Incidence of microsatellite instability-high hepatocellular carcinoma among Japanese patients and response to pembrolizumab

Biomarkers for Immunotherapy Efficacy in Advanced Hepatocellular Carcinoma: A Comprehensive Review

Hepatocellular carcinoma (HCC), the most common primary liver malignancy and the sixth most common cancer globally, remains fatal for many patients with inappropriate responses to treatment. Recent advancements in immunotherapy have transformed the treatment landscape for advanced HCC. However, variability in patient responses to immunotherapy highlights the need for biomarkers that can predict treatment outcomes. This manuscript comprehensively reviews the evolving role of biomarkers in immunotherapy efficacy, spanning from blood-derived indicators-alpha-fetoprotein, inflammatory markers, cytokines, circulating tumor cells, and their DNA-to tissue-derived indicators-programmed cell death ligand 1 expression, tumor mutational burden, microsatellite instability, and tumor-infiltrating lymphocytes. The current body of evidence suggests that these biomarkers hold promise for improving patient selection and predicting immunotherapy outcomes. Each biomarker offers unique insights into disease biology and the immune landscape of HCC, potentially enhancing the precision of treatment strategies. However, challenges such as methodological variability, high costs, inconsistent findings, and the need for large-scale validation in well-powered two-arm trial studies persist, making them currently unsuitable for integration into standard care. Addressing these challenges through standardized techniques and implementation of further studies will be critical for the future incorporation of these biomarkers into clinical practice for advanced HCC.

Hepatocellular Carcinoma: The Evolving Role of Systemic Therapies as a Bridging Treatment to Liver Transplantation

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths. Classically, liver transplantation (LT) can be curative for HCC tumors within the Milan criteria. Bridging strategies to reduce the dropouts from LT waiting lists and/or to downstage patients who are beyond the Milan criteria are widely utilized. We conducted a literature-based review to evaluate the role of systemic therapies as a bridging treatment to liver transplantation (LT) in HCC patients. Tyrosine kinase inhibitors (TKIs) can be used as a systemic bridging therapy to LT in patients with contraindications for locoregional liver-directed therapies. Immune checkpoint inhibitor (ICI) treatment can be utilized either as a monotherapy or as a combination therapy with bevacizumab or TKIs prior to LT. Acute rejection after liver transplantation is a concern in the context of ICI treatment. Thus, a safe ICI washout period before LT and cautious post-LT immunosuppression strategies are required to reduce post-LT rejections and to optimize clinical outcomes. Nevertheless, prospective clinical trials are needed to establish definitive conclusions about the utility of systemic therapy as a bridging modality prior to LT in HCC patients.

Predicting effect of anti-PD-1/PD-L1 inhibitors therapy for hepatocellular carcinoma by detecting plasma metabolite based on UHPLC-MS

Introduction

Anti-PD-1/PD-L1 inhibitors therapy has become a promising treatment for hepatocellular carcinoma (HCC), while the therapeutic efficacy varies significantly among effects for individual patients are significant difference. Unfortunately, specific predictive biomarkers indicating the degree of benefit for patients and thus guiding the selection of suitable candidates for immune therapy remain elusive.no specific predictive biomarkers are available indicating the degree of benefit for patients and thus screening the preferred population suitable for the immune therapy.

Methods

Ultra-high-pressure liquid chromatography-mass spectrometry (UHPLC-MS) considered is an important method for analyzing biological samples, since it has the advantages of high rapid, high sensitivity, and high specificity. Ultra-high-pressure liquid chromatography-mass spectrometry (UHPLC-MS) has emerged as a pivotal method for analyzing biological samples due to its inherent advantages of rapidity, sensitivity, and specificity. In this study, potential metabolite biomarkers that can predict the therapeutic effect of HCC patients receiving immune therapy were identified by UHPLC-MS.

Results

A partial least-squares discriminant analysis (PLS-DA) model was established using 14 glycerophospholipid metabolites mentioned above, and good prediction parameters (R2 = 0.823, Q2 = 0.615, prediction accuracy = 0.880 and p < 0.001) were obtained. The relative abundance of glycerophospholipid metabolite ions is closely related to the survival benefit of HCC patients who received immune therapy.

