PD 1 checkpoint inhibition in solid organ transplants: 2 sides of a coin - case report

Experience with pembrolizumab in a renal transplant patient with advanced lung cancer: a case report and review

The treatment of non-small cell lung cancer (NSCLC) has undergone a change because of the advancement of new therapies, like immune checkpoint inhibitors (ICIs), including pembrolizumab. A 64-year-old woman received a kidney transplant in 2012 because of chronic kidney disease secondary to glomerulosclerosis, diagnosed in 2020 with stage IV NSCLC because of metastasis in the contralateral lung, with programmed death ligand 1programmed death ligand 1 expression of 98%, starting treatment with ICIs, despite presenting a graft rejection risk around 40%. After three ICIs cycles, the patient presented a partial response, with good tolerance to treatment and no signs of graft failure. ICIs were maintained for 19 cycles, until disease progression was observed on a reassessment computed tomography, with a progression-free interval of 18 months, with no evidence of treatment rejection. In transplant patients diagnosed with some type of tumor, antineoplastic therapies may be less effective than in the general population. The current evidence derives from observational studies and case series, since this patient population was excluded from clinical trials, suggesting that the use of ICIs in patients with kidney transplants can lead to acute graft rejection. This is still a controversial issue, it is necessary to improve the quality of the data, with the implementation of clinical trials or prospective studies.

Experience with pembrolizumab in a renal transplant patient with advanced lung cancer: a case report and review

The treatment of non-small cell lung cancer (NSCLC) has undergone a change due to the advancement of new therapies, like immune checkpoint inhibitors (ICIs), including pembrolizumab. A 64-year-old woman received a kidney transplant in 2012 due to chronic kidney disease secondary to glomerulosclerosis, diagnosed in 2020 with stage IV NSCLC due to metastasis in the contralateral lung, with PD-L1 expression of 98%, starting treatment with ICIs, despite presenting a graft rejection risk around 40%. After 3 ICI cycles, the patient presented a partial response, with good tolerance to treatment and no signs of graft failure. ICIs were maintained for 19 cycles, until disease progression was observed on a reassessment computed tomography, with a progression-free interval of 18 months, with no evidence of treatment rejection. In transplant patients diagnosed with some type of tumor, antineoplastic therapies may be less effective than in the general population. The current evidence derives from observational studies and case series, since this patient population was excluded from clinical trials, suggesting that the use of ICIs in patients with kidney transplants can lead to acute graft rejection. This is still a controversial issue, it is necessary to improve the quality of the data, with the implementation of clinical trials or prospective studies.

Immune checkpoint inhibitor induced nephrotoxicity: An ongoing challenge

Although immune checkpoint inhibitors (ICIs) have dramatically revolutionized the field of oncology over the last decade, severe immune-related adverse events (irAEs) are potentially life-threatening. In comparison with toxicities involving the skin, gastrointestinal tract and endocrine system, nephrotoxicity is less common but often underestimated due to difficult diagnosis. Management usually consists of treatment discontinuation and/or corticosteroid use. In this review, we summarize current knowledge of ICI-induced nephrotoxicity, evaluating drawbacks and future perspectives.

Update in the treatment of non-melanoma skin cancers: the use of PD-1 inhibitors in basal cell carcinoma and cutaneous squamous-cell carcinoma

Non-melanoma skin cancer (NMSC) includes a wide range of cutaneous tumors, the most frequent of which are basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (CSCC). Although NMSC is usually cured by surgical resection, in rare cases it can progress to locally advanced and metastatic disease. Risk factors for advanced disease include comorbidities, neglect, and immunosuppression. Advanced NMSC may require systemic treatment if surgery and radiation are not feasible. Chemotherapy, epidermal growth factor receptor (EGFR) inhibitors in CSCC, and hedgehog inhibitors in BCC have been used but are generally of limited benefit, with responses often short-lived and toxicity issues. Given the high mutational burden of NMSC, the use of immunotherapy has been investigated and two anti-PD-1 antibodies, cemiplimab and pembrolizumab, are approved for the treatment of advanced CSCC not curable by surgery or radiation. Both have shown durable responses with good tolerability in patients in phase II trials and anti-PD-1 therapy is now the standard of care for locally advanced and metastatic CSCC. PD-1 blockade is also approved as second-line therapy in advanced BCC, with frequent and durable responses after failure on hedgehog inhibitor therapy. PD-1 checkpoint inhibition is being assessed for NMSC in combination with other modalities, including oncolytic viruses and EGFR inhibitors. Adjuvant and neoadjuvant use of cemiplimab and pembrolizumab is also being investigated with several ongoing trials. Further clinical trials of immunotherapy must be prioritized in NMSC for further improvement in outcomes.

