Lower Risk of Infectious Deaths in Cardiac Transplant Patients Receiving Basiliximab Versus Anti-thymocyte Globulin as Induction Therapy

Assessment of immunosuppression induction with basiliximab compared to antithymocyte-globulin in adult heart transplant patients

BACKGROUND

Patients undergoing heart transplants are at risk of rejection which can have significant morbidity and mortality. Induction immunosuppression at the time of transplant reduces the early risk and has additional benefits. The induction agent of choice within our program was changed from rabbit antithymocyte-globulin (rATG) to basiliximab, so it was necessary to evaluate whether this had any impact on patient outcomes.

OBJECTIVES

Our primary objective was to describe rejection, infection, and other outcomes in adult heart transplant patients at the University of Alberta Hospital in Edmonton, Canada.

METHODS

This study was a nonrandomized, retrospective cohort study.

RESULTS

Sixty-three patients were included with median ages 50 years versus 54 years. More female patients received rATG (20% vs. 42.4%). The most common indication for transplant in both cohorts was ICM (63.3% vs. 57.6%). Patients who received rATG had significantly higher PRA (0% vs. 43%, p < .001). Acute rejection episodes were similar between basiliximab and rATG at 3 months (16.7% vs. 15.1%; p = 1.0) and 6-months (30.0% vs. 18.1%; p = .376). Infections were not statistically different with basiliximab compared to rATG at 3-months, 43.3% vs. 63.6% and at 6-months 60.0% vs. 66.7%). There were no fatalities in either group.

CONCLUSIONS

Our study did not demonstrate differences in rejection with basiliximab compared to rATG. Mortality did not differ, but basiliximab-treated patients had fewer infections and infection-related hospitalizations than those treated with rATG. Larger studies with longer durations are needed to more completely describe the differences in rejection and infectious outcomes.

Induction therapy in heart transplantation: A systematic review and network meta-analysis for developing evidence-based recommendations

INTRODUCTION

Induction therapy (IT) utility in heart transplantation (HT) remains contested. Commissioned by a clinical-practice guidelines panel to evaluate the effectiveness and safety of IT in adult HT patients, we conducted this systematic review and network meta-analysis (NMA).

METHODS

We searched for studies from January 2000 to October 2022, reporting on the use of any IT agent in adult HT patients. Based on patient-important outcomes, we performed frequentist NMAs separately for RCTs and observational studies with adjusted analyses, and assessed the certainty of evidence using the GRADE framework.

RESULTS

From 5156 publications identified, we included 7 RCTs and 12 observational studies, and report on two contemporarily-used IT agents-basiliximab and rATG. The RCTs provide only very low certainty evidence and was uninformative of the effect of the two agents versus no IT or one another. With low certainty in the evidence from observational studies, basiliximab may increase 30-day (OR 1.13; 95% CI 1.06-1.20) and 1-year (OR 1.11; 95% CI 1.02-1.22) mortality compared to no IT. With low certainty from observational studies, rATG may decrease 5-year cardiac allograft vasculopathy (OR .82; 95% CI .74-.90) compared to no IT, as well as 30-day (OR .85; 95% CI .80-.92), 1-year (OR .87; 95% CI .79-.96), and overall (HR .84; 95% CI .76-.93) mortality compared to basiliximab.

CONCLUSION

With low and very low certainty in the synthetized evidence, these NMAs suggest possible superiority of rATG compared to basiliximab, but do not provide compelling evidence for the routine use of these agents in HT recipients.

Effect of Different Induction Immunosuppression on the Incidence of Infectious Complications after Kidney Transplantation-Single Center Study

Background/Objectives: Potent immunosuppression lowers the incidence of acute graft rejection but increases the risk of infections. In order to decrease either infectious complications or acute rejection, it is necessary to identify risk groups of patients profiting from personalized induction immunosuppressive treatment. The aim of our analysis was to find whether there were higher incidences of infectious complications after kidney transplantation (KT) in groups with different induction immunosuppressive treatment and also to find independent risk factors for recurrent infections. Materials: We retrospectively evaluated all patients with induction treatment with basiliximab after kidney transplantation from 2014 to 2019 at our center relative to age- and sex-matched controls of patients with thymoglobulin induction immunosuppression. Results: Our study consisted of two groups: basiliximab (39) and thymoglobulin (39). In the thymoglobulin group we observed an increased incidence of recurrent infection in every observed interval; however, acute rejection was seen more often in the basiliximab group. A history of respiratory diseases and thrombocytopenia were identified as independent risk factors for recurrent bacterial infections from the first to sixth month after KT. Decreased eGFR from the first month, infections caused by multi-drug-resistant bacteria, and severe infections (reflected by the need for hospitalization) were identified as independent risk factors for recurrent bacterial infections from the first to the twelfth month after KT. Conclusions: We found that in the group of patients with thymoglobulin induction immunosuppressive treatment, infectious complications occurred significantly more often during the entire monitored period with decreased incidence of acute humoral and cellular rejection occurred more often.

Detection and management of HLA sensitization in candidates for adult heart transplantation

Heart transplantation (HT) remains the preferred therapy for patients with advanced heart failure. However, for sensitized HT candidates who have antibodies to human leukocyte antigens , finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting HT has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease. This State-of-the-Art review discusses the assessment of human leukocyte antigens antibodies, potential desensitization strategies including mechanisms of action and specific protocols, the approach to a potential donor including the use of complement-dependent cytotoxicity, flow cytometry, and virtual crossmatches, and peritransplant induction management.

Basiliximab induction versus no induction in adult heart transplantation

BACKGROUND

Induction immunosuppression in heart transplant recipients varies greatly by center. Basiliximab (BAS) is the most commonly used induction immunosuppressant but has not been shown to reduce rejection or improve survival. The objective of this retrospective study was to compare rejection, infection, and mortality within the first 12 months following heart transplant in patients who received BAS or no induction.

METHODS

This was a retrospective cohort study of adult heart transplant recipients given BAS or no induction from January 1, 2017 to May 31, 2021. The primary endpoint was incidence of treated acute cellular rejection (ACR) at 12-months post-transplant. Secondary endpoints included ACR at 90 days post-transplant, incidence of antibody-mediated rejection (AMR) at 90 days and 1 year, incidence of infection, and all-cause mortality at 1 year.

RESULTS

A total of 108 patients received BAS, and 26 patients received no induction within the specified timeframe. There was a lower incidence of ACR within the first year in the BAS group compared to the no induction group (27.7 vs. 68.2%, p < .002). BAS was independently associated with a lower probability of having a rejection event during the first 12-months post-transplant (hazard ratio (HR) .285, 95% confidence interval [CI] .142-.571, p < .001). There was no difference in the rate of infection and in mortality after hospital discharge at 1-year post-transplant (6% vs. 0%, p = .20).

