Early outcomes of thymoglobulin and basiliximab induction in kidney transplantation: application of statistical approaches to reduce bias in observational comparisons

Effects of Antithymocyte Globulin, Basiliximab, and Induction-Free Treatment in Living Donor Kidney Transplant Recipients on Tacrolimus-Based Immunosuppression

OBJECTIVES

Induction treatment in renal transplant is associated with better graft survival. However, intensified immunosuppression is known to cause unwanted side effects such as infection and malignancy. Furthermore, the effects of the routine use of immunosuppressants in low-risk kidney transplant recipients are still not clear. In this study, we assessed the first-year safety and efficacy of induction treatment.

MATERIALS AND METHODS

We examined first living donor kidney transplant patients who were on tacrolimus based immunosuppression therapy. We formed 3 groups according to the induction status: antithymocyte globulin induction, basiliximab induction, and no induction. We collected outcome data on delayed graft function, graft loss, creatinine levels, estimated glomerular filtration rates, acute rejection episodes, hospitalization episodes, and infection episodes, including cytomegalovirus infection and bacterial infections.

RESULTS

We examined a total of 126 patients (age 35 ± 12 years; 65% male). Of them, 25 received antithymocyte globulin, 52 received basiliximab, and 49 did notreceive any induction treatment. We did not observe any statistically significant difference among the 3 groups in terms of acute rejection episodes, delayed graft function, and first-year graft loss. The estimated glomerular filtration rates were similar among the groups. Overall bacterial infectious complications and cytomegalovirus infection showed similar prevalence among all groups. Hospitalization was less common in the induction-free group.

CONCLUSIONS

In low-risk patients, induction-free regimens could be associated with a better safety profile without compromising graft survival. Therefore, induction treatment may be disregarded in first living donor transplant patients who receive tacrolimusbased triple immunosuppression treatment.

The comparative efficacy and safety of basiliximab and antithymocyte globulin in deceased donor kidney transplantation: a multicenter cohort study

BACKGROUND

Generally, an induction agent is chosen based on the conditions of the deceased donor and the recipient. Antithymocyte globulin (ATG) is preferred in relatively high-risk conditions. No clear evidence indicates which induction agent is safer or more efficient for deceased donor kidney transplantation (DDKT). This study compares the efficacy and safety of basiliximab (BSX) and ATG according to donor characteristics in DDKT.

METHODS

A total of 724 kidney transplant recipients from three transplant centers were enrolled, and propensity score matching was performed. Based on a donor age of 60 years, donor kidney with acute kidney injury (AKI), and Kidney Donor Profile Index (KDPI) score of 65%, we investigated how the choice of induction therapy agent affected the posttransplant clinical outcomes of delayed graft function (DGF), acute rejection (AR), infectious complications, and allograft and patient survival.

RESULTS

AR and DGF did not differ significantly according to induction agent in elderly/young donor, AKI/non-AKI, and high-KDPI/ low-KDPI subgroups. The infection rate did not show meaningful differences. The differences in death-censored allograft survival and patient survival rates between induction agents were not statistically significant.

CONCLUSION

Our study suggests that BSX can produce clinical outcomes similarly favorable to those of ATG even in DDKT cases with relatively poor donor conditions. Nonetheless, the donor and recipient conditions, immunological risk, and infection risk must be all taken into consideration when choosing an induction agent. Therefore, clinicians should carefully select the induction therapy agent for DDKT based on the risks and benefits in each DDKT case.

Untangling the Knots of Regulatory T Cell Therapy in Solid Organ Transplantation

Numerous preclinical studies have provided solid evidence supporting adoptive transfer of regulatory T cells (Tregs) to induce organ tolerance. As a result, there are 7 currently active Treg cell-based clinical trials in solid organ transplantation worldwide, all of which are early phase I or phase I/II trials. Although the results of these trials are optimistic and support both safety and feasibility, many experimental and clinical unanswered questions are slowing the progression of this new therapeutic alternative. In this review, we bring to the forefront the major challenges that Treg cell transplant investigators are currently facing, including the phenotypic and functional diversity of Treg cells, lineage stability, non-standardized ex vivo Treg cell manufacturing process, adequacy of administration route, inability of monitoring and tracking infused cells, and lack of biomarkers or validated surrogate endpoints of efficacy in clinical trials. With this plethora of interrogation marks, we are at a challenging and exciting crossroad where properly addressing these questions will determine the successful implementation of Treg cell-based immunotherapy in clinical transplantation.

The Risk of Postkidney Transplant Outcomes by Induction Choice Differs by Recipient Age

Supplemental Digital Content is available in the text.

Background.

Among adult kidney transplant (KT) recipients, the risk of post-KT adverse outcomes differs by type of induction immunosuppression. Immune response to induction differs as recipients age; yet, choice of induction is barely tailored by age likely due to a lack of evidence of the risks and benefits.

Methods.

Using Scientific Registry of Transplant Recipients data, we identified 39336 first-time KT recipients (2010–2016). We estimated the length of stay (LOS), acute rejection (AR), graft failure, and death by induction type using logistic and Cox regression weighted by propensity score to adjust for confounders. We tested whether these estimates differed by age (65+ versus 18–64 y) using a Wald test.