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.

Identifying Candidates for Immunotherapy among Patients with Non-Melanoma Skin Cancer: A Review of the Potential Predictors of Response

BACKGROUND

Non-melanoma skin cancer (NMSC) stands as an umbrella term for common cutaneous malignancies, including basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC), together with rarer cutaneous cancers, such as Merkel cell carcinoma (MCC) and other forms of adnexal cancers. The majority of NMSCs can be successfully treated with surgery or radiotherapy, but advanced and metastatic stages may require systemic approaches such as immunotherapy with immune checkpoint inhibitors (ICIs).

SUMMARY

Since immunotherapy is not effective in all patients and can potentially lead to severe adverse effects, an important clinical question is how to properly identify those who could be suitable candidates for this therapeutic choice. In this paper, we review the potential features and biomarkers used to predict the outcome of ICIs therapy for NMSCs. Moreover, we analyze the role of immunotherapy in special populations, such as the elderly, immunocompromised patients, organ transplant recipients, and subjects suffering from autoimmune conditions.

KEY MESSAGES

Many clinical, serum, histopathological, and genetic features have been investigated as potential predictors of response in NMSCs treated with ICIs. Although this field of research is very promising, definitive, cost-effective, and reproducible biomarkers are still lacking and further efforts are needed to validate the suggested predictors in larger cohorts.

Treatment of metastatic cutaneous squamous cell carcinoma in a solid organ transplant recipient with programmed death-1 checkpoint inhibitor therapy

Limited data exist on the use of immune checkpoint inhibitors (ICI) for the treatment of metastatic cutaneous squamous cell carcinoma (CSCC) in solid organ transplant recipients (SOTR). We report a case of a SOTR who developed metastatic disease following multiple surgeries, three cycles of adjuvant radiotherapy, and minimization of immunosuppression. He was subsequently treated with pembrolizumab and achieved a complete response. However, the patient developed ICI-induced allograft rejection requiring therapy discontinuation. The allograft was salvaged following IVIg and steroids. The patient developed recurrent disease which failed rechallenge with pembrolizumab but achieved a partial response following cemiplimab administration. This case illustrates the potential to treat metastatic CSCC in a SOTR with anti-programmed death-1 therapy and preserve graft function despite allograft rejection.

Endothelial Stromal PD-L1 (Programmed Death Ligand 1) Modulates CD8+ T-Cell Infiltration After Heart Transplantation

BACKGROUND

The role of checkpoint axes in transplantation has been partially addressed in animal models but not in humans. Occurrence of fulminant myocarditis with allorejection-like immunologic features in patients under anti-PD1 (programmed death cell protein 1) treatment suggests a key role of the PD1/PD-L1 (programmed death ligand 1) axis in cardiac immune homeostasis.

METHODS

We cross-sectionally studied 23 heart transplant patients undergoing surveillance endomyocardial biopsy. Endomyocardial tissue and peripheral blood mononuclear cells were analyzed by flow cytometry. Multivariate logistic regression analyses including demographic, clinical, and hemodynamic parameters were performed. Murine models were used to evaluate the impact of PD-L1 endothelial graft expression in allorejection.

RESULTS

We found that myeloid cells dominate the composition of the graft leukocyte compartment in most patients, with variable T-cell frequencies. The CD (cluster of differentiation) 4:CD8 T-cell ratios were between 0 and 1.5. The proportion of PD-L1 expressing cells in graft endothelial cells, fibroblasts, and myeloid leukocytes ranged from negligible up to 60%. We found a significant inverse logarithmic correlation between the proportion of PD-L1+HLA (human leukocyte antigen)-DR+ endothelial cells and CD8+ T cells (slope, -18.3 [95% CI, -35.3 to -1.3]; P=0.030). PD-L1 expression and leukocyte patterns were independent of demographic, clinical, and hemodynamic parameters. We confirmed the importance of endothelial PD-L1 expression in a murine allogeneic heart transplantation model, in which Tie2Crepdl1fl/fl grafts lacking PD-L1 in endothelial cells were rejected significantly faster than controls.

