Immune checkpoint inhibitors in heart or lung transplantation: Early results from a registry initiative

Immune checkpoint analysis of T-cell responses to pp65 and IE-1 antigens in end-stage lung diseases

Lung transplant (LTX) patients are at high risk of cytomegalovirus (CMV) infection, which is often associated with high mortality and morbidity. Reactivation of CMV causes cell injury due to the cytopathic effect of viral replication and triggering of T cell immunity. The aim of this study was to compare expression of immune checkpoints (ICs) (PD-1, CTLA-4, LAG-3 and TIGIT) in CD4, CD8 and CD56 and activation markers CD137, CD154 and CD69 of end-stage patients awaiting lung transplant. Eighteen pre-LTX positive for anti-CMV IgG titres and 18 healthy subjects were enrolled. IC and activation markers have been evaluated through flow cytometric analysis in HC and pre-LTX patients. Reactive (QF+) and unreactive (QF-) patients were stratified according to QuantiFERON-CMV assays. ICs' and activation markers' expression were determined before and after in vitro stimulation with pp-65 and IE-1 antigens. Lower expression of PD-1 was observed in CD4 and CD8 cells of pre-LTX patients than controls, whereas CTLA4 appeared upregulated in CD56 and CD8 cells. TIGIT is increased on the surface of CD4, CD8 and NK cells after peptide stimulation in QF-negative patients and PD-1 is only downregulated after stimulation in the QF-positive patients. This study provides new evidence of immune dysregulation in patients with end-stage lung disorders, particularly in relation to immune checkpoint cell biology. The change in QF+ mostly happens on cytotoxic cells NK and CD8, while the changes in QF- were observed in adaptive immune cells, including CD4 and CD8.

PD-1 expression in transbronchial biopsies of lung transplant recipients is a possible early predictor of rejection

Introduction

Chronic lung allograft dysfunction (CLAD) is the main cause of the reduced survival of lung transplanted (LTx) patients. The possible role of immune checkpoint molecules in establishing tolerance has been scarcely investigated in the setting of lung transplantation.

Methods

We conducted a retrospective, observational pilot study on a consecutive series of transbronchial cryobiopsies (TCB) obtained from 24 patients during LTx follow-up focusing on PD-1, one of the most investigated immune checkpoint molecules.

Results

Results showed that PD-1-expressing T lymphocytes were present in all TCB with a histological diagnosis of acute rejection (AR; 9/9), but not in most (11/15) of the TCB not resulting in a diagnosis of AR (p=0.0006). Notably, the presence of PD-1-expressing T lymphocytes in TCB resulted in a 10-times higher risk of developing chronic lung allograft dysfunction (CLAD), the main cause of the reduced survival of lung transplanted patients, thus being associated with a clearly worst clinical outcome.

Discussion

Results of this pilot study indicate a central role of PD-1 in the development of AR and its evolution towards CLAD and suggest that the evaluation of PD-1-expressing lymphocytes in TCB could offer a prognostic advantage in monitoring the onset of AR in patients who underwent lung transplantation.

Checkpoint Inhibitor Immune-Related Adverse Events: A Multimodality Pictorial Review

Cancer immunotherapies are drugs that modulate the body's own immune system as an anticancer strategy. Checkpoint inhibitor immunotherapies interfere with cell surface binding proteins that function to promote self-recognition and tolerance, ultimately leading to upregulation of the immune response. Given the striking success of these agents in early trials in melanoma and lung cancer, they have now been studied in many types of cancer and have become a pillar of anticancer therapy for many tumor types. However, abundant upregulation results in a new class of side effects, known as immune-related adverse events (IRAEs). It is critical for the practicing radiologist to be able to recognize these events to best contribute to care for patients on checkpoint inhibitor immunotherapy. Here, we provide a comprehensive system-based review of immune-related adverse events and associated imaging findings. Further, we detail the best imaging modalities for each as well as describe problem solving modalities. Given that IRAEs can be subclinical before becoming clinically apparent, radiologists may be the first provider to recognize them, providing an opportunity for early treatment. Awareness of IRAEs and how to best image them will prepare radiologists to make a meaningful contribution to patient care as part of the clinical team.

