Pilot evaluation of PD-1 inhibition in metastatic cancer patients with a history of liver transplantation: the Mayo Clinic experience

Immune checkpoint inhibitors in liver transplantation: Current practice, challenges, and opportunities

Immune checkpoint inhibitors are becoming a mainstay of cancer treatment. While first studied and approved for patients with unresectable disease, due to their efficacy, they are becoming increasingly used in the perioperative period across many cancer types. In patients with HCC, immune checkpoint inhibitors have now become the standard of care in the advanced setting and have shown promising results in the adjuvant setting after liver resection. While these drugs continue to show promise, their role in the peritransplant setting still remains a question. In this review, we explore the current use of this class of medications in patients with HCC, as well as the immunologic role of the pathways that they inhibit. We also identify potential for future research opportunities to better understand the role of these medications.

Downstaging Hepatocellular Carcinoma with Checkpoint Inhibitor Therapy Improves Access to Curative Liver Transplant

PURPOSE

Liver transplantation is curative for hepatocellular carcinoma (HCC). Checkpoint inhibitor therapy (CPIT) has been used in unresectable HCC, but recent advances have demonstrated CPIT as an innovative method of downstaging advanced HCC with the caveat that CPIT prior to transplantation has risks including irreversible graft rejection. We report the outcomes of Mayo Clinic Arizona patients who underwent downstaging with CPIT.

METHODS

This retrospective chart review was conducted for Mayo Clinic Arizona patients who were diagnosed with HCC who underwent downstaging with CPIT with the goal of meeting criteria for transplantation.

RESULTS

We present nine cases with HCC outside Milan who underwent CPIT. Four received a transplant; one was delisted due to his exceptional therapeutic response. All received liver-directed therapy. Peak alpha-fetoprotein pre-CPIT ranged from 8-29,523 ng/mL, which decreased to 2.2-19.6 ng/mL on CPIT. CPIT included atezolizumab/bevacizumab, ipilimumab/nivolumab, nivolumab, and pembrolizumab; one patient received two regimens. CPIT was held prior to transplant at a median of 3 months. Three patients received methylprednisolone for immunosuppression induction; one received thymoglobulin. One patient developed acute cellular rejection at 5 weeks, 9 weeks, and 5 months post-transplant; given the late onset, these were not attributed to CPIT and were successfully treated. During an average follow-up of 16.5 months, no tumor recurrence has occurred.

CONCLUSION

We describe nine patients with HCC outside Milan with inadequate response with liver-directed therapy, who achieved marked responses with CPIT, allowing for consideration of successful liver transplantation. Our case series supports the consideration of locoregional therapies and CPIT for downstaging to within transplant criteria.

Immunosuppression in liver transplant oncology: position paper of the Italian Board of Experts in Liver Transplantation (I-BELT)

Liver transplant oncology (TO) represents an area of increasing clinical and scientific interest including a heterogeneous group of clinical-pathological settings. Immunosuppressive management after LT is a key factor relevantly impacting result. However, disease-related guidance is still lacking, and many open questions remain in the field. Based on such a substantial lack of solid evidences, the Italian Board of Experts in Liver Transplantation (I-BELT) (a working group including representatives of all national transplant centers), unprecedently promoted a methodologically sound consensus conference on the topic, based on the GRADE approach. The group final recommendations are herein presented and commented. The 18 PICOs and Statements and their levels of evidence and grades of recommendation are reported and grouped into seven areas: (1) risk stratification by histopathological and bio-molecular parameters and role of mTORi post-LT; (2) steroids and HCC recurrence; (3) management of immunosuppression when HCC recurs after LT; (4) mTORi monotherapy; (5) machine perfusion and HCC recurrence after LT; (6) physiopathology of tumor-infiltrating lymphocytes and immunosuppression, the role of inflammation; (7) immunotherapy in liver transplanted patients. The interest in mammalian targets of rapamycin inhibitors (mTORi), for steroid avoidance and the need for a reduction to CNI exposure emerged from the consensus process. A selected list of unmet needs prompting further investigations have also been developed. The so far heterogeneous and granular approach to immunosuppression in oncologic patients deserves greater efforts for a more standardized therapeutic response to the different clinical scenarios. This consensus process makes a first unprecedented step in this direction, to be developed on a larger scale.

Immunotherapy as a Complement to Surgical Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver tumor in adults, and the fourth leading cause of cancer-related deaths worldwide. While surgical and ablative therapies remain the standard of care in early localized disease, late presentation with advanced stages of disease, impaired hepatic function, or local recurrence following surgical resection preclude operative management as the sole treatment modality in a subgroup of patients. As such, systemic therapies, namely immunotherapy, have become an integral part of the HCC treatment algorithm over the past decade. While agents, such as atezolizumab/bevacizumab, have well-established roles as first-line systemic therapy in intermediate- and advanced-stage HCC, the role of immunotherapy in disease amenable to surgical management continues to evolve. In this review, we will discuss the current evidence and aggregate impact of immunotherapy in the context of HCC amenable to surgical management, including its application in the neoadjuvant and adjuvant settings.

New advances in the study of PD-1/PD-L1 inhibitors-induced liver injury

The application of immune checkpoint inhibitors (ICIs) has made extraordinary achievements in tumor treatment. Among them, programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors can improve the prognosis of advanced tumors, and have been widely used in clinical practice to treat many types of cancers. However, excessive immune response can also induce immune-related adverse events (irAEs) involving many organs. Of these, immune-related liver injury is the relatively common and carries the highest morbidity, which has attracted the attention of hepatologists all over the world. The incidence of this type of liver injury depends specifically on factors such as the type of drug being combined, viral infection, type of cancer and liver transplantation. Although there is no unanimity on the mechanism of PD-1/PD-L1 inhibitor-induced liver injury, in this review, we also summarize the current evidence that provides insights into the pathogenesis of PD-1/PD-L1 inhibitor-induced liver injury, including the fact that PD-1/PD-L1 inhibitors cause reactivation of CTLs, aberrant presentation of autoantigens, hepatic immune tolerance environment is disrupted, and cytokine secretion, among other effects. Patients usually develop liver injury after the use of PD-1/PD-L1 inhibitors, and clinical symptoms mainly include weakness, muscle pain, nausea and vomiting, and jaundice. Histologically, the main manifestation is lobular hepatitis with lobular inflammatory infiltration. Since the specific biomarkers for PD-1/PD-L1 inhibitor-associated liver injury have not been identified yet, alpha-fetoprotein, IL-6, and IL-33 have the potential to be biomarkers for predicting this type of liver injury in the future, but this requires further research. We also describe the examination and treatment of this type of liver injury, which usually includes eliminating related influencing factors, regularly monitoring liver function, temporarily retaining or permanently stopping ICIs treatment according to the severity of toxicity, and using corticosteroids. This review may provide useful information for the future clinical practice of PD-1/PD-L1 inhibitors.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Immunotherapy for transplantation of hepatocellular carcinoma: the next frontier in adjunctive therapy

PURPOSE OF REVIEW

The increasing success of liver transplantation in hepatocellular carcinoma (HCC) drives an ever-evolving search for innovative strategies to broaden eligible patients' pools. Recent advances in immuno-oncology have turned the spotlight on immune checkpoint inhibitors (ICIs). This review offers an updated overview of ICIs in liver transplantation for HCC, exploring neoadjuvant and adjuvant approaches and addressing unanswered questions on safety, patients' selection, and response predictors.

