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

Basiliximab vs. No Induction Therapy in Kidney Transplant Recipients with a Low Immunological Risk Profile Receiving Tacrolimus/Mycophenolate/Steroids Maintenance Immunosuppression

Background: Induction therapy with basiliximab is recommended in kidney transplant (KT) recipients with a low immunological risk (LIR) profile. Whether basiliximab is associated with a decreased risk of acute rejection (AR) and graft loss is controversial. Methods: In our institution, LIR patients (absence of anti-HLA antibodies before KT) are inducted with basiliximab in case of living-donor KT, while deceased-donor KT recipients receive no induction. Maintenance immunosuppression is similar, including a combination of tacrolimus (Tac), mycophenolate (MPA) and steroids. In this single-center retrospective study, we included all adult LIR patients who underwent KT between 1 January 2015 and 31 December 2022. Results: Of the 471 patients included, 354 received no induction and 117 received basiliximab. The median (IQR) number of HLA A-B-DR mismatches was 3 (2-3) and 2 (2-4) in the no induction group and the basiliximab group, respectively. The cumulative incidences in the no induction group vs. the basiliximab group of acute rejection and graft loss over 5 years post-KT were similar at 8.9% vs. 7.8% (p = 0.8) and 8.5% vs. 4.2% (p = 0.063), respectively. In multivariable Cox regression analysis, delayed graft function emerged as an independent risk factor for acute rejection (hazard ratio [HR] 2.75, 95% confidence interval [CI] 1.23-6.13, p = 0.014) and graft loss (HR 9.32, CI 4.10-21.1, p < 0.001). Conclusions: Basiliximab did not provide any advantage in terms of rate of acute rejection and graft survival within 5 years post KT compared with a strategy without induction therapy in patients with a low immunological risk profile receiving triple maintenance immunosuppression Tac/MPA/steroids.

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.

Use and Outcomes of Induction Therapy in Well-Matched Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

The optimal induction treatment in low-immune risk kidney transplant recipients is uncertain. We therefore investigated the use and outcomes of induction immunosuppression in a low-risk cohort of patients who were well matched with their donor at HLA-A, -B, -DR, -DQB1 on the basis of serologic typing.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study was an observational study of first adult kidney-only transplant recipients in the United States recorded by the Organ Procurement and Transplant Network.

RESULTS

Among 2976 recipients, 57% were treated with T cell-depleting antibodies, 28% were treated with an IL-2 receptor antagonist, and 15% were treated without induction. There was no difference in allograft survival, death-censored graft survival, or death with function between patients treated with an IL-2 receptor antagonist and no induction therapy. In multivariable models, patients treated with T cell-depleting therapy had a similar risk of graft loss from any cause, including death (hazard ratio, 1.19; 95% confidence interval, 0.98 to 1.45), compared with patients treated with an IL-2 receptor antagonist or no induction. The findings were consistent in subgroup analyses of Black recipients, patients grouped by calculated panel reactive antibody, and donor source. The incidence of acute rejection at 1 year was low (≤5%) and did not vary between treatment groups.

CONCLUSIONS

Use of induction therapy with T cell-depleting therapy or IL-2 receptor antagonists in first kidney transplant recipients who are well matched with their donor at the HLA-A, -B, -DR, -DQB1 gene loci is not associated with improved post-transplant outcomes.

Induction Therapy and Therapeutic Antibodies

Prevention of allograft rejection is one of the crucial goals in solid organ transplantation to ensure durability of the graft and is chiefly mediated by cellular and humoral pathways targeting cell surface alloantigens. The risk of rejection is highest in the first post-transplant year and wanes with time albeit the risk always exists and varies with the type of organ transplanted. Induction therapies refer to the use of high-intensity immunosuppression in the immediate post-operative period to mitigate the highest risk of rejection. This term encompasses chiefly the use of antibody therapies directed against one of the key pathways in T-cell activation or abrogating effects of circulating alloantibodies. These antibodies carry more potent immunomodulatory effect than maintenance immunosuppressive therapy alone and many of them lead to durable immune cell depletion. A variety of monoclonal and polyclonal antibodies have been utilized for use not only for induction therapy, but also for treatment of allograft rejection when it occurs and as components of desensitization therapy before and after transplantation to modulate circulating alloantibodies.

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.

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.

Clinical Outcomes in Pediatric Renal Transplant Recipients Who Received Steroid-Based Immunosuppressive Regimen

BACKGROUND

Although the clinical outcomes of pediatric renal transplantation (RT) in developed countries have improved significantly, the data on clinical outcomes in developing countries are wildly different.

METHODS

Children and adolescents who had undergone RT at Ramathibodi Hospital between March 2001 and August 2014 were included.

RESULTS

Patients were divided into 2 groups: living related donor (LRD) group (n = 13) and deceased donor (DD) group (n = 30). Prolonged cold ischemic time over 13 hours was significantly associated with delayed graft function (P = .029). The prevalence of infection was 90.7%, in which urinary tract infection (UTI) was the most common infection. Although almost none of the patients in the LRD group received induction therapy, the prevalence of rejection was not significantly different between the 2 groups (P = .817). The comparison of graft survivals between LRD and DD groups were 100% vs 100%, 92.3% vs 100%, and 85.7% vs 81.8% at 1, 3, and 5 years, respectively (P = .938). Recurrent UTI and cytomegalovirus (CMV) infection had a negative effect on graft function at 1-year follow-up (P < .05). Rejections, bladder dysfunction, and donors aged ≥50 years were associated with graft deterioration at 3 years after RT (P < .01). None of these patients died with functioning graft.

CONCLUSION

This study demonstrated good graft and patient survival in Thai pediatric RT recipients. Although recurrent UTI and CMV infection were related to graft dysfunction at 1-year follow-up, infections had no effect on graft and patient survival in long-term follow-up.