CONCLUSION

BAS appears to be associated with greater freedom from rejection without an increase in infections. BAS may be a preferred to a no induction strategy in patients undergoing heart transplantation.

Impact of induction therapy on cytomegalovirus infection and post-transplant outcomes in pediatric heart transplant recipients receiving routine antiviral prophylaxis

OBJECTIVES

Induction therapy has been increasingly used in pediatric heart transplantation. This study evaluated the impact of anti-thymocyte globulin (ATG) versus basiliximab as induction therapy on post-transplant cytomegalovirus (CMV) infection, rejection at 1 year, coronary allograft vasculopathy (CAV), and mortality in pediatric heart transplant recipients receiving antiviral prophylaxis.

RESULTS

Of the 96 patients (age < 18 years) analyzed, 46 (47.9%) patients received basiliximab, and 50 (52.1%) received ATG. Median follow-up was 3.0 (IQR, 1.7-4.9) years with 32.3% reporting CMV infection. The ATG group, as compared with the basiliximab group, had similar incidences of CMV infection (36% vs. 28.3%, p = .418), CMV viremia (22% vs. 19.6%, p = .769), and CMV-positive tissue biopsy (30% vs. 22%, p = .486). The ATG group had lower incidences of rejection at 1 year (16% vs. 36.9%, p = .022) and CAV (4% vs. 23.9%, p = .006) with no difference in mortality (8% vs. 15.2%, p = .343), compared with the basiliximab group. Multivariate analysis showed that induction with ATG was associated with a lower risk of rejection at 1 year (OR, .31; 95% CI, .09-.94; p = .039) with no impact on the incidences of CMV infection (HR, 2.06; 95% CI, .54-7.89; p = .292), CAV (HR, .30; 95% CI, .04-2.58; p = .275), and mortality (HR, .39; 95% CI, .09-1.82; p = .233) compared to basiliximab induction.

DISCUSSION AND CONCLUSIONS

In conclusion, induction with ATG was associated with reduction in risk of rejection at 1 year with no effects on CMV infection, CAV, and mortality in pediatric heart transplant recipients with universal antiviral prophylaxis compared with basiliximab induction therapy.

Review of Postoperative Care for Heart Transplant Recipients

The early postoperative management strategies after heart transplantation include optimizing the function of the denervated heart, correcting the causes of hemodynamic instability, and initiating and maintaining immunosuppressive therapy, allograft rejection surveillance, and prophylaxis against infections caused by immunosuppression. The course of postoperative support is influenced by the quality of allograft myocardial protection prior to implantation and reperfusion, donor-recipient heart size matching, surgical technique of orthotopic heart transplantation, and patient factors (eg, preoperative condition, immunologic compatibility, postoperative vasomotor tone, severity and reversibility of pulmonary vascular hypertension, pulmonary function, mediastinal blood loss, and end-organ perfusion). This review provides an overview of the early postoperative care of recipients and includes a brief description of the surgical techniques for orthotopic heart transplantation.

Lower dose of ATG combined with basiliximab for haploidentical hematopoietic stem cell transplantation is associated with effective control of GVHD and less CMV viremia

Currently, the graft-versus-host disease (GVHD) prophylaxis consists of an immunosuppressive therapy mainly based on antithymocyte globulin (ATG) or post-transplant cyclophosphamide (PTCy). GVHD remains a major complication and limitation to successful allogeneic haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We modified the ATG-based GVHD prophylaxis with the addition of basiliximab in the setting of haplo-HSCT and attempted to explore the appropriate dosages. We conducted a retrospective analysis of 239 patients with intermediate- or high-risk hematologic malignancies who received haplo-HSCT with unmanipulated peripheral blood stem cells combined or not with bone marrow. All patients received the same GVHD prophylaxis consisting of the combination of methotrexate, cyclosporine or tacrolimus, mycofenolate-mofetil, and basiliximab with different doses of ATG (5-9mg/kg). With a median time of 11 days (range, 7-40 days), the rate of neutrophil engraftment was 96.65%. The 100-day cumulative incidences (CIs) of grade II-IV and III-IV aGVHD were 15.8 ± 2.5% and 5.0 ± 1.5%, while the 2-year CIs of total cGVHD and extensive cGVHD were 9.8 ± 2.2% and 4.1 ± 1.5%, respectively. The 3-year CIs of treatment-related mortality (TRM), relapse, overall survival (OS), and disease-free survival (DFS) were 14.6 ± 2.6%, 28.1 ± 3.4%, 60.9 ± 3.4%, 57.3 ± 3.4%, respectively. Furthermore, the impact of the reduction of the ATG dose to 6 mg/kg or less in combination with basiliximab on GVHD prevention and transplant outcomes among patients was analyzed. Compared to higher dose of ATG(>6mg/kg), lower dose of ATG (≤6mg/kg) was associated with a significant reduced risk of CMV viremia (52.38% vs 79.35%, P<0.001), while the incidences of aGVHD and cGVHD were similar between the two dose levels. No significant effect was found with regard to the risk of relapse, TRM, and OS. ATG combined with basiliximab could prevent GVHD efficiently and safely. The optimal scheme of using this combined regimen of ATG and basiliximab is that administration of lower dose ATG (≤6mg/kg), which seems to be more appropriate for balancing infection control and GVHD prophylaxis.

Retrospective Evaluation of Rabbit Antithymocyte Globulin Induction in Heart Transplant Patients

The dosing intensity of antithymocyte globulin as induction therapy in heart transplantation remains controversial. We sought to evaluate the efficacy and safety of rabbit antithymocyte globulin at a total dose of 4.5 mg/kg compared with <4.5 mg/kg.

Novel Immunosuppression in Solid Organ Transplantation

Solid organ transplantation and survival has improved tremendously in the last few decades, much of the success has been attributed to the advancements in immunosuppression. While steroids are being replaced and much of the immunosuppressive strategies focus on steroid free regimens, novel agents have introduced in the induction, maintenance, and treatment of acute rejection phase. MTOR inhibitors have helped with the renal sparing side effect from the calcineurin inhibitors, newer agents such as rituximab have decreased the incidence of donor-specific antibodies which led to decreased incidence of acute rejection reactions. In this chapter we discuss the newer therapies directed specifically for solid organ transplantation.

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.

Hospitalizations for Respiratory Syncytial Virus and Vaccine Preventable Infections following Pediatric Heart Transplantation

OBJECTIVE

To determine the risk factors for acquiring a respiratory syncytial virus (RSV) and vaccine-preventable infections (R/VPI) in pediatric heart transplant recipients and the associated morbidity and hospital resource use.