Discussion

This study reveals that glycerophospholipid metabolites play a crucial role in predicting the efficacy of immune therapy for HCC.

The progress of research on immune checkpoint inhibitor resistance and reversal strategies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in humans, which is prone to recurrence and metastasis and has a poor prognosis. The occurrence and progression of HCC are closely related to immune elimination, immune homeostasis, and immune escape of the immune system. In recent years, immunotherapy, represented by immune checkpoint inhibitors (ICIs), has shown powerful anti-tumor capabilities in HCC patients. However, there are still some HCC patients who cannot benefit from ICIs treatment due to their innate or acquired drug resistance. Therefore, it is of great practical significance to explore the possible mechanisms of resistance to ICIs in HCC and to use them as a target to design strategies to reverse resistance, to overcome drug resistance in HCC and to improve the prognosis of patients. This article summarizes the possible primary (tumor microenvironment alteration, and signaling pathways, etc.) and acquired (immune checkpoint upregulation) resistance mechanisms in patients with HCC treated with ICIs, and based on this, discusses the status and effectiveness of combination drug strategy to reverse drug resistance, to provide a reference for subsequent related studies and decisions.

Current state and challenges of emerging biomarkers for immunotherapy in hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is the most prevalent form of primary liver cancer. According to the American Cancer Society, among patients diagnosed with advanced liver cancer, HCC has the sixth-highest incident rate, resulting in a poor prognosis. Surgery, radiofrequency ablation, transcatheter arterial chemoembolization, radiation, chemotherapy, targeted therapy and immunotherapy are the current treatment options available. Immunotherapy, which has emerged as an innovative treatment strategy over the past decade, is serving a vital role in the treatment of advanced liver cancer. Since only a small number of individuals can benefit from immunotherapy, biomarkers are required to help clinicians identify the target populations for this precision medicine. These biomarkers, such as PD-1/PD-L1, tumor mutational burden and circulating tumor DNA, can be used to investigate interactions between immune checkpoint inhibitors and tumors. The present review summarizes information on the currently available biomarkers used for immunotherapy and the challenges that are present.

Sequencing Systemic Therapy in Hepatocellular Carcinoma

OPINION STATEMENT

Multiple treatment options are now approved for unresectable hepatocellular carcinoma (HCC). An immune checkpoint inhibitor (ICI)-containing regimen should be highly considered as the first-line treatment when there is no contraindication, especially in those with hepatitis virus-related HCC, due to proven superior overall survival (OS) compared to sorafenib. Atezolizumab plus bevacizumab and durvalumab plus tremelimumab remain the treatment of choice among all ICI-containing regimens, unless contraindications to either of the medications exist. Although sorafenib is still the only medication currently approved for select patients with Child-Pugh B (CP) HCC in the first-line setting, atezolizumab plus bevacizumab is being studied in this patient population. Moreover, patients with post-liver transplantation recurrence may benefit from tyrosine kinase inhibitors (TKIs), while more studies are still needed to determine the safety of ICIs in this setting. Interestingly, multiple potential biomarkers, including tumor mutational burden (TMB), microsatellite instability (MSI) status, and PD-L1 expression level, have inconsistently predicted response to ICIs in patients with HCC. Limited evidence is available to guide treatment choice in later-line settings after progressing on ICIs, and decisions should be based on the safety profile of the treatment regimen and patient preference. Multiple trials are ongoing to elucidate the optimal treatment sequence. Of note, we believe that TKIs (e.g., cabozantinib, regorafenib, lenvatinib, and sorafenib) could be more beneficial in later-line settings to broaden inhibition of other pathways apart from vascular endothelial growth factor (VEGF). When conventional treatment options are exhausted, tissue biopsy may be helpful to reveal rare targetable mutations, such as RET gene fusions.