Systematic Review of Programmed Cell Death-1 Inhibitor Therapy for Advanced-Stage Cutaneous Squamous Cell Carcinoma in Solid-organ Transplant Recipients

BACKGROUND

Programmed cell death-1 (PD-1) inhibitors represent an effective treatment option for advanced cutaneous squamous cell carcinoma (cSCC). However, solid organ transplant (SOT) recipients with cSCC have traditionally been excluded from clinical trials.

OBJECTIVE

To assess the safety and efficacy of PD-1 inhibitors for stage III-IV cSCC in SOT recipients.

MATERIALS & METHODS

A systematic review was performed using the PubMed, EMBASE, and Scopus databases.

RESULTS

We identified 21 articles describing 33 SOT recipients (26 kidney, four liver, two lung, and one heart) with stage III-IV cSCC treated with PD-1 inhibitors. Eleven patients (33.3%) experienced allograft rejection. Of the 25 cases with iRECIST scores, twelve patients (48.0%) had a complete response (CR), eight (32.0%) showed a partial response (PR), three (12.0%) progressive disease, and two (8.0%) stable disease (SD). Including patients without available iRECIST scores, 21 patients (63.6%) showed tumor response. Eleven patients died, with six (50.0%) due to tumor progression and one (11.1%) due to allograft rejection after foregoing dialysis.

CONCLUSION

PD-1 inhibitors demonstrate efficacy for advanced cSCC and confer a risk of allograft rejection in SOT recipients, requiring careful assessment of risks and benefits. If anti-PD-1 therapy is pursued, use of mTOR inhibitors, prophylactic steroids, and donor-derived cell-free DNA monitoring may mitigate the risk of rejection.

Immune checkpoint inhibitors for solid organ transplant recipients: clinical updates

Transplant care continues to advance with increasing clinical experience and improvements in immunosuppressive therapy. As the population ages and long-term survival improves, transplant patient care has become more complex due to comorbidities, frailty, and the increased prevalence of cancer posttransplantation. Immune checkpoint inhibitors (ICIs) have become a standard treatment option for many cancers in non-transplant patients, but the use of ICIs in transplant patients is challenging due to the possibility of disrupting immune tolerance. However, over the past few years, ICIs have gradually started to be used in transplant patients as well. In this study, we review the current use of ICIs after all solid organ transplantation procedures (kidney, liver, heart, and lung). Increasing data suggest that the type and number of immunosuppressants may affect the risk of rejection after immunotherapy. Immunotherapy for cancer in transplant patients may be a feasible option for selected patients; however, prospective trials in specific organ transplant recipients are needed.

Fatal Allograft Rejection and Cardiac Allograft Vasculopathy After Treatment With Pembrolizumab for Metastatic Melanoma in a Heart Transplant Recipient: A Case Report

Checkpoint inhibitors decrease the progression of many cancers. However, the experience in immunosuppressed patients is limited, with reports of possible serious adverse events. We present a heart transplant recipient treated with pembrolizumab for metastatic melanoma who developed fatal rejection. The patient was a 29 year-old man who underwent heart transplantation at the age of 10 years for congenital heart disease. Seventeen years after transplant, he was diagnosed with scalp melanoma pT3a, N2a, M0, Stage IIIA, positive for BRAF V600E mutation treated with excision, which metastasized to his lungs and brain a year later. Dabrafenib and trametinib were started with transient response. Additional options and their risks were discussed, and pembrolizumab was started 4 months later due to the incomplete response to previous therapy. Five days after initiation the patient presented with moderate cellular rejection and possible antibody mediated rejection (ISHLT Grade 2R, pAMR 1H). Pembrolizumab was discontinued, and he was treated with steroids. Seven months later he presented in cardiogenic shock and severe coronary allograft vasculopathy. Biopsy was negative for cellular rejection, but suspicious for antibody mediated rejection (ISHLT Grade 0R, pAMR 1H), and he had a new serum alloantibody. Despite steroids and plasmapheresis he remained in refractory cardiogenic shock and died of cardiac arrest.

Chemotherapy, targeted therapy and immunotherapy: Which drugs can be safely used in the solid organ transplant recipients?

