnant long-term attrition rates. With first-year survival and attrition rates almost at a pinnacle, further progress in long-term survival will come from targeting endpoints beyond first-year rejection and survival rates.

Long-term renal allograft survival in the United States: a critical reappraisal.

Renal allograft survival has increased tremendously over past decades; this has been mostly attributed to improvements in first-year survival. This report describes the evolution of renal allograft survival in the United States where a total of 252 910 patients received a single-organ kidney transplant between 1989 and 2009. Half-lives were obtained from the Kaplan-Meier and Cox models. Graft half-life for deceased-donor transplants was 6.6 years in 1989, increased to 8 years in 1995, then after the year 2000 further increased to 8.8 years by 2005. More significant improvements were made in higher risk transplants like ECD recipients where the half-lives increased from 3 years in 1989 to 6.4 years in 2005. In low-risk populations like living-donor-recipients half-life did not change with 11.4 years in 1989 and 11.9 years in 2005. First-year attrition rates show dramatic improvements across all subgroups; however, attrition rates beyond the first year show only small improvements and are somewhat more evident in black recipients. The significant progress that has occurred over the last two decades in renal transplantation is mostly driven by improvements in short-term graft survival but long-term attrition is slowly improving and could lead to bigger advances in the future.

The PROMISE study: a phase 2b multicenter study of voclosporin (ISA247) versus tacrolimus in de novo kidney transplantation.

Voclosporin (VCS, ISA247) is a novel calcineurin inhibitor being developed for organ transplantation. PROMISE was a 6-month, multicenter, randomized, open-label study of three ascending concentration-controlled groups of VCS (low, medium and high) compared to tacrolimus (TAC) in 334 low-risk renal transplant recipients. The primary endpoint was demonstration of noninferiority of biopsy proven acute rejection (BPAR) rates. Secondary objectives included renal function, new onset diabetes after transplantation (NODAT), hypertension, hyperlipidemia and pharmacokinetic-pharmacodynamic evaluation. The incidence of BPAR in the VCS groups (10.7%, 9.1% and 2.3%, respectively) was noninferior to TAC (5.8%). The incidence of NODAT for VCS was 1.6%, 5.7% and 17.7% versus 16.4% in TAC (low-dose VCS, p = 0.03). Nankivell estimated glomerular filtration rate was respectively: 71, 72, 68 and 69 mL/min, statistically lower in the high-dose group, p = 0.049. The incidence of hypertension and adverse events was not different between the VCS groups and TAC. VCS demonstrated an excellent correlation between trough and area under the curve (r(2) = 0.97) and no difference in mycophenolic acid exposure compared to TAC. This 6-month study shows VCS to be as efficacious as TAC in preventing acute rejection with similar renal function in the low- and medium-exposure groups, and potentially associated with a reduced incidence of NODAT.

Elevated incidence of posttransplant erythrocytosis after simultaneous pancreas kidney transplantation.

Posttransplant erythrocytosis (PTE) poses a potential risk of thrombosis in kidney transplantation. Clinical observation of our systemically drained simultaneous kidney pancreas transplant (S-SPK) patients showed a higher incidence of PTE and need for phlebotomies. To evaluate the incidence of PTE we analyzed hematocrit (Hct) levels and frequency of phlebotomies in 94 SPK as compared to 174 living donor (LD) recipients and 53 type-I diabetic with kidney transplant only. For study purposes we defined PTE as Hct >50% or the necessity for phlebotomies. Kaplan-Meier plots and Cox proportional hazard models were used to examine the association between the transplant type and PTE. We found an increased incidence of PTE in SPK compared to LD (p < 0.001). In the multivariate model, SPK had a 5-fold risk for the development of PTE (AHR 5.3, 95% CI 1.8, 15.9). The incidence of therapeutic phlebotomy was 13% among SPK patients and 4% in LD kidney recipients; 19 patients altogether. A total of 64 units were phlebotomized (48-SPK and 16-LD). Type I diabetic patients with a kidney transplant showed a 0% incidence of PTE. We observed a greater incidence of PTE and phlebotomies in S-SPK compared to LD with kidney only transplant recipients.

The success of continued steroid avoidance after kidney transplantation in the US.

There has been a significant increase in the use of steroid avoidance regimens as initial treatment for kidney transplant recipients. Early results of the effectiveness of this strategy has been mixed with certain prospective trials indicating increased acute rejection but population-based studies indicating similar or better graft survival as compared to steroid maintenance. We conducted a retrospective study of national registry data to evaluate risk factors for discontinuation of steroid avoidance protocols based on patient characteristics and concomitant immunosuppression. We evaluated 84 647 solitary kidney transplant recipients in the US with at least 6 months graft survival including 24 218 initially discharged without maintenance steroids. We utilized logistic models to assess risk factors for new initiation of steroids after initial steroid-avoidance and survival models to describe graft survival for patients after return to steroids. The most prominent risk factors for new initiation of steroids after deceased donor kidney transplantation included African-American race (AOR = 1.32, p < 0.01), retransplants (AOR = 1.81, p < 0.01), highly sensitized recipients (AOR = 1.29, p < 0.01), recipients with Medicaid (AOR = 1.85, p < 0.01), elevated HLA-MM (AOR = 1.26, p < 0.01) and older donor age (AOR = 1.19, p < 0.01). Concomitant medications were also significantly associated with the propensity to newly initiate steroids. Cumulatively the study suggests that both patient characteristics and concomitant medications are strongly associated with the success of steroid avoidance immunosuppressive regimens.

Fixed- or controlled-dose mycophenolate mofetil with standard- or reduced-dose calcineurin inhibitors: the Opticept trial.