CONCLUSIONS

Loss of graft endothelial PD-L1 expression may play a role in regulating CD8+ T-cell infiltration in human heart transplantation. Murine model results suggest that loss of graft endothelial PD-L1 may facilitate alloresponses and rejection.

Management of the kidney transplant patient with Cancer: Report from a Multidisciplinary Consensus Conference

INTRODUCTION

Cancer is the second most common cause of mortality and morbidity in Kidney Transplant Recipients (KTRs). Immunosuppression can influence the efficacy of cancer treatment and modification of the immunosuppressive regimen may restore anti-neoplastic immune responses improving oncologic prognosis. However, patients and transplant physicians are usually reluctant to modify immunosuppression, fearing rejection and potential graft loss. Due to the lack of extensive and recognised data supporting how to manage the immunosuppressive therapy in KTRs, in the context of immunotherapy, chemotherapy, radiotherapy and loco-regional treatments, a Consensus Conference was organised under the auspices of the European Society of Organ Transplantation and the Italian Society of Organ Transplantation. The conference involved a multidisciplinary group of transplant experts in the field across Europe.

METHODS

The overall process included a) the formulation of 12 specific questions based on the PICO methodology, b) systematic literature review and summary for experts for each question, c) a two-day conference celebration and the collection of experts' agreements. The conference was articulated in three sessions: "Immunosuppressive therapy and immunotherapy", "Systemic therapy", "Integrated Therapy", while the final experts' agreement was collected with a televoting procedure and defined according to the majority criterion.

RESULTS

Twenty-six European experts attended the conference and expressed their vote. A total of 14 statements were finally elaborated and voted. Strong agreement was found for ten statements, moderate agreement for two, moderate disagreement for one and uncertainty for the last one.

CONCLUSIONS

The consensus statements provide guidance to transplant physicians caring for kidney transplant recipients with cancer and indicate key aspects that need to be addressed by future clinical research.

Application of Immune Checkpoint Inhibitors in Solid Organ Transplantation Recipients: A Systematic Review

BACKGROUND

Solid organ transplantation (SOT) is a treatment method for end-stage organ diseases and improve their life quality, while using long-term immunosuppressant drugs (ISD) is needed to suppress the function of the immune system. Immune checkpoint inhibitors (ICIs) are a class of anti-tumor drugs that kill tumors by activating the autoimmune system. The primary objective of our systematic review is to investigate the risk factors for organ rejection and the efficacy of ICIs in solid organ transplantation recipients (SOTRs).

METHODS

We searched four databases to find relevant articles up to January 2021. A total of 61 articles involving 106 SOTRs met the screening criteria and were included in our systematic review. The collected data were statistical described, and the risk factors were analyzed by logistic regression.

RESULTS

Forty-four patients (41.5%) developed host-versus-graft response (HVGR) after ICIs. mTOR inhibitors (pre-ICIs) (p = 0.069, OR = 0.377, 95% CI 0.132-1.078) and calcineurin inhibitors (post-ICIs) (p = 0.056, OR = 0.375, 95%CI 0.137-1.025) may help reduce the incidence of HVGR. Hormones (pre-ICIs) (p = 0.026, OR = 3.150, 95%CI 1.150-8.628) and anti-metabolites (pre-ICIs) (p = 0.022, OR = 3.214, 95%CI 1.185-8.720) may adversely affect the efficacy of ICIs. Only 35.6% of patients both responded well to ICIs treatment and did not develop HVGR.

CONCLUSIONS

Our systematic review summarizes the use of ICIs in SOTRs and evaluates the efficacy of ICIs and the risk factors that induce HVGR. Through risk factor analysis, we found that mTOR inhibitors and calcineurin inhibitors may help to reduce the occurrence of HVGR; hormones and anti-metabolic drugs may have adverse effects on the efficacy of ICIs. In addition, there is a contradictory relationship between the occurrence of HVGR and the efficacy of ICIs.

