Randomized Trial of Three Induction Antibodies in Kidney Transplantation: Long-Term Results

Induction outcomes in adult kidney transplantation: Two decades of UNOS data analysis

OBJECTIVES

In the US, 92 % of kidney transplant recipients are treated with induction therapy. This analysis assesses the impact of induction immunosuppression on outcomes such as graft failure, patient mortality, and length of hospitalization.

MATERIAL AND METHODS

Retrospective analysis of the UNOS database in adults who received a kidney transplant from January 2000 to June 2022. Analysis focused on induction regimens including anti-thymocyte globulin (ATG), alemtuzumab and basiliximab with maintenance immunosuppression of calcineurin inhibitors, mycophenolate with or without prednisone. Multivariable logistic regression was performed to identify factors correlating with outcomes. Kaplan-Meier product limit method assessed survival.

RESULTS

Alemtuzumab correlated with increased graft failure in deceased-donor and living-donor kidney transplants (HR 1.075 [1.015-1.138] p = 0.013 and HR 1.096 [1.011-1.188] p = 0.026 respectively) and with increased mortality in living-donor kidney transplants (HR 1.215 [1.107-1.332] p < 0.001). Steroids maintenance was associated with fewer acute rejections in both deceased-donor and living-donor kidney transplants (HR = 0.875 [0.84-0.90] p < 0.001 and HR = 0.88 [0.83-0.93] p < 0.001 respectively). Odds of CMV was lower with alemtuzumab. Induction with alemtuzumab was associated with shorter length of stay in both deceased-donor and living-donor kidney transplants and longer time to first hospitalization in living-donor kidney transplants compared to ATG.

CONCLUSIONS

Alemtuzumab correlated with shorter length of stay, fewer re-hospitalizations and less CMV infections. However, it was associated with higher odds of graft failure and mortality in adult kidney transplant recipients.

Immunosuppressive drug combinations after kidney transplantation and post-transplant diabetes: A systematic review and meta-analysis

Post-transplant diabetes mellitus (PTDM) is a frequent complication after kidney transplantation (KT). This systematic review investigated the effect of different immunosuppressive regimens on the risk of PTDM. We performed a systematic literature search in MEDLINE and CENTRAL for randomized controlled trials (RCTs) that included KT recipients with any immunosuppression and reported PTDM outcomes up to 1 October 2023. The analysis included 125 RCTs. We found no differences in PTDM risk within induction therapies. In de novo KT, there was an increased risk of developing PTDM with tacrolimus versus cyclosporin (RR 1.71, 95%CI [1.38-2.11]). No differences were observed between tacrolimus+mammalian target of rapamycin inhibitor (mTORi) and tacrolimus+MMF/MPA, but there was a tendency towards a higher risk of PTDM in the cyclosporin+mTORi group (RR 1.42, 95%CI [0.99-2.04]). Conversion from cyclosporin to an mTORi increased PTDM risk (RR 1.89, 95%CI [1.18-3.03]). De novo belatacept compared with a calcineurin inhibitor resulted in 50% lower risk of PTDM (RR 0.50, 95%CI [0.32-0.79]). Steroid avoidance resulted in 31% lower PTDM risk (RR 0.69, 95%CI [0.57-0.83]), whereas steroid withdrawal resulted in no differences. Immunosuppression should be decided on an individual basis, carefully weighing the risk of future PTDM and rejection.

The use of lymphocyte-depleting antibodies in specific populations of kidney transplant recipients: A systematic review and meta-analysis

BACKGROUND

Recommendations of the use of antibody induction treatments in kidney transplant recipients (KTR) are based on moderate quality and historical studies. This systematic review aims to reevaluate, based on actual studies, the effects of different antibody preparations when used in specific KTR subgroups.

METHODS

We searched MEDLINE and CENTRAL and selected randomized controlled trials (RCT) and observational studies looking at different antibody preparations used as induction in KTR. Comparisons were categorized into different KTR subgroups: standard, high risk of rejection, high risk of delayed graft function (DGF), living donor, and elderly KTR. Two authors independently assessed the risk of bias.

RESULTS

Thirty-seven RCT and 99 observational studies were finally included. Compared to anti-interleukin-2-receptor antibodies (IL2RA), anti-thymocyte globulin (ATG) reduced the risk of acute rejection at two years in standard KTR (RR 0.74, 95%CI 0.61-0.89) and high risk of rejection KTR (RR 0.55, 95%CI 0.43-0.72), but without decreasing the risk of graft loss. We did not find significant differences comparing ATG vs. alemtuzumab or different ATG dosages in any KTR group.

CONCLUSIONS

Despite many studies carried out on induction treatment in KTR, their heterogeneity and short follow-up preclude definitive conclusions to determine the optimal induction therapy. Compared with IL2RA, ATG reduced rejection in standard-risk, highly sensitized, and living donor graft recipients, but not in high DGF risk or elderly recipients. More studies are needed to demonstrate beneficial effects in other KTR subgroups and overall patient and graft survival.

Early Posttransplant Blood Transfusion and Risk for Worse Graft Outcomes

Introduction

Blood transfusion is a risk factor for allosensitization. Nevertheless, blood transfusion posttransplant remains a common practice. We evaluated the effect of posttransplant blood transfusion on graft outcomes.