RECENT FINDINGS

ICIs have transitioned from being a last-chance therapeutic hope to becoming an integral cornerstone in the treatment of advanced HCC, holding great promise as a compelling option not only to downstage patients for transplantation but also as an alternative strategy in addressing posttransplantation disease recurrence. Despite ongoing refinements in immunotherapeutic agents, the complex molecular pathways involved emphasize the need for a comprehensive approach to integrate immunotherapy in liver transplantation.

SUMMARY

Initial concerns about graft rejection, with ICIs as a bridging therapy to liver transplantation, were successfully addressed using adequate immunosuppressants strategies and minimized with a sufficient washout period. Post-liver transplantation disease recurrence remains challenging, requiring a balance between effective therapy and preserving graft function. Emphasis should be placed on clinical trials validating the risk-benefit ratio of ICIs for liver transplantation, guiding appropriate patients' selection, and establishing clear management pathways.

Systemic Therapy for Advanced Hepatocellular Carcinoma: ASCO Guideline Update

PURPOSE

To update an evidence-based guideline to assist in clinical decision-making for patients with advanced hepatocellular carcinoma (HCC).

METHODS

ASCO convened an Expert Panel to update the 2020 guideline on systemic therapy for HCC. The panel updated the systematic review to include randomized controlled trials (RCTs) published through October 2023 and updated recommendations.

RESULTS

Ten new RCTs met the inclusion criteria and were added to the evidence base.

RECOMMENDATIONS

Atezolizumab + bevacizumab (atezo + bev) or durvalumab + tremelimumab (durva + treme) may be offered first-line for patients with advanced HCC, Child-Pugh class A liver disease, and Eastern Cooperative Oncology Group performance status 0-1. Where there are contraindications to these therapies, sorafenib, lenvatinib, or durvalumab may be offered first-line. Following first-line treatment with atezo + bev, second-line therapy with a tyrosine kinase inhibitor (TKI), ramucirumab (for patients with alpha-fetoprotein [AFP] ≥400 ng/mL), durva + treme, or nivolumab + ipilimumab (nivo + ipi) may be recommended for appropriate candidates. Following first-line therapy with durva + treme, second-line therapy with a TKI is recommended. Following first-line treatment with sorafenib or lenvatinib, second-line therapy options include cabozantinib, regorafenib for patients who previously tolerated sorafenib, ramucirumab (AFP ≥400 ng/mL), nivo + ipi, or durvalumab; atezo + bev or durva + treme may be considered for patients who did not have access to these therapies in the first-line setting, and do not have contraindications. Pembrolizumab or nivolumab are also options for appropriate patients following sorafenib or lenvatinib. Third-line therapy may be considered in Child-Pugh class A patients with good PS, using one of the agents listed previously that has a nonidentical mechanism of action with previously received therapy. A cautious approach to systemic therapy is recommended for patients with Child-Pugh class B advanced HCC. Further guidance on choosing between options is included within the guideline.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

Immunotherapy and Liver Transplantation: The Future or the Failure?

A quarter century has passed since the milestone study by Mazzaferro and colleagues on liver transplantation (LT) for hepatocellular carcinoma (HCC). The increasing demand for LT for HCC has led to the continued efforts to expand LT indications. Downstaging to within Milan criteria has been incorporated into the organ allocation policy for HCC in the United States in 2017 and provides acceptable long-term survival. The present review focuses on the rationale of neoadjuvant immune checkpoint inhibitor (ICI) in HCC, the experience of ICI in the pre- and posttransplant setting.

Recent advances in the management of hepatocellular carcinoma

Liver cancer remains a challenge of global health, being the 4th leading cause of cancer death worldwide. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, and is usually precipitated by chronic viral infections (hepatitis B and C), non-alcoholic steatohepatitis, heavy alcohol use, and other factors which may lead to chronic inflammation and cirrhosis of the liver. There have been significant advances in the systemic treatment options for HCC over the past decades, with several approvals of both immune checkpoint inhibitors and tyrosine kinase inhibitors in patients with preserved liver function. These advances have led to improvement in survival outcomes, with expected survival of greater than 18 months, in those with sensitive tumors, adequate liver function, and those functionally fit to receive sequential therapies. Several ongoing and promising trials are now evaluating combinational strategies with novel systemic agents and combinations of systemic therapy with locoregional therapy. In view of these trials, further advances in the treatment of HCC are foreseen in the near future.

Transplant Oncology: An Emerging Discipline of Cancer Treatment

Transplant oncology is an emerging concept of cancer treatment with a promising prospective outcome. The applications of oncology, transplant medicine, and surgery are the core of transplant oncology to improve patients' survival and quality of life. The main concept of transplant oncology is to radically cure cancer by removing the diseased organ and replacing it with a healthy one, aiming to improve the survival outcomes and quality of life of cancer patients. Subsequently, it seeks to expand the treatment options and research for hepatobiliary malignancies, which have seen significantly improved survival outcomes after the implementation of liver transplantation (LT). In the case of colorectal cancer (CRC) in the transplant setting, where the liver is the most common site of metastasis of patients who are considered to have unresectable disease, initial studies have shown improved survival for LT treatment compared to palliative therapy interventions. The indications of LT for hepatobiliary malignancies have been slowly expanded over the years beyond Milan criteria in a stepwise manner. However, the outcome improvements and overall patient survival are limited to the specifics of the setting and systematic intervention options. This review aims to illustrate the representative concepts and history of transplant oncology as an emerging discipline for the management of hepatobiliary malignancies, in addition to other emerging concepts, such as the uses of immunotherapy in a peri-transplant setting as well as the use of circulating tumor DNA (ctDNA) for surveillance post-transplantation.

