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

Postoperative care of the transplanted patient

The successful delivery of optimal peri-operative care to pediatric heart transplant recipients is a vital determinant of their overall outcomes. The practitioner caring for these patients must be familiar with and treat multiple simultaneous issues in a patient who may have been critically ill preoperatively. In addition to the complexities involved in treating any child following cardiac surgery, caretakers of newly transplanted patients encounter multiple transplant-specific issues. This chapter details peri-operative management strategies, frequently encountered early morbidities, initiation of immunosuppression including induction, and short-term outcomes.

Immunosuppression therapy for pediatric heart transplantation

OPINION STATEMENT

Outcomes following cardiac transplantation in childhood continue to improve. Advances in immunosuppressive therapy over the past two decades likely have contributed to this trend. The evolution in the management of immunosuppression in children has been based on clinical experience rather than on evidence-based medicine; indeed, there have been no pivotal randomized controlled trials of any form of immunosuppression in pediatric thoracic transplantation. Important trends in immunosuppressive therapy and transplant outcomes have been obtained from large transplant registries. Several trends have been identified since the last review of this topic in this journal. First, there is increased knowledge of the pharmacodynamics and pharmacokinetics of immunosuppressive drugs in children, with notable advances in the field of pharmacogenomics. These studies help explain individual variations in drug exposure, efficacy, and adverse events. They also help explain racial and ethnic variations in drug metabolism and efficacy. Second, there have been clear trends in the use of specific immunosuppressive medications. Use of induction therapy, especially polyclonal T cell-depleting antibody preparations, has increased significantly in recent years. The calcineurin inhibitor (CNI) tacrolimus is being used as the cornerstone of maintenance therapy in lieu of cyclosporine in more and more centers. Mounting evidence suggests that use of adjunctive agents (notably mycophenolate mofetil [MMF]) may improve outcomes, including survival, suggesting that monotherapy with CNIs is not the ideal maintenance therapy. Despite its increased cost, MMF has largely replaced azathioprine as the adjunctive agent of choice. Inhibitors of the mammalian target of rapamycin (i.e., sirolimus and everolimus) have not yet assumed a major place as adjunctive agents, as their safety and efficacy have not been well established in children. With the improvements in immunosuppressive therapy, the justification for routine corticosteroid use is far from clear, and many centers have shown excellent outcomes with complete steroid avoidance. Third, there is increasing interest in the importance of anti-HLA antibodies as important risk factors for adverse graft and patient outcomes. This is generating intense interest in treatments that target B cells and plasma cells. Finally, there is increasing realization that the "one size fits all" approach to immunosuppressive therapy is an obsolete concept and that the ultimate goal is to tailor immunosuppressive therapy to the needs of the individual patient. The development of reliable biomarkers of the patient's immune response to the allograft will be essential for optimal individualized immunosuppressive management.

Choice of induction regimens on the risk of cytomegalovirus infection in donor-positive and recipient-negative kidney transplant recipients

BACKGROUND

Late occurrence of cytomegalovirus (CMV) infection remains a concern in CMV-seronegative kidney and/or pancreas transplant recipients of CMV-seropositive organs (donor positive/recipient negative, D+/R-) despite the use of prophylaxis. We investigated the impact of various antibody induction regimens on CMV infection in this group of patients.

METHODS

A total of 254 consecutive D+/R- kidney and/or pancreas transplant patients were studied. The induction agents rabbit anti-thymocyte globulin (rATG) or basiliximab were used according to the center practice. All patients received prophylaxis with valganciclovir (VGCV) for either 3 or 6 months. The occurrence of CMV infection was confirmed by positive DNA viremia. Multivariate Cox regression analyses were performed to determine risk factors for CMV infection.

RESULTS

The cumulative incidence of CMV infection was 58, 112, and 59 cases per 1000 patient-years for patients who received no antibody induction, induction with rATG, or basiliximab induction, respectively (P=0.02). The use of rATG but not basiliximab was associated with an increased risk for CMV infection (adjusted hazard ratio [AHR] 2.13, 95% confidence interval [CI] 1.24-3.54, P=0.006). Acute rejection and its treatment with rATG were not associated with an increased risk for CMV infection when an additional course of VGCV was given following the treatment. Longer duration of prophylaxis was associated with a reduced risk for CMV infection (AHR 0.54, 95% CI 0.33-0.87, P=0.011).

CONCLUSIONS

Induction with rATG is associated with increased risk of CMV infection. Longer duration of prophylaxis is beneficial.

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.

Induction therapy: why, when, and which agent?

The long-term outcome of paediatric transplantation has improved over the last decade with an increase in the armamentarium of immunosuppressive agents. However, the battle against the hostile immune response at the time of and after transplantation continues. Induction therapy can reduce early injury, to optimize the long-term allograft survival. The goal of induction immunosuppression in paediatric transplantation is to permit the use of lower doses of maintenance immunosuppressive agents without increased rates of acute allograft rejection and chronic allograft damage. The aim of this review is to summarize the current literature relating to the use of antibody agents for induction in paediatric solid organ transplantation.

Induction Immunosuppression for Orthotopic Heart Transplantation: A Review

Objectives

To describe the appropriateness and safety of induction immunosuppression for patients at risk for fatal rejection, and to describe the safety and effectiveness profiles of the induction regimens available in the United States.

Data Sources

MEDLINE/PubMed database, EMBASE database, Google Scholar; references from pertinent articles were also reviewed to identify additional data.

Study Selection

A systematic literature review from January 1, 1980, through June 30, 2008, was performed. Included articles ranged from case series to prospective randomized controlled double-blind placebo-controlled trials that detailed the following topics with respect to induction immunosuppression: risk of fatal rejection, renal sparing, malignancy, OKT3, rabbit or equine antithymocyte globulin, daclizumab, basiliximab, and alemtuzumab.

Results

Patients at highest risk for fatal rejection experienced a survival benefit from induction immunosuppression, whereas all other patients experienced no benefit or harm. Most of the early data detail positive experiences with polyclonal antibody regimens. Several newer trials compare the use of polyclonal strategies with the use of anti-CD25 targeted monoclonal antibodies. Few researchers have assessed the usefulness of an anti-CD52 approach. Overall, induction therapy remains a poorly studied and widely variable practice among the major US heart transplant centers.

Conclusion

At present, the unrestricted use of induction for all patients does not seem prudent. Induction should be individualized for each patient on the basis of a well-designed protocol, careful analysis of the transplant center's demographics, and the effectiveness and safety profiles of the regimens used.

Infectious complications associated with monoclonal antibodies and related small molecules

Biologics are increasingly becoming part of routine disease management. As more agents are developed, the challenge of keeping track of indications and side effects is growing. While biologics represent a milestone in targeted and specific therapy, they are not without drawbacks, and the judicious use of these "magic bullets" is essential if their full potential is to be realized. Infectious complications in particular are not an uncommon side effect of therapy, whether as a direct consequence of the agent or because of the underlying disease process. With this in mind, we have reviewed and summarized the risks of infection and the infectious disease-related complications for all FDA-approved monoclonal antibodies and some related small molecules, and we discuss the probable mechanisms involved in immunosuppression as well as recommendations for prophylaxis and treatment of specific disease entities.