Methods

We included nonsensitized, first-time, kidney-alone recipients transplanted between 1 July 2015 and 31 December 2017. Patients were grouped based on receiving blood transfusion in the first 30 days posttransplant. The primary end point was a composite outcome of biopsy-proven acute rejection, death of any cause, or graft failure in the first year posttransplant. Secondary outcomes included the individual components of the primary outcome and the cumulative incidence of de novo donor-specific antibodies (DSAs).

Results

Two hundred seventy-three patients were included. One hundred twenty-seven (47%) received blood transfusion. Patients in the transfusion group were more likely to be older, have had a deceased donor, and have received induction with basiliximab. There was no difference between groups in the composite primary outcome (adjusted hazard ratio = [HR] 1.34; 95% confidence interval [CI], 0.83–2.17; P = 0.23). The cumulative incidence of de novo DSAs during the first year posttransplant was similar between groups (12.8% transfusion vs. 10.9% no transfusion, P = 0.48).

Conclusion

Early transfusion of blood products in kidney transplant recipients receiving induction with lymphocyte depletion was not associated with an increased hazard of experiencing acute rejection, death from any cause, or graft loss.

Long-Term Infectious and Noninfectious Outcomes of Monthly Alemtuzumab as a Calcineurin Inhibitor- and Steroid-Free Regimen for Pancreas Transplant Recipients

Multiple doses of alemtuzumab for immunosuppressive therapy of patients with hematologic malignancies and hematopoietic stem cell transplant have been associated with a high rate of infection. In transplantation, limited alemtuzumab dosing has been successfully used as induction immunosuppression. The effect of multiple doses of alemtuzumab, used as maintenance therapy to minimize steroid and/or calcineurin inhibitor toxicity in solid organ transplant recipients, is unknown. We evaluated the infectious and noninfectious outcomes of 179 pancreas transplant recipients treated with alemtuzumab for induction and maintenance therapy (extended alemtuzumab exposure (EAE)) from 2/28/2003 through 8/31/2005, compared with 159 pancreas transplant recipients with standard induction and maintenance (SIM) therapy performed before (1/1/2002 until 12/31/2002) and after (1/1/2006 until 12/31/2006) the implementation of EAE. EAE was associated with higher risk of overall infections (hazard ratio (HR) 1.33 (1.06–1.66), P=0.01), bacterial infections (HR 1.33 (1.05–1.67), P=0.02), fungal infections (HR 1.86 (1.28–2.71), P < 0.01), and cytomegalovirus infections (HR 2.29 (1.39–3.77), P < 0.01). In addition, EAE was associated with higher risk of acute cellular rejection (HR 2.09 (1.46–2.99), P < 0.01). In conclusion, while a limited alemtuzumab dosing is safe and effective for induction therapy in pancreas transplantation, EAE combined with steroid and calcineurin minimization is associated with a high risk of infectious complications and acute cellular rejection.

Impact of human leukocyte antigen and calculated panel reactive antibody on BK viremia in kidney transplant recipients: A single-center experience and literature review

BACKGROUND

The aim of this retrospective analysis was to investigate the effect of human leukocyte antigen (HLA) and calculated panel reactive antibody (cPRA) on BK virus activation as evidenced by BK viremia (BKV).

PATIENTS AND METHODS

At our institution, 649 kidney transplant patients were screened for BKV from 2009 to 2017. Patients were considered to have BKV if they had >10 000 copies/mL of BK DNA in their blood. Donor and recipient HLA and cPRA, demographic, clinical and laboratory data, as well as immunosuppressive medications were collected.

RESULTS

We identified 122 BK positive and 527 BK negative patients. Only 25% of the patients had cPRA of 20% or more, and 64% had more than three HLA-A, -B, and -DR mismatches. In both univariate and multivariate analyses, male gender, age, and maintenance of steroid therapy significantly increased the risk of BKV (P = 0.005, 0.005 and <0.001, respectively). The degree of cPRA and the individual HLA allele and HLA allele matching did not significantly affect BKV.

CONCLUSION

Neither the degree of HLA mismatching nor cPRA appears to affect BKV. Moreover, no specific HLA allele, HLA allele matching, or cPRA were associated with BKV.

Efficacy and Safety of Induction Therapy in Kidney Transplantation: A Network Meta-Analysis

BACKGROUND

Rejection and infection can occur after kidney transplantation and are important factors in preserving graft kidney function. The use of immunosuppressant agents in transplantation is therefore important, and the question of which induction therapy should be used as an immunosuppressant is controversial.

OBJECTIVE

The goal of this study was to assess the comparative benefits and harms of various maintenance immunosuppressive induction agents in adults undergoing kidney transplantation by using a network meta-analysis and to generate rankings of the different immunosuppressive regimens according to their safety and efficacy.

METHODS

CENTRAL, MEDLINE, EMBASE, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and trial registers were searched until May 2017 to identify randomized controlled trials on immunosuppression for kidney transplantation.