STUDY DESIGN

Patients <18 years who underwent heart transplantation from September 2003 to December 2018 at hospitals using the Pediatric Health Information System database were identified. Their transplant hospitalization and subsequent hospitalizations for R/VPI through December 2018 were analyzed. Risk factors for R/VPI hospitalizations were evaluated using negative regression binomial models adjusted for demographic and clinical confounders. Total hospital costs were adjusted for 2018 US$.

RESULTS

Of 3815 transplant recipients, 681 (17.9%) had an R/VPI hospitalization during 23 746 available person-years of follow-up. There were 984 R/VPIs diagnosed during 951 hospitalizations, and 440 (44.7%) occurred the first year after transplantation. The most common causes were RSV (n = 380; 38.6%), influenza (n = 265; 26.9%), and pneumococcus (n = 105; 10.7%). In adjusted analyses, there was an increased risk of R/VPI hospitalization in patients requiring mechanical circulatory support before transplantation, patients receiving induction with ≥2 immunosuppressive agents, and patients <2 years in the first year after transplantation. The median length of stay for an R/VPI hospitalization was 4 days (IQR, 2-8 days) with a median total cost of $11 081 (IQR, $6215-$24 322).

CONCLUSIONS

Hospitalization for R/VPIs occurred frequently after heart transplantation and were associated with significant costs. Potential strategies to minimize R/VPI include expanding vaccine use through accelerated immunization schedules, further studies of use of palivizumab beyond 2 years of age, and immunogenicity monitoring after vaccination with re-immunization based on guidelines.

Risk Factors for Extended-Spectrum β-lactamase-Producing Enterobacterales Bloodstream Infection Among Solid-Organ Transplant Recipients

BACKGROUND

Approximately 40% of all Enterobacterales (EB) bloodstream infections (BSIs) among solid organ transplant recipients (SOTRs) are due to extended-spectrum β-lactamase (ESBL)-producing organisms, but risk factors for such infections remain ill defined in this population. We sought to determine the risk factors for ESBL-EB BSIs among SOTRs.

METHODS

A multicenter case-control study was performed. All SOTRs with an EB BSI at the Hospital of the University of Pennsylvania and University of Maryland Medical Center between 1 January 2007 and 30 June 2018 and at The Johns Hopkins Hospital between 1 January 2005 and 31 December 2015 were included. Cases were those with an ESBL-EB BSI. Controls were those with a non-ESBL-EB BSI. Multivariable logistic regression was performed to determine risk factors for ESBL-EB BSI.

RESULTS

There were 988 episodes of EB BSI, of which 395 (40%) were due to an ESBL-EB. On multivariable analysis, the independent risk factors for ESBL-EB BSI included: ESBL-EB on prior culture (aOR, 12.75; 95% CI, 3.23-50.33; P < .001), a corticosteroid-containing immunosuppression regimen (aOR 1.30; 95% CI 1.03-1.65; P = .030), acute rejection treated with corticosteroids (aOR 1.18; 95% CI 1.16-1.19; P < .001), and exposure to third-generation cephalosporins (aOR 1.95; 95% CI 1.48-2.57; P < .001), echinocandins (aOR 1.61; 95% CI 1.08-2.40; P = .020), and trimethoprim-sulfamethoxazole (aOR 1.35; 95% CI 1.10-1.64; P = .003).

CONCLUSIONS

We identified several novel risk factors that are uniquely important to the SOTR population, including exposure to trimethoprim-sulfamethoxazole and corticosteroid-containing immunosuppressive regimens. Further studies exploring these associations and testing interventions aimed at these modifiable risk factors among SOTRs are needed.

Impact of induction strategy change on first-year rejection in pediatric heart transplantation at a single center-From postoperative basiliximab to either postoperative anti-thymocyte globulin or preoperative basiliximab

BACKGROUND

Our pediatric heart transplant center transitioned from post-bypass basiliximab (BAS) induction to either anti-thymocyte globulin (ATG) or pre-bypass BAS. The purpose of this study was to compare first-year rejection rates before and after this change.

METHODS

A single-center retrospective analysis was conducted of pediatric heart transplant recipients from 2010 to 2019. Primary outcome was first-year rejection. Bivariate analysis, Kaplan-Meier curves, and multivariable regression were performed across eras.

RESULTS

Forty-three early era patients (55%) received post-bypass BAS, and 35 late era patients (45%) received pre-bypass BAS (n = 17) or ATG (n = 18). First-year rejection decreased in the late era (31% vs 53%, p = .05). This finding was more pronounced after excluding infants (38% vs 73%, p = .006). Late era was associated with a decreased likelihood of rejection (all cohort OR 0.19, 95% CI 0.05-0.66; infants excluded OR 0.17, 95% CI 0.04-0.61). No differences in post-transplant lymphoproliferative disease, donor-specific antibody, or infection were observed.

CONCLUSIONS

Fewer late era patients receiving ATG or pre-bypass BAS induction had first-year rejection compared to the early era patients receiving standard post-bypass BAS induction. This programmatic shift in induction strategy was readily achievable and potentially effective in reducing first-year rejection.

Heart Transplant Immunosuppression Strategies at Cedars-Sinai Medical Center

Heart transplant is the optimal treatment for selected patients with end-stage heart failure. Immunosuppression after heart transplantation has significantly reduced the incidence of rejection and improved patient outcomes with the routine use of calcineurin inhibitors. Antimetabolites and proliferation signal inhibitors add to the improvement in patient outcomes as well. The goal of induction therapy is to provide intense immunosuppression when the risk of allograft rejection is highest. Most maintenance immunosuppressive protocols employ a 3-drug regimen consisting of a calcineurin inhibitor, an antimetabolite agent and glucocorticoids. The management of rejection proceeds in a stepwise fashion based on the severity of rejection detected on biopsy and the patient's clinical presentation. This review will cover induction, maintenance, rejection therapy and some special considerations including sensitization, renal sparing protocol, and corticosteroid weaning. It will end in consideration of potential future directions in immunosuppressive strategies to promote patient and graft survival.

Influence of Induction Therapy Using Basiliximab With Delayed Tacrolimus Administration in Heart Transplant Recipients - Comparison With Standard Tacrolimus-Based Triple Immunosuppression

BACKGROUND

Appropriate indications and protocols for induction therapy using basiliximab have not been fully established in heart transplant (HTx) recipients. This study elucidated the influence of induction therapy using basiliximab along with delayed tacrolimus (Tac) initiation on the outcomes of high-risk HTx recipients.Methods and Results:A total of 86 HTx recipients treated with Tac-based immunosuppression were retrospectively reviewed. Induction therapy was administered to 46 recipients (53.5%) with impaired renal function, pre-transplant sensitization, and recipient- and donor-related risk factors (Induction group). Tac administration was delayed in the Induction group. Induction group subjects showed a lower cumulative incidence of acute cellular rejection grade ≥1R after propensity score adjustment, but this was not significantly different (hazard ratio [HR]: 0.63, 95% confidence interval [CI]: 0.37-1.08, P=0.093). Renal dysfunction in the Induction group significantly improved 6 months post-transplantation (P=0.029). The cumulative incidence of bacterial or fungal infections was significantly higher in the Induction group (HR: 10.6, 95% CI: 1.28-88.2, P=0.029).