Hepatocellular Carcinoma: The Role of Immunotherapy and Transplantation in the Era of Transplant Oncology

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer deaths worldwide. As most patients present with advanced disease, curative therapy such as surgical resection and radiofrequency ablation are rarely utilized. With the advent of immunotherapy, historical treatment approaches such as liver transplantation are being challenged. In particular, the use of immune checkpoint inhibitors (ICIs) has emerged as a safe and useful option in the treatment of HCC. However, there is concern over adverse effects, such as graft rejection and graft loss. This updated review discusses the role of immunotherapy in the pre- and post-transplantation setting and provides insights into the potential of immunotherapy as an adjunct to liver transplantation. We deliberate on the use of ICI in the setting of the Milan criteria as well as the University of California San Francisco's expanded criteria for liver transplantation. Current data suggest that ICI has utility, especially in the pretransplantation setting. Nevertheless, larger, purposefully designed clinical trials are needed to clearly identify patients who will benefit most from ICI treatment in the transplant setting and determine parameters that will minimize the risk of graft rejection and maximize the benefits of this adjunct treatment.

Immunotherapy and Liver Transplantation: A Narrative Review of Basic and Clinical Data

Immune checkpoint inhibitors (ICIs) have improved the management of patients with intermediate- and advanced-stage HCC, even making some of them potential candidates for liver transplantation. However, acute rejection has been observed after ICI therapy, challenging its safety in transplant settings. We summarize the key basic impact of immune checkpoints on HCC and liver transplantation. We analyze the available case reports and case series on the use of ICI therapy prior to and after liver transplantation. A three-month washout period is desirable between ICI therapy and liver transplantation to reduce the risk of acute rejection. Whenever possible, ICIs should be avoided after liver transplantation, and especially so early after a transplant. Globally, more robust prospective data in the field are required.

Evolving Landscape in Liver Transplantation for Hepatocellular Carcinoma: From Stage Migration to Immunotherapy Revolution

Liver transplantation (LT) represents the primary curative option for HCC. Despite the extension of transplantation criteria and conversion with down-staging loco-regional treatments, transplantation is not always possible. The introduction of new standards of care in advanced HCC including a combination of immune checkpoint inhibitor-based therapies led to an improvement in response rates and could represent a promising strategy for down-staging the tumor burden. In this review, we identify reports and series, comprising a total of 43 patients who received immune checkpoint inhibitors as bridging or down-staging therapies prior to LT. Overall, treated patients registered an objective response rate of 21%, and 14 patients were reduced within the Milan criteria. Graft rejection was reported in seven patients, resulting in the death of four patients; in the remaining cases, LT was performed safely after immunotherapy. Further investigations are required to define the duration of immune checkpoint inhibitors, their minimum washout period and the LT long-term safety of this strategy. Some randomized clinical trials including immunotherapy combinations, loco-regional treatment and/or tyrosine kinase inhibitors are ongoing and will likely determine the appropriateness of immune checkpoint inhibitors' administration before LT.

Therapeutic Effects of Anti-PD1 Immunotherapy on Hepatocellular Carcinoma Under Administration of Tacrolimus

BACKGROUND

Liver transplantation (LT) is the treatment of choice for patients with hepatocellular carcinoma (HCC). Recurrence of HCC after LT occurs in 10% to 20% of cases. Preclinical studies to evaluate immune checkpoint inhibitors in conjunction with immunosuppressant treatment in transplant recipients have been lacking. Here, we evaluated the efficacy, safety, and mechanism of programmed cell death-1 (PD1) blockade under tacrolimus treatment in transplant recipients.

METHODS

We used a murine allogeneic skin transplantation model and murine syngeneic subcutaneous and orthotopic HCC models and measured the tumor volume and the change in tumor-infiltrating lymphocytes under PD1 blockade and tacrolimus treatment.

RESULTS

Tacrolimus treatment prolonged allograft survival in the allogeneic transplantation model and enhanced tumor growth in both subcutaneous and orthotopic HCC models. PD1 blockade suppressed tumor growth and lung metastasis in correlation with the number of infiltrating CD8 + T cells. Under tacrolimus treatment, PD1 blockade still resulted in an antitumor effect accompanied by a significant increase in tumor-infiltrating CD8 + T cells, natural killer cells, dendritic cells, and natural killer T cells. Tacrolimus treatment rescued the acceleration of transplant rejection induced by PD1 blockade in the allogeneic transplantation model.

CONCLUSIONS

Our data suggest that treatment with high-dose tacrolimus in conjunction with PD1 blockade has an antitumor effect and reduces transplant rejection in mouse models of allograft skin transplantation and HCC. Thus, these results suggest that a clinical trial of PD1 inhibitors for HCC in LT merits consideration.

Tissue Expression of Programmed Cell Death 1 Ligand1 (PD-L1) in Biopsies of Transplant Livers of Pediatric Patients as a Possible Marker of Acute Cellular Rejection

INTRODUCTION

Preclinical models have demonstrated that PD-1 and its ligand programmed death ligand1 (PD-L1) play significant roles in both graft induction and the maintenance of immune tolerance. It has also been suggested that PD-L1 tissue expression may predict graft rejection; however, the available data are sparse and inconclusive. Some studies were conducted on patients with cancer; most of them do not concern the liver, especially within the context of the use of immunohistochemical tests. Therefore, the aim of our study was to assess the relationship between tissue expression of PD-L1 in a unique material, i.e., in the liver biopsies of pediatric patients after transplantation with the presence of acute cellular rejection (ACR).

MATERIAL AND METHODS

This retrospective study enrolled 55 biopsies from 55 patients who underwent protocol liver biopsies. The control group consisted of 19 biopsies from 13 patients diagnosed with acute cellular rejection (rejection activity index/RAI/ from 2 to 8). An immunohistochemical (IHC) staining for PD-L1 was performed in all of the liver specimens; its expression was analyzed in different regions of liver tissue (in inflammatory infiltrates and within the endothelium and hepatocytes). The following changes were re-evaluated in each specimen: features of any kind of rejection (acute cellular, antibody-mediated, chronic); the presence and severity of fibrosis (Ishak scale); and the presence of cholestasis and steatosis. Clinical parameters were also evaluated, including tests of liver function (AST, ALT, GGT, bilirubin).

RESULTS

The age of patients in the study group ranged from 2.37 to 18.9 years (median 13.87 years), with the time after transplantation being 1-17 years (median 8.36 years). The age of patients in the control group ranged from 1.48 to 17.51 years (median 7.93 years), with their biopsies being taken 0.62-14.39 years (median 1.33 years) after transplantation. We found a statistically significant relationship between PD-L1 expression on inflammatory infiltrates and ACR; however, there was no statistically significant relationship between PD-L1 endothelial expression and ACR. PD-L1 was not positive in the hepatocytes regardless of if it was the study or control group that was under observation.