RESULTS

Twenty-seven studies involving 4484 participants were eligible for analysis. Induction and maintenance treatments were administered for 12 months. There was no evidence of differences in outcomes between therapies on all-cause mortality, graft loss, cytomegalovirus, BK virus, neutropenia, thrombocytopenia, and biopsy-proven acute rejection. However, compared with intravenous basiliximab (an interleukin-2 receptor antagonist [IL-2RA]), the most effective treatments to decrease biopsy-proven acute rejection were intravenous alemtuzumab and rabbit antithymocyte globulin (rATG). The odds ratios were 0.45 (95% confidence interval [CI], 0.29-40.78) and 0.63 (95% CI, 0.42-0.95), respectively. As a side effect, rATG was accompanied by more bacterial infection than the IL-2RA (OR, 1.8 [95% CI, 1.01-2.8]).

CONCLUSIONS

The determination of induction in kidney transplantation is important for future prognosis of the graft kidney. Alemtuzumab and rATG exhibited lower biopsy-proven acute rejection than the IL-2RA. As a side effect, rATG produced frequent bacterial infections.

Comparative efficacy and safety of antibody induction therapy for the treatment of kidney: a network meta-analysis

To evaluate the efficacy and safety of antibody induction therapies in kidney transplantation. Systematic literature searches were undertaken using MEDLINE, Embase, and Cochrane Library database from 1980 to 2016. Randomized controlled trials (RCTs) comparing three antibody induction therapies (alemtuzumab, interleukin-2 receptor antibodies and antithymocyte globulin) between each other were identified. Bayesian network meta-analysis was used to combine both the direct and indirect evidence on treatment efficacy and its safety. Antibody induction therapy studies, comprising of 18 RCTs (3444 kidney transplant recipients), were included. Overall, alemtuzumab treatment was superior to the ATG group (OR: 0.49, 95% CI: 0.32 to 0.71) and IL-2RAs group (OR: 0.36, 95% CI: 0.25 to 0.52) for reducing the 1-year acute rejection in kidney transplant recipients. Although alemtuzumab treatment was nearly same with ATG group and IL-2RAs group in improving patient survival and renal function, it can reduce the adverse effects of cytomegalovirus infection more efficiently than ATG group (OR: 0.59, 95% CI: 0.32 to 0.95) and IL-2RAs group (OR: 1.08, 95% CI: 0.61 to 1.73). Alemtuzumab was not associated with increased other adverse effects. Alemtuzumab treatment is safe and effective for kidney transplant recipients. No serious adverse effects were observed in trials or in general populations.

Immunosuppression in Solid-Organ Transplantation: Essentials and Practical Tips

A multidisciplinary team approach is essential for successful management of patients with solid-organ transplant. Transplant nursing encompasses care and support of transplant recipients as well as caregivers and organ donors through all phases of transplantation, from pretransplant evaluation to posttransplant recovery and maintenance. The field of solid-organ transplantation has advanced rapidly, and new treatments continue to emerge. Nurses who are responsible for the care of transplant recipients should have a knowledge base in transplant immunology and pharmacology. This review discusses mechanism of action, indication, side effects, and drug interactions of commonly used immunosuppressive medications in solid-organ transplantation. Nonoral routes of drug administration, therapeutic drug monitoring, and patient monitoring strategies are also included as practical tips for bedside nurses who are responsible for delivery of direct patient care and education of patients and their caregivers. This review focuses on the following medications: antithymocyte globulins, basiliximab, alemtuzumab, corticosteroids, tacrolimus, cyclosporine, azathioprine, mycophenolate mofetil/mycophenolate sodium, sirolimus, everolimus, belatacept, intravenous immunoglobulin, and rituximab.

Comparing Outcomes between Antibody Induction Therapies in Kidney Transplantation

Kidney transplant recipients often receive antibody induction. Previous studies of induction therapy were often limited by short follow-up and/or absence of information about complications. After linking Organ Procurement and Transplantation Network data with Medicare claims, we compared outcomes between three induction therapies for kidney recipients. Using novel matching techniques developed on the basis of 15 clinical and demographic characteristics, we generated 1:1 pairs of alemtuzumab-rabbit antithymocyte globulin (rATG) (5330 pairs) and basiliximab-rATG (9378 pairs) recipients. We used paired Cox regression to analyze the primary outcomes of death and death or allograft failure. Secondary outcomes included death or sepsis, death or lymphoma, death or melanoma, and healthcare resource utilization within 1 year. Compared with rATG recipients, alemtuzumab recipients had higher risk of death (hazard ratio [HR], 1.14; 95% confidence interval [95% CI], 1.03 to 1.26; P<0.01) and death or allograft failure (HR, 1.18; 95% CI, 1.09 to 1.28; P<0.001). Results for death as well as death or allograft failure were generally consistent among elderly and nonelderly subgroups and among pairs receiving oral prednisone. Compared with rATG recipients, basiliximab recipients had higher risk of death (HR, 1.08; 95% CI, 1.01 to 1.16; P=0.03) and death or lymphoma (HR, 1.12; 95% CI, 1.01 to 1.23; P=0.03), although these differences were not confirmed in subgroup analyses. One-year resource utilization was slightly lower among alemtuzumab recipients than among rATG recipients, but did not differ between basiliximab and rATG recipients. This observational evidence indicates that, compared with alemtuzumab and basiliximab, rATG associates with lower risk of adverse outcomes, including mortality.