CONCLUSIONS

These results suggest that basiliximab-based induction therapy with delayed Tac initiation may suppress mild acute cellular rejection and improve renal function in recipients with renal dysfunction, resulting in its non-inferior outcome, even in high-risk patients, when applied to the appropriate recipients. However, it should be carefully considered in recipients at a high risk of bacterial and fungal infections.

Cytomegalovirus myocarditis in solid organ transplant recipients: A case series and review of literature

Cytomegalovirus (CMV) is a DNA virus of the Herpesviridae family and is estimated to affect 15%-30% of high-risk solid organ transplant recipients. Typical manifestations of CMV end-organ disease in this population include colitis, esophagitis, and pneumonitis, and myocarditis is a rarely reported manifestation. We describe two cases of CMV myocarditis in solid organ transplant recipients and review the literature regarding previously published cases of CMV myocarditis.

Pharmacokinetics of Basiliximab for the Prevention of Graft-versus-Host Disease in Patients Undergoing Hematopoietic Cell Transplantation with Minimal-Intensity Cyclophosphamide and Fludarabine

STUDY OBJECTIVE

Basiliximab is an immunosuppressive monoclonal antibody used for rejection prevention following solid organ transplantation; the pharmacokinetics (PK) of basiliximab in this setting are known. Basiliximab may also be used for prophylaxis and treatment of graft-versus-host disease (GVHD) in patients undergoing allogeneic hematopoietic cell transplantation (HCT); however, the PK of basiliximab in this setting are not known. Clinical transplant providers expect variation in the volume of distribution and clearance after nonmyeloablative allogeneic transplantation (NMAT) compared with solid organ transplantation. Blood loss, organ site-specific antibody accumulation, and differences in blood product use during the two transplantation approaches may generate differences in basiliximab PK. Therefore, the objective of this study was to describe the PK of basiliximab after its addition to a minimally intense NMAT regimen, in conjunction with cyclosporine, for GVHD prophylaxis in patients with hematologic malignancies.

DESIGN

Population PK analysis of a single-center, single-arm, phase II clinical trial.

SETTING

Academic cancer research center.

PATIENTS

Fourteen adults with hematologic malignancies (acute myeloid leukemia, acute lymphoblastic leukemia, chronic lymphocytic leukemia, myelodysplastic syndrome, non-Hodgkin's lymphoma, Hodgkin's lymphoma, myelofibrosis, or severe aplastic anemia) and undergoing NMAT with a fully HLA-matched (10 of 10 antigen matched) related or unrelated donor.

MEASUREMENTS AND MAIN RESULTS

Basiliximab was used in conjunction with cyclosporine to deplete activated T cells in vivo as GVHD prophylaxis. We developed a novel competitive enzyme-linked immunosorbent assay (ELISA) method using recombinant interleukin-2 receptor alpha-chain (IL-2Ra) and a commercially available soluble sIL-2R ELISA kit to permit the quantification of serum basiliximab concentrations and characterization of the PK properties of the drug in this patient population. Using a nonlinear mixed effects model with NONMEM software, a one-compartment model with first-order elimination best described the PK, as covariate analysis using stepwise covariate modeling did not improve the base model.

CONCLUSION

We suggest a one-compartment population model with first-order elimination to capture the PK profile for basiliximab for this patient population.

A Single-Center Experience of the Optimal Initial Immunosuppressive Strategy for Preventing Early Acute Cellular Rejection in Orthotopic Heart Transplantation Associated With Renal Dysfunction

BACKGROUND

Renal dysfunction is a common complication following heart transplantation that may be worsened by the early initiation of calcineurin inhibitors. Antithymocyte globulin (ATG) or basiliximab has been used to delay or avoid calcineurin inhibitors. The most effective strategy for preventing early acute cellular rejection in this context is uncertain.

METHODS

We retrospectively reviewed all heart transplant cases between January 2012 and June 2017. The standard therapy consisted of mycophenolate mofetil, prednisolone, and tacrolimus. In patients at high risk of post-transplant renal dysfunction, an early calcineurin inhibitor-free regimen with basiliximab and/or ATG was used. Patients were assigned to cohorts based on the initial immunosuppressive strategy. The primary end point was the freedom rate of acute cellular rejection within 4 weeks post-transplant.

RESULTS

Of 93 cases, 21 patients received standard therapy, 64 patients received an initial calcineurin inhibitor-free regimen with basiliximab, and 8 patients received ATG and basiliximab. Freedom from acute rejection was greater in the ATG plus basiliximab group (all rejection free), compared to 40 (63%) of 64 patients treated with basiliximab and 10 (48%) of 21 patients treated with standard therapy (P < .05, log rank test). In patients treated with basiliximab, early administration (<24 hours) was associated with a higher freedom from acute rejection compared to ≥24 hours, (72% vs 29%, P < .05).

CONCLUSIONS

The combination of ATG and basiliximab was more effective in preventing acute cellular rejection. In those patients treated with basiliximab, rejection rates were no worse than standard therapy; however, it was only effective when administered within 24 hours.

Impact of induction immunosuppression on patient survival in heart transplant recipients treated with tacrolimus and mycophenolic acid in the current allocation era

BACKGROUND

The practice of induction therapy with either rabbit anti-thymocyte globulin (r-ATG) or interleukin-2 receptor antagonists (IL-2RA) is common among heart transplant recipients. However, its benefits in the setting of contemporary maintenance immunosuppression with tacrolimus/mycophenolic acid (TAC/MPA) are unknown.

METHODS

We compared post-transplant mortality among three induction therapy strategies (r-ATG vs IL2-RA vs no induction) in a retrospective cohort analysis of heart transplant recipients maintained on TAC/MPA in the Organ Procurement Transplant Network (OPTN) database between the years 2006 and 2015. We used a multivariable model adjusting for clinically important co-morbidities, and a propensity score analysis using the inverse probability weighted (IPW) method in the final analysis.

RESULTS

In multivariable IPW analysis, r-ATG (HR = 1.23; 95% CI = 1.05-1.46, P = 0.01) remained significantly associated with a higher mortality. There was a trend toward having a higher mortality in the IL2-RA (HR = 1.11; 95% CI = 1.00-1.24, P = 0.06) group. Subgroup analyses failed to show a patient survival benefit in using either r-ATG or IL2-RA among any of the subgroups analyzed.

