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

Atezolizumab plus bevacizumab as a downstaging therapy for liver transplantation in hepatocellular carcinoma with portal vein thrombosis: The first report

Atezolizumab plus bevacizumab is the preferred first-line treatment regimen for patients with advanced hepatocellular carcinoma. Limited data have shown promising results with the use of immune checkpoint inhibitors like nivolumab to downstage these patients for liver transplantation (LT). Here, we describe the first case of successful downstaging with atezolizumab plus bevacizumab in a patient with multifocal hepatocellular carcinoma and main portal vein tumoral thrombosis, followed by ABO-incompatible live donor LT. This illustrated case highlights that atezolizumab plus bevacizumab therapy may be a potential bridging tool for curative LT.

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.

Neoadjuvant systemic therapy for hepatocellular carcinoma

Surgical resection and liver transplant remain the only curative therapies for most patients with hepatocellular carcinoma (HCC). Systemic therapy options have typically been ineffective, but recent advances, such as the combination of immune checkpoint inhibitors and targeted therapies, have shown great promise. Neoadjuvant systemic therapy in resectable or locally advanced HCC is under active investigation with encouraging results in small, early-phase trials. Many of these completed and ongoing trials include combinations of systemic therapy (e.g. immune checkpoint inhibitors, tyrosine kinase inhibitors), transarterial therapies, and radiation. Despite early successes, larger trials with evaluation of long-term oncologic outcomes are needed to determine the role of neoadjuvant systemic therapy in patients with HCC who may be eligible for curative intent surgery or transplant.

Transplant oncology - Current indications and strategies to advance the field

Liver transplantation (LT) was originally described by Starzl as a promising strategy to treat primary malignancies of the liver. Confronted with high recurrence rates, indications drifted towards non-oncologic liver diseases with LT finally evolving from a high-risk surgery to an almost routine surgical procedure. Continuously improving outcomes following LT and evolving oncological treatment strategies have driven renewed interest in transplant oncology. This is not only reflected by constant refinements to the criteria for LT in patients with HCC, but especially by efforts to expand indications to other primary and secondary liver malignancies. With new patient-centred oncological treatments on the rise and new technologies to expand the donor pool, the field has the chance to come full circle. In this review, we focus on the concept of transplant oncology, current indications, as well as technical and ethical aspects in the context of donor organs as precious resources.

Successful liver transplantation with ctDNA clearance after PD‑1 inhibitor plus FOLFOX‑HAIC treatment in HCC: A case report

Liver transplantation (LT) is the primary treatment for patients with early-stage hepatocellular carcinoma (HCC). However, the 5-year survival rate after LT remains low for patients with advanced HCC. Recently, combining programmed cell death protein-1 (PD-1) inhibitors with hepatic arterial infusion chemotherapy (HAIC) has achieved promising outcomes in advanced HCC treatment. However, there is a lack of sufficient clinical data demonstrating its effectiveness as a pre-LT down-staging treatment. The current study presented a case of advanced HCC beyond the Milan criteria who underwent LT and achieved a favorable outcome following PD-1 inhibitor combined with FOLFOX-HAIC therapy. Of note, due to treatment-induced tumor necrosis, precise post-treatment tumor size evaluation became challenging. To address this, circulating tumor DNA (ct-DNA) clearance was used as the LT criterion. After three cycles of Pembrolizumab and FOLFOX-HAIC therapy, the patient's serum ctDNA became undetectable and serum α-fetoprotein levels returned to normal. Magnetic resonance imaging results also revealed a significant reduction in liver tumor size post down-staging treatment. Subsequent to LT, serum ctDNA was monitored every two months, consistently yielding diminished results. There were no clinical signs of recurrence 19 months post-LT. These findings suggest that Pembrolizumab in combination with FOLFOX-HAIC may serve as a potential down-staging strategy prior to LT. In addition, ctDNA clearance may be considered a viable biomarker for LT eligibility.