CONCLUSION

PD-L1 appears to be a promising marker to predict graft rejection.

Liver transplantation immunology: Immunosuppression, rejection, and immunomodulation

Outcomes after liver transplantation have continuously improved over the past decades, but long-term survival rates are still lower than in the general population. The liver has distinct immunological functions linked to its unique anatomical configuration and to its harbouring of a large number of cells with fundamental immunological roles. The transplanted liver can modulate the immunological system of the recipient to promote tolerance, thus offering the potential for less aggressive immunosuppression. The selection and adjustment of immunosuppressive drugs should be individualised to optimally control alloreactivity while mitigating toxicities. Routine laboratory tests are not accurate enough to make a confident diagnosis of allograft rejection. Although several promising biomarkers are being investigated, none of them is sufficiently validated for routine use; hence, liver biopsy remains necessary to guide clinical decisions. Recently, there has been an exponential increase in the use of immune checkpoint inhibitors due to the unquestionable oncological benefits they provide for many patients with advanced-stage tumours. It is expected that their use will also increase in liver transplant recipients and that this might affect the incidence of allograft rejection. Currently, the evidence regarding the efficacy and safety of immune checkpoint inhibitors in liver transplant recipients is limited and cases of severe allograft rejection have been reported. In this review, we discuss the clinical relevance of alloimmune disease, the role of minimisation/withdrawal of immunosuppression, and provide practical guidance for using checkpoint inhibitors in liver transplant recipients.

Optimizing the Safe Washout Period for Liver Transplantation Following Immune Checkpoint Inhibitors with Atezolizumab, Nivolumab, or Pembrolizumab

BACKGROUND

Using immune checkpoint inhibitors (ICIs) as a downstaging therapy for liver transplantation (LT) has improved outcomes for patients with advanced hepatocellular carcinoma (HCC). However, this therapy carries a risk of post-transplant graft rejection. The washout (WO) period between the last ICI dose and LT seems critical in preventing postoperative rejection. This study aimed to optimize the WO period by balancing tumor burden suppression and rejection prevention using ICIs before LT.

METHODS

We reviewed published case reports or series from March 2020 to December 2022 regarding LT for HCC after downstaging or bridge therapy with ICIs and included 4 of our cases. Most patients received atezolizumab, nivolumab, or pembrolizumab; these ICIs shared a half-life of around 28 days. Therefore, we excluded cases without definite WO period data and those using non-atezolizumab/nivolumab/pembrolizumab ICIs and ultimately enrolled 22 patients for analysis. We compared their clinical outcomes and estimated the rejection-free survival for every 0.5 half-life interval.

RESULTS

Most study subjects received nivolumab (n = 25). Six patients had severe rejections (nivolumab group, n = 5) and needed rescue management. Of the 6 cases, 1 patient died after rejection, and 2 underwent re-transplantation. The median WO period in these 6 patients was 22 days (IQR: 9-35 days). In addition, we found that a 1.5 half-life (42 days) was the shortest safe WO period associated with significant rejection-free survival (P = .005).

CONCLUSIONS

Our results showed that 42 days was the safest WO period before LT for HCC after ICI with atezolizumab, nivolumab, or pembrolizumab.

Allograft rejection following immune checkpoint inhibitors in solid organ transplant recipients: A safety analysis from a literature review and a pharmacovigilance system

AIM

This study aimed to systematically characterize transplant rejection after immune checkpoint inhibitors (ICIs) initiation in solid organ transplant recipients (SOTRs).

METHODS

Data were extracted from the US FDA Adverse Event Reporting System (FAERS) database and case reports in the literature. Disproportionality analysis including information component and reported odds ratio (ROR) was performed to access potential risk signals.

RESULTS

A total of 168 patients with transplant rejection after ICIs usage were identified in the FAERS database, and 89 cases were identified in the literature review. ICIs were significantly associated with transplant rejection (ROR₀₂₅ : 2.2). A strong risk signal was found for combination therapy with pembrolizumab and ipilimumab compared to monotherapy.

CONCLUSION

Immune checkpoint inhibitors were significantly associated with transplant rejection in SOTRs.

2022 KLCA-NCC Korea practice guidelines for the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Immune Checkpoint Inhibitors for Solid Tumors in the Adjuvant Setting: Current Progress, Future Directions, and Role in Transplant Oncology

The rationale for administering immune checkpoint inhibitors (ICIs) in the adjuvant setting is to eradicate micro-metastases and, ultimately, prolong survival. Thus far, clinical trials have demonstrated that 1-year adjuvant courses of ICIs reduce the risk of recurrence in melanoma, urothelial cancer, renal cell carcinoma, non-small cell lung cancer, and esophageal and gastroesophageal junction cancers. Overall survival benefit has been shown in melanoma while survival data are still not mature in other malignancies. Emerging data also show the feasibility of utilizing ICIs in the peri-transplant setting for hepatobiliary malignancies. While ICIs are generally well-tolerated, the development of chronic immune-related adverse events, typically endocrinopathies or neurotoxicities, as well as delayed immune-related adverse events, warrants further scrutiny regarding the optimal duration of adjuvant therapy and requires a thorough risk-benefit determination. The advent of blood-based, dynamic biomarkers such as circulating tumor DNA (ctDNA) can help detect minimal residual disease and identify the subset of patients who would likely benefit from adjuvant treatment. In addition, the characterization of tumor-infiltrating lymphocytes, neutrophil-to-lymphocyte ratio, and ctDNA-adjusted blood tumor mutation burden (bTMB) has also shown promise in predicting response to immunotherapy. Until additional, prospective studies delineate the magnitude of overall survival benefit and validate the use of predictive biomarkers, a tailored, patient-centered approach to adjuvant ICIs that includes extensive patient counseling on potentially irreversible adverse effects should be routinely incorporated into clinical practice.

Preoperative Immunotherapy in Hepatocellular Carcinoma: Current State of the Art

Hepatocellular carcinoma (HCC) is a malignancy that requires multidisciplinary evaluation to develop individualized and tailored treatment concepts. While liver resection and transplantation represent the mainstay of curative treatment in patients with early-stage HCC, disease recurrence remains an important burden. Immune checkpoint inhibitors (ICI) have become standard of care in the palliative setting, achieving promising response rates with overall good tolerability. Accordingly, ICIs are being evaluated in (neo)adjuvant concepts in order to improve survival. Nevertheless, neoadjuvant therapies are not recommended by current guidelines as they have not been proven to improve the outcome in large Phase III trials yet. Especially in the context of liver transplantation (LT), perioperative ICI usage is in need of a particularly critical risk-benefit assessment, as the immunotherapy may significantly increase the risk of rejection. In this review, we summarize available data on ICI-based perioperative treatment strategies in HCC. We discuss current drawbacks and challenges of this treatment concept and specifically highlight the risk of allograft rejection when ICI are given in patients (subsequently) considered for liver transplantation.

