Retrospective evaluation of the efficacy and safety of belatacept with thymoglobulin induction and maintenance everolimus: A single-center clinical experience

Hepatitis B Virus Reactivation in Kidney Transplant Recipients Treated With Belatacept

Introduction

Hepatitis B virus (HBV) reactivation in kidney transplant recipients has been reported in 3% to 9% of anti-HBc antibody (HBcAb)-positive HBs antigen (HBsAg)-negative patients. It has not been studied in patients receiving belatacept, a selective costimulation blocker.

Methods

We performed a retrospective study of all transplant recipients receiving belatacept in 2 kidney transplantation centers in France. Among HBcAb-positive patients, we analyzed HBV reactivation rate, outcomes, and risk factors.

Results

A total of 135 patients treated with belatacept were included: 32 were HBcAb-positive and 2 were HBsAg-positive. Seven patients reactivated HBV (21.9% of HBcAb-positive patients), including 5 HBsAg-negative patients (16.7% of HBcAb-positive HBsAg-negative patients). Reactivation occurred 54.8 (± 70.9) months after transplantation. One patient presented with severe hepatitis and 1 patient developed cirrhosis. There was no significant difference in survival between patients that reactivated HBV and patients that did not: 5-year patient survival of 100% (28.6; 100) and 83.4% (67.6; 100), respectively (P = 0.363); and 5-year graft survival of 100% (28.6; 100) and 79.8% (61.7; 100), respectively (P = 0.335). No factor, including HBsAb positivity and antiviral prophylaxis, was statistically associated with the risk of HBV reactivation.

Conclusion

HBV reactivation rate was high in patients treated with belatacept when compared with previous transplantation studies. HBV reactivation did not impact survival. Further studies are needed to confirm these results. A systematic antiviral prophylaxis for these patients should be considered and evaluated.

Targeting inflammation and immune activation to improve CTLA4-Ig-based modulation of transplant rejection

For the last few decades, Calcineurin inhibitors (CNI)-based therapy has been the pillar of immunosuppression for prevention of organ transplant rejection. However, despite exerting effective control of acute rejection in the first year post-transplant, prolonged CNI use is associated with significant side effects and is not well suited for long term allograft survival. The implementation of Costimulation Blockade (CoB) therapies, based on the interruption of T cell costimulatory signals as strategy to control allo-responses, has proven potential for better management of transplant recipients compared to CNI-based therapies. The use of the biologic cytotoxic T-lymphocyte associated protein 4 (CTLA4)-Ig is the most successful approach to date in this arena. Following evaluation of the BENEFIT trials, Belatacept, a high-affinity version of CTLA4-Ig, has been FDA approved for use in kidney transplant recipients. Despite its benefits, the use of CTLA4-Ig as a monotherapy has proved to be insufficient to induce long-term allograft acceptance in several settings. Multiple studies have demonstrated that events that induce an acute inflammatory response with the consequent release of proinflammatory cytokines, and an abundance of allograft-reactive memory cells in the recipient, can prevent the induction of or break established immunomodulation induced with CoB regimens. This review highlights advances in our understanding of the factors and mechanisms that limit CoB regimens efficacy. We also discuss recent successes in experimentally designing complementary therapies that favor CTLA4-Ig effect, affording a better control of transplant rejection and supporting their clinical applicability.

Pediatric Kidney Transplantation-Can We Do Better? The Promise and Limitations of Epitope/Eplet Matching