Downstaging Techniques for Hepatocellular Carcinoma in Candidates Awaiting Liver Transplantation

During the last decade, downstaging for hepatocellular carcinoma has expanded the pool of patients eligible for liver transplantation. The literature is rife with attempts to elucidate best treatment strategies with novel locoregional and systemic therapies continuing to emerge. Several trials have confirmed the large-scale success of downstaging protocols, with equitable long-term survival and recurrence rates after liver transplant. We review the currently available techniques used for downstaging, including their indications, complications, and efficacies. New frontiers have focused on the potential role of immunotherapy in the neoadjuvant setting, although more research is needed to delineate its role in current treatment paradigms.

Downstaging Hepatocellular Carcinoma before Transplantation: Role of Immunotherapy Versus Locoregional Approaches

Hepatocellular carcinoma (HCC) continues to be a leading cause of cancer-related death in the United States. With advances in locoregional therapy for unresectable HCC during the last 2 decades and the recent expansion of transplant criteria for HCC, as well as ongoing organ shortages, patients are spending more time on the waitlist, which has resulted in an increased usage of locoregional therapies. The plethora of molecularly targeted therapies and immune checkpoint inhibitors under investigation represent the new horizon of treatment of HCC not only in advanced stages but also potentially at every stage of diagnosis and management.

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.

Reprogramming of Treg cells in the inflammatory microenvironment during immunotherapy: a literature review

Regulatory T cells (Treg), as members of CD4+ T cells, have garnered extensive attention in the research of tumor progression. Treg cells have the function of inhibiting the immune effector cells, preventing tissue damage, and suppressing inflammation. Under the stimulation of the tumor inflammatory microenvironment (IM), the reprogramming of Treg cells enhances their suppression of immune responses, ultimately promoting tumor immune escape or tumor progression. Reducing the number of Treg cells in the IM or lowering the activity of Treg cells while preventing their reprogramming, can help promote the body's anti-tumor immune responses. This review introduces a reprogramming mechanism of Treg cells in the IM; and discusses the regulation of Treg cells on tumor progression. The control of Treg cells and the response to Treg inflammatory reprogramming in tumor immunotherapy are analyzed and countermeasures are proposed. This work will provide a foundation for downregulating the immunosuppressive role of Treg in the inflammatory environment in future tumor immunotherapy.

Potential tactics with certain gut microbiota for the treatment of unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) constitutes an extremely malignant form of primary liver cancer. Intricate connections linking to the immune system might be associated with the pathogenesis of HCC. Meanwhile, immunotherapy with immune checkpoint inhibitors has been established to be a favorable therapeutic possibility for advanced HCC. Although curative opportunities for advanced HCC are restricted, the immune checkpoint immunotherapy has developed as the main choice for treating HCC. However, patients with metabolic-associated fatty liver disease (MAFLD)-linked HCC might be less likely to benefit from the immunotherapy alone. The limitation of the effect of the immunotherapy might be owing to the impaired T cell activation in MAFLD patients, which could be well explained by a dysfunctional gut-liver axis. Gut microbiota and their metabolites including several bile acids could contribute to modulating the responses of the immune checkpoint immunotherapy. Roles of gut microbiota in the development of cancers have expected great interest in the latest studies. Here, an interplay between the gut and liver has been presented, which might suggest to affect the efficacy of immune checkpoint immunotherapy against HCC.

Immune checkpoint inhibitors in liver transplant: a case series

BACKGROUND

Immune checkpoint inhibitors (ICIs) in the setting of liver transplant (LT) pose a risk of rejection and hold unclear benefit in both the neoadjuvant (pre-transplant) and post-transplant salvage setting. In the pre-transplant setting, neoadjuvant ICIs may serve as a bridge to LT by downstaging disease burden to fit within transplant criteria. Outcomes in this setting include patients who had successful transplants without complications to patients who suffered severe complications, including fatal hepatic necrosis and graft failure requiring re-transplant. Some authors suggest having a period of three months between checkpoint inhibition and transplant may help mitigate adverse effects. In the post-LT setting, there are few treatment options if there is a recurrence of disease, which forces treatment teams to reconsider checkpoint inhibitors. Again, a longer period of time between transplant and checkpoint inhibition may reduce risk of rejection. Case reports of patients treated with ICIs post-transplant utilized either nivolumab or pembrolizumab. As combination atezolizumab/bevacizumab is a relatively new treatment option for unresectable hepatocellular carcinoma (HCC), there are only three reported cases using this combination in the post-LT setting. While there were no cases of rejection, all three cases had progression of disease. As immunotherapy joins transplantation as a mainstay of treatment for HCC, it remains unclear how to best navigate when the treatment course involves both immune activation and immunosuppression.