Postoperative adjuvant therapy for hepatocellular carcinoma with microvascular invasion

Hepatocellular carcinoma (HCC) is one of the most lethal tumors in the world. Liver resection (LR) and liver transplantation (LT) are widely considered as radical treatments for early HCC. However, the recurrence rates after curative treatment are still high and overall survival is unsatisfactory. Microvascular invasion (MVI) is considered to be one of the important prognostic factors affecting postoperative recurrence and long-term survival. Unfortunately, whether HCC patients with MVI should receive postoperative adjuvant therapy remains unknown. In this review, we summarize the therapeutic effects of transcatheter arterial chemoembolization, hepatic arterial infusion chemotherapy, tyrosine protein kinase inhibitor-based targeted therapy, and immune checkpoint inhibitors in patients with MVI after LR or LT, aiming to provide a reference for the best adjuvant treatment strategy for HCC patients with MVI after LT or LR.

Immunotherapy for Hepatocellular Carcinoma in the Setting of Liver Transplantation: A Review

The emerging field of immuno-oncology has brought exciting developments in the treatment of hepatocellular carcinoma (HCC). It has also raised urgent questions about the role of immunotherapy in the setting of liver transplantation, both before and after transplant. A growing body of evidence points to the safety and efficacy of immunotherapeutic agents as potential adjuncts for successful down-staging of advanced HCCs to allow successful transplant in carefully selected patients. For patients with recurrent HCC post-transplant, immunotherapy has a limited, yet growing role. In this review, we describe optimal regimens in the setting of liver transplantation.

Immunotherapy for hepatocellular carcinoma recurrence after liver transplantation, can we harness the power of immune checkpoint inhibitors?

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death globally and liver transplantation (LT) can serve as the best curative treatment option. However, HCC recurrence after LT remains the major obstacle to the long-term survival of recipients. Recently, immune checkpoint inhibitors (ICIs) have revolutionized the treatment of many cancers and provided a new treatment strategy for post-LT HCC recurrence. Evidence has been accumulated with the real-world application of ICIs in patients with post-LT HCC recurrence. Notably, the use of these agents as immunity boosters in recipients treated with immunosuppressors is still controversial. In this review, we summarized the immunotherapy for post-LT HCC recurrence and conducted an efficacy and safety evaluation based on the current experience of ICIs for post-LT HCC recurrence. In addition, we further discussed the potential mechanism of ICIs and immunosuppressive agents in regulating the balance between immune immunosuppression and lasting anti-tumor immunity.

Immune checkpoint inhibitors in malignancies after liver transplantation: A systematic review and pooled analysis

BACKGROUND AND AIMS

Treatment of de novo malignancies and recurrent hepatocellular carcinoma with immune checkpoint inhibitors (ICI) in liver transplant recipients (LT) is an attractive strategy that is infrequently pursued because of the lack of strong evidence regarding their safety and efficacy. In this systematic review with pooled analysis, we aimed to assess safety and efficacy of ICI therapy following LT.

METHODS

We performed a systematic search of case reports and series published until January 2022. We included 31 publications reporting a total of 52 patients treated with ICIs after LT and assessed in a pooled analysis the risk of graft rejection and the outcome of ICI therapy.

RESULTS

Acute graft rejection occurred in 15 patients (28.8%) and 7 patients (13.4% of the total cohort) died because of graft loss. Rejection was associated with shorter overall survival (OS) (17.2 months, confidence interval [CI] 12.1-22.2 vs. 3.5 months, CI 1.6-5.4, p < 0.001). Disease control rate was 44.2% (n = 23), and in these patients, OS was longer than in non-responders (26.4 months, CI 20.8-32.0 vs. 3.4 months, CI 2.1-4.7, p < 0.001).

CONCLUSIONS

Observational, off-label experience suggests that treatment with ICI for advanced malignancies in LT recipients might not be discarded a priori. This notwithstanding, ICI treatment in these patients is associated with a substantial risk of graft rejection and mortality. Prospective studies are needed to provide adequate safety and efficacy figures of ICI treatment in this fragile population.

Immune microenvironment and therapeutic progress of recurrent hepatocellular carcinoma after liver transplantation

HCC is a highly lethal tumor, and orthotopic liver transplantation, as one of the radical treatment methods for HCC, has opened-up a new therapeutic approach for the treatment of primary liver cancer. However, tumor recurrence after liver transplantation is the main reason that affects the long-term survival of recipients. At present, the application of ICIs has brought dawn to patients with refractory HCC. However, because of the special immune tolerance state created by long-term oral immunosuppressants in patients with HCC after liver transplantation, the current focus is how to regulate the immune balance of such patients and simultaneously maximize the anti-tumor effect. This article reviews the relationship between liver cancer and immunity, immune tolerance of liver transplantation, immune microenvironment after liver transplantation for HCC, and the application of immunotherapy in the recurrence of liver transplantation for HCC.

Immune checkpoint inhibitor therapy for malignant tumors in liver transplantation recipients: A systematic review of the literature

BACKGROUND

Treatment for de novo or recurrent tumors of liver transplantation (LT) recipients is challenging and immune checkpoint inhibitor (ICI) is recently well developed and could be a potentially effective option for this population. There remains limited evidence on the safety and efficacy of ICI therapy in LT recipients.

METHODS

A systematic literature search was conducted on PubMed database through April 1, 2022, to identify publications reporting ICI treatment for malignant tumors in LT recipients. We summarized the allograft rejection, mortality, and tumor response of ICI treatment.

RESULTS

24 articles with 41 LT recipients were identified. The age of LT recipients ranged from 14 to 78, 76.2% were male, 56.1% had recurrent HCC, and 87.8% received anti-PD-1 therapy. Allograft rejection occurred in 31.7% of patients, death was reported in 46.3% and 6 cases died secondary to allograft rejection. Progressive disease rate of this population was 48.8% and 10 patients responded to immunotherapy. Half of recipients with positive PD-L1 staining (4/8) experienced allograft rejection.

CONCLUSIONS

ICI therapy has potential therapeutic value on malignant tumors for LT recipients, accompanied by a high rate of allograft rejection and mortality. PD-L1 expression, type of ICI, and immunosuppression agent should be taken into consideration before initiation of immunotherapy. Further studies are needed to optimize this anticancer treatment approach in these patients.