Current Evidence for Immune Checkpoint Inhibition in Advanced Hepatocellular Carcinoma

The treatment of advanced unresectable HCC (aHCC) remains a clinical challenge, with limited therapeutic options and poor prognosis. The results of IMbrave150 and HIMALAYA have changed the treatment paradigm for HCC and established immune checkpoint inhibition (ICI), either combined with anti-angiogenic therapy or dual ICI, as preferred first-line therapy for eligible patients with aHCC. Numerous other combination regimens involving ICI are under investigation with the aim of improving the tumour response and survival of patients with all stages of HCC. This review will explore the current evidence for ICI in patients with advanced HCC and discuss future directions, including the unmet clinical need for predictive biomarkers to facilitate patient selection, the effects of cirrhosis aetiology on response to ICI, and the safety of its use in patients with impaired liver function.

Predictive Biomarkers for Immune-Checkpoint Inhibitor Treatment Response in Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has one of the highest mortality rates among solid cancers. Late diagnosis and a lack of efficacious treatment options contribute to the dismal prognosis of HCC. Immune checkpoint inhibitor (ICI)-based immunotherapy has presented a new milestone in the treatment of cancer. Immunotherapy has yielded remarkable treatment responses in a range of cancer types including HCC. Based on the therapeutic effect of ICI alone (programmed cell death (PD)-1/programmed death-ligand1 (PD-L)1 antibody), investigators have developed combined ICI therapies including ICI + ICI, ICI + tyrosine kinase inhibitor (TKI), and ICI + locoregional treatment or novel immunotherapy. Although these regimens have demonstrated increasing treatment efficacy with the addition of novel drugs, the development of biomarkers to predict toxicity and treatment response in patients receiving ICI is in urgent need. PD-L1 expression in tumor cells received the most attention in early studies among various predictive biomarkers. However, PD-L1 expression alone has limited utility as a predictive biomarker in HCC. Accordingly, subsequent studies have evaluated the utility of tumor mutational burden (TMB), gene signatures, and multiplex immunohistochemistry (IHC) as predictive biomarkers. In this review, we aim to discuss the current state of immunotherapy for HCC, the results of the predictive biomarker studies, and future direction.

Biomarker discovery and application-An opportunity to resolve the challenge of liver cancer diagnosis and treatment

Liver cancer is one of the most common malignancies, with severe morbidity and mortality. While considerable progress has been made in liver cancer treatment, the 5-year overall survival (OS) of patients has not improved significantly. Reasons include the inadequate capability of early screening and diagnosis, a high incidence of recurrence and metastasis, a high degree of tumor heterogeneity, and an immunosuppressive tumor microenvironment. Therefore, the identification and validation of specific and robust liver cancer biomarkers are of major importance for early screening, timely diagnosis, accurate prognosis, and the prevention of tumor progression. In this review, we highlight some of the latest research progress and potential applications of liver cancer biomarkers, describing hotspots and prospective directions in biomarker discovery.

FDA-Approved Monoclonal Antibodies for Unresectable Hepatocellular Carcinoma: What Do We Know So Far?

Unresectable hepatocellular carcinoma (HCC) is an advanced primary liver malignancy with a poor prognosis. The Food and Drug Administration (FDA) has, to date, approved nivolumab, pembrolizumab, ramucirumab, nivolumab/ipilimumab, atezolizumab/bevacizumab, as well as tremelimumab/durvalumab, as first- or second-line monoclonal antibodies (mAbs) for unresectable HCC. The present review examines the current state of knowledge, and provides a useful update on the safety and efficacy of these therapeutic agents, thus attempting to define the suitability of each mAb for different patient subgroups.