CONCLUSION

In this contemporary cohort of heart transplant recipients receiving TAC/MPA, neither r-ATG nor IL2-RA were associated with a survival benefit. On the contrary, adjusted analyses showed a significantly higher mortality in the r-ATG group and a trend toward higher mortality in the IL2-RA group. While caution is needed in interpreting treatment effects in an observational cohort, these data call into question the benefit of induction therapy as a common practice and highlight the need for more studies.

Incidence of cytomegalovirus in cardiac transplant recipients receiving induction immunosuppression with antithymocyte globulin

BACKGROUND

Cytomegalovirus (CMV) is a major cause of morbidity and mortality in cardiac transplant recipients. Use of induction immunosuppression in cardiac transplantation may have an impact on the incidence of CMV, but literature is limited.

METHODS

Single-center, retrospective cohort study comparing the risk of CMV infection and disease in cardiac transplant patients receiving antithymocyte globulin (ATG) induction therapy to those receiving no antibody induction.

RESULTS

A total of 75 patients were included in our analysis, 50 who received ATG induction and 25 who did not. CMV infection occurred in 10 (20%) and 5 (20%) patients in the ATG and No ATG groups, respectively (P > 0.99). CMV disease occurred in 10 (20%) and 4 (16%) patients in the ATG and No ATG groups, respectively (P = 0.763). The median time from transplant to CMV infection was 200.0 [142.5, 364.5] days in the ATG group vs 221.0 [192.0, 299.0] days in the No ATG group (P = 0.723). The median time from end of CMV prophylaxis to CMV infection was 94.5 [66.5, 151.0] days in the ATG group vs 53.0 [41.0,149.5] days in the No ATG group (P = 0.202). Freedom from CMV infection was highest in the D+/R+ group and lowest in the D+/R- group.

CONCLUSION

In cardiac transplant recipients, ATG induction was not associated with an increased incidence of CMV infection or disease in the setting of valganciclovir prophylaxis and an initial maintenance immunosuppression regimen of primarily steroids, mycophenolate mofetil, and tacrolimus.

A Review of Induction with Rabbit Antithymocyte Globulin in Pediatric Heart Transplant Recipients

Pediatric heart transplantation (pHTx) represents only a small proportion of cardiac transplants. Due to these low numbers, clinical data relating to induction therapy in this special population are far less extensive than for adults. Induction is used more widely in pHTx than in adults, mainly because of early steroid withdrawal or complete steroid avoidance. Antithymocyte globulin (ATG) is the most frequent choice for induction in pHTx, and rabbit antithymocyte globulin (rATG, Thymoglobulin^®) (Sanofi Genzyme) is the most widely-used ATG preparation. In the absence of large, prospective, blinded trials, we aimed to review the current literature and databases for evidence regarding the use, complications, and dosages of rATG. Analyses from registry databases suggest that, overall, ATG preparations are associated with improved graft survival compared to interleukin-2 receptor antagonists. Advantages for the use of rATG have been shown in low-risk patients given tacrolimus and mycophenolate mofetil in a steroid-free regimen, in sensitized patients with pre-formed alloantibodies and/or a positive donor-specific crossmatch, and in ABO-incompatible pHTx. Registry and clinical data have indicated no increased risk of infection or post-transplant lymphoproliferative disorder in children given rATG after pHTx. A total rATG dose in the range 3.5–7.5 mg/kg is advisable.

Induction regimen and survival in simultaneous heart-kidney transplant recipients

BACKGROUND

Induction therapy in simultaneous heart-kidney transplantation (SHKT) is not well studied in the setting of contemporary maintenance immunosuppression consisting of tacrolimus (TAC), mycophenolic acid (MPA), and prednisone (PRED).

METHODS

We analyzed the Organ Procurement and Transplant Network registry from January 1, 2000, to March 3, 2015, for recipients of SHKT (N = 623) maintained on TAC/MPA/PRED at hospital discharge. The study cohort was further stratified into 3 groups by induction choice: induction (n = 232), rabbit anti-thymoglobulin (r-ATG; n = 204), and interleukin-2 receptor-α (n = 187) antagonists. Survival rates were estimated using the Kaplan-Meier estimator. Multivariable inverse probability weighted Cox proportional hazard regression models were used to assess hazard ratios associated with post-transplant mortality as the primary outcome. The study cohort was censored on March 4, 2016, to allow at least 1-year of follow-up.

RESULTS

During the study period, the number of SHKTs increased nearly 5-fold. The Kaplan-Meier survival curve showed superior outcomes with r-ATG compared with no induction or interleukin-2 receptor-α induction. Compared with the no-induction group, an inverse probability weighted Cox proportional hazard model showed no independent association of induction therapy with the primary outcome. In sub-group analysis, r-ATG appeared to lower mortality in sensitized patients with panel reactive antibody of 10% or higher (hazard ratio, 0.19; 95% confidence interval, 0.05-0.71).

CONCLUSION

r-ATG may provide a survival benefit in SHKT, especially in sensitized patients maintained on TAC/MPA/PRED at hospital discharge.

Low-dose basiliximab induction therapy in heart transplantation

We prospectively studied efficacy and safety outcomes of two 10-mg doses of intravenous basiliximab on day 0 and day 4 for induction therapy in 17 consecutive de novo heart transplant recipients. By the 2-week assessment post-transplant, there were no deaths, graft failures, or acute cellular rejections (ACRs) ISHLT grade ≥ 2R. By the 1-year assessment post-transplant, there were 1 (6%) infectious death, no graft failures, 2 (12%) grade 2R ACRs, 6 (35%) asymptomatic cytomegalovirus (CMV) infections, and 4 (25%) treated infections. Our study was the first to show that low-dose basiliximab induction in heart transplant resulted in favorable efficacy and safety outcomes. Additionally, calcineurin inhibitor (CNI) initiation in a low-risk population could be safely delayed using the strategy of modified low-dose postoperative basiliximab. This strategy also appears to allow subsequent early corticosteroid wean, although with the concomitant maintenance of higher CNI levels and higher dosing of mycophenolate.

Postoperative management of heart transplantation patients

Heart transplant recipients are at risk for a number of post-transplantation complications such as graft dysfunction, rejection, and infection. The rates of many complications are decreasing over time, and prognosis is improving. However, these patients continue to experience significant morbidity and mortality. This review focuses on the optimal management of heart transplant recipients in the postoperative period, based on current knowledge. More information is needed about the best ways to predict, prevent, and treat primary graft dysfunction, right ventricular failure, and cellular and antibody-mediated rejection.