Immunity reloaded: Deconstruction of the PD-1 axis in B cell lymphomas

Over the past decade therapies targeting the PD-1 axis with monoclonal antibodies to reinstate host immune function have revolutionized the clinical management of some cancers but have had minimal impact on others. This dichotomy is exemplified by B cell lymphomas. Whilst striking results are observed in classical Hodgkin Lymphoma (cHL) and Primary Mediastinal B Cell Lymphoma (PMBL), responses in other B cell lymphomas are infrequent. Even with cHL and PMBL, responses are not always durable and adverse effects can result in treatment discontinuation. A more nuanced approach to manipulate the PD-1 axis is required before the full benefits of PD-1 axis blockade can be realised. In this review, we provide an outline of PD-1 axis biology, including the range of cellular expression, the molecular mechanisms underlying regulation and the impacts of downstream signalling. These may permit the development of alternate strategies to PD-1 axis blockade to enhance the therapeutic efficacy in B cell lymphomas.

Immune Checkpoint Inhibitors in Transplantation-A Case Series and Comprehensive Review of Current Knowledge

Cancer is a leading cause of morbidity and deaths in solid organ transplant recipients. In immunocompetent patients, cancer prognosis has been dramatically improved with the development of immune checkpoint inhibitors (ICI), as programmed cell death protein 1/programmed death-ligand 1 and cytotoxic T lymphocyte-associated antigen 4 inhibitors, that increase antitumor immune responses. ICI has been developed outside of the scope of transplantation because of the theoretical risk of graft rejection, which has later been confirmed by the publication of several cases and small series. The use of ICI became unavoidable for treating advanced cancers including in organ transplant patients, but their management in this setting remains highly challenging, as to date no strategy to adapt the immunosuppression and to prevent graft rejection has been defined. In this article, we report a monocentric series of 5 solid organ transplant recipients treated with ICI and provide a comprehensive review of current knowledge of ICI management in the setting of solid organ transplantation. Strategies warranted to increase knowledge through collecting more exhaustive data are also discussed.

Immune Checkpoint Blockade in Advanced Cutaneous Squamous Cell Carcinoma: What Do We Currently Know in 2020?

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer that predominantly arises in chronically sun-damaged skin. Immunosuppression, genetic disorders such as xeroderma pigmentosum (XP), exposure to certain drugs and environmental noxae have been identified as major risk factors. Surgical removal of cSCC is the therapy of choice and mostly curative in early stages. However, a minority of patients develop locally advanced tumors or distant metastases that are still challenging to treat. Immune checkpoint blockade (ICB) targeting CTLA-4, PD-L1 and PD-1 has tremendously changed the field of oncological therapy and especially the treatment of skin cancers as tumors with a high mutational burden. In this review, we focus on the differences between cSCC and cutaneous melanoma (CM) and their implications on therapy, summarize the current evidence on ICB for the treatment of advanced cSCC and discuss the chances and pitfalls of this therapy option for this cancer entity. Furthermore, we focus on special subgroups of interest such as organ transplant recipients, patients with hematologic malignancies, XP and field cancerization.

Poor Outcomes With the Use of Checkpoint Inhibitors in Kidney Transplant Recipients

BACKGROUND

Checkpoint inhibitors are now frequently used for oncologic conditions. The impact of these therapies in solid organ transplant recipients was not assessed in clinical trials. Subsequent case reports highlight the major detrimental interactions of checkpoint inhibitors and the high risk of allograft rejection with their use. Patient outcomes have not been assessed in long-term follow-up.

METHODS

We conducted a retrospective review of kidney transplant recipients with metastatic cancer who received checkpoint inhibitors at a single center between April 2015 and May 2018.

RESULTS

Six kidney transplant recipients with metastatic cancers that were not responding to first-line treatments met study criteria. These include 2 with squamous cell cancers, 2 with melanoma, 1 with renal cell cancer, and 1 with adenocarcinoma of the lung. Four patients received anti-programmed cell death protein-1 (PD-1) antibody and 2 received a combination of anticytotoxic T-lymphocyte-associated protein 4 and anti-PD-1 antibodies. Three out of 6 patients developed acute kidney injury. Two were biopsy-proven acute rejections with subsequent graft failures. The third was attributed to rejection, but improved after discontinuing the checkpoint inhibitor. Five out of 6 patients had cancer progression and only 1 patient had remission.

CONCLUSIONS

Providers and patients need to be aware of the high risk of rejection and the poor remission rate with the use of checkpoint inhibitors in kidney transplant patients. More research is warranted to assess the optimal maintenance immunosuppression during the use of checkpoint inhibitor therapy that would not diminish the chances of remission.