CASE DESCRIPTION

Patients who had an LT and were treated with ICIs (pre or post LT) at the University of Cincinnati were included in this retrospective chart review.

CONCLUSIONS

Fatal rejection remains a significant risk even 4 years after LT. Neoadjuvant ICIs also pose a risk for acute cellular rejection; however, this may not always be clinically significant. Graft versus host disease (GVHD) may be an additional, previously unreported risk of ICIs in the setting of LT. Prospective studies are needed to understand benefits and risks of checkpoint inhibitors in the LT setting.

Clinical consensus statement: Establishing the roles of locoregional and systemic therapies for the treatment of intermediate-stage hepatocellular carcinoma in Canada

BACKGROUND

Hepatocellular carcinoma (HCC) a leading cause of cancer mortality worldwide and approximately one-third of patients present with intermediate-stage disease. The treatment landscape of intermediate-stage HCC is rapidly evolving due to developments in local, locoregional and systemic therapies. Treatment recommendations focused on this heterogenous disease stage and that take into account the Canadian reality are lacking. To address this gap, a pan-Canadian group of experts in hepatology, transplant, surgery, radiation therapy, nuclear medicine, interventional radiology, and medical oncology came together to develop consensus recommendations on management of intermediate-stage HCC relevant to the Canadian context.

METHODS

A modified Delphi framework was used to develop consensus statements with strengths of recommendation and supporting levels of evidence graded using the AHA/ACC classification system. Tentative consensus statements were drafted based on a systematic search and expert input in a series of iterative feedback cycles and were then circulated via online survey to assess the level of agreement.

RESULTS & CONCLUSION

The pre-defined ratification threshold of 80 % agreement was reached for all statements in the areas of multidisciplinary treatment (n = 4), intra-arterial therapy (n = 14), biologics (n = 5), radiation therapy (n = 3), surgical resection and transplantation (n = 7), and percutaneous ablative therapy (n = 4). These generally reflected an expansion in treatment options due to developments in previously established or emergent techniques, introduction of new and more active therapies and increased therapeutic flexibility. These developments have allowed for greater treatment tailoring and personalization as well as a paradigm shift toward strategies with curative intent in a wider range of disease settings.

Emerging treatment strategies in hepatobiliary cancer

INTRODUCTION

There have been significant advances in the treatment of hepatobiliary cancers, especially for advanced-stage disease. However, data is limited for optimal therapy selection in the first line and sequencing of available options.

AREAS COVERED

This review covers the systemic treatment of hepatobiliary cancers with an emphasis on the advanced stage. The previously published and ongoing trials will be discussed to create an algorithm for the current practice and to give future perspectives on how the field could go forward.

EXPERT OPINION

While there is no standard-of-care option in the adjuvant treatment of hepatocellular cancer, capecitabine is the standard of care for biliary tract cancer. The efficacy of adjuvant gemcitabine and cisplatin and the added benefit of radiotherapy to chemotherapy are yet to be defined. For the advanced stage, immunotherapy-based combinations became the standard of care for both hepatocellular and biliary tract cancers. The molecularly targeted therapy has profoundly changed the second-line and later treatment for biliary tract cancers, while the optimal second-line treatment for advanced hepatocellular cancer is yet to be defined due to rapid advances in the first-line setting.

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.