A rare case of unresectable, microsatellite instability-high hepatocellular carcinoma and an examination of the tumor microenvironment

Hepatocellular carcinoma (HCC) is a common cause of cancer-related deaths worldwide, and the mortality rate of patients with unresectable HCC is very high. Microsatellite instability (MSI) is an essential biomarker for response to immune checkpoint inhibitors (ICI) in various tumors. However, the frequency of MSI in HCC is low (1.11%). There is only one case report of MSI-high HCC, and it is not well understood how high MSI affects the tumor microenvironment of HCC. Hence, we describe an interesting patient with unresectable MSI-high HCC, including the evaluation of immune status in the tumor microenvironment. A 68-year-old man presented to our department with HCC in liver segment 1. Contrast-enhanced CT revealed a liver tumor of 6.0 cm in maximum size. The patient underwent extended left and caudate lobectomy of the liver for HCC. Four months after surgical resection, contrast-enhanced computed tomography (CECT) detected 13 recurrent nodules. The patient was diagnosed with unresectable hepatocellular carcinoma recurrence, and we decided to administer systematic chemotherapy. Lenvatinib was administered over approximately 2 years as a first-line treatment, which resulted in intrahepatic tumor shrinkage. However, follow-up CECT showed new lesions, hepatogastric mesentery lymph node swelling, and peritoneal dissemination. After MSI-high status was identified, the patient began to receive pembrolizumab (200 mg, every 3 weeks). Eleven cycles of pembrolizumab therapy were administered over approximately 8 months, during which the diameter of the hepatogastric mesentery lymph node swelling and peritoneal dissemination showed shrinkage but later re-increased. As the third- and fourth-line therapy has been administered, the tumors and lymph nodes have shrunk. We report a rare case in which multikinase inhibitors were effectively used to treat MSI-high HCC.

Immune checkpoint inhibitors in HCC: Cellular, molecular and systemic data

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer related deaths in the world, and for patients with advanced disease there are few therapeutic options available. The complex immunological microenvironment of HCC and the success of immunotherapy in several types of tumours, has raised the prospect of potential benefit for immune based therapies, such as immune checkpoint inhibitors (ICIs), in HCC. This has led to significant breakthrough research, numerous clinical trials and the rapid approval of multiple systemic drugs for HCC by regulatory bodies worldwide. Although some patients responded well to ICIs, many have failed to achieve significant benefit, while others showed unexpected and paradoxical deterioration. The aim of this review is to discuss the pathophysiology of HCC, the tumour microenvironment, key clinical trials evaluating ICIs in HCC, various resistance mechanisms to ICIs, and possible ways to overcome these impediments to improve patient outcomes.

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

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.

Advances in Pharmacotherapy of Hepatocellular Carcinoma: A State-of-the-Art Review

BACKGROUND

Due to the number of emerging new treatment options, the systemic treatment of hepatocellular carcinoma (HCC) is rapidly changing. We provide here an overview of the current landscape of systemic treatment of HCC and discuss its potential future development.

SUMMARY

HCC is a leading cause of tumor-related death worldwide. Despite the efforts aimed at reducing the prevalence of HCC through vaccination and antiviral treatment, and the implementation of screening programs for early tumor detection, most patients are diagnosed with or progress to advanced HCC. For approximately 10 years, sorafenib has been the only effective systemic treatment available for these patients. Recently, however, a number of new systemic compounds, comprising several multi-kinase inhibitors and immune-checkpoint inhibitors, have been approved for treatment of HCC. These new agents are opening a plethora of therapeutic options for the future therapy of HCC.

KEY MESSAGES

The rapid progress in the treatment of HCC raises the question of the optimal combination and sequence of these agents in the treatment of patients with advanced disease. The substantial improvements in terms of objective response and survival indicate that the use of immune-checkpoint inhibitors-based treatment combinations may be extended to patients with intermediate-stage HCC.

Microsatellite instability in patients with hepato-biliary-pancreatic malignancies in clinical practice (KHBO 1903)

BACKGROUND

This study aimed to determine the prevalence of microsatellite instability (MSI)-high status in hepato-biliary-pancreatic malignancies in clinical practice and the clinical characteristics of and therapeutic results of pembrolizumab on patients with MSI-high cancers.

METHODS

The subjects were 283 patients who had undergone MSI tests for unresectable, metastatic hepato-biliary-pancreatic malignancies at seven hospitals. The tests were polymerase chain reaction fragment analyses using the microsatellite markers consisting of BAT25, BAT26, NR21, NR24, and MONO27. Formalin-fixed, paraffin-embedded blocks, prepared according to the guidelines of the Japan Society of Pathology were used within 4 years after sampling. There were 13 patients with cancers high in MSI, including eight patients receiving pembrolizumab treatment. The clinical characteristics of these patients and therapeutic outcomes of their pembrolizumab treatment were investigated.