2022 KLCA-NCC Korea Practice Guidelines for the Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Role of immunotherapy in downsizing hepatocellular carcinoma prior to liver transplantation

Hepatocellular carcinoma (HCC) is an aggressive primary liver neoplasm that, according to tumor stage, can be treated with resection, transplantation, locoregional treatment options, or systemic therapy. Although interventions only in early-stage disease can offer complete tumor regression, systemic therapy in advanced disease can significantly prolong overall survival, according to published clinical trials. The emergence of immunotherapy in the field of cancer therapy has had a positive impact on patients with HCC, resulting in atezolizumab–bevacizumab currently being the first-line option for treatment of advanced HCC. In light of this, application of immunotherapy in the preoperative process could increase the number of patients fulfilling the criteria for liver transplantation (LT). Implementation of this approach is faced with challenges regarding the safety of immunotherapy and the possibly increased risk of rejection in the perioperative period. Case reports and clinical trials assessing the safety profile and effectiveness of neoadjuvant immunotherapy, highlight important aspects regarding this newly evolving approach to HCC management. More studies need to be conducted in order to reach a consensus regarding the optimal way to administer immunotherapy prior to LT. In this review, we summarize the role, safety profile and future considerations regarding the use of neoadjuvant immunotherapy prior to LT in patients with HCC.

Hepatocellular Carcinoma, Alpha Fetoprotein, and Liver Allocation for Transplantation: Past, Present and Future

Hepatocellular carcinoma (HCC) is one of the leading indications for liver transplantation and has been the treatment of choice due to the oncologic benefit for patients with advanced chronic liver disease (AdvCLD) and small tumors for the last 25 years. For HCC patients undergoing liver transplantation, alpha fetoprotein (AFP) has increasingly been applied as an independent predictor for overall survival, disease free recurrence, and waitlist drop out. In addition to static AFP, newer studies evaluating the AFP dynamic response to downstaging therapy show enhanced prognostication compared to static AFP alone. While AFP has been utilized to select HCC patients for transplant, despite years of allocation policy changes, the US allocation system continues to take a uniform approach to HCC patients, without discriminating between those with favorable or unfavorable tumor biology. We aim to review the history of liver allocation for HCC in the US, the utility of AFP in liver transplantation, the implications of weaving AFP as a biomarker into policy. Based on this review, we encourage the US transplant community to revisit its HCC organ allocation model, to incorporate more precise oncologic principles for patient selection, and to adopt AFP dynamics to better stratify waitlist dropout risk.

2022 KLCA-NCC Korea practice guidelines for the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Therapeutic strategies for post-transplant recurrence of hepatocellular carcinoma

Despite stringent selection criteria, hepatocellular carcinoma recurrence after liver transplantation (LT) still occurs in up to 20% of cases, mostly within the first 2–3 years. No adjuvant treatments to prevent such an occurrence have been developed so far. However, a balanced use of immunosuppression with minimal dose of calcineurin inhibitors and possible addition of mammalian target of rapamycin inhibitors is strongly advisable. Moreover, several pre- and post-transplant predictors of recurrence have been identified and may help determine the frequency and duration of post-transplant follow-up. When recurrence occurs, the outcomes are poor with a median survival of 12 mo according to most retrospective studies. The factor that most impacts survival after recurrence is timing (within 1–2 years from LT according to different authors). Several therapeutic options may be chosen in case of recurrence, according to timing and disease presentation. Surgical treatment seems to provide a survival benefit, especially in case of late recurrence, while the benefit of locoregional treatments has been suggested only in small retrospective studies. When systemic treatment is indicated, sorafenib has been proved safe and effective, while only few data are available for lenvatinib and regorafenib in second line. The use of immune checkpoint inhibitors is controversial in this setting, given the safety warnings for the risk of acute rejection.

Low-dose PD-1 inhibitor combined with lenvatinib for preemptive treatment of recurrence after liver transplantation for hepatocellular carcinoma: Case report and literature review

Orthotopic liver transplantation (OLT), as one of the curative methods for the treatment of hepatocellular carcinoma (HCC), has brought hope to patients with HCC. However, treatment options for HCC recurrence and metastasis after liver transplantation are limited. Immune checkpoint inhibitor (ICI), such as programmed cell death protein 1 (PD-1) inhibitor, have been successfully used in advanced or metastatic HCC, but the data on the safety of PD-1 inhibitor after liver transplantation is limited. In this article, we report a 47-year-old patient with acute-on-chronic liver failure and multiple HCC who was successfully treated with liver transplantation. On the 45th day after OLT, the patient’s alpha fetoprotein (AFP) and lens culinaris agglutinin-reactive fraction of AFP (AFP-L3) were increased, and imaging examination showed no residual tumor. The patient had high risk factors for tumor recurrence before operation, so the possibility of tumor recurrence was considered. When the tumor markers showed an upward trend, we immediately treated the patient with lenvatinib 8 mg, after half a month, the AFP and AFP-L3 continued to increase compared with before. Then we used low-dose nivolumab 40mg, the patient’s AFP and AFP-L3 gradually decreased. One month later, a second low-dose nivolumab 40mg was given, and the patient’s tumor markers gradually decreased to normal. No acute rejection and other complications occurred during the treatment. So far, we have followed up this patient for 2 years, and no tumor recurrence was observed. To our knowledge, this is the first reported case using a low dose of nivolumab in combination with lenvatinib to prevent recurrence of HCC after liver transplantation.

Anti-PD-1/PD-L1 immunotherapy in conversion treatment of locally advanced hepatocellular carcinoma

Curative surgery and locoregional therapy are radical therapies for patients with HCC. But more than 80% of HCC patients cannot be fitful for radical therapies because of local progression or distant metastasis at initial diagnosis. Among patients with unresectable locally advanced hepatocellular carcinoma (HCC), some patients can be converted to be technically resectable by conversion treatment and salvage surgery. For unresectable locally advanced hepatocellular, conversion treatment prior to salvage surgery with transcatheter arterial chemoembolization (TACE) and other locoregional therapies improve outcomes. PD-1/PD-L1 inhibitors as immune checkpoint inhibitor (ICI) therapy which show high antineoplastic activity in HCC patients by preclinical and clinical researches can also be a good choice for conversion therapy. PD-1/PD-L1 inhibitor combined with locoregional therapy plus antiangiogenic agents or not is most potential conversion therapy comparing to PD-1 inhibitor monotherapy and PD-1/PD-L1 inhibitor combined with antiangiogenic agents or CTLA-4 inhibitor. As more clinical evidence reported, PD-1/PD-L1 immunotherapy would be widely used in conversion treatment of locally advanced hepatocellular carcinoma.

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.