Kidney transplant is the optimal treatment for end-stage kidney disease as it offers significant survival and quality of life advantages over dialysis. While recent advances have significantly improved early graft outcomes, long-term overall graft survival has remained largely unchanged for the last 20 years. Due to the young age at which children receive their first transplant, most children will require multiple transplants during their lifetime. Each subsequent transplant becomes more difficult because of the development of de novo donor specific HLA antibodies (dnDSA), thereby limiting the donor pool and increasing mortality and morbidity due to longer time on dialysis awaiting re-transplantation. Secondary prevention of dnDSA through increased post-transplant immunosuppression in children is constrained by a significant risk for viral and oncologic complications. There are currently no FDA-approved therapies that can meaningfully reduce dnDSA burden or improve long-term allograft outcomes. Therefore, primary prevention strategies aimed at reducing the risk of dnDSA formation would allow for the best possible long-term allograft outcomes without the adverse complications associated with over-immunosuppression. Epitope matching, which provides a more nuanced assessment of immunological compatibility between donor and recipient, offers the potential for improved donor selection. Although epitope matching is promising, it has not yet been readily applied in the clinical setting. Our review will describe current strengths and limitations of epitope matching software, the evidence for and against improved outcomes with epitope matching, discussion of eplet load vs. variable immunogenicity, and conclude with a discussion of the delicate balance of improving matching without disadvantaging certain populations.

Long-Term Immunosuppression Management: Opportunities and Uncertainties

The long-term management of maintenance immunosuppression in kidney transplant recipients remains complex. The vast majority of patients are treated with the calcineurin inhibitor tacrolimus as the primary agent in combination with mycophenolate, with or without corticosteroids. A tacrolimus trough target 5-8 ng/ml seems to be optimal for rejection prophylaxis, but long-term tacrolimus-related side effects and nephrotoxicity support the ongoing evaluation of noncalcineurin inhibitor-based regimens. Current alternatives include belatacept or mammalian target of rapamycin inhibitors. For the former, superior kidney function at 7 years post-transplant compared with cyclosporin generated initial enthusiasm, but utilization has been hampered by high initial rejection rates. Mammalian target of rapamycin inhibitors have yielded mixed results as well, with improved kidney function tempered by higher risk of rejection, proteinuria, and adverse effects leading to higher discontinuation rates. Mammalian target of rapamycin inhibitors may play a role in the secondary prevention of squamous cell skin cancer as conversion from a calcineurin inhibitor to an mammalian target of rapamycin inhibitor resulted in a reduction of new lesion development. Early withdrawal of corticosteroids remains an attractive strategy but also is associated with a higher risk of rejection despite no difference in 5-year patient or graft survival. A major barrier to long-term graft survival is chronic alloimmunity, and regardless of agent used, managing the toxicities of immunosuppression against the risk of chronic antibody-mediated rejection remains a fragile balance.

Review: Ischemia Reperfusion Injury-A Translational Perspective in Organ Transplantation

Thanks to the development of new, more potent and selective immunosuppressive drugs together with advances in surgical techniques, organ transplantation has emerged from an experimental surgery over fifty years ago to being the treatment of choice for many end-stage organ diseases, with over 139,000 organ transplants performed worldwide in 2019. Inherent to the transplantation procedure is the fact that the donor organ is subjected to blood flow cessation and ischemia during harvesting, which is followed by preservation and reperfusion of the organ once transplanted into the recipient. Consequently, ischemia/reperfusion induces a significant injury to the graft with activation of the immune response in the recipient and deleterious effect on the graft. The purpose of this review is to discuss and shed new light on the pathways involved in ischemia/reperfusion injury (IRI) that act at different stages during the donation process, surgery, and immediate post-transplant period. Here, we present strategies that combine various treatments targeted at different mechanistic pathways during several time points to prevent graft loss secondary to the inflammation caused by IRI.

Costimulation Blockade in Kidney Transplant Recipients

Costimulation between T cells and antigen-presenting cells is essential for the regulation of an effective alloimmune response and is not targeted with the conventional immunosuppressive therapy after kidney transplantation. Costimulation blockade therapy with biologicals allows precise targeting of the immune response but without non-immune adverse events. Multiple costimulation blockade approaches have been developed that inhibit the alloimmune response in kidney transplant recipients with varying degrees of success. Belatacept, an immunosuppressive drug that selectively targets the CD28-CD80/CD86 pathway, is the only costimulation blockade therapy that is currently approved for kidney transplant recipients. In the last decade, belatacept therapy has been shown to be a promising therapy in subgroups of kidney transplant recipients; however, the widespread use of belatacept has been tempered by an increased risk of acute kidney transplant rejection. The purpose of this review is to provide an overview of the costimulation blockade therapies that are currently in use or being developed for kidney transplant indications.