RESULTS

MSI-high was detected in 13 (4.6%) of the 283 patients with hepato-biliary-pancreatic malignancies. None of these 13 patients had been diagnosed with Lynch syndrome. Of the Eight patients receiving pembrolizumab, a complete response was observed in three patients, a partial response in one patient, and stable disease in three patients. The objective response rate was 50% and the disease control rate was 87.5%.

CONCLUSION

MSI-high was detected in 4.6% of patients with hepato-biliary-pancreatic malignancies. There was a 50% objective response rate to pembrolizumab treatment for MSI-high cancers. The evaluation of MSI status by the current method using appropriately prepared tissue samples was to be a reliable and accurate approach to both the determination of MSI status and estimation of the effectiveness of pembrolizumab.

Current Landscape of Immune Checkpoint Inhibitor Therapy for Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy, with increasing incidence over the past several decades. The majority of patients with HCC present with advanced unresectable disease, making treatment options with curative intent limited and survival outlooks dismal. Systemic therapy with sorafenib had been traditionally used, with marginal benefit. Immunotherapy, successfully used to treat other malignant tumors, has recently been shown to be safe and well tolerated and to have promising long-term outcomes in patients with advanced HCC. We herein review the outcomes of immune checkpoint inhibitors (ICI) from major clinical trials, summarize predictors of treatment response, and highlight adverse events related to ICI treatment.

Abstract

Hepatocellular carcinoma (HCC) is the most frequent primary liver tumor. As a result of advanced disease being often present at diagnosis, only a small percentage of patients are amenable to curative-intent treatment options such as surgical resection and liver transplantation. Systemic therapy consisting of tyrosine kinase inhibitors such as sorafenib had been used for over a decade with limited efficacy. More recently, treatment with immune checkpoint inhibitors has revolutionized the treatment landscape of various malignant tumors. With this shifting paradigm, recent data have demonstrated encouraging outcomes among patients with HCC. In particular, several trials have investigated the safety and efficacy of various immune checkpoint inhibitors (ICI) either as monotherapy or in the form of combined treatments. We sought to provide an overview of recent clinical trials among patients with advanced HCC as well as to highlight predictors of response and immune-related adverse events and to review the evidence on perioperative administration of ICI in patients with resectable HCC.

Predictive biomarkers of response to immune checkpoint inhibitors in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and fourth leading cause of cancer death. While drug discovery to improve disease survival was historically poor, there is now evidence of significant potential for immune checkpoint inhibitors (ICPIs) in treatment of the disease, and indeed such drug approvals are beginning to emerge.

AREAS COVERED

HCC typically arises in the context of cirrhosis and chronic liver disease (CLD), and HCC exhibits significant biological heterogeneity, in part reflecting the broad range of aetiologies of CLD. Different classes and combinations of ICPI-based therapy exist, but not all patients will respond and predictive biomarkers are not yet available to guide clinician decision making, unlike some other cancer types. In this review, we discuss the emerging biomarkers for ICPI sensitivity in HCC, including tumour genomic features, perturbation of the gut microbiome and systemic inflammatory markers.

EXPERT OPINION

Additional profiling studies are required to appreciate existing trends with clinical outcome and to further drive clinical studies in disease stratification by response. This will only be possible within collaborative and international efforts, especially regarding biopsy collection. A close collaboration between basic scientists and clinicians will be the key to shape the next future of HCC biomarker research.

Microscopic Portal Vein Invasion in Relation to Tumor Focality and Dimension in Patients with Hepatocellular Carcinoma

BACKGROUND

Microscopic portal vein invasion (microPVI) and tumor multifocality are hepatocellular carcinoma (HCC) prognosis factors. To investigate whether microPVI and multifocality are directly related to each other.