Characteristics and outcomes of lung cancer in solid organ transplant recipients

OBJECTIVES

Lung cancer is the third most common malignancy that develops in patients following solid organ transplantation and is the leading cause of cancer deaths in the general population. The aims of this study are to examine the characteristics of patients who developed lung cancer following solid organ transplantation at our institution and to compare their outcomes to those of lung cancer patients without a history of transplant.

MATERIALS AND METHODS

We performed a single-institution retrospective study of 44 solid organ transplant recipients who developed lung cancer and compared their characteristics to a cohort of 74 lung cancer patients without a history of transplant. We performed propensity score weighted analyses to compare outcomes between the two groups, including a cox proportional hazards model of overall survival.

RESULTS

52 % of post-transplant patients who developed lung cancer were diagnosed with stage III or IV disease. In the propensity score weighted analysis that accounted for age at diagnosis, sex, lung cancer stage at diagnosis, Charlson comorbidity index score, and ECOG performance score, post-transplant patients were more likely to have squamous cell histology (p < 0.01) and had worse overall survival compared to the non-transplant cohort (HR = 1.88, 95 % CI 1.13-3.12, p = 0.02). The difference in survival remained significant after accounting for differences in lung cancer histology and treatment (HR = 2.40, 95 % CI 1.27-3.78, p < 0.01).

CONCLUSIONS

When compared to non-transplant patients with lung cancer, post-transplant patients have worse overall survival after accounting for differences in age, sex, lung cancer stage, comorbidities, and performance status. This survival difference is not solely attributable to differences in tumor histology and treatments received. This may suggest that post-transplant malignancies are more aggressive and difficult to treat.

Deciphering UV-induced DNA Damage Responses to Prevent and Treat Skin Cancer

Ultraviolet (UV) radiation is among the most prevalent environmental factors that influence human health and disease. Even 1 h of UV irradiation extensively damages the genome. To cope with resulting deleterious DNA lesions, cells activate a multitude of DNA damage response pathways, including DNA repair. Strikingly, UV-induced DNA damage formation and repair are affected by chromatin state. When cells enter S phase with these lesions, a distinct mutation signature is created via error-prone translesion synthesis. Chronic UV exposure leads to high mutation burden in skin and consequently the development of skin cancer, the most common cancer in the United States. Intriguingly, UV-induced oxidative stress has opposing effects on carcinogenesis. Elucidating the molecular mechanisms of UV-induced DNA damage responses will be useful for preventing and treating skin cancer with greater precision. Excitingly, recent studies have uncovered substantial depth of novel findings regarding the molecular and cellular consequences of UV irradiation. In this review, we will discuss updated mechanisms of UV-induced DNA damage responses including the ATR pathway, which maintains genome integrity following UV irradiation. We will also present current strategies for preventing and treating nonmelanoma skin cancer, including ATR pathway inhibition for prevention and photodynamic therapy for treatment.

In Situ Immune Profiling of Heart Transplant Biopsies Improves Diagnostic Accuracy and Rejection Risk Stratification

Recognizing that guideline-directed histologic grading of endomyocardial biopsy tissue samples for rejection surveillance has limited diagnostic accuracy, quantitative, in situ characterization was performed of several important immune cell types in a retrospective cohort of clinical endomyocardial tissue samples. Differences between cases were identified and were grouped by histologic grade versus clinical rejection trajectory, with significantly increased programmed death ligand 1+, forkhead box P3+, and cluster of differentiation 68+ cells suppressed in clinically evident rejections, especially cases with marked clinical-histologic discordance. Programmed death ligand 1+, forkhead box P3+, and cluster of differentiation 68+ cell proportions are also significantly higher in "never-rejection" when compared with "future-rejection." These findings suggest that in situ immune modulators regulate the severity of cardiac allograft rejection.