Results.

Overall, rabbit antithymocyte globulin (rATG) was associated with a decreased risk of AR (odds ratio = 0.79, 95% confidence interval [CI], 0.72-0.85) compared with basiliximab. The effect of induction on LOS and death (interaction P = 0.03 and 0.003) differed by recipient age. Discharge was on average 11% shorter in rATG among younger recipients (relative time = 0.89; 95% confidence interval [CI], 0.81-0.99) but not among older recipients (relative time = 1.01; 95% CI, 0.95-1.08). rATG was not associated with mortality among older (hazard ratio = 1.05; 95% CI, 0.96-1.15), but among younger recipients (hazard ratio = 0.87; 95% CI, 0.80-0.95), it was associated with reduced mortality risk.

Conclusions.

rATG should be considered to prevent AR, especially among recipients with high-immunologic risk regardless of age; however, choice of induction should be tailored to reduce LOS and risk of mortality, particularly among younger recipients.

Outcomes of Interleukin-2 Receptor Antagonist Induction Therapy in Standard-Risk Renal Transplant Recipients Maintained on Tacrolimus: A Systematic Review and Meta-Analysis

INTRODUCTION

The additive benefit of interleukin-2 receptor antagonist (IL2-RA) induction in standard-risk kidney transplant recipients, while maintained on tacrolimus-based immunosuppressive therapy, is uncertain.

METHODS

We divided the studies included in this meta-analysis into 2 groups: group A (included studies that used same dose of tacrolimus in both arms of each study) and group B (included studies that compared patients who received induction therapy and low-dose tacrolimus vs. those who received no-induction therapy and high dose of tacrolimus).

RESULTS

In group A, 11 studies were included (n = 2,886). IL2-RA induction therapy was not associated with significant differences in comparison to no-induction therapy in terms of acute rejection rates at 6 months post-transplant (risk ratio = 1.12 and 95% confidence interval [CI] range: 0.94-1.35) or graft survival at 1 year post-transplant (risk ratio = 0.78 and 95% CI range: 0.45-1.36). In group B, 2 studies were included (n = 669). There was no difference between both arms in terms of acute rejection rates (risk ratio = 0.62, with 95% CI range: 0.33-1.14) or graft survival (risk ratio = 1 and 95% CI range: 0.57-1.74).

CONCLUSION

IL2-RA induction therapy does not improve outcomes in patients maintained on tacrolimus-based immunotherapy in standard-risk population.

The Impact of Different Induction Immunosuppressive Therapy on Long-Term Kidney Transplant Function When Measured by Iothalamate Clearance

Background

Improvement in short-term outcomes after kidney transplant has been achieved by using different induction and maintenance therapeutic approaches. Long-term outcomes have not matched the expectations of the transplant stakeholders. Our study aimed to address the early impact of induction agents on long-term outcome of kidney transplant when measured by iothalamate clearance.

Methods

All adult kidney transplant recipients between January of 2012 and December of 2016 were reviewed. Six hundred forty-nine patients were divided into three groups based on the induction agent (basiliximab, alemtuzumab, and thymoglobulin). Protocoled 4 months and 48 months kidney allograft function evaluations with iothalamate clearance test were compared among the three groups.

Results

Patients who received basiliximab were significantly older with no difference among African American and Caucasians. The 48 months assessment showed significant decline in median iothalamate clearance in basiliximab group at 49 mL/min vs. alemtuzumab group 64.8 mL/min and thymoglobulin 60 mL/min with P = 0.007. The basiliximab group developed a significant higher proteinuria measured by spot urine to creatinine ratio at 48 months.

Conclusions

The use of basiliximab as an induction agent for kidney transplant is associated with significant decline in kidney function 4 years post transplantation when measured by iothalamate clearance.

Practice Patterns and Outcomes of Online Hemodiafiltration: A Real-World Evidence Study in a Russian Dialysis Network

BACKGROUND

Evidence suggests that online hemodiafiltration (OL-HDF) is associated with improved survival. Whether the dose-response relationship between convective volume and mortality may be confounded by selection bias or descends from practice patterns is not clear. We sought to evaluate the role of patients' characteristics and practice patterns on OL-HDF dose and mortality in a large private dialysis network in the Republic of Russia.

METHODS

In this multicenter, historical cohort study, we included adult incident patients on OL-HDF with at least 90 days of survival on renal replacement therapy in centers belonging to the Russian Federation Fresenius Medical Care network (January 1, 2011, to December 31, 2016). We evaluated predictors and outcomes (survival) of substitution volume target achievement (Qsub > 21 L/session).

RESULTS

Among 1,081 enrolled patients, the average Qsub was 22.9 (±3.2) L/session; the mean ultrafiltration volume was 1.6 (±0.8) L/session. The mean age was 55.8 ± 13.2; 42% were woman. Most common comorbidities were congestive heart failure (39.7%) and peripheral vascular disease (21.7%). The average hemoglobin was 9.3 ± 1.3. The case-mix adjusted center effect accounted for 20% of variance in Qsub. The top 10 most important variables associated with higher Qsub were effective Qb, serum protein, Charlson's comorbidity index, hemoglobin, year of dialysis initiation (proxy of high Qsub treatment policy in the clinic network), predialysis heart rate, serum bicarbonate, serum phosphate, age, serum sodium, and dry body weight. In addition, we found that the association of Qb with Qsub is moderated by year of enrollment, intradialytic weight gain, and coronary artery disease, whereas higher hemoglobin concentration moderated the relationship between treatment time and Qsub. Finally, Qsub between 21 and 25 L/session was associated with longer 5-year survival.