METHODS

We retrospectively analyzed the relationships between microPVI, multifocality, and maximum tumor diameter (MTD) in prospectively collected transplanted HCC patients.

RESULTS

HCCs with 1, 2, or ≥ 3 foci had more microPVI in larger than in smaller HCCs, with microPVI being present in 52.24% of single large foci. Conversely, microPVI patients had similar percentages of single and multifocal lesions. A linear regression model of MTD, showed microPVI best associated with MTD, with 2.49 as coefficient, whereas multifocality had a 0.83 coefficient. A logistic regression model of microPVI showed significant association with tumor multifocality, especially for small HCCs. Trends for microPVI and multifocality in relation to MTD revealed that both increased with MTD but more significantly for microPVI. Survival was similar in patients with small HCCs, with or without microPVI, but was significantly worse in microPVI patients with larger HCCs. No patient survival differences were found in relation to focality.

CONCLUSIONS

MTD had stronger associations with microPVI than with multifocality. microPVI was associated with worse survival in patients with large HCCs, but survival was not impacted by number of tumor foci. microPVI and multifocality appear weakly related, having different behavior in relation to MTD and survival.

Exploring microsatellite instability in patients with advanced hepatocellular carcinoma and its tumor microenvironment

Background and Aim

Immune checkpoint inhibitors and their combination with other agents have recently been available in advanced hepatocellular carcinoma (HCC). Hence, a thorough understanding of the tumor microenvironment based on tumor samples is yet to be achieved. This study aimed to explore the tumor microenvironment in advanced HCC in terms of microsatellite instability‐high (MSI‐H) by using tumor samples from advanced HCC patients eligible for systemic therapy.

Methods

MSI‐H was assessed by polymerase chain reaction, and the expression of mismatch repair proteins, PD‐L1, CD8, VEGF, and HLA‐class1 was evaluated by immunohistochemistry. Whole‐exome sequencing was performed for MSI‐H tumor samples.

Results

Of 50 patients, one (2.0%) was confirmed with MSI‐H. In the MSI‐H advanced HCC tumor, a high tumor mutation burden, infiltration of CD8⁺ lymphocytes, and low expression of VEGF were identified. Although PD‐L1 expression was negative, there was shrinkage of tumor following pembrolizumab. However, another tumor nonresponsive to pembrolizumab was present simultaneously. Checking the Cancer Genome Atlas (TCGA) database, we found a similar case to this patient. The TCGA case had unique gene features of miR‐21 and miR‐155 overexpression and hypermethylation of the MSH2 gene.

Conclusion

We identified a very small number of MSI‐H cases in HCC using one tumor biopsy sample for each patient with advanced HCC. In addition, epigenetic aberrations possibly lead to MSI‐H in HCC patients. Since different HCC clones might coexist in the liver, sampling from multiple tumors should be considered to clarify the true proportion of MSI‐H in HCC and to analyze tumor microenvironments.

The Immunology of Hepatocellular Carcinoma

Liver cancer is the third leading cause of cancer death worldwide. Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver. Liver resection or transplantation offer the only potentially curative options for HCC; however, many patients are not candidates for surgical resection, either due to presentation at advanced stages or poor liver function and portal hypertension. Liver transplantation is also limited to patients with certain characteristics, such as those that meet the Milan criteria (one tumor ≤ 5 cm, or up to three tumors no larger than 3 cm, along with the absence of gross vascular invasion or extrahepatic spread). Locoregional therapies, such as ablation (radiofrequency, ethanol, cryoablation, microwave), trans-arterial therapies like chemoembolization (TACE) or radioembolization (TARE), and external beam radiation therapy, have been used mainly as palliative measures with poor prognosis. Therefore, emerging novel systemic treatments, such as immunotherapy, have increasingly become popular. HCC is immunogenic, containing infiltrating tumor-specific T-cell lymphocytes and other immune cells. Immunotherapy may provide a more effective and discriminatory targeting of tumor cells through induction of a tumor-specific immune response in cancer cells and can improve post-surgical recurrence-free survival in HCC. We herein review evidence supporting different immunomodulating cell-based technology relative to cancer therapy in vaccines and targeted therapies, such as immune checkpoint inhibitors, in the management of hepatocellular carcinoma among patients with advanced disease.

