Alemtuzumab for cytolytic induction of immunosuppression in heart transplant recipients

Immune Checkpoint Inhibitor-Associated Cardiotoxicity: Current Understanding on Its Mechanism, Diagnosis and Management

Immune checkpoint inhibitors (ICIs) that target cytotoxic T lymphocyte antigen 4, programmed cell death-1, and PD-ligand 1 have revolutionized cancer treatment, achieving unprecedented efficacy in multiple malignancies. ICIs are increasingly being used in early cancer settings and in combination with various other types of therapies, including targeted therapy, radiotherapy, and chemotherapy. However, despite the excellent therapeutic effect of ICIs, these medications typically result in a broad spectrum of toxicity reactions, termed immune-related adverse events (irAEs). Of all irAEs, cardiotoxicity, uncommon but with high mortality, has not been well recognized. Herein, based on previous published reports and current evidence, we summarize the incidence, diagnosis, clinical manifestations, underlying mechanisms, treatments, and outcomes of ICI-associated cardiotoxicity and discuss possible management strategies. A better understanding of these characteristics is critical to managing patients with ICI-associated cardiotoxicity.

Alemtuzumab Induction Versus Conventional Immunosuppression in Heart Transplant Recipients

The use of alemtuzumab for induction therapy in orthotopic heart transplantation remains controversial, despite its observed benefits in other transplant populations. This study aimed to evaluate whether alemtuzumab conferred a lower risk of rejection while reducing toxicities commonly attributed to standard immunosuppression in orthotopic heart transplantation. We included adult patients who underwent orthotopic heart transplantation and received induction therapy with alemtuzumab (n = 26) or standard immunosuppression (n = 26). The primary end point was freedom from grade ≥2 rejection at 12 months. Baseline characteristics were similar between the groups with the exception of poorer renal function in the alemtuzumab group (P < .05). The primary end point of freedom from grade ≥2 rejection at 12 months was not different between alemtuzumab and standard therapy (76.9% vs 96.2%, P = .077), likely due to similarities in the rates of antibody-mediated rejection in the 2 groups. However, grade ≥2 acute cellular rejection was considerably lower with alemtuzumab (0% vs 19.2%, P = .02), as was acute cellular rejection of any severity (50% vs 7.7%, P = .004). Deterioration in renal function was significantly greater among patients receiving standard therapy as evidenced by decreases in glomerular filtration rate (-25.6 vs -9.2 mL/min, P = .032). No differences in hematologic or infectious complications were observed. In conclusion, alemtuzumab reduced several important rejection-related outcomes while ameliorating the toxicities associated with standard immunosuppression therapy, making it a promising agent for induction in orthotopic heart transplantation.

Acute Cellular Rejection and Infection Rates in Alemtuzumab vs Traditional Induction Therapy Agents for Lung and Heart Transplantation: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Heart and lung transplantation is a high-risk procedure requiring intensive immunosuppressive therapy for preventing organ rejection. Alemtuzumab, a CD52-specific monoclonal antibody, is increasingly used for induction therapy compared with conventional agents. However, there has been no systematic review comparing its efficacy with traditional therapeutic drugs.

METHODS

PubMed and EMBASE were searched to October 1, 2017, for articles on alemtuzumab in cardiothoracic transplant surgery. Of the 433 studies retrieved, 8 were included in the final meta-analysis.

RESULTS

In lung transplantation, alemtuzumab use was associated with lower odds of acute cellular rejection compared with antithymocyte globulin (odds ratio [OR], 0.21; 95% CI, 0.11-0.40; P < .001), lower acute rejection rates (OR, 0.12; 95% CI, 0.03-0.55; P < .01), and infection rates (OR, 0.69; 95% CI, 0.35-1.36; P = .33) when compared with basiliximab. Multivariate meta-regression analysis found that mean age, male sex, single lung transplant, double lung transplant, cytomegalovirus or Epstein-Barr virus status, idiopathic pulmonary fibrosis, cystic fibrosis, and mean ischemic time did not significantly influence acute rejection outcomes. For heart transplantation, alemtuzumab use was associated with lower acute rejection rates when compared with tacrolimus (OR, 0.44; 95% CI, 0.30-0.66; P < .001).

CONCLUSIONS

Alemtuzumab use was associated with lower rejection rates when compared with conventional induction therapy agents (antithymocyte globulin, basiliximab, and tacrolimus) in heart and lung transplantation. However, this was based on observational studies. Randomized controlled trials are needed to verify its clinical use.

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.

Human leukocyte antigens and alloimmunization in heart transplantation: an open debate

Considerable advances in heart transplantation outcome have been achieved through the improvement of donor-recipient selection, better organ preservation, lower rates of perioperative mortality and the use of innovative immunosuppressive protocols. Nevertheless, long-term survival is still influenced by late complications. We support the introduction of HLA matching as an additional criterion in the heart allocation. Indeed, allosensitization is an important factor affecting heart transplantation and the presence of anti-HLA antibodies causes an increased risk of antibody-mediated rejection and graft failure. On the other hand, the rate of heart-immunized patients awaiting transplantation is steadily increasing due to the limited availability of organs and an increased use of ventricular assist devices. Significant benefits may result from virtual crossmatch approach that prevents transplantation in the presence of unacceptable donor antigens. A combination of both virtual crossmatch and a tailored desensitization therapy could be a good compromise for a favorable outcome in highly sensitized patients. Here, we discuss the unresolved issue on the clinical immunology of heart transplantation.