In solid organ transplant recipients, cancer is associated with worse prognosis than in the general population. Among the causes of increased cancer‐associated mortality, are the limitations in selecting the optimal anticancer regimen in solid organ transplant recipients, because of the associated risks of graft toxicity and rejection, drug‐to‐drug interactions, reduced kidney or liver function, and patient frailty and comorbid conditions. The advent of immunotherapy has generated further challenges, mainly because checkpoint inhibitors increase the risk of rejection, which may have life‐threatening consequences in recipients of life‐saving organs. In general, there are no safe or unsafe anticancer drugs. Rather, the optimal choice of the anticancer regimen results from a careful risk/benefit assessment, from the awareness of potential pharmacokinetic and pharmacodynamic drug‐to‐drug interactions, and of the risk of drug overexposure in patients with kidney or liver dysfunction. In this review, we summarize general principles that may help the oncologists and transplant physicians in the multidisciplinary management of recipients of solid organ transplantation with cancer who are candidates for chemotherapy, targeted therapy, or immunotherapy.

Immune Checkpoints Expression in Chronic Lung Allograft Rejection

Chronic lung allograft dysfunction (CLAD) is the main cause of poor survival and low quality of life of lung transplanted patients. Several studies have addressed the role of dendritic cells, macrophages, T cells, donor specific as well as anti-HLA antibodies, and interleukins in CLAD, but the expression and function of immune checkpoint molecules has not yet been analyzed, especially in the two CLAD subtypes: BOS (bronchiolitis obliterans syndrome) and RAS (restrictive allograft syndrome). To shed light on this topic, we conducted an observational study on eight consecutive grafts explanted from patients who received lung re-transplantation for CLAD. The expression of a panel of immune molecules (PD1/CD279, PDL1/CD274, CTLA4/CD152, CD4, CD8, hFoxp3, TIGIT, TOX, B-Cell-Specific Activator Protein) was analyzed by immunohistochemistry in these grafts and in six control lungs. Results showed that RAS compared to BOS grafts were characterized by 1) the inversion of the CD4/CD8 ratio; 2) a higher percentage of T lymphocytes expressing the PD-1, PD-L1, and CTLA4 checkpoint molecules; and 3) a significant reduction of exhausted PD-1-expressing T lymphocytes (PD-1^pos/TOX^pos) and of exhausted Treg (PD-1^pos/FOXP3^pos) T lymphocytes. Results herein, although being based on a limited number of cases, suggest a role for checkpoint molecules in the development of graft rejection and offer a possible immunological explanation for the worst prognosis of RAS. Our data, which will need to be validated in ampler cohorts of patients, raise the possibility that the evaluation of immune checkpoints during follow-up offers a prognostic advantage in monitoring the onset of rejection, and suggest that the use of compounds that modulate the function of checkpoint molecules could be evaluated in the management of chronic rejection in LTx patients.

Implications of cancer prior to and after heart transplantation

Cancer and cardiovascular disease share many risk factors. Due to improved survival of patients with cancer, the cohort of cancer survivors with heart failure referred for heart transplantation (HT) is growing. Specific considerations include time interval between cancer treatment and HT, risk for recurrence and risk for de novo malignancy (dnM). dnM is an important cause of post-HT morbidity and mortality, with nearly a third diagnosed with malignancy by 10 years post-HT. Compared with the age-matched general population, HT recipients have an approximately 2.5-fold to 4-fold increased risk of developing cancer. HT recipients with prior malignancy show variable cancer recurrence rates, depending on years in remission before HT: 5% recurrence if >5 years in remission, 26% recurrence if 1-5 years in remission and 63% recurrence if <1 year in remission. A myriad of mechanisms influence oncogenesis following HT, including reduced host immunosurveillance from chronic immunosuppression, influence of oncogenic viruses, and the cumulative intensity and duration of immunosuppression. Conversely, protective factors include acyclovir prophylaxis, use of proliferation signal inhibitors (PSI) and female gender. Management involves reducing immunosuppression, incorporating a PSI for immunosuppression and heightened surveillance for allograft rejection. Cancer treatment, including immunotherapy, may be cardiotoxic and lead to graft failure or rejection. Additionally, there exists a competing risk to reduce immunosuppression to improve cancer outcomes, which may increase risk for rejection. A multidisciplinary cardio-oncology team approach is recommended to optimise care and should include an oncologist, transplant cardiologist, transplant pharmacist, palliative care, transplant coordinator and cardio-oncologist.