Use of polyclonal/monoclonal antibody therapies in transplantation

INTRODUCTION

For over thirty years, antibody (mAb)-based therapies have been a standard component of transplant immunosuppression, and yet much remains to be learned in order for us to truly harness their therapeutic capabilities. Current mAbs used in transplant directly target and destroy graft-destructive immune cells, interrupt cytokine and costimulation-dependent T and B cell activation, and prevent down-stream complement activation. Areas covered: This review summarizes our current approaches to using antibody-based therapies to prevent and treat allograft rejection. It also provides examples of promising novel mAb therapies, and discusses the potential for future mAb development in transplantation. Expert opinion: The broad capability of antibodies, in parallel with our growing ability to synthetically modulate them, offers exciting opportunities to develop better biologic therapeutics. In order to do so, we must further our understanding about the basic biology underlying allograft rejection, and gain better appreciation of how characteristics of therapeutic antibodies affect their efficacy.

Polyclonal and monoclonal antibodies for induction therapy in kidney transplant recipients

BACKGROUND

Prolonging kidney transplant survival is an important clinical priority. Induction immunosuppression with antibody therapy is recommended at transplantation and non-depleting interleukin-2 receptor monoclonal antibodies (IL2Ra) are considered first line. It is suggested that recipients at high risk of rejection should receive lymphocyte-depleting antibodies but the relative benefits and harms of the available agents are uncertain.

OBJECTIVES

We aimed to: evaluate the relative and absolute effects of different antibody preparations (except IL2Ra) when used as induction therapy in kidney transplant recipients; determine how the benefits and adverse events vary for each antibody preparation; determine how the benefits and harms vary for different formulations of antibody preparation; and determine whether the benefits and harms vary in specific subgroups of recipients (e.g. children and sensitised recipients).

SEARCH METHODS

Randomised controlled trials (RCTs) comparing monoclonal or polyclonal antibodies with placebo, no treatment, or other antibody therapy in adults and children who had received a kidney transplant.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing monoclonal or polyclonal antibodies with placebo, no treatment, or other antibody therapy in adults and children who had received a kidney transplant.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) together with their 95% confidence intervals (CI).

MAIN RESULTS

We included 99 studies (269 records; 8956 participants; 33 with contemporary agents). Methodology was incompletely reported in most studies leading to lower confidence in the treatment estimates.Antithymocyte globulin (ATG) prevented acute graft rejection (17 studies: RR 0.63, 95% CI 0.51 to 0.78). The benefits of ATG on graft rejection were similar when used with (12 studies: RR 0.61, 0.49 to 0.76) or without (5 studies: RR 0.65, 0.43 to 0.98) calcineurin inhibitor (CNI) treatment. ATG (with CNI therapy) had uncertain effects on death (3 to 6 months, 3 studies: RR 0.41, 0.13 to 1.22; 1 to 2 years, 5 studies: RR 0.75, 0.27 to 2.06; 5 years, 2 studies: RR 0.94, 0.11 to 7.81) and graft loss (3 to 6 months, 4 studies: RR 0.60, 0.34 to 1.05; 1 to 2 years, 3 studies: RR 0.65, 0.36 to 1.19). The effect of ATG on death-censored graft loss was uncertain at 1 to 2 years and 5 years. In non-CNI studies, ATG had uncertain effects on death but reduced death-censored graft loss (6 studies: RR 0.55, 0.38 to 0.78). When CNI and older non-CNI studies were combined, a benefit was seen with ATG at 1 to 2 years for both all-cause graft loss (7 studies: RR 0.71, 0.53 to 0.95) and death-censored graft loss (8 studies: RR 0.55, 0.39 to 0.77) but not sustained longer term. ATG increased cytomegalovirus (CMV) infection (6 studies: RR 1.55, 1.24 to 1.95), leucopenia (4 studies: RR 3.86, 2.79 to 5.34) and thrombocytopenia (4 studies: RR 2.41, 1.61 to 3.61) but had uncertain effects on delayed graft function, malignancy, post-transplant lymphoproliferative disorder (PTLD), and new onset diabetes after transplantation (NODAT).Alemtuzumab was compared to ATG in six studies (446 patients) with early steroid withdrawal (ESW) or steroid minimisation. Alemtuzumab plus steroid minimisation reduced acute rejection compared to ATG at one year (4 studies: RR 0.57, 0.35 to 0.93). In the two studies with ESW only in the alemtuzumab arm, the effect of alemtuzumab on acute rejection at 1 year was uncertain compared to ATG (RR 1.27, 0.50 to 3.19). Alemtuzumab had uncertain effects on death (1 year, 2 studies: RR 0.39, 0.06 to 2.42; 2 to 3 years, 3 studies: RR 0.67, 95% CI 0.15 to 2.95), graft loss (1 year, 2 studies: RR 0.39, 0.13 to 1.30; 2 to 3 years, 3 studies: RR 0.98, 95% CI 0.47 to 2.06), and death-censored graft loss (1 year, 2 studies: RR 0.38, 0.08 to 1.81; 2 to 3 years, 3 studies: RR 2.45, 95% CI 0.67 to 8.97) compared to ATG. Creatinine clearance was lower with alemtuzumab plus ESW at 6 months (2 studies: MD -13.35 mL/min, -23.91 to -2.80) and 2 years (2 studies: MD -12.86 mL/min, -23.73 to -2.00) compared to ATG plus triple maintenance. Across all 6 studies, the effect of alemtuzumab versus ATG was uncertain on all-cause infection, CMV infection, BK virus infection, malignancy, and PTLD. The effect of alemtuzumab with steroid minimisation on NODAT was uncertain, compared to ATG with steroid maintenance.Alemtuzumab plus ESW compared with triple maintenance without induction therapy had uncertain effects on death and all-cause graft loss at 1 year, acute rejection at 6 months and 1 year. CMV infection was increased (2 studies: RR 2.28, 1.18 to 4.40). Treatment effects were uncertain for NODAT, thrombocytopenia, and malignancy or PTLD.Rituximab had uncertain effects on death, graft loss, acute rejection and all other adverse outcomes compared to placebo.