Tailored use of belatacept in adolescent kidney transplantation

Adolescent transplant recipients are at risk for nonadherence, development of de novo donor-specific antibody (dnDSA), and allograft loss. Belatacept, a selective T cell costimulatory blocker, is associated with reduced dnDSA, improved renal function, and prolonged allograft survival when compared to calcineurin inhibitor-based regimens in adults; however, its use in children is scant. Three adolescents were initiated on belatacept between August 2017 and September 2018 at the time of kidney transplantation. Selection criteria included age ≥ 14 and EBV IgG + serostatus. Intraoperative alemtuzumab and methylprednisolone were given as induction therapy. Tailored maintenance therapy included steroid-free belatacept and sirolimus for two patients. One patient was initially maintained steroid-free on belatacept and belimumab, an inhibitor of B cell activating factor to treat concurrent systemic lupus erythematous; steroids were added subsequently. Renal function, biopsy-proven rejection, dnDSA, allograft survival, infection, nonadherence, and proteinuria were monitored. Renal function was 86, 73, 52 mL/min/1.73 m² at 20, 20, and 8 months, respectively. There was 100% adherence to therapy and no development of dnDSA. All patients had treatable infections. One developed steroid-responsive acute cellular rejection. Belatacept-based regimens can be tailored for adolescent recipients with good short-term clinical outcomes.

Hepatitis B virus reactivation during belatacept treatment after kidney transplantation

We report a case of HBV reactivation following belatacept treatment in a patient who underwent kidney transplantation in 2015 for HIV-associated nephropathy (HIVAN). Human immunodeficiency virus viral load was undetectable prior to transplantation, and CD4+ lymphocyte count was greater than 300/mL. Baseline HBV serology at transplantation was HBsAg negative, anti-HBcAb positive, anti-HBsAb 312 UI/L, and HBeAg negative/anti-HBeAb positive. Liver function tests were normal, and viral DNA was undetectable. Two years later, the patient presented with severe acute hepatitis after a progressive disappearance of anti-HbsAb, quickly followed by HBV reactivation. Immunosuppressive treatment was drastically reduced, and treatment with entecavir was started. The outcome was favorable, and HBV DNA became undetectable after 9 weeks of treatment. This is the first report of acute hepatitis related to HBV reactivation in a kidney transplant recipient treated with belatacept. The risk for HBV reactivation in patients treated with belatacept should not be underestimated, especially in those with resolved HBV infection.

Belatacept in renal transplant recipient with mild immunologic risk factor: A pilot prospective study (BELACOR)

The benefit of belatacept on antibody-mediated rejection (ABMR) incidence after kidney transplant with preformed donor-specific antibodies (DSAs) has never been assessed. Between 2014 and 2016, we conducted a multicenter prospective clinical trial with 49 patients to determine kidney allograft outcome in recipients with preformed DSAs (maximal mean fluorescence intensity 500 to 3000) treated with belatacept (BELACOR trial). Immunosuppressive strategy included antithymocyte globulin, belatacept, mycophenolate mofetil, and steroids. An ancillary control group was designed retrospectively, including patients fulfilling the same inclusion criteria treated with calcineurin inhibitors. In BELACOR group, no patient exhibited acute ABMR, patient and allograft survival at 1 year was 100% and 95.4%, respectively, and the estimated glomerular filtration rate was 53.2 mL/min/1.73 m² . However, the 12-month incidence of acute T cell-mediated rejection was 25.4% (14.5% to 42.4%). Comparison with the control group showed significantly higher T cell-mediated rejection incidence only in the BELACOR group (P = .003). Considering the DSAs, the outcome was similar in the 2 groups except a significantly higher number of patients displayed a complete disappearance of class II DSAs in the BELACOR group (P = .001). Belatacept was not associated with an acute ABMR increased risk and may be considered as immunosuppressive strategy in transplant recipients with preformed DSAs (maximal mean fluorescence intensity 500 to 3000). Prospective randomized trials are needed to confirm these results.