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.

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.

Effects of antibody induction on transplant outcomes in human leukocyte antigen zero-mismatch deceased donor kidney recipients

BACKGROUND

We aimed to investigate the impact of antibody induction on outcomes in human leukocyte antigen (HLA) 0-mismatched deceased donor kidney recipients.

METHODS

Using the Organ Procurement and Transplant Network/United Network of Organ Sharing database as of November 2009, we identified 44,008 adult deceased donor kidney recipients who received primary kidney transplants alone between 2003 and 2008 (HLA 0 mismatch, n = 6274; ≥ 1 mismatch, n=37,734; median follow-up: 834 days). The impact of induction (thymoglobulin, interleukin-2 receptor antagonists [IL-2RA], or alemtuzumab; vs. no induction) on rejection (initial hospitalization, 6 months, first year), death-censored graft failure, and mortality were analyzed using multivariate logistic and Cox regression in the two groups. The impact of individual agents on outcomes was further analyzed in 0-mismatch recipients.

RESULTS

There was a decreased risk of rejection over the first 6 months for HLA 0-mismatch recipients of antibody induction (adjusted odds ratio=0.71, P=0.003), but this effect was not observed at 1 year; in comparison, induction was associated with a reduced risk of rejection over the first year for HLA-mismatched recipients (0.87, P<0.001). The use of thymoglobulin (0.72, P=0.02) and IL-2RA (0.67, P=0.004) was associated with a decreased risk of rejection compared with no-induction at 6 months but was not different at 1 year (thymoglobulin: 0.77, P=0.05; IL-2RA:0.81, P=0.11) in HLA 0-mismatched recipients. Induction was not associated with improved graft or patient survival in HLA 0-mismatch recipients.

CONCLUSION

In HLA 0-mismatch deceased donor recipients, antibody induction was associated with a decreased risk of rejection at 6 months posttransplant. Its use did not improve graft and patient survival over the follow-up period.

Comparison of azathioprine with mycophenolate mofetil in a living donor kidney transplant programme

There are conflicting data regarding the comparative efficacy of mycophenolate mofetil (MMF) versus azathioprine (AZA) as maintenance immunosuppressive agent in kidney transplantation. The data are even less in combination with tacrolimus (TAC) in living donor kidney transplantation. A total of 205 living donor kidney transplants, on TAC-based triple drug immunosuppression were included in the study. A total of 113 patients received AZA and rest 92 were on MMF based protocol. TAC levels were monitored and graft biopsy was done whenever rejection was suspected. The outcomes were evaluated in terms acute rejection (AR) episodes at 1 year, infections, renal function, graft loss, and death between two groups. The study group comprised 163 males (79.5%) and 42 (20.5%) females. The mean age of patients was 42.4±11.8 years in the AZA group and 39.4 ±13.4 in the MMF group (P=0.09). The mean duration of follow-up was 491.7±240.7 and 478.8±334.4 days respectively in the AZA and MMF groups (P=0.75). Thirty-seven of 92 (40.2%) patients in the MMF group and 70/113 (61.9%) patients in the AZA group received IL-2 RAb induction (P=0.002). 32 patients (15.6 %) developed AR within a year. The incidence of AR was similar in patients who received MMF (12/92, 13%) and those who received AZA (20/113, 17.5%), (P=0.36). There was no difference in the incidence of AR in the subgroup of patients who received IL-2 RAb compared to those who did not receive induction in the two groups (5/37 vs. 7/55 in the MMF group and 10/70 vs. 10/43 in the AZA group, P=0.72). The incidence of infections was similar in the two groups (19/92, 20.6% vs. 25/113, 22.1%, P=0.79). Three patients developed CMV disease, of which two were in the MMF group. Graft loss occurred in 7/205 (3.4%) and death in 8/205 (3.9%) patients. Six of eight patients who died had functioning grafts. The rate of graft loss (3/92 vs. 4/113, P=0.97) and death (5/92 vs. 3/113, P=0.27) was similar in two groups. The overall patient survival was 94.5% and death censored graft survival was 97.4%. Cost comparison suggests AZA to be 6-10 times cheaper than MMF. This study suggests that, in tacrolimus-based immunosuppression, azathioprine may be as good as MMF as maintenance immunosuppressive drug in living donor kidney transplantation. It is also a more cost-effective immunosuppression.

Multivariate analysis of antibody induction therapy and their associated outcomes in live donor kidney transplantation in the recent era

The majority of kidney transplant recipients in the United States receive antibody induction, but its impact on outcomes in living donor transplant is not well-described. We used Organ Procurement and Transplant Network/United Network for Organ Sharing (OPTN/UNOS) data as of November 2009 to compare acute rejection (AR) and graft survival among all primary adult living donor kidney recipients of no antibody induction, antithymocyte globulin (ATG) and interleukin-2 receptor antagonists (IL-2RA) in an earlier era (1998-2002; n=21,919) and a later era (2003-2008, n=26,837). The incidence of AR in the overall cohort decreased from 18.5% in 1998 to 8% in 2008. From 1998 to 2002, antibody induction was associated with a decreased risk of acute rejection at six months (RR 0.67, 95% CI 0.62-0.72) and one yr (RR 0.71, 0.65-0.76), while in the recent era, induction was not associated with acute rejection at six months (RR 0.97, 0.88-1.07) or one yr (RR 1.01, 0.91-1.10). There was no difference in graft survival over five yr with antibody induction in either era. Although antibody induction was associated with a decreased risk of AR from 1998 to 2002, it was not associated with a decreased risk of acute rejection from 2003 to 2008, nor was it associated with a difference in graft survival in either era.