AUTHORS' CONCLUSIONS

ATG reduces acute rejection but has uncertain effects on death, graft survival, malignancy and NODAT, and increases CMV infection, thrombocytopenia and leucopenia. Given a 45% acute rejection risk without ATG induction, seven patients would need treatment to prevent one having rejection, while incurring an additional patient experiencing CMV disease for every 12 treated. Excluding non-CNI studies, the risk of rejection was 37% without induction with six patients needing treatment to prevent one having rejection.In the context of steroid minimisation, alemtuzumab prevents acute rejection at 1 year compared to ATG. Eleven patients would require treatment with alemtuzumab to prevent 1 having rejection, assuming a 21% rejection risk with ATG.Triple maintenance without induction therapy compared to alemtuzumab combined with ESW had similar rates of acute rejection but adverse effects including NODAT were poorly documented. Alemtuzumab plus steroid withdrawal would cause one additional patient experiencing CMV disease for every six patients treated compared to no induction and triple maintenance, in the absence of any clinical benefit. Overall, ATG and alemtuzumab decrease acute rejection at a cost of increased CMV disease while patient-centred outcomes (reduced death or lower toxicity) do not appear to be improved.

Randomized trial of rATg/Daclizumab vs. rATg/Alemtuzumab as dual induction therapy in renal transplantation: Results at 8years of follow-up

Our goal in using dual induction therapy is to bring the kidney transplant recipient closer (through more effectively timed lymphodepletion) to an optimally immunosuppressed state. Here, we report long-term results of a prospective randomized trial comparing (Group I,N=100) rATG/Dac (3 rATG, 2 Dac doses) vs. (Group II,N=100) rATG/Alemtuzumab(C1H) (1 dose each), using reduced tacrolimus dosing, EC-MPS, and early corticosteroid withdrawal. Lower EC-MPS dosing was targeted in Group II to avoid severe leukopenia. Median follow-up was 96mo post-transplant. There were no differences in 1st BPAR (including borderline) rates: 10/100 vs. 9/100 in Groups I and II during the first 12mo(P=0.54), and 20/100 vs. 20/100 throughout the study(P=0.90). Equally favorable renal function was maintained in both treatment arms(N.S.). While not significant, more patients in Group II experienced graft loss, 25/100 vs. 18/100 in Group I(P=0.23). Actuarial patient/graft survival at 96mo was 92%/83% vs. 85%/73% in Groups I and II(N.S.). DWFG-due-to-infection(N.S.), EC-MPS withholding-due-to-leukopenia during the first 2mo(P=0.03), and incidence of viral infections(P=0.09) were higher in Group II, whereas EC-MPS withholding-due-to-GI symptoms was higher in Group I(P=0.009). No other adverse event differences were observed. While long-term anti-rejection and renal function efficacy were demonstrated in both treatment arms, slight over-immunosuppression of Group II patients occurred.

Acute Rejection Rates and Graft Outcomes According to Induction Regimen among Recipients of Kidneys from Deceased Donors Treated with Tacrolimus and Mycophenolate

BACKGROUND AND OBJECTIVES

IL-2 receptor antagonist (IL2-RA) is recommended as a first-line agent for induction therapy in renal transplantation. However, this remains controversial in deceased donor renal transplantation (DDRT) maintained on tacrolimus (TAC)/mycophenolic acid (MPA) with or without steroids.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied the United Network for Organ Sharing Registry for patients receiving DDRT from 2000 to 2012 maintained on TAC/MPA at transplantation hospital discharge (n=74,627) to compare outcomes of IL2-RA and other induction agents. We initially divided the cohort into two groups on the basis of steroid use at the time of discharge: steroid (n=59,010) versus no steroid (n=15,617). Each group was stratified into induction categories: IL2-RA, rabbit antithymocyte globulin (r-ATG), alemtuzumab, and no induction. The main outcomes were incidence of acute rejection within the first year and overall graft failure (defined as graft failure and/or death) post-transplantation. Propensity score (PS), specifically inverse probability of treatment weight, analysis was used to minimize selection bias caused by nonrandom assignment of induction therapies.