Immune Checkpoint Inhibitor Nephrotoxicity: Update 2020

Immune checkpoint inhibitors (ICPIs) have transformed the landscape of oncology, but are associated with a variety of autoimmune adverse events, including AKI. ICPI-associated AKI (ICPI-AKI) is emerging as an increasingly frequent cause of AKI in patients with cancer, and poses unique diagnostic and management challenges to clinicians who care for these patients. In this review, we describe the incidence and risk factors for ICPI-AKI, including proton pump inhibitor use, CKD, and combination immunotherapy. We discuss the limitations of the various definitions used for ICPI-AKI in prior studies, and propose a novel classification system (definite, probable, and possible ICPI-AKI) that recognizes the diagnostic uncertainty inherent in many cases. We discuss the key clinicopathologic features and treatment strategies for ICPI-AKI, including the role of kidney biopsy versus empirical treatment with steroids. We also explore the under-studied area of ICPI use in the setting of solid organ transplantation, where nephrologists and oncologists must balance the risk of rejection versus treating the underlying malignancy. Finally, we summarize existing data on the role of ICPI rechallenge after an episode of ICPI-AKI.

The Safety and Efficacy of Checkpoint Inhibitors in Transplant Recipients: A Case Series and Systematic Review of Literature

Limited data exist on safety and efficacy of immune checkpoint inhibitors (ICIs) among organ transplant recipients. The objective of this study was to report a case series of two patients with renal transplant who received treatment with an ICI and to conduct a pooled analysis of published cases to describe the safety and efficacy of ICIs in organ transplant patients. A systematic search in the Google Scholar and PubMed databases was carried out to include all the published cases of organ transplant patients who received treatment with ICIs including programmed cell death protein 1 (PD-1), programmed death-ligand 1, or cytotoxic lymphocyte antigen-4 inhibitors since their inscription to January 31, 2019. In the present series of two cases with renal allografts who received pembrolizumab, one patient with squamous cell carcinoma of the skin experienced complete response (CR), whereas another patient with melanoma had a mixed response. Both patients experienced allograft rejection, but graft was salvaged. The pooled analysis of 64 patients published in literature showed that overall allograft rejection rate is 41% in organ transplant recipients following ICI therapy. The graft rejection rate was 44% (17/39) for renal, 39% (7/19) for liver, and 20% (1/5) for cardiac allografts. The highest risk was seen among patients who were treated with PD-1 inhibitors, 20/42 (48%)-13/24 (54%) on nivolumab and 7/18 (39%) on pembrolizumab. The risk was lowest with ipilimumab, 23% (3/13). The overall response rate (CR + partial response [PR]) was 20% with ipilimumab, 26% with nivolumab, and 53% with pembrolizumab, whereas disease control rate (CR + PR + stable disease) was 35% with ipilimumab, 37% with nivolumab, and 53% with pembrolizumab. None of the variables including age, gender, type of cancer, type of allograft, type of immunosuppression, time since transplantation to initiation of ICI, and prior history of rejection were significantly associated with the transplant rejection on univariate analysis. The efficacy of ICI among patients with organ transplant appears promising, warranting testing in prospective clinical trials. The risk of rejection and allograft loss is considerable; therefore, the risk and alternative form of therapies should be thoroughly discussed with the transplant patients prior to initiating ICI therapy. IMPLICATIONS FOR PRACTICE: Transplant recipients are at higher risk of developing cancers. Although immune checkpoint inhibitors have been shown to improve the outcome in more than one cancer type, transplant recipients were excluded from these trials. Most of the data on the safety and efficacy of immune checkpoint inhibitors in transplant patients are based upon case series and case reports. The pooled data from these reports suggest that anti-programmed death-ligand 1 inhibitors have reasonable safety and efficacy among organ transplant patients, which warrants testing in clinical trials.

Systematic Review of the Safety of Immune Checkpoint Inhibitors Among Kidney Transplant Patients

INTRODUCTION

Kidney transplant (Ktx) recipients are excluded from clinical trials of immune checkpoint inhibitors. The aim of this systematic review was to assess the safety of immune checkpoint inhibitors among Ktx patients.

METHODS

A literature search was conducted using MEDLINE, EMBASE, and Cochrane Database from inception through April 2019. We included studies that reported outcomes of Ktx recipients who received immune checkpoint inhibitors for cancer treatment. Outcomes of interest were allograft rejection and/or allograft failure.