Unraveling the Synergy between Atezolizumab and Bevacizumab for the Treatment of Hepatocellular Carcinoma

Tyrosine kinase inhibitors (TKIs) with antiangiogenic properties, such as sorafenib, have been the standard choice to systemically treat hepatocellular carcinoma for over a decade. More recently, encouraging results were obtained using immune checkpoint inhibitors, although head-to-head comparisons with sorafenib in phase 3 trials could not demonstrate superiority in terms of overall survival. The IMbrave150 was a breakthrough study that resulted in atezolizumab/bevacizumab, a combination of an antiangiogenic and an immune checkpoint inhibitor, as a new standard of care for advanced HCC. This review discusses the mode of action, clinical efficacy, and biomarker research for both drug classes and for the combination therapy. Moreover, the synergy between atezolizumab and bevacizumab is highlighted, unraveling pathophysiological mechanisms underlying an enhanced anticancer immunity by changing the immunosuppressed to a more immunoreactive tumor microenvironment (TME). This is achieved by upregulation of antigen presentation, upregulation of T-cell proliferation, trafficking and infiltration, impairing recruitment, and proliferation of immunosuppressive cells in the TME. However, more insights are needed to identify biomarkers of response that may improve patient selection and outcome.

Immunotherapy Use Prior to Liver Transplant in Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related mortality worldwide, and its incidence has increased rapidly in the United States over the past two decades. Liver transplant is considered curative, but is not always possible, and pre-transplant immunotherapy is of great interest as a modality for downstaging the tumor burden. We present a review of the literature on pre-liver transplant immunotherapy use in patients with HCC. Our literature search queried publications in Ovid MEDLINE, Ovid Embase, and Web of Science, and ultimately identified 24 original research publications to be included for analysis. We found that the role of PD-1 and PD-L1 in risk stratification for rejection is of special interest to researchers, and ongoing randomized clinical trials PLENTY and Dulect 2020-1 will provide insight into the role of PD-1 and PD-L1 in liver transplant management in the future. This literature search and the resulting review represents the most thorough collection, analysis, and presentation of the literature on the subject to date.

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.

Primary Resistance to Immunotherapy-Based Regimens in First Line Hepatocellular Carcinoma: Perspectives on Jumping the Hurdle

Simple Summary

Immune checkpoint inhibitors (ICIs) had been explored extensively in patients affected by unresectable hepatocellular carcinoma. These agents were expected to be the keystones of the disease’s first-line treatment because they were theoretically able to revert the immune suppressive tumor microenvironment of the cancerous liver, and because of their manageable safety profile. However, when used as monotherapies, they showed important activity and efficacy limitations. In this mini-review, we summarize the characteristics of the different ICIs-based regimens which constitute the present gold standard of first-line treatment, then, moving from their shortcomings, we discuss the rationale supporting the strategies currently under investigation: systemic triplets and new paradigms of immune-therapeutic agents such as CAR-T and vaccines.

Abstract

Immune checkpoint inhibitors (ICIs) are a key component of different stages of hepatocellular carcinoma (HCC) treatment, particularly in the first line of treatment. A lesson on the primary resistance which hampers their efficacy and activity was learned from the failure of the trials which tested them as first-line mono-therapies. Despite the combination of anti-PD(L)1 agents with anti-VEGF, anti CTLA4, or TKIs demonstrating relevant improvements in efficacy, the “doublets strategy” still shows room for improvement, due to a limited overall survival benefit and a high rate of progressive disease as best response. In this review, we discuss the results from the currently tested doublet strategies (i.e., atezolizumab+bevacizumab, durvalumab+tremelimumab with a mention to the newly presented ICIs/TKIs combinations), which highlight the need for therapeutic improvement. Furthermore, we examine the rationale and provide an overview of the ongoing trials testing the treatment intensification strategy with triplet drugs: anti-PD1+anti-CTLA4+anti-VEGF/TKIs and anti-PD1+anti-VEGF+alternative immunity targets. Lastly, we report on the alternative strategy to integrate ICIs into the new paradigm of immune therapeutics constituted by CAR-T and anti-cancer vaccines. This review provides up-to-date knowledge of ongoing clinical trials of the aforementioned strategies and critical insight into their mechanistic premises.

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.