CONCLUSIONS

Both center-dependent clinical practice standards and patient clinical conditions substantially contributed to the risk of low Qsub. We confirmed previous evidence indicating better survival among patients with Qsub ≥ 21 L/session.

Outcome Comparison between Low-Dose Rabbit Anti-Thymocyte Globulin and Basiliximab in Low-Risk Living Donor Kidney Transplantation

The objective of this study was to compare outcomes between basiliximab and low-dose r-ATG in living donor kidney transplantation recipients with low immunological risk. Patients in the low-dose r-ATG group received 1.5 mg/kg of r-ATG for 3 days (total 4.5 mg/kg). Graft survival, patient survival, acute rejection, de novo donor specific antibody (DSA), estimated glomerular filtration rate (e-GFR) changes, and infection status were compared. Among 268 patients, 37 received r-ATG, and 231 received basiliximab. There was no noticeable difference in the graft failure rate (r-ATG vs. basiliximab: 2.7% vs. 4.8%) or rejection (51.4% vs. 45.9%). de novo DSA was more frequent in the r-ATG group (11.4% vs. 2.4%, p = 0.017). e-GFR changes did not differ noticeably between groups. Although most infections showed no noticeable differences between groups, more patients in the r-ATG group had cytomegalovirus (CMV) antigenemia and serum polyomavirus (BK virus) (73.0% vs. 51.9%, p = 0.032 in CMV; 37.8% vs. 15.6%, p = 0.002 in BK), which did not aggravate graft failure. Living donor kidney transplantation patients who received low-dose r-ATG and patients who received basiliximab showed comparable outcomes in terms of graft survival, function, and overall infections. Although CMV antigenemia, BK viremia were more frequent in the r-ATG group, those factors didn’t change the graft outcomes.

Evidence of Interleukin-2-Receptor-Antibody Induction in Low-Risk Living Donor Kidney Transplantation: A Single-Center Pilot Study

BACKGROUND

The recommended standard immunosuppressive therapy for renal transplant recipients comprises an initial induction therapy mainly with an interleukin-2-receptor antibody (IL2-RA) and a triple maintenance therapy. With tacrolimus and mycophenolate acid it is unknown whether IL2-RA application affects the short- and long-term results. This question is addressed in the present analysis.

METHODS

From July 2007 to June 2019 a total of 127 living donor kidney transplant recipients meeting the center-specific definition of immunologic low risk situation (first transplantation, HLA-mismatch ≤3, panel reactive antibody ≤10%) were identified. In 83 recipients with a first-degree relationship to the donor we omitted the IL2-RA induction (IL2-RA-). The remaining 44 recipients, mostly not first-degree relatives, served as controls (IL2-RA+). Biopsy-proven acute rejection and long-term patient and graft survival rates were compared.

RESULTS

Biopsy-proven acute rejection rates after 3 months were similar in both groups with 4.8% (IL2-RA-) vs 13.7% (IL2-RA+; P = .0937), including borderline rejection rates of 18.0% (IL2-RA-) vs 18.3% (IL2-RA+; P = 1.000), respectively. Ten-year long-term survival rates were comparable between the IL2-RA- and the IL2-RA+ group with 95.6% vs 93.5% (patient survival; P = .5465) and 92.1% vs 90.6% (death-censored graft survival; P = .8893).

CONCLUSION

For low-risk living donor kidney transplant recipients with first-degree relationship to the donor, it is safe to omit induction therapy with IL2-RA.

Use of Basiliximab with the Standard Immunosuppressive Protocol in Pediatric Renal Transplantation: A Double-Blind Randomized Clinical Trial

BACKGROUND

Several randomized clinical trials performed on adult renal transplant recipients have shown a significant reduction in the incidence of acute rejection by using basiliximab as induction therapy. However, few studies have been conducted on kidney graft survival following the use of the drug among pediatric transplant recipients.

OBJECTIVE

To address the efficacy and safety of basiliximab in the improvement of the survival of children with kidney transplants.

METHODS

This randomized, double-blind single-center clinical trial was conducted on 28 children (57% male) who underwent live-unrelated renal transplantation. They were randomly assigned into an intervention group receiving basiliximab (10 mg in patients weighing <40 kg or 20 mg in patients ≥40 kg) as induction therapy in combination with the standard immunosuppressive regimen (n=14), or to the control group (n=14) receiving only the standard immunosuppressive regimen (without basiliximab). The outcome was assessed by the measurement of serum creatinine level before transplantation, and 24, 48, and 72 hours as well as 3, 6, and 12 months post-transplantation. The estimated glomerular filtration rate at 12 months post-transplantation and graft survival were also measured. The number of acute rejection episodes in transplant recipients was also considered.