RESULTS

Median (25th, 75th percentiles) follow-up times were 3.9 (1.1, 5.9) and 3.2 (1.1, 4.9) years for steroid and no steroid groups, respectively. Acute rejection within the first year and overall graft failure within 5 years of transplantation were more common in the no induction category (13.3%; P<0.001 and 28%; P=0.01, respectively) in the steroid group and the IL2-RA category (11.1%; P=0.16 and 27.4%; P<0.001, respectively) in the no steroid group. Compared with IL2-RA, PS-weighted and covariate-adjusted multivariable logistic and Cox analyses showed that outcomes in the steroid group were similar among induction categories, except that acute rejection was significantly lower with r-ATG (odds ratio [OR], 0.68; 95% confidence interval [95% CI], 0.62 to 0.74). In the no steroid group, compared with IL2-RA, odds of acute rejection with r-ATG (OR, 0.80; 95% CI, 0.60 to 1.00) and alemtuzumab (OR, 0.68; 95% CI, 0.53 to 0.88) were lower, and r-ATG was associated with better graft survival (hazard ratio, 0.86; 95% CI, 0.75 to 0.99).

CONCLUSIONS

In DDRT, compared with IL2-RA induction, no induction was associated with similar outcomes when TAC/MPA/steroids were used. r-ATG seems to offer better graft survival over IL2-RA in steroid avoidance protocols.

Pretransplant CD4 Count Influences Immune Reconstitution and Risk of Infectious Complications in Human Immunodeficiency Virus-Infected Kidney Allograft Recipients

In current practice, human immunodeficiency virus-infected (HIV(+) ) candidates with CD4 >200 cells/mm(3) are eligible for kidney transplantation; however, the optimal pretransplant CD4 count above this threshold remains to be defined. We evaluated clinical outcomes in patients with baseline CD4 >350 and <350 cells/mm(3) among 38 anti-thymocyte globulin (ATG)-treated HIV-negative to HIV(+) kidney transplants performed at our center between 2006 and 2013. Median follow-up was 2.6 years. Rates of acute rejection and patient and graft survival were not different between groups. Occurrence of severe CD4 lymphopenia (<200 cells/mm(3) ), however, was more common among patients with a baseline CD4 count 200-349 cells/mm(3) compared with those transplanted at higher counts (75% vs. 30% at 4 weeks [p = 0.04] and 71% vs. 5% at 52 weeks [p = 0.001], respectively, after transplant). After adjusting for age, baseline CD4 count of 200-349 cells/mm(3) was an independent predictor of severe CD4 lymphopenia at 4 weeks (relative risk [RR] 2.6; 95% confidence interval [CI] 1.3-5.1) and 52 weeks (RR 14.3; 95% CI 2-100.4) after transplant. Patients with CD4 <200 cells/mm(3) at 4 weeks had higher probability of serious infections during first 6 months after transplant (19% vs. 50%; log-rank p = 0.05). These findings suggest that ATG must be used with caution in HIV(+) kidney allograft recipients with a pretransplant CD4 count <350 cells/mm(3) .

Influence of immune activation on the risk of allograft rejection in human immunodeficiency virus-infected kidney transplant recipients

BACKGROUND

HIV infection is associated with high rates of acute rejection following kidney transplantation. The underlying mechanisms for such predisposition are incompletely understood. Pathological immune activation is a hallmark of chronic HIV infection that persists despite effective antiretroviral therapy. We hypothesized that the baseline levels of T cell activation in HIV(+) candidates would correlate with their risk of acute rejection following kidney transplantation.

METHODS

Single-center retrospective cohort analysis of HIV(+) adult kidney transplants performed between October 2006 and September 2013. The frequency of CD3(+)HLA-DR(+) cells measured by flow cytometry served as a surrogate marker of immune activation. Patients were categorized into tertiles of activation, and the rates of biopsy-proven acute rejection were compared across groups.

RESULTS

(1) Compared to matched HIV(-) controls, the baseline number of CD3(+)HLA-DR(+) cells was higher in HIV(+) kidney transplant candidates. (2) Abnormally high levels of activation did not decrease with transplant-associated immunosuppression. (3) Patients categorized within the lower and middle CD3(+)HLA-DR(+) tertiles had higher probability of rejection during the first 3years post-transplant compared to those in the higher activation tertile (36.9% vs. 0%; log-rank P=0.04).

CONCLUSIONS

Pathological immune activation in HIV(+) transplant candidates does not explain their increased susceptibility to allograft rejection. Paradoxically, those with the highest levels of immune activation seem to be less prone to rejection.

Alemtuzumab (Campath-1H) experience in kidney transplantation what we have learned; current practices; and scope for the future?

PURPOSE OF REVIEW

Alemtuzumab (Campath) usage as a preconditioning agent in kidney transplantation has gained considerable interest in the recent future. Alemtuzumab is currently available only by special request from Sanofi through its Campath distribution program. It is restricted to transplant programs with prior and continued experience with the agent. There may be a resurgence of interest for the utilization of this agent because of its ease of administration, and less cost and comparable or improved outcome in comparison to other induction agents.

RECENT FINDINGS

Alemtuzumab when combined with standard calcineurin inhibitor and mycophenolate mofetil is well tolerated and efficacious as an induction therapy and allows for long-term steroid avoidance in high-risk renal transplant recipients.