Current status of liver transplantation for non-B non-C liver cirrhosis and hepatocellular carcinoma

Recently, non-B non-C chronic liver diseases, including alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH), have markedly increased worldwide. Liver transplantation (LT) is an effective curative therapy for hepatocellular carcinoma (HCC) as well as decompensated liver cirrhosis. In Japan, where the source of liver grafts is strongly dependent on living donors, efforts have been made to unify the indications for eligibility of HCC patients for LT, leading to the development of 5-5-500 criteria. Along with the expansion of eligibility for LT, the current changing trends in underlying liver diseases of LT recipients, which are related to the rising tide of non-B non-C cirrhosis and HCC, are highlighting the importance of peri-transplant management of patients with various comorbidities. The post-LT prognosis of patients with ALD is significantly affected by de novo malignancies and metabolic syndrome-related complications as well as posttransplant alcohol relapse. NAFLD/NASH patients often suffer from obesity, type 2 diabetes mellitus, and other metabolic syndrome-related disorders, and nonneoplastic factors such as cardiovascular events and recurrence of NAFLD/NASH have a significant impact on post-LT outcomes. Patient management in the peri-transplant period as well as risk assessment for LT are key to improving post-LT outcomes in the era of a growing number of cases of LT for non-B non-C liver diseases.

Novel immunosuppressive effect of FK506 by upregulation of PD-L1 via FKBP51 in heart transplantation

The calcineurin inhibitor-FK506-is a first-line immunosuppressant that regulates T-cell secretion of IL-2 and other cytokines. However, the mechanism of its protective effect on target cells and its role on tumor recurrence and interaction with anti-tumor immune checkpoint inhibitors, such as PD-L1 blocking, are still unclear. Here, in a murine heart transplantation model, we observed the upregulation of programmed death-ligand 1 (PD-L1) expression by FK506 in both dendritic cells (DCs) and allografts. Blocking PD-L1 during FK506 treatment increased IFN-γ and TNF-α expression, enhanced CD4⁺ and CD8⁺ T-cell proliferation, and suppressed Treg differentiation. Moreover, PD-L1 decreased T-cell infiltration and induced T cell apoptosis in both the spleen and graft. PD-L1 was not only required in FK506-mediated immunosuppression but also upregulated by FK506. Treatment with SAFit2, a FKBP51 selective inhibitor, reduced the expression of PD-L1 on DCs and the grafts and interfered with the immunosuppressive effect of FK506, suggesting that the mechanism depends on FK506-binding protein (FKBP) 51 expression. Overall, our results add new insights into the role of FK506, not only on T-cell cytokine secretion but also on co-inhibitory molecular regulation and target cell immune privilege.

Systemic Treatment of Advanced Unresectable Hepatocellular Carcinoma after First-Line Therapy: Expert Recommendations from Hong Kong, Singapore, and Taiwan

BACKGROUND

Asia has a high burden of hepatocellular carcinoma (HCC) due to the high rates of chronic hepatitis B infection and accounts for 70% of HCC cases globally. In the past 20 years, the systemic treatment landscape of advanced HCC has evolved substantially - from tyrosine kinase inhibitors to immune-oncology agents plus anti-vascular endothelial growth factor agents. The appropriate sequence of therapies has become critical in optimizing patient outcomes given the increase in systemic therapeutic options. This article evaluates the evidence and provides expert recommendations for the use of systemic therapies after first-line treatment in patients with advanced HCC.

SUMMARY

Based on three virtual meetings held in early 2021, a team of 17 experts comprising oncologists, a hepatologist, and a hepatobiliary surgeon from Hong Kong, Singapore, and Taiwan reviewed available data about systemic treatments for HCC after first line and formulated 28 statements. These statements aimed to provide expert guidance on selecting first and subsequent lines of therapies as well as recommending therapies in special circumstances, such as poor liver function, posttransplantation, recent gastrointestinal bleeding, or autoimmune diseases. Data supporting the statements were drawn from clinical trials and real-world studies. The 28 statements were then evaluated anonymously using a 5-point Likert scale, and 24 reached consensus, predefined as achieving 75% agreement. Statements generated covered the selection of first-line systemic therapy, considerations and goals of second-line systemic therapies, treatment selection following first-line therapy, and treatment recommendations following first-line tyrosine kinase inhibitors, immune-oncology monotherapy, or immune-oncology combination therapy. The authors also shared expert opinion on the use of second-line systemic therapy in patients with liver dysfunction, liver transplantation, and recent gastrointestinal or autoimmune disease.

KEY MESSAGES

These expert statements summarize the latest data and expert opinion on selecting systemic treatment following first-line therapy in patients with unresectable advanced or metastatic HCC.

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.

An analysis report on the application of immune checkpoint inhibitors after liver transplantation

Up to now, a variety of immune checkpoint inhibitors (ICIs) have been proved to have good therapeutic effects in the treatment of hepatocellular carcinoma (HCC). However, the effects of their applications in liver transplant (LT) recipients are still unclear. In this analysis report, the clinical applications and therapeutic effects of ICIs on LT recipients with hepatic tumor recurrence or de novo carcinoma based on eight databases, including PubMed, EMBASE, Web of Science, Google Scholar, China National Knowledge Infrastructure, Wanfang Data, and CQVIP, were investigated. And the prior treatment, disease response, adverse reactions, and prognosis of patients with malignant tumors after LT and receiving ICI treatments were analyzed. After screening, a total of 28 articles with 47 recipients on the application of ICIs after LT were included. In these patients, their median age was 57 (14–71) years and the main type of tumor after LT was HCC (59.6%). The overall remission rate following ICI treatment was 29.8% (14/47) and the disease progression rate was 68.1% (32/47). Among all these patients, 31.9% (15/47) of patients had immune rejection; the median survival time was 6.5 (0.3–48) months, and the fatality rate was 61.7% (29/47). Considering that the therapeutic effect of ICIs in LT recipients with HCC recurrence or de novo carcinoma is not ideal, ICI treatment should be carefully considered for LT patients, and further research is needed.