RESULTS

The mean±SD age of participants was 12.3±4.2 years. No difference was observed between the two groups in terms of serum creatinine level before and after transplantation at various time points. The mean±SD eGFR at 12 months post-transplantation was 87.8±8.4 in the basiliximab and 85.2±5.8 in the control group (p=0.37). No significant difference was observed between the two groups in terms of acute rejection episodes (25% in basiliximab and 33% in the control group). The graft survival at 1-year post-transplantation was 93% in the basiliximab and 86% in the control group (p=0.54).

CONCLUSION

Adding basiliximab to the standard immunosuppressive regimen may not improve the graft survival.

Implication of interleukin-2 receptor antibody induction therapy in standard risk renal transplant in the tacrolimus era: a meta-analysis

Background

Interleukin-2 (IL-2) antagonist has been used as an induction therapy in many centres in calcineurin inhibitor-sparing regimens. Tacrolimus has overwhelmingly replaced cyclosporine in the maintenance immunosuppressive protocols in many transplant centres. The aim of our study and meta-analysis is to explore the effect of IL-2 induction therapy on the rate of rejection and patient and graft survival in standard-risk renal transplant patients with tacrolimus-based maintenance immunotherapy. Secondary aims included assessment of the effect of IL-2 induction therapy on creatinine change and the risk of cytomegalovirus (CMV) infection.

Methods

We conducted a systematic review in different databases to identify studies and research work that assessed the effect of IL-2 antibody induction therapy on renal transplant outcomes. Inclusion criteria for our meta-analysis were all studies that compared IL-2 induction therapy with placebo or no induction therapy in standard-risk renal transplant recipients on tacrolimus-based maintenance immunosuppressive therapy. Data collected were the name of the first author, journal title, year of publication, country where the study was conducted, number of patients in the IL-2 induction therapy arm and in the placebo arm, number of patients who had biopsy-proven rejection and graft survival in each arm. A random effects model was used for the meta-analysis.

Results

Of the 470 articles found in different databases, 7 were included in the meta-analysis. Forest plot analysis for rate of rejection during the follow-up period post-transplant showed no significant difference between the groups. There was no evidence of heterogenicity between included studies (I ² = 21.8%, P = 0.27). The overall risk difference was -0.02 [95% confidence interval (CI) -0.05-0.01]. A random effects meta-analysis for patient and graft survival was performed using forest plot analysis and showed no significant effect of IL-2 receptor (IL-2R) antibody induction on patient or graft survival compared with placebo. The overall risk difference was -0.01 (95% CI -0.04-0.01) and 0.00 (95% CI -0.00-0.01), respectively. Three of the included studies showed no effect of basiliximab on creatinine change, two showed no effect on risk of CMV infection and two showed less risk of post-transplant diabetes in the basiliximab group.

Conclusion

IL-2R antibody induction therapy has no significant effect on the rate of rejection or patient or graft survival in standard-risk renal transplant recipients on tacrolimus-based maintenance immunotherapy. More randomized controlled studies are needed.

Detecting high-risk chronic kidney disease-mineral bone disorder phenotypes among patients on dialysis: a historical cohort study

BACKGROUND

The clinical management of chronic kidney disease-mineral bone disorder (CKD-MBD) remains extremely challenging, partially due to difficulties in defining high-risk phenotypes based on serum biomarkers. We evaluated the prevalence and outcomes of 27 mutually exclusive CKD-MBD phenotypes in a large, multi-national cohort of chronic dialysis patients over a 5-year follow-up study.

METHODS

In this historical cohort study, we enrolled all haemodialysis patients registered in EuCliD® on 1 July 2011 across 28 Europe, the Middle East and Africa (EMEA) and South American countries. We created 27 mutually exclusive phenotypes based on combinations of serum parathyroid hormone (PTH), phosphorus (P) and calcium (Ca) 6-month averages (L, low; T, target; H, high). We tested the association between CKD-MBD phenotypes and 5-year mortality and hospitalization risk by outcome risk score-adjusted proportional hazard regression.

RESULTS

We enrolled 35 721 eligible patients. Eastern European and South American countries generally achieved poorer CKD-MBD control when compared with Western European countries (prevalence ratio: 0.79; P < 0.001). There were 15 795 deaths [126.7 deaths/1000 person-years; 95% confidence interval (CI) 124.7-128.7]; 18 014 had at least one hospitalization (203.9 hospitalizations/1000 person-years; 95% CI 201.0-206.9); the incidence of the composite endpoint was 280.0 events/1000 person-years (95% CI 276.6-283.5). In the fully adjusted model, relative mortality risk ranged from hazard ratio (HR) = 1.07 (PTH/Ca/P: TLT) to HR = 1.59 (PTH/Ca/P: LTL), whereas the relative composite endpoint risk ranged from HR = 1.07 (PTH/Ca/P: TTH) to HR = 1.36 (PTH/Ca/P: LTL).

CONCLUSION

We identified several CKD-MBD phenotypes associated with reduced hospitalization-free survival and increased mortality. Ranking of relative risk estimates or excess events concurs in informing healthcare priority setting.