Use of Anti-Thymocyte Globulin for Induction Therapy in Cardiac Transplantation: A Review

The most common causes of death after heart transplantation (HTx) include acute rejection and multi-organ failure in the early period and malignancy and cardiac allograft vasculopathy (CAV) in the late period. Polyclonal antibody preparations such as rabbit anti-thymocyte globulin (ATG) may reduce early acute rejection and the later occurrence of CAV after HTx. ATG therapy depletes T cells, modulates adhesion and cell-signaling molecules, interferes with dendritic cell function, and induces B-cell apoptosis and regulatory and natural killer T-cell expansion. Evidence from animal studies and from retrospective clinical studies in humans indicates that ATG can be used to delay calcineurin inhibitor (CNI) exposure after HTx, thus benefiting renal function, and to reduce the incidence of CAV and ischemia-reperfusion injury in the transplanted heart. ATG may reduce de novo antibody production after HTx. ATG does not appear to increase cytomegalovirus infection rates with longer prophylaxis (6-12 months). In addition, ATG may reduce the risk of lymphoproliferative disease and does not appear to confer an additive effect on acquiring lymphoma after HTx. Randomized, controlled trials may provide stronger evidence of ATG association with patient survival, graft rejection, renal protection through delayed CNI initiation, as well as other benefits. It can also help establish optimal dosing and patient criteria to maximize treatment benefits.

Heart Transplantation-The Pediatric Cardiac Critical Care Perspective

OBJECTIVES

Although there have been tremendous advancements in the care of severe pediatric cardiovascular disease, heart transplantation remains the standard therapy for end-stage heart disease in children. As such, these patients comprise an important and often complex subset of patients in the ICU. The purpose of this article is to review the causes and management of allograft dysfunction and the medications used in the transplant population.

DATA SOURCES

MEDLINE, PubMed, and Cochrane Database of systemic reviews.

CONCLUSIONS

Pediatric heart transplant recipients represent a complex group of patients that frequently require critical care. Their immunosuppressive medications, while being vital to maintenance of allograft function, are associated with significant short- and long-term complications. Graft dysfunction can occur from a variety of etiologies at different times following transplantation and remains a major limitation to long-term posttransplant survival.

A Proposal for Early Dosing Regimens in Heart Transplant Patients Receiving Thymoglobulin and Calcineurin Inhibition

There is currently no consensus regarding the dose or duration of rabbit antithymocyte globulin (rATG) induction in different types of heart transplant patients, or the timing and intensity of initial calcineurin inhibitor (CNI) therapy in rATG-treated individuals. Based on limited data and personal experience, the authors propose an approach to rATG dosing and initial CNI administration. Usually rATG is initiated immediately after exclusion of primary graft failure, although intraoperative initiation may be appropriate in specific cases. A total rATG dose of 4.5 to 7.5 mg/kg is advisable, tailored within that range according to immunologic risk and adjusted according to immune monitoring. Lower doses (eg, 3.0 mg/kg) of rATG can be used in patients at low immunological risk, or 1.5 to 2.5 mg/kg for patients with infection on mechanical circulatory support. The timing of CNI introduction is dictated by renal recovery, varying between day 3 and day 0 after heart transplantation, and the initial target exposure is influenced by immunological risk and presence of infection. Rabbit antithymocyte globulin and CNI dosing should not overlap except in high-risk cases. There is a clear need for more studies to define the optimal dosing regimens for rATG and early CNI exposure according to risk profile in heart transplantation.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Immune Therapy

OBJECTIVE

In this Consensus Statement, we review the etiology and pathophysiology of inflammatory processes seen in critically ill children with cardiac disease. Immunomodulatory therapies aimed at improving outcomes in patients with myocarditis, heart failure, and transplantation are extensively reviewed.

DATA SOURCES

The author team experience and along with an extensive review of the medical literature were used as data sources.

DATA SYNTHESIS

The authors synthesized the data in the literature to present current immumodulatory therapies. For each drug, the physiologic rationale, mechanism of action, and pharmacokinetics are synthesized, and the evidence in the literature to support the therapy is discussed.

CONCLUSIONS

Immunomodulation has a crucial role in the treatment of certain pediatric cardiac diseases. Immunomodulatory treatments that have been used to treat myocarditis include corticosteroids, IV immunoglobulin, cyclosporine, and azathioprine. Contemporary outcomes of pediatric transplant recipients have improved over the past few decades, partly related to improvements in immunomodulatory therapy to prevent rejection of the donor heart. Immunosuppression therapy is commonly divided into induction, maintenance, and acute rejection therapy. Common induction medications include antithymocyte globulin, muromonab-CD3, and basiliximab. Maintenance therapy includes chronic medications that are used daily to prevent rejection episodes. Examples of maintenance medications are corticosteroids, cyclosporine, tacrolimus, sirolimus, everolimus, azathioprine, and mycophenolate mofetil. Rejection of the donor heart is diagnosed either by clinically or by biopsy and is treated with intensification of immunosuppression.

Comparison of Basiliximab and Anti-Thymocyte Globulin as Induction Therapy in Pediatric Heart Transplantation: A Survival Analysis

Background

Basiliximab and anti‐thymocyte globulin are widely used drugs for induction therapy after pediatric heart transplantation. The aim of this study was to determine whether any differences could be observed between basiliximab and anti‐thymocyte globulin, with respect to long‐term mortality, in a population of pediatric cardiac transplant recipients.

Methods and Results

An analysis of pediatric heart transplant patients (aged <18 years) from the United Network for Organ Sharing database was conducted that compared patients receiving basiliximab with those that received anti‐thymocyte globulin for the risk of all‐cause mortality. Secondary endpoints included death attributable to graft failure, cardiovascular causes, infection, or malignancy. Of the 2275 patients, 685 received basiliximab and 1590 anti‐thymocyte globulin. One‐year survival was similar for both groups; however, at 5 and 10 years, basiliximab was associated with poorer long‐term survival (68% versus 76% at 5 years [P<0.001] and 49% versus 65% at 10 years [P<0.001], respectively). Basiliximab was associated with higher risk of death attributable to graft failure (P=0.013), but not death attributable to cardiovascular causes (P=0.444), infection (P=0.095), or malignancy (P=0.392). After multivariate analysis, use of basiliximab (versus use of anti‐thymocyte globulin) remained significantly associated with all‐cause mortality (hazard ratio, 1.27; 95% confidence interval, 1.02–1.57; P=0.030).

Conclusions

In pediatric heart transplant patients, use of basiliximab for induction therapy was associated with an increased risk of mortality, when compared with those receiving anti‐thymocyte globulin.

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.