PD-1 Blockade for Hepatocellular Carcinoma: Current Research and Future Prospects

The treatment of hepatocellular carcinoma (HCC) has witnessed radical changes over the last few years, with the introduction of immune checkpoint inhibitors (ICI) in clinical practice, namely the combination of atezolizumab plus bevacizumab as the standard of care for first-line treatment of advanced HCC. The immunosuppressive microenvironment of the chronically inflamed liver makes HCC a fertile ground for the use of ICI. This review focuses on anti-programmed cell death-1 (PD-1) monoclonal antibodies (mAb), which have been extensively studied, as monotherapy, in combination with other ICI or with antiangiogenic agents. Currently, anti-PD-1 agents are approved by the United States Food and Drug Administration for second-line treatment in advanced HCC: nivolumab, alone or in combination with ipilimumab, and pembrolizumab. Lack of demonstration of survival benefit in first and second line led to the investigation of PD-1 agents in combination with multi-kinase inhibitors, with a number of first-line treatment regimens being actively investigated. Mounting evidence suggests a potential role of PD-1 blockade as adjuvant or neoadjuvant therapies. A key challenge remains the identification of biomarkers of response, since only a minority of patients appear to benefit from ICI.

Clinical Trials of Immune Checkpoint Inhibitors in Hepatocellular Carcinoma

Introduction: Several immune checkpoint inhibitors (CPIs) are under clinical development in hepatocellular carcinoma (HCC) and the field is advancing rapidly. In this comprehensive review, we discuss published results and report on ongoing clinical trials. Methods: A literature search was carried out using PubMed and EMBASE; data reported at international meetings and clinicaltrials.gov were included as well. The search was updated 5 March 2021. We evaluated studies with monotherapy CPI's, combinations of CPI's and combinations of CPI's with other treatment modalities separately. Only studies with at least 10 included patients were considered. Results: We identified 2649 records published in the English language literature. After review, 29 studies remained, including 12 studies with preliminary data only. The obtained overall response rate of PD-1/PDL-1 monotherapy in phase II studies in the second-line setting was 15-20% with disease control in approximately 60% of patients. The responses were of long duration in a subset of patients. Furthermore, the safety profiles were manageable. However, a phase III study comparing nivolumab with sorafenib in the first-line setting and a phase III study evaluating pembrolizumab versus best supportive care in the second-line setting did not meet their prespecified endpoints. More recently, a phase I/II study of nivolumab and ipilimumab has resulted in a response rate of approximately 30% with a median OS of 22 months in the second-line setting. Multiple trials have been initiated to evaluate CPIs in combination with molecularly targeted drugs, especially anti-angiogenic drugs or local therapy. A phase III study investigating atezolizumab plus bevacizumab versus sorafenib in the first-line setting showed significantly increased survival in the combination arm. Conclusions: The combination of atezolizumab and bevacizumab represents a new standard of care in the first-line setting for fit patients with preserved liver function. CPIs can produce durable tumor remission and induce long-standing anti-tumor immunity in a subgroup of patients with advanced HCC. Although phase III trials of CPI monotherapy have been negative, the combination of PD-1/PD-L1 inhibitors with other anti-angiogenic drugs, CTLA-4 inhibitors or other modalities may result in new treatment options for patients with HCC. Research on predictive biomarkers is crucial for further development of CPIs in HCC.