Long-term Nonhuman Primate Renal Allograft Survival Without Ongoing Immunosuppression in Recipients of Delayed Donor Bone Marrow Transplantation

BACKGROUND

We have previously reported successful induction of renal allograft tolerance in nonhuman primates (NHP) after an initial posttransplant period of conventional immunosuppression (delayed tolerance) using a nonmyeloablative conditioning regimen consisting of anti-CD154 and anti-CD8 mAbs plus equine antithymocyte globulin (Atgam) and donor bone marrow transplantation (DBMT). Because these reagents are not currently clinically available, the protocol was revised to be applicable to human recipients of deceased donor allografts.

METHOD

Four cynomolgus monkeys received major histocompatibility complex-mismatched kidney allografts with conventional immunosuppression for 4 months. The recipients were then treated with a nonmyeloablative conditioning regimen consisting of thymoglobulin, belatacept, and DBMT. The results were compared with recipients treated with conditioning regimen consisting of Atgam and anti-CD154 mAb, with and without anti-CD8 mAb.

RESULTS

In 4 consecutive NHP recipients treated with the modified conditioning regimen, homeostatic recovery of CD8 TEM was delayed until after day 20 and multilineage chimerism was successfully induced. Three of the 4 recipients achieved long-term allograft survival (>728, >540, >449 days) without ongoing maintenance immunosuppression. Posttransplant MLR showed loss of antidonor CD8 T cell and CD4 IFNγ responses with expansion of CD4FOXP3 regulatory T cells. However, the late development of donor-specific antibody in NHP recipients confirms the need for additional anti-B-cell depletion with agents, such as rituximab, as has been shown in our clinical trials.

CONCLUSIONS

This study provides proof of principle that induction of mixed chimerism and long-term renal allograft survival without immunosuppression after delayed DBMT is possible with clinically available reagents.

Center practice drives variation in choice of US kidney transplant induction therapy: a retrospective analysis of contemporary practice

To assess factors that influence the choice of induction regimen in contemporary kidney transplantation, we examined center-identified, national transplant registry data for 166 776 US recipients (2005-2014). Bilevel hierarchical models were constructed, wherein use of each regimen was compared pairwise with use of interleukin-2 receptor blocking antibodies (IL2rAb). Overall, 82% of patients received induction, including thymoglobulin (TMG, 46%), IL2rAb (22%), alemtuzumab (ALEM, 13%), and other agents (1%). However, proportions of patients receiving induction varied widely across centers (0-100%). Recipients of living donor transplants and self-pay patients were less likely to receive induction treatment. Clinical factors associated with use of TMG or ALEM (vs. IL2rAb) included age, black race, sensitization, retransplant status, nonstandard deceased donor, and delayed graft function. However, these characteristics explained only 10-33% of observed variation. Based on intraclass correlation analysis, "center effect" explained most of the variation in TMG (58%), ALEM (66%), other (51%), and no induction (58%) use. Median odds ratios generated from case-factor adjusted models (7.66-11.19) also supported large differences in the likelihood of induction choices between centers. The wide variation in induction therapy choice across US transplant centers is not dominantly explained by differences in patient or donor characteristics; rather, it reflects center choice and practice.

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.

Induction Therapy for Kidney Transplant Recipients: Do We Still Need Anti-IL2 Receptor Monoclonal Antibodies?

Induction therapy with antilymphocyte biological agents is widely used after kidney transplantation, most commonly T lymphocyte-depleting rabbit-derived antithymocyte globulin (rATG) or an IL-2 receptor antagonist (IL2RA). Early randomized trials showed that rATG or IL2RA induction reduces early acute rejection, prompting recommendations by Kidney Disease Improving Global Outcomes that IL2RA induction be used routinely in first-line therapy after kidney transplantation, with lymphocyte-depleting induction reserved for high-risk cases. These studies, however, mainly used outdated maintenance regimens. No large randomized trial has examined the effect of IL2RA or rATG induction versus no induction in patients receiving tacrolimus, mycophenolic acid and steroids. With this triple maintenance therapy, the addition of induction may achieve an absolute risk reduction for acute rejection of only 1-4% in standard-risk patients without improving graft or patient survival. In contrast, rATG induction lowers the relative risk of acute rejection by almost 50% versus IL2RA in patients with high immunological risk. These recent data raise questions about the need for IL2RA in kidney transplantation, as it may no longer be beneficial in standard-risk transplantation and may be inferior to rATG in high-risk situations. Updated evidence-based guidelines are necessary to support clinicians deciding whether and what induction therapy is required for their transplant patients today.

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.

Efficacy and safety of antibody induction therapy in the current era of kidney transplantation

BACKGROUND

Antibody induction with polyclonal rabbit-antithymocyte globulin (rATG) or an interleukin-2 receptor antagonist (IL-2RA) is widely used in kidney transplantation.

METHODS

Collaborative Transplant Study data from 38 311 first deceased-donor kidney transplants (2004-13) were analysed. Transplants were classified as 'normal risk' or 'increased risk' according to current guidelines. Cox regression analysis was applied to subpopulations of propensity score-matched recipients.