RESULTS

Twenty-seven articles with a total of 44 Ktx patients treated with immune checkpoint inhibitor were identified. Of 44 Ktx patients, 18 were reported to have acute rejection. Median time from immune checkpoint inhibitors to acute rejection diagnosis was 24 (interquartile range, 10-60) days. Reported types of acute allograft rejection were cellular rejection (33%), mixed cellular and antibody-mediated rejection (17%), and unspecified type (50%). Fifteen (83%) had allograft failure and 8 (44%) died. Three patients had a partial remission (17%), 1 patient achieved cancer response (6%), and 5 patients had stable disease (28%).

CONCLUSION

The findings of our study raise awareness of the increased risk for acute allograft rejection/failure following immune checkpoint inhibitors for cancer treatment among Ktx patients, in particular with programmed cell death 1 (PD-1) inhibitors. Future large-scale clinical studies are required to appraise the pathogenesis and plan optimal balanced therapy that helps sustain graft tolerance.

Immune checkpoint inhibitor nephrotoxicity: what do we know and what should we do?

Immune checkpoint inhibitors have dramatically improved cancer therapy for many patients. These humanized monoclonal antibodies against various immune checkpoints (receptors and ligands) effectively treat a number of malignancies by unleashing the immune system to destroy cancer cells. These drugs are not excreted by the kidneys or liver, have a long half-life, and undergo receptor-mediated clearance. Although these agents have greatly improved the prognosis of many cancers, immune-related end organ injury is a complication that has come to light in clinical practice. Although less common than other organ involvement, kidney lesions resulting in acute kidney injury and/or proteinuria are being described. Acute tubulointerstitial nephritis is the most common lesion seen on kidney biopsy, while acute tubular injury and glomerular lesions occur less commonly. Clinical findings and laboratory tests are suboptimal in predicting the underlying renal lesion, making kidney biopsy necessary in the majority of cases to definitely diagnose the lesion and potentially guide therapy. Immune checkpoint inhibitor discontinuation and corticosteroid therapy are recommended for acute tubulointerstitial nephritis. Based on a handful of cases, re-exposure to these drugs in patients who previously developed acute tubulointerstitial nephritis has been mixed. Although it is unclear whether re-exposure is appropriate, it should perhaps be considered in patients with limited options. When this approach is taken, patients should be closely monitored for recurrence of acute kidney injury. Treatment of cancer in patients with a kidney transplant with immune checkpoint inhibitors risks the development of acute rejection in some patients and requires close surveillance.

Programmed Cell Death 1 (PD-1) Inhibitors in Renal Transplant Patients with Advanced Cancer: A Double-Edged Sword?

Given advancements in cancer immunity, cancer treatment has gained breakthrough developments. Immune checkpoint inhibitors, such as programmed cell death 1 (PD-1) inhibitors, are the most promising drugs in the field and have been approved to treat various types of cancer, such as metastatic melanoma, head and neck squamous cell carcinoma, and urothelial carcinoma. However, whether PD-1 inhibitors should be administered to renal transplant patients with advanced cancer remains unclear because the T-cells produced after administration of these inhibitors act against not only tumor antigens but also donor alloantigens. Thus, the use of PD-1 inhibitors in kidney-transplanted patients with advanced cancer is limited on account of the high risk of graft failure due to acute rejection. Hence, finding optimal treatment regimens to enhance the tumor-specific T-cell response and decrease T-cell-mediated alloreactivity after administration of a PD-1 inhibitor is necessary. Thus far, no recommendations for the use of PD-1 inhibitors to treat cancer in renal transplant patients are yet available, and very few cases reporting kidney-transplanted patients treated with PD-1 inhibitors are available in the literature. Therefore, in this work, we review the published cases and suggest feasible approaches for renal transplant patients with advanced malignancy treated by a PD-1 inhibitor. Of the 22 cases we obtained, four patients maintained intact grafts without tumor progression after treatment with a PD-1 inhibitor. Among these patients, one maintained steroid dose before initiation of anti-PD1, two received immunosuppressive regimens with low-dose steroid and calcineurin inhibitor (CNI)-elimination with sirolimus before initiation of anti-PD-1 therapy, and one received combined anti-PD-1, anti-vascular endothelial growth factor (VEGF), and chemotherapy with unchanged immunosuppressive regimens. mammalian target of rapamycin (mTOR) inhibitors and anti-VEGF may act as regulators of tumor-specific and allogenic T-cells. However, more studies are necessary to explore the optimal therapy and ensure the safety and efficacy of PD-1 inhibitors in kidney-transplanted patients.