Rabbit antithymocyte globulin induction and risk of post-transplant lymphoproliferative disease in adult and pediatric solid organ transplantation: An update

The most modifiable risk factor for post-transplant lymphoproliferative disease (PTLD) is the type and dose of induction and maintenance immunosuppressive therapy. It is challenging to identify the contribution of a single agent such as rabbit antithymocyte globulin (rATG) in the setting of multidrug therapy. Registry analyses can be helpful but are limited by methodological restrictions and inclusion of historical patient cohorts. These are typically from eras when rATG dosing was markedly higher than current dosing (e.g. total dose 14 mg/kg versus 6 mg/kg now), accompanied by higher exposure to maintenance therapies, and often an absence of antiviral prophylaxis. The largest registry analysis to assess rATG specifically found no risk of PTLD after kidney transplantation, but conflicting results have been reported, highlighting the difficulty of interpreting this type of analysis. The relative rarity of PTLD means that individually controlled trials are underpowered to assess its occurrence, but the available data do not suggest an effect of rATG. A pooled analysis of data from studies of rATG induction in kidney and heart transplantation found the incidence of PTLD to be comparable to published reports in the overall transplant population. Data on the effect of rATG dose are inconclusive, but in patients receiving antiviral prophylaxis it does not appear to be influential. Nevertheless, it would seem reasonable to employ the lowest dose of rATG compatible with effective induction, particularly in EBV-seronegative recipients and other high-risk groups such as heart-lung transplant recipients. Overall, the risk of PTLD following rATG induction therapy with modern dosing regimens and under current management conditions appears unlikely to make an important contribution to the risk:benefit balance.

Impact of induction immunosuppression on survival in heart transplant recipients: a contemporary analysis of agents

INTRODUCTION

The impact of induction immunosuppression on long-term survival in heart transplant recipients is unclear. Over the past three decades, practices have varied as induction agents have changed and experiences grew. We sought to evaluate the effect of contemporary induction immunosuppression agents in heart transplant recipients with the primary endpoint of survival, utilizing national registry data.

METHODS

We queried the United Network for Organ Sharing (UNOS) data registry for all heart transplants from 1987 to 2012. We restricted our analysis to adult (≥18 yr) recipients performed from 2001-2011 (to allow for the potential for a minimum of 12 months post-transplant follow-up) who received either: no antibody based induction (NONE) or the contemporary agents (INDUCED) of either: basiliximab/daclizumab (IL-2Rab), alemtuzumab, or ATG/ALG/thymoglobulin. Kaplan-Meier estimates of the survival function as well as Cox proportional hazards models were utilized.

RESULTS

Of the 17 857 heart transplants that met the inclusion criteria, there were 4635 (26%) reported deaths during the follow-up period. There were 8216 (46%) patients who were INDUCED. Of the INDUCED agents, 55% were IL-2Rab, 4% alemtuzumab, and 40% ALG/ATG/thymoglobulin. Donor and recipient characteristics were evaluated. Overall, being INDUCED did not significantly affect survival in univariable (p = 0.522) and multivariable (p = 0.130) Cox models as well as a propensity score adjusted model (p = 0.733). Among those induced, ATG/ALG/thymoglobulin appeared to have superior survival as compared with IL-2Rab (log-rank p = 0.007, univariable hazard ratio [HR] = 0.886; 95% CI: 0.811-0.968; p = 0.522). However, in a multivariable Cox model that adjusted for recipient age, VAD, BMI, steroid use, CMV match, and ischemic time, the hazard ratio for ALG/ATG/thymoglobulin vs. IL-2Rab was no longer statistically significant (HR = 0.948; 95% CI: 0.850-1.058; p = 0.341).

CONCLUSION

In a contemporary analysis of heart transplant recipients, an overall analysis of induction agents does not appear to impact survival, as compared to no induction immunosuppression. While ALG/ATG/thymoglobulin appeared to have a beneficial effect on survival compared to IL-2Rab in the univariable model, this difference was no longer statistically significant once we adjusted for clinically relevant covariates.

Thymoglobulin induction in heart transplantation: patient selection and implications for maintenance immunosuppression

Clinical data relating to rabbit antithymocyte globulin (rATG) induction in heart transplantation are far less extensive than for other immunosuppressants, or indeed for rATG in other indications. This was highlighted by the low grade of evidence and the lack of detailed recommendations for prescribing rATG in the International Society for Heart and Lung Transplantation (ISHLT) guidelines. The heart transplant population includes an increasing frequency of patients on mechanical circulatory support (MCS), often with ongoing infection and/or presensitization, who are at high immunological risk but also vulnerable to infectious complications. The number of patients with renal impairment is also growing due to lengthening waiting times, intensifying the need for strategies that minimize calcineurin inhibitor (CNI) toxicity. Additionally, the importance of donor-specific antibodies (DSA) in predicting graft failure is influencing immunosuppressive regimens. In light of these developments, and in view of the lack of evidence-based prescribing criteria, experts from Germany, Austria, and Switzerland convened to identify indications for rATG induction in heart transplantation and to develop an algorithm for its use based on patient characteristics.

Myeloablative haploidentical hematopoietic stem cell transplantation using basiliximab for graft-versus-host disease prophylaxis

OBJECTIVES

We retrospectively compared the prophylactic effect of basiliximab and antithymocyte globulin (ATG) after haploidentical hematopoietic stem cell transplantation (HSCT) in patients with leukemia.

METHODS

Haploidentical HSCT using basiliximab for graft-versus-host disease (GVHD) prophylaxis in 10 patients with leukemia was retrospectively compared to ATG for GVHD prophylaxis in 24 patients.

RESULTS

All the patients achieved neutrophil engraftment. One patient in the ATG group did not achieve platelet engraftment. The incidence of grade II-IV and grade III-IV acute GVHD was 30 and 20%, respectively, in the basiliximab group and 16.7 and 4.2%, respectively, in the ATG group (P > 0.05). Extensive cGVHD developed in 40 and 22.2% of patients in the basiliximab group and ATG group, respectively (P > 0.05). Basiliximab resulted in mild infection and a low incidence (10%) of infection-related mortality; ATG resulted in relative severe infection with 29.2% infection-related mortality (P > 0.05). During the follow-up period, 20% of the basiliximab group and 22.7% of the ATG group relapsed (P > 0.05). In the basiliximab group and the ATG group, the 3-year accumulative overall survival rate was, respectively, 80 and 52.5% and the 3-year leukemia-free survival, respectively, was 60 and 49.6% (P > 0.05).

DISCUSSION

The incidences of grade II-IV and grade III-IV aGVHD in the basiliximab group were similar to those in halpoidentical HSCT containing ATG. Compared to the ATG group, the basiliximab group had a lower rate of transplantation-related mortality and better long-term survival, but without statistical significance.