RESULTS

rATG or IL-2RA induction was given to 64% of increased-risk and 53% of normal-risk patients, respectively. rATG and IL-2RA induction were each associated with reduced risk for graft loss versus no induction in increased-risk patients [hazard ratio (HR) 0.85, P = 0.046 and HR 0.89, P = 0.011, respectively]. The HR values for incidence of treated rejection in increased-risk patients for rATG and IL-2RA versus no induction were 0.75 (P = 0.037) and 0.77 (P < 0.001), respectively. In the normal risk subpopulation, neither induction therapy significantly affected the risk of graft loss or treated rejection. Hospitalization for infection was increased by rATG (P < 0.001) and IL-2RA (P < 0.001) induction. In contrast to patients transplanted during 1994-2003, among patients transplanted during 2004-13, rATG did not significantly affect the risk of non-Hodgkin's lymphoma versus no induction (P = 0.68).

CONCLUSION

Induction therapy following kidney transplantation should be targeted to increased-risk transplants. In this analysis, a beneficial effect of antibody induction in normal-risk transplants could not be demonstrated.

Induction Immunosuppressive Therapy Use in Deceased Donor Kidney Transplantation: 11-Year Experience in Veracruz, Mexico

BACKGROUND

Induction therapy reduces the frequency of acute rejection and delayed graft function in renal transplantation. Basiliximab and Thymoglobulin are most commonly used agents for induction.

METHODS

A retrospective study of two transplant centers in Veracruz, Mexico compared induction therapy in deceased donor renal transplantation from 2003 to 2014. Efficacy and safety outcomes evaluated were primary graft nonfunction, delayed graft function, acute rejection episodes and hospitalizations during first year, and patient and graft survival. P < .05 was considered statistically significant.

RESULTS

Seventy deceased kidney donors (40 male) were studied. Mean donor age was 32.9 ± 14.3 years, mean donor BMI 25.6 ± 4.3 kg/m(2), and mean donor creatinine 1.13 ± 0.58 mg/dL. Main cause of death was trauma (62.9%). In total, 125 kidney transplantations were performed, with female predominance (53.6%) and mean age 33.8 ± 11.8 years. Of these, 66.4% used basiliximab and 33.6% Thymoglobulin. Thymoglobulin patients were significantly older, with lower weight and BMI, and were on dialysis longer than basiliximab patients. DGF was present in 19.3% of basiliximab patients vs 16.7% in Thymoglobulin patients, acute rejection occurred in 16.9% of basiliximab patients vs 19% Thymoglobulin patients. A total of 33.7% basiliximab patients were hospitalized during the first year vs 47.6% Thymoglobulin-induced patients (P > .05). Mean graft survival was 84.2 ± 5.3 months (73.8-94.7) basiliximab vs 32.4 ± 28.7 months (28.7-36.1) Thymoglobulin, Kaplan-Meier survival did not show statistically significant differences between groups (P = .276; CI 95%).

CONCLUSION

Similar transplant outcomes were obtained using basiliximab or Thymoglobulin induction in our population.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

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.

Taming inflammation by targeting cytokine signaling: new perspectives in the induction of transplantation tolerance

Transplantation tolerance remains an elusive goal, partly due to limitations in our understanding of the interplay between inflammatory mediators and their role in the activation and regulation of T lymphocytes. Although multiple mechanisms acting both centrally and peripherally are responsible for tolerance induction, the signaling pathways leading to activation or regulation of adaptive immunity are often complex, branched, redundant and modulated by the microenvironment's inflammatory milieu. Accumulating evidence clearly indicates that inflammatory cytokines limit the tolerogenic potential of immunomodulatory protocols by supporting priming of the immune system and counteracting regulatory mechanisms, ultimately promoting rejection. In this review, we summarize recent progress in the development of novel therapeutics to manipulate this inflammatory environment and achievements in targeted inhibition of inflammatory cytokine signaling. Ultimately, robust transplant tolerance induction will probably require a multifaceted, holistic approach that integrates the various mechanisms of tolerance induction, incorporates the dynamic alterations in costimulatory requirements of alloreactive T cells, while maintaining endogenous mechanisms of immune regulation.

The role of Thymoglobulin induction in kidney transplantation: an update

The rabbit antithymocyte globulin Thymoglobulin first became available over 25 yr ago and is the most widely used lymphocyte-depleting preparation in solid organ transplantation. Thymoglobulin targets a wide range of T-cell surface antigens as well as natural killer-cell antigens, B-cell antigens, plasma cell antigens, adhesion molecules and chemokine receptors, resulting in profound, long-lasting T-cell depletion. Randomized studies have established the anti-rejection efficacy of Thymoglobulin in kidney transplantation. Experimental and clinical data suggest that Thymoglobulin administration may ameliorate ischemia reperfusion injury, thus reducing the incidence of delayed graft function (DGF). Studies have demonstrated the benefit of using Thymoglobulin to facilitate immunosuppression minimization, both for corticosteroid and calcineurin inhibitor (CNI) withdrawal or avoidance, with potential improvement in cardiovascular and renal outcomes. The optimal cumulative dose for Thymoglobulin induction is 6-7.5 mg/kg, with vigilant short- and long-term monitoring of hematological status. Induction with Thymoglobulin is now indicated in immunologically high-risk patients, in those at increased risk of DGF and to maintain efficacy in low-risk transplant recipients receiving steroid or CNI minimization or avoidance regimens. We suggest that in future trials Thymoglobulin be tested with costimulation signal blockers and other immunosuppressants with the objective of establishing operational tolerance.