SUMMARY

The transplant community has advanced through a learning curve with the use of alemtuzumab over time; starting from an agent that was tried out to induce proper tolerance, minimization of nephrotoxic calcineurin inhibitors, and currently as a comparable depletional therapy that can reduce acute rejection in high-risk kidney transplant recipients.

Outcomes Associated with Steroid Avoidance and Alemtuzumab among Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

Alemtuzumab is a humanized anti-CD52 monoclonal antibody used as induction in kidney transplantation (KTX) since 2003. Few studies have evaluated long-term outcomes of this agent or changes in outcomes over time.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective cohort study was performed examining United States registry data from 2003 to 2014 of primary KTX recipients receiving induction with alemtuzumab (AZ; n=5521) or antithymocyte globulin (ATG; n=8504) and maintenance immunosuppression with tacrolimus and mycophenolate mofetil and early withdrawal of steroids. The primary outcome was overall death-censored graft survival (DCGS), and secondary outcomes were overall patient survival and 1-year acute rejection. Multivariate models were fit with donor, recipient, and transplant covariates. Because poorer outcomes with AZ may occur from a learning curve impact with the use of a new medication, transplant year was categorized into three time periods to evaluate outcomes over time (2003-2005, 2006-2008, ≥2009), and an interaction term of induction type with transplant year category was included in all models to test for era impacts.

RESULTS

On multivariate analysis of DCGS there was a significant interaction between AZ and era (P<0.001). AZ was significantly associated with inferior DCGS in the earliest 2003-2005 era (adjusted hazard ratio [aHR], 2.21; 95% confidence interval [95% CI], 1.72 to 2.84) but not in the middle 2006-2008 era (aHR, 1.14; 95% CI, 0.96 to 1.36) or the most recent 2009-2014 era (aHR, 1.08; 95% CI, 0.90 to 1.29) compared with ATG. Risk-adjusted patient survival (aHR, 1.32; 95% CI, 1.08 to 1.61; aHR, 1.26; 95% CI, 1.09 to 1.46; and aHR, 1.10; 95% CI, 0.93 to 1.29 by era, respectively) and acute rejection (adjusted odds ratio [aOR], 1.17; 95% CI, 0.96 to 1.42; aOR, 0.94; 95% CI, 0.82 to 1.07; aOR, 0.89; 95% CI, 0.81 to 0.98 by era, respectively) with AZ was comparable with ATG in the most recent era; however, there was no significant interaction with time (P=0.13 and P=0.06, respectively).

CONCLUSIONS

Current alemtuzumab utilization is associated with comparable graft and patient survival and acute rejection compared with ATG. Graft survival with alemtuzumab has improved over time.

Induction Therapies in Live Donor Kidney Transplantation on Tacrolimus and Mycophenolate With or Without Steroid Maintenance

BACKGROUND AND OBJECTIVES

Induction therapy with IL-2 receptor antagonist (IL2-RA) is recommended as a first line agent in living donor renal transplantation (LRT). However, use of IL2-RA remains controversial in LRT with tacrolimus (TAC)/mycophenolic acid (MPA) with or without steroids.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Organ Procurement and Transplantation Network registry was studied for patients receiving LRT from 2000 to 2012 maintained on TAC/MPA at discharge (n=36,153) to compare effectiveness of IL2-RA to other induction options. The cohort was initially divided into two groups based on use of maintenance steroid at time of hospital discharge: steroid (n=25,996) versus no-steroid (n=10,157). Each group was further stratified into three categories according to commonly used antibody induction approach: IL2-RA, rabbit anti-thymocyte globulin (r-ATG), and no-induction in the steroid group versus IL2-RA, r-ATG and alemtuzumab in the no-steroid group. The main outcomes were the risk of acute rejection at 1 year and overall allograft failure (graft failure or death) post-transplantation through the end of follow-up. Propensity score-weighted regression analysis was used to minimize selection bias due to non-random assignment of induction therapies.

RESULTS

Multivariable logistic and Cox analysis adjusted for propensity score showed that outcomes in the steroid group were similar between no-induction (odds ratio [OR], 0.96; 95% confidence interval [95% CI], 0.86 to 1.08 for acute rejection; and hazard ratio [HR], 0.99; 95% CI, 0.90 to 1.08 for overall allograft failure) and IL2-RA categories. In the no-steroid group, odds of acute rejection with r-ATG (OR, 0.73; 95% CI, 0.59 to 0.90) and alemtuzumab (OR, 0.53; 95% CI, 0.42 to 0.67) were lower; however, overall allograft failure risk was higher with alemtuzumab (HR, 1.27; 95% CI, 1.03 to 1.56) but not with r-ATG (HR, 1.19; 95% CI, 0.97 to 1.45), compared with IL2-RA induction.

CONCLUSIONS

Compared with no-induction therapy, IL2-RA induction was not associated with better outcomes when TAC/MPA/steroids were used in LRT recipients. r-ATG appears to be an acceptable and possibly the preferred induction alternative for IL2-RA in steroid-avoidance protocols.