Role of Alpha-Fetoprotein in Hepatocellular Carcinoma Drug Resistance

Hepatocellular carcinoma (HCC) is a major type of primary liver cancer and a major cause of cancer-related deaths worldwide because of its high recurrence rate and poor prognosis. Surgical resection is currently the major treatment measure for patients in the early and middle stages of the disease. Because due to late diagnosis, most patients already miss the opportunity for surgery upon disease confirmation, conservative chemotherapy (drug treatment) remains an important method of comprehensive treatment for patients with middle- and late-stage liver cancer. However, multidrug resistance (MDR) in patients with HCC severely reduces the treatment effect and is an important obstacle to chemotherapeutic success. Alpha-fetoprotein (AFP) is an important biomarker for the diagnosis of HCC. The serum expression levels of AFP in many patients with HCC are increased, and a persistently increased AFP level is a risk factor for HCC progression. Many studies have indicated that AFP functions as an immune suppressor, and AFP can promote malignant transformation during HCC development and might be involved in the process of MDR in patients with liver cancer. This review describes drug resistance mechanisms during HCC drug treatment and reviews the relationship between the mechanism of AFP in HCC development and progression and HCC drug resistance.

The Role of Immunotherapy in Hepatocellular Carcinoma: A Systematic Review and Pooled Analysis of 2,402 Patients

BACKGROUND

Immune checkpoints inhibitors (ICIs) have emerged as a treatment option for several malignancies. Nivolumab, pembrolizumab, nivolumab plus ipilimumab, and atezolizumab plus bevacizumab have been approved for the management of advanced-stage hepatocellular carcinoma (HCC). We aimed to systematically review the literature and summarize the characteristics and outcomes of patients with HCC treated with ICIs.

METHODS

A systematic literature search of PubMed, the Cochrane Library, and ClinicalTrials.gov was performed according to the PRISMA statement (end of search date: November 7, 2020). Quality of evidence assessment was also performed.

RESULTS

Sixty-three articles including 2,402 patients were analyzed, 2,376 of whom received ICIs for unresectable HCC. Response to ICIs could be evaluated in 2,116 patients; the overall objective response rate (ORR) and disease control rate (DCR) were 22.7% and 60.7%, respectively, and the mean overall survival (OS) was 15.8 months. The ORR, DCR, and OS for nivolumab (n = 846) were 19.7%, 51.1%, and 18.7 months, respectively; for pembrolizumab (n = 435) they were 20.7%, 64.6% and 13.3 months, respectively. The combination of atezolizumab/bevacizumab (n = 460) demonstrated an ORR and DCR of 30% and 77%, respectively. The overall rate of treatment discontinuation because of adverse events was 14.9%. Fifteen patients received ICIs in the liver transplant (LT) setting (one pre-LT for bridging, 14 for post-LT recurrence); fatal graft rejection was reported in 40.0% (n = 6/15) and mortality in 80.0% (n = 12/15).

CONCLUSION

ICIs are safe and effective against unresectable HCC, but caution is warranted regarding their use in the LT setting because of the high graft rejection rate.

IMPLICATIONS FOR PRACTICE

This systematic review pooled the outcomes from studies reporting on the use of immune checkpoint inhibitors (ICIs) for the management of 2,402 patients with advanced-stage hepatocellular carcinoma (HCC), 2,376 of whom had unresectable HCC. The objective response rate and disease control rate were 22.7% and 60.7%, respectively, and the mean overall survival was 15.8 months. The overall rate of treatment discontinuation because of adverse events was 14.9%. Fifteen patients received ICIs in the liver transplant (LT) setting (one pre-LT for bridging, 14 for post-LT recurrence). Six of these patients experienced graft rejection (40.0%).

Immunotherapy and Targeted Therapy for Hepatocellular Carcinoma: A Literature Review and Treatment Perspectives

Advanced hepatocellular carcinoma is a prevalent and potentially aggressive disease. For more than a decade, treatment with sorafenib has been the only approved therapeutic approach. Moreover, no agent has been proven to prolong survival following the progression of disease after sorafenib treatment. However, in recent years, this scenario has changed substantially with several trials being conducted to examine the effects of immunotherapy and novel targeting agents. Several immune checkpoint inhibitors have shown promising results in early-stage clinical trials. Moreover, phase III trials with large cohorts have demonstrated remarkable improvement in survival with the use of new targeted therapies in second-line treatment. Treatment regimens involving the combination of two immune checkpoint inhibitors as well as immune checkpoint inhibitors and anti-angiogenic targeted therapies have shown potential to act