Basiliximab induction in patients receiving tacrolimus-based immunosuppressive regimens

PURPOSE

The use of basiliximab induction increased significantly in recent years based on its superior efficacy and excellent safety profile demonstrated in studies with cyclosporine-based immunosuppression. However, its clinical utility in patients receiving tacrolimus-based immunosuppressive regimens is still uncertain.

METHODS

We retrospectively reviewed data of 366 low immunological risk recipients of deceased donor kidney transplants. Of them, 134 received basiliximab and tacrolimus (TAC-IL2-RA), 100 received basiliximab and delayed tacrolimus(dTAC-IL2-RA), and 132 patients received tacrolimus without basiliximab(TAC-No). The endpoints were the incidence of acute rejection, graft function, and patient and graft survivals at 1 year.

RESULTS

The incidence of acute rejection was higher in dTAC-IL2-RA compared to TAC-IL-2RA and TAC-No Groups (33 vs.14.9 vs. 14.3 %, p < 0.001). Inferior creatinine clearance was observed in dTAC-IL2-RA Group compared to TAC-IL2-RA and TAC-No Groups at months 1 (41.6 vs. 49.9 vs. 44.8 mL/min, p = 0.004), 3 (49.8 vs. 57.2 vs. 53.5 mL/min, p = 0.017), and 6 (53.1 vs. 61.8 vs. 57.0 mL/min, p = 0.001). Patients who received basiliximab (TAC-IL2-RA and dTAC-IL2-RA Groups) had lower incidence of posttransplant diabetes (24 vs.18 vs. 39.3 %, p = 0.009). Patient and graft survivals were similar among the groups.

CONCLUSIONS

In low immunological risk kidney transplant recipients receiving tacrolimus, the use of basiliximab induction was not associated with lower rejection rates and did not allow delayed tacrolimus introduction.

Immunosuppressive protocols and immunological challenges related to hand transplantation

There are many immunological challenges related to hand transplantation. Curbing the immune system's ability to effectively mount an immune response against the graft is the goal. As the various components of the immune response are defined and their mechanisms of action delineated, more specific immunosuppressive agents and protocols have been developed. Complications related to immunosuppression in hand transplant recipients are similar to incidences among solid organ recipients. With longer follow-up, the increased cardiovascular risk factors or the development of a neoplasm will likely cause mortality. Standardizing immunosuppression in hand transplantation with the long-term goal of minimization is critically needed.

Endorsement of the Kidney Disease Improving Global Outcomes (KDIGO) guidelines on kidney transplantation: a European Renal Best Practice (ERBP) position statement

KDIGO (Kidney Disease: Improving Global Outcomes) is an international independent body aiming to 'improve the care and outcomes of kidney disease patients worldwide, through the development and implementation of clinical practice guidelines'. Recently, the KDIGO work group has produced comprehensive clinical practice guidelines for the care of kidney transplant recipients (KTRs). The guideline makes recommendations for immunosuppression, graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy and other complications that are common in KTRs, including haematological and bone disorders. Because most guidelines were 'soft' rather than 'strong', and because global guidelines need to be adapted and implemented into the regional context where they are used, the European Renal Best Practice (ERBP) Advisory Board appointed a work group of transplant nephrologists and surgeons to review the newest KDIGO guideline and comment on its relevance and applicability for European KTRs. In this article, we concentrate only on those guidelines which we considered worth amending or adapting. All guidelines not mentioned are fully endorsed.

Effect of interleukin-2 receptor antibody therapy on acute rejection risk and severity, long-term renal function, infection and malignancy-related mortality in renal transplant recipients

In renal transplantation, the use of interleukin-2 receptor antibody (IL-2Ra) has been associated with reduced rejection rates, but the effect of this agent on rejection severity and type, long-term graft function and risk of infection and malignancy-related mortality remains unclear. Using Australia and New Zealand Dialysis and Transplant Registry, all live- and deceased-donor renal transplant recipients in Australia between 2000 and 2006 were included. Of the 3344 renal transplant recipients, 1874 (56.0%) received no induction and 1470 (44.0%) had received IL-2Ra. Compared with no induction, IL-2Ra was associated with reduced rejection risk (relative risk 0.70, 95% CI 0.60, 0.81) and higher estimated glomerular filtration rate at 5 years (difference in means 3.51, 95% CI 0.83, 6.19). Severity and type of rejection were similar in both the groups. The adjusted rate of death attributed to malignancy for no induction and IL-2Ra per 1000 patient-years was 1.48 and 1.63, respectively, whereas death attributed to infection was 2.42 and 2.16 respectively. This registry analysis demonstrates that IL-2Ra induction in kidney transplantation is associated with substantial clinical benefits of reduced risk of acute rejection and improved long-term graft function without an increase in adverse events.