CONCLUSION

The prophylactic regimen of basiliximab with haploidentical HSCT against GVHD seems safe and promising. More studies needed to verify this.

Immunosuppression following heart transplantation: prospects and challenges

Immunosuppression after heart transplantation has significantly reduced the incidence of cellular rejection and improved patient outcomes with the routine use of calcineurin inhibitors. Antimetabolites and proliferation signal inhibitors add to the improvement in patient outcomes, particularly with respect to the reduced burden of cardiac allograft vasculopathy. Patients with antibody sensitization are potentially at higher risk of postoperative complications. Sensitized patients are undergoing heart transplantation with increased frequency, in part due to the emergence of ventricular assist device use as a bridge to heart transplantation. Despite improvements in immunosuppressive therapies, many challenges face physicians and patients, which will further refine and improve care of the post-heart transplant patient.

Immunosuppressive T-cell antibody induction for heart transplant recipients

BACKGROUND

Heart transplantation has become a valuable and well-accepted treatment option for end-stage heart failure. Rejection of the transplanted heart by the recipient's body is a risk to the success of the procedure, and life-long immunosuppression is necessary to avoid this. Clear evidence is required to identify the best, safest and most effective immunosuppressive treatment strategy for heart transplant recipients. To date, there is no consensus on the use of immunosuppressive antibodies against T-cells for induction after heart transplantation.

OBJECTIVES

To review the benefits, harms, feasibility and tolerability of immunosuppressive T-cell antibody induction versus placebo, or no antibody induction, or another kind of antibody induction for heart transplant recipients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 11, 2012), MEDLINE (Ovid) (1946 to November Week 1 2012), EMBASE (Ovid) (1946 to 2012 Week 45), ISI Web of Science (14 November 2012); we also searched two clinical trial registers and checked reference lists in November 2012.

SELECTION CRITERIA

We included all randomised clinical trials (RCTs) assessing immunosuppressive T-cell antibody induction for heart transplant recipients. Within individual trials, we required all participants to receive the same maintenance immunosuppressive therapy.

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently. RevMan analysis was used for statistical analysis of dichotomous data with risk ratio (RR), and of continuous data with mean difference (MD), both with 95% confidence intervals (CI). Methodological components were used to assess risks of systematic errors (bias). Trial sequential analysis was used to assess the risks of random errors (play of chance). We assessed mortality, acute rejection, infection, Cytomegalovirus (CMV) infection, post-transplantation lymphoproliferative disorder, cancer, adverse events, chronic allograft vasculopathy, renal function, hypertension, diabetes mellitus, and hyperlipidaemia.

MAIN RESULTS

In this review, we included 22 RCTs that investigated the use of T-cell antibody induction, with a total of 1427 heart-transplant recipients. All trials were judged to be at a high risk of bias. Five trials, with a total of 606 participants, compared any kind of T-cell antibody induction versus no antibody induction; four trials, with a total of 576 participants, compared interleukin-2 receptor antagonist (IL-2 RA) versus no induction; one trial, with 30 participants, compared monoclonal antibody (other than IL-2 RA) versus no antibody induction; two trials, with a total of 159 participants, compared IL-2 RA versus monoclonal antibody (other than IL-2 RA) induction; four trials, with a total of 185 participants, compared IL-2 RA versus polyclonal antibody induction; seven trials, with a total of 315 participants, compared monoclonal antibody (other than IL-2 RA) versus polyclonal antibody induction; and four trials, with a total of 162 participants, compared polyclonal antibody induction versus another kind, or dose of polyclonal antibodies.No significant differences were found for any of the comparisons for the outcomes of mortality, infection, CMV infection, post-transplantation lymphoproliferative disorder, cancer, adverse events, chronic allograft vasculopathy, renal function, hypertension, diabetes mellitus, or hyperlipidaemia. Acute rejection occurred significantly less frequently when IL-2 RA induction was compared with no induction (93/284 (33%) versus 132/292 (45%); RR 0.73; 95% CI 0.59 to 0.90; I(2) 57%) applying the fixed-effect model. No significant difference was found when the random-effects model was applied (RR 0.73; 95% CI 0.46 to 1.17; I(2) 57%). In addition, acute rejection occurred more often statistically when IL-2 RA induction was compared with polyclonal antibody induction (24/90 (27%) versus 10/95 (11%); RR 2.43; 95% CI 1.01 to 5.86; I(2) 28%). For all of these differences in acute rejection, trial sequential alpha-spending boundaries were not crossed and the required information sizes were not reached when trial sequential analysis was performed, indicating that we cannot exclude random errors.We observed some occasional significant differences in adverse events in some of the comparisons, however definitions of adverse events varied between trials, and numbers of participants and events in these outcomes were too small to allow definitive conclusions to be drawn.

AUTHORS' CONCLUSIONS

This review shows that acute rejection might be reduced by IL-2 RA compared with no induction, and by polyclonal antibody induction compared with IL-2 RA, though trial sequential analyses cannot exclude random errors, and the significance of our observations depended on the statistical model used. Furthermore, this review does not show other clear benefits or harms associated with the use of any kind of T-cell antibody induction compared with no induction, or when one type of T-cell antibody is compared with another type of antibody. The number of trials investigating the use of antibodies against T-cells for induction after heart transplantation is small, and the number of participants and outcomes in these RCTs is limited. Furthermore, the included trials are at a high risk of bias. Hence, more RCTs are needed to assess the benefits and harms of T-cell antibody induction for heart-transplant recipients. Such trials ought to be conducted with low risks of systematic and random error.

Current strategies and future trends in immunosuppression after heart transplantation

PURPOSE OF REVIEW

Current immunosuppressive drugs have provided excellent outcomes after heart transplantation. However, more patients suffer from long-term complications of these drugs. A series of prospective randomized trials has been conducted and has offered disparate results. This report reviews the challenges of immunosuppressive therapy during the past decade, describes recent reports and explores potential future trends in immunosuppressive protocols in heart transplantation.

RECENT FINDINGS

The traditional combination of cyclosporine, azathioprine and steroids has been changed to tacrolimus (Tac) or cyclosporine in combination with mycophenolate mofetil (MMF) and steroids due to the results of several trials. The use of mammalian target of rapamycin inhibitors in combination with Tac or cyclosporine A has not shown a clear benefit compared with MMF. All different combinations have shown some positive effects counteracted by side-effects and negative synergism of combinations. Future protocols need to be adapted according to individual patient's needs and risks.

SUMMARY

The changing population of heart transplantation patients has become older and sicker. Immunosuppression strategies should be developed for each patient based on their risk for rejection and their risk for developing important complications of immunosuppressive therapy.