Immune Checkpoint Inhibitors as Therapy to Down-Stage Hepatocellular Carcinoma Prior to Liver Transplantation

Hepatocellular Carcinoma (HCC) is the most common liver malignancy and third leading cause of cancer death worldwide. For early- and intermediate-stage disease, liver-directed therapies for locoregional control, or down-staging prior to definitive surgical therapy with hepatic resection or liver transplantation, have been studied broadly, and are the mainstays of current treatment guidelines. As HCC incidence has continued to grow, and with more patients presenting with advanced disease, our current treatment modalities do not suffice, and better therapies are needed to improve disease-specific and overall survival. Until recently, sorafenib was the only systemic therapy utilized, and was associated with dismal results. The advent of immuno-oncology has been of significant interest, and has changed the paradigm of therapy for HCC. Lately, combination regimens including atezolizumab plus bevacizumab; durvalumab plus tremelimumab; and pembrolizumab plus Lenvatinib have shown impressive responses of between 25-35%; this is much higher than responses observed with single agents. Complete responses with checkpoint inhibitor therapy have been observed in advanced-stage HCC patients. These dramatic results have naturally led to several questions. Can or should checkpoint inhibitors, or other immunotherapy combinations, be used routinely before resection or transplant? Is there a synergistic effect of immunotherapy with locoregional therapy, and will pre-treatment increase disease-free survival after surgical intervention? Is it immunologically safe to use these therapies prior to transplantation? Much is still to be learned in terms of the dosing, timing, and overall utility of the use of immune checkpoint inhibitors for pre-transplant care and down-staging. More studies will be needed to understand the management of adverse events while maximizing the therapeutic window of these agents. In this review, we look at the current data on therapy with immune checkpoint inhibitors in advanced HCC, with a focus on pre-transplant treatment prior to liver transplant.

Immune Checkpoint Inhibitor Use in Solid Organ Transplant Recipients: A Systematic Review

Chronic immunosuppression in solid organ transplant recipients (SOTRs) leads to an increased risk of a wide variety of cancers. Immune checkpoint inhibitor (ICI) therapy is indicated for many of these; however, the risks and benefits of ICI use in the SOTR population have not been well characterized. We performed a systematic literature review identifying 119 reported cases of ICI use among SOTRs. Treatments used included PD-1 inhibition (75.6%), CTLA-4 inhibition (12.6%), PD-L1 inhibition (1.7%), and combination and/or sequential ICI therapy (10.1%). The most common cancers included cutaneous melanoma (35.3%), hepatocellular carcinoma (22.7%), and cutaneous squamous cell carcinoma (18.5%). The overall objective response rate (ORR) was 34.5%, with a median duration of response of 8.0 months. Ongoing response was seen in 21.0%. Cutaneous squamous cell carcinoma had significantly better ORR compared with other cancer types (68.2% vs 26.8%; odds ratio [OR], 5.85; P =.0006). Factors associated with improved ORR included increasing time from transplant to ICI (OR, 1.09; P =.008) and preemptive reduction in intensity of the graft maintenance immunosuppressive regimen (50.0% vs 18.5%; OR, 4.40; P =.0088). Rejection occurred in 41.2%, graft failure in 23.5%, and immune-related adverse events in 18.5%. Factors significantly associated with allograft rejection included allograft PD-L1 positivity (100% vs 0%; P<.0001) and absence of tacrolimus in the immunosuppressive regimen (48.7% vs 25.6%; OR, 0.36; P =.019). The most common cause of death was progressive malignancy (64.0%), followed by graft failure (24.0%). Our analysis provides current benchmark data to help inform management of SOTRs with advanced cancers that are reflected by our patient cohort. Biomarker development, more robust datasets, and prospective study of concomitant immunosuppression management may help refine decision-making in this complex scenario in the future. Close coordination of care between the medical oncologist and transplant specialist is encouraged to help optimize treatment outcomes.

Increased Expressions of Programmed Death Ligand 1 and Galectin 9 in Transplant Recipients Who Achieved Tolerance After Immunosuppression Withdrawal

Programmed death 1 (PD1)/its ligand PD-L1 concomitant with T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3)/its ligand galectin 9 (Gal-9) and the forkhead box P3 (FOXP3) might be involved in tolerance after liver transplantation (LT). Liver biopsies from 38 tolerant, 19 nontolerant (including 16 samples that triggered reintroduction of immunosuppression [IS] and 19 samples after IS reintroduction), and 38 control LT patients were studied. The expressions of PD1, PD-L1, Gal-9, and FOXP3 were determined by immunohistochemical and immunofluorescence (IF) staining. The success period of IS withdrawal was calculated using Kaplan-Meier curve analysis. Tolerant and control patients exhibited higher PD-L1, Gal-9, and FOXP3 levels than nontolerant patients at the moment of triggering IS reintroduction. High expressions of PD-L1 and Gal-9 were associated with prolonged success of tolerance (83.3% versus 36.7% [P < 0.01] and 73.1% versus 42.9% [P = 0.03]). A strong correlation between PD-L1 and Gal-9 expression levels was detected (Spearman r = 0.73; P ≤ 0.001), and IF demonstrated colocalization of PD-L1 and Gal-9 in the cytoplasm of hepatocytes. In conclusion, the present study demonstrated that increased expressions of PD-L1 and Gal-9 were associated with sustained tolerance after IS withdrawal in pediatric liver transplantation.

Utilization of Immunotherapy for the Treatment of Hepatocellular Carcinoma in the Peri-Transplant Setting: Transplant Oncology View

Simple Summary

Hepatocellular carcinoma is the second most common cause of cancer-related deaths and accounts for over eighty percent of primary liver cancers worldwide. Regarding the Milan Criteria, only a small portion of HCC patients are eligible for liver transplantation due to advanced-stage disease and large tumor size preventing/delaying organ allocation. Recently, the use of anti-programmed cell death protein 1 and programmed cell death ligand 1 (PD-1 and PD-L1) checkpoint inhibitors in the treatment of cancers have evolved rapidly and these therapies have been approved for the treatment of HCC, however, the main concerns about organ rejection in liver transplant patients who will be treated with ICPIs are still the same in both pre-and post-transplant setting. To alleviate those concerns, more global collaborations to explore the safety and efficacy of ICPIs in both the pre-and post-organ transplantation settings are required. The decision to administer ICPI treatment in liver transplant patients should be made on a case-by-case basis according to the goal of care and the availability and efficacy of other treatment options.

Abstract

Hepatocellular carcinoma (HCC) represents the second most common cause of cancer-related deaths and accounts for over eighty percent of primary liver cancers worldwide. Surgical resection and radiofrequency ablation in small tumors are included in the treatment options for HCC patients with good liver function profiles. According to the Milan Criteria, only a small portion of HCC patients are eligible for liver transplantation due to advanced-stage disease and large tumor size preventing/delaying organ allocation. Recently, the use of anti-programmed cell death protein 1 and programmed cell death ligand 1 (PD-1 and PD-L1) checkpoint inhibitors in the treatment of cancers have evolved rapidly and these therapies have been approved for the treatment of HCC. Immune checkpoint inhibitors have resulted in good clinical outcomes in pre-and post-transplant HCC patients, although, some reports showed that certain recipients may face rejection and graft loss. In this review, we aim to illustrate and summarize the utilization of immune checkpoint inhibitor therapies in pre-and post-liver transplants for HCC patients and discuss the assessment of immune checkpoint inhibitor regulators that might determine liver transplant outcomes.