Steroid avoidance in two-haplotype-matched living donor renal transplants with basiliximab induction therapy

BACKGROUND

Induction therapy and haplotype matching are utilized to mitigate immunologic risk in renal transplantation. The incidence of acute rejection (AR) of renal allografts has been reported to be as low as 9.3% within the first year among two-haplotype-matched siblings with no induction and triple-drug maintenance immunosuppression. We report our use of basiliximab induction in a series of two-haplotype-matched living donor renal transplants (LDRT).

METHODS

We retrospectively reviewed 25 patients who received a two-haplotype-matched LDRT with basiliximab induction therapy. The primary endpoints were acute rejection (AR) episodes at 6 and 12 months and 1-year patient and graft survival rates. The secondary endpoints were the incidence of delayed graft function (DGF), cytomegalovirus (CMV), and BK virus (BKV).

RESULTS

The rate of AR at 6 months was 0% (0/25) and 4% (1/25) at 12 months. The 1-year graft and patient survival rates were 100%. The incidence of DGF was 4% (1/25), while the incidences of CMV and BKV were 0%.

CONCLUSION

Basiliximab induction therapy with a steroid-sparing regimen yields favorable results in two-haplotype-matched LDRT, including a notable reduction in the rates of AR as compared to triple-drug maintenance immunosuppression without induction. These patients have excellent graft survival with no increased incidences of secondary infections.

Rabbit antithymocyte globulin (thymoglobulin): 25 years and new frontiers in solid organ transplantation and haematology

The more than 25 years of clinical experience with rabbit antithymocyte globulin (rATG), specifically Thymoglobulin, has transformed immunosuppression in solid organ transplantation and haematology. The utility of rATG has evolved from the treatment of allograft rejection and graft-versus-host disease to the prevention of various complications that limit the success of solid organ and stem cell transplantation. Today, rATG is being successfully incorporated into novel therapeutic regimens that seek to reduce overall toxicity and improve long-term outcomes. Clinical trials have demonstrated the efficacy and safety of rATG in recipients of various types of solid organ allografts, recipients of allogeneic stem cell transplants who are conditioned with both conventional and nonconventional regimens, and patients with aplastic anaemia. Over time, clinicians have learnt how to better balance the benefits and risks associated with rATG. Advances in the understanding of the multifaceted mechanism of action will guide research into new therapeutic areas and future applications.

A review of the evidence for use of thymoglobulin induction in renal transplantation

Depleting antilymphocyte, or antithymocyte antibodies, have long been an integral part of induction regimens and continue today to be used in the management of patients at risk of early rejection or those in whom the introduction of calcineurins or other immune suppressants must be delayed. Registry data demonstrate that the most commonly used depleting antibody, rabbit anti-human thymocyte globulin (rATG), is associated with improved outcomes following renal transplantation in high-risk patients, particularly in conjunction with steroid-avoidance regimens. Two prospective randomized trials in high-risk renal allograft patients have also demonstrated an advantage of r-ATG induction compared to the nondepleting interleukin receptor (IL2RA) antibodies. In low-immunologic-risk patients, however, r-ATG induction and IL2RA induction appear to be equivalent in terms of rejection prophylaxis and long-term function. Other studies have shown that sequential rATG-containing regimens were superior to no induction and allowed for successful late introduction of calcineurin inhibitors. The side effect profile of the depleting antibody included increased incidence of fever, hematologic abnormalities, cytomegalovirus infections when prophylaxis was not employed, and in some studies, increased incidence of posttransplant lymphoproliferative disease. This review describes the evidence supporting the use of depleting ATGs in kidney transplantation.

Interleukin-2 receptor antibody does not reduce rejection risk in low immunological risk or tacrolimus-treated intermediate immunological risk renal transplant recipients

AIM

The use of interleukin-2 receptor antibody (IL-2Ra) induction has been associated with reduced rejection rates in renal transplant recipients. However, the effect of IL-2Ra induction on graft and patient outcomes in renal transplant recipients with differing immunological risk remains unclear.

METHODS

Using Australia and New Zealand Dialysis and Transplant Registry, renal transplant recipients in Australia between 1995 and 2005 were included. Recipients were stratified into low immunological risk (primary grafts with < or = 2 human leucocyte antigen (HLA)-mismatches and panel-reactive antibody (PRA) < 10%) or intermediate immunological risk (subsequent grafts or >2 HLA-mismatches or PRA > 25%) recipients. Recipients receiving T-cell depletive induction therapy or steroid and/or calcineurin-free inhibitor regimens were excluded. Outcomes analysed included the presence of rejection at 6 months, estimated glomerular filtration rate at 1 and 5 years, graft and patient survival.

RESULTS

218 of 1220 (18%) low-risk and 883 of 3204 (28%) intermediate-risk recipients received IL-2Ra. In intermediate-risk recipients, IL-2Ra induction was associated with a 26% reduction in the incidence of acute rejection; but this benefit was restricted only to recipients initiated on cyclosporine-based immunosuppressive regimens. In contrast, the use of IL-2Ra in low-risk recipients was not associated with reduced rejection risk. There was no association between IL-2Ra induction and other graft or patient outcomes in both low- and intermediate-risk recipients.

CONCLUSION

This registry analysis suggests that IL-2Ra induction may be associated with a reduction in rejection risk in cyclosporine-treated intermediate immunological risk recipients, but not in low-risk renal transplant recipients.