Mycophenolate mofetil (MMF) was developed with cyclosporine as a fixed-dose immunosuppressant. More recent data indicate a relationship between mycophenolic acid (MPA) exposure in individuals and clinical endpoints of rejection and toxicity. This 2-year, open-label, randomized, multicenter trial compared the efficacy and safety of concentration-controlled MMF (MMF(CC)) dosing with a fixed-dose regimen in 720 kidney recipients. Patients received either (A) MMF(CC) and reduced-level calcineurin inhibitor (MMF(CC)/CNI(RL)); (B) MMF(CC) and standard-level CNI (MMF(CC)/CNI(SL)); or (C) fixed-dose MMF and CNI(SL) (MMF(FD)/CNI(SL)). Antibody induction and steroid use were according to center practice. The primary endpoint was noninferiority (alpha= 0.05) of group A versus group C for treatment failure (including biopsy-proven acute rejection [BPAR], graft loss and death) at 1 year. Although mean CNI trough levels in group A did not reach the prespecified targets, they were statistically lower than those in groups B and C (p < or = 0.01 for each comparison). BPAR rates (8.5%) were low across groups. Group A had 19% fewer treatment failures (23% vs. 28%, p = 0.18). MMF doses were highest (p < 0.05), with withdrawals for adverse events the fewest (p = 0.02), in group A. Of the 80% of subjects taking tacrolimus (Tac), those with higher MPA exposure had significantly less rejection (p < 0.001) and diarrhea correlated with Tac, but not with MPA levels. Thus, MMF(CC) with low-dose CNI resulted in outcomes not inferior to those with standard CNI exposure and MMF(FD), indicating potential utility of MMF(CC) in CNI-sparing regimens.

The overlapping risk profile between dialysis patients listed and not listed for renal transplantation.

The survival advantage of kidney transplantation extends to many high-risk ESRD patients; however, numerous factors ultimately determine which patients are evaluated and listed for the procedure. Broad goals of patient evaluation comprise identifying patients who will benefit from transplantation and excluding patients who might be placed at risk. There is limited data detailing whether current access limitations and screening strategies have achieved the goal of listing the most appropriate patients. The study estimated the life expectancy of adult patients in the United States prior to transplantation with ESRD onset from 1995 to 2003. Factors associated with transplant listing were examined based on patient prognosis after ESRD. Approximately one-third of patients listed for transplantation within 1 year of ESRD had 5-year life expectancy. The number of patients not listed with 'good' prognosis was significantly higher than those listed with 'poor' prognosis (134 382 vs. 16 807, respectively). Age, race, gender, insurance coverage and body mass index (BMI) were associated with likelihood for listing with 'poor' prognosis and not listing with 'good' prognosis. Over the past decade, many ESRD patients viable for transplantation have not listed for transplantation while higher-risk patients have listed rapidly.

Mammalian target of rapamycin inhibitor dyslipidemia in kidney transplant recipients.

The incidence, pathogenesis, consequences and treatment of mammalian target of rapamycin (mTOR) inhibitor dyslipidemia are not well described. We conducted a systematic review of randomized controlled trials reporting cholesterol and triglycerides in mTOR versus non-mTOR inhibitor immunosuppressive treatment regimens in kidney transplant recipients. All but one of 17 trials reported higher levels of cholesterol and triglycerides, or an increased prevalence of treatment with lipid-lowering agents. Approximately 60% of mTOR inhibitor-treated patients received lipid-lowering agents (2-fold higher than controls). There appeared to be little difference between dyslipidemias caused by sirolimus (14 trials) versus everolimus (3 trials). It was difficult to determine the extent to which declines in lipids over time posttransplant were due to lipid-lowering therapy, changes in doses and/or discontinuations of mTOR inhibitors. From the four trials that measured lipoproteins, it appeared that at least some of the increase in total cholesterol with mTOR inhibitors was due to increased low-density lipoprotein cholesterol. What direct or indirect effects mTOR inhibitors have on atherosclerotic cardiovascular disease in kidney transplant patients are unknown. However, in the absence of the necessary clinical trials, dyslipidemia should be managed, as it would be in nontransplant patients at high risk for cardiovascular disease.

The effects of renal transplantation on circulating precursor dendritic cells.

BACKGROUND: Dendritic cells (DCs) are potent antigen-presenting cells that induce and regulate immune responses. Recent advances allow accurate quantification of peripheral blood (PB) myeloid and plasmacytoid DC populations (mDC and pDC, respectively), although the response to renal transplantation (RT) remains unknown. METHODS: Using flow cytometry, PBDC levels were quantified in patients with end-stage renal disease (ESRD) undergoing renal transplantation. RESULTS: PBDC levels were significantly reduced in ESRD patients pretransplantation compared to healthy controls, with further reduction noted immediately following a hemodialysis session. RT resulted in a dramatic decrease in both subsets, with a greater reduction of pDC levels. Both subset levels were significantly lower than in control patients undergoing abdominal surgery without RT. Subgroup analysis revealed significantly greater mDC reduction in RT recipients receiving antilymphocyte therapy, with preferential binding of antibody preparation to this subset. Samples from later time points revealed a gradual return of PBDC levels back to pretransplant values concurrent with overall reduction of immunosuppression. Finally, PBDC levels were significantly reduced in patients with BK virus nephropathy compared to recipients with stable graft function, despite lower overall immunosuppression. CONCLUSIONS: Our findings suggest that PBDC levels may reflect the degree of immunosuppression in renal allograft recipients. Furthermore, PBDC monitoring may represent a novel strategy to predict important outcomes such as acute rejection, long-term graft loss, and infectious complications.