Comparison of alemtuzumab vs. antithymocyte globulin induction therapy in primary non-sensitized renal transplant patients treated with rapid steroid withdrawal

Alemtuzumab and rabbit antithymocyte globulin (rATG) are commonly used for induction therapy in renal transplantation. This retrospective, single-center, cohort study evaluated cumulative incidence of one-yr biopsy-proven acute rejection (BPAR) among 200 consecutive primary non-sensitized kidney transplant recipients who received either alemtuzumab (n = 100) or rATG (n = 100) induction followed by rapid steroid taper, tacrolimus, and mycophenolate mofetil. Protocol biopsies, plasma and urine BK virus PCR, serum creatinine and iothalamate glomerular filtration rate (iGFR), were obtained at 1, 4, and 12 months from transplantation. The one-yr BPAR rates were similar between the alemtuzumab and rATG groups; however, rejection Banff IA and higher was more common in the alemtuzumab arm (18% vs. 5%, p = 0.047). After adjusting for confounding variables, alemtuzumab was still associated with Banff IA and higher rejection (adjusted OR: 3.7, CI: 1.2-10.5, p = 0.02). Despite similar rates of BK viremia, more patients in the alemtuzumab arm developed BK nephropathy (16% vs. 3%, p = 0.046). One-year iGFR (53.4 ± 20.2 vs. 71.9 ± 27.2 mL/min/1.73 m(2), p = 0.002) and three-yr graft survival (89.5% vs. 95%, p = 0.05) were lower in the alemtuzumab group. In low immunological risk kidney transplant recipients on steroid-free immunosuppression, alemtuzumab was associated with more severe rejection and BK nephropathy compared to rATG.

Multivariable risk of developing new onset diabetes after transplant-results from a single-center study of 481 adult, primary kidney transplant recipients

BACKGROUND

Understanding the relative contributions of baseline demographics and immunosuppressive therapy on NODAT risk may help in developing preventive strategies.

METHODS

Using our prospectively followed cohort of 481 adult, primary kidney transplant recipients without pre-transplant diabetes, we determined the significant baseline predictors for the hazard rate of developing NODAT via Cox stepwise regression. The multivariable influence of first BPAR (defined as a time-dependent covariate) was also tested.

RESULTS

Median follow-up was 57 mo post-transplant; the overall percentage who developed NODAT was 22.5% (108/481). Four baseline predictors of a greater NODAT hazard rate were found (by order of selection): higher BMI (p < 0.000001), planned maintenance with SRL (p = 0.0003), non-white recipient (p = 0.0004), and older recipient age (p = 0.0004). Approximately one-half of the 106 patients in the highest demographic risk category (BMI ≥25 kg/m(2) , non-white race, and age at transplant ≥40 yr) developed NODAT; actuarial NODAT risk ranged from 10% to 30% in the lower demographic risk categories. First BPAR was also associated with significantly higher NODAT in multivariable analysis (p = 0.02)-the highly elevated NODAT rate observed during the first few months post-transplant and following first BPAR appears to demonstrate the diabetogenic effect of using high-dose (intravenous) corticosteroids.

CONCLUSIONS

The disturbingly high NODAT rate found among patients having multiple demographic risk factors is still an important problem that awaits a better solution.

Single-centre study of 628 adult, primary kidney transplant recipients showing no unfavourable effect of new-onset diabetes after transplant

AIMS/HYPOTHESIS

To better understand the implications of new-onset diabetes after transplant (NODAT), we used our prospectively followed cohort of 628 adult primary kidney transplant recipients to determine the prognostic impact of pretransplant diabetes and NODAT.

METHODS

The study cohort consisted of all participants in four randomised immunosuppression trials performed at our centre since May 2000. For each cause-specific hazard analysed, Cox stepwise regression was used to determine a multivariable model of significant baseline predictors; the multivariable influence of having pretransplant diabetes and NODAT (t) (the latter defined as a zero-one, time-dependent covariate) was subsequently tested. Similar analyses of estimated glomerular filtration rate (eGFR) at 36 and 60 months post transplant were performed using stepwise linear regression. Finally, a repeated measures analysis of mean HbA1c as a function of diabetes category (pretransplant diabetes vs NODAT) and randomised trial (first to fourth) was performed.

RESULTS

Median follow-up was 56 months post transplant. Patients with pretransplant diabetes comprised 23.4% (147/628), and 22.5% (108/481) of the remaining patients developed NODAT. Pretransplant diabetes had no prognostic influence on first biopsy-proven acute rejection and death-censored graft failure hazard rates, nor on eGFR, but was associated with significantly higher rates of death with a functioning graft (DWFG) (p = 0.003), DWFG due to a cardiovascular event (p = 0.005) and infection that required hospitalisation (p = 0.03). NODAT (t) had no unfavourable impact on any of these hazard rates nor on eGFR, with actuarial freedom from DWFG remaining at over 90% among patients in pre- and post-NODAT states at 72 months post transplant/NODAT. Mean HbA1c for patients in the first to fourth randomised trials, averaged across diabetes category, decreased by trial (7.28%, 6.92%, 6.87% and 6.64% [56.1, 52.1, 51.6 and 49.1 mmol/mol], respectively; p = 0.02).

CONCLUSIONS/INTERPRETATION

Less-than-expected post-NODAT risk for graft loss and death may exist in the current climate of tighter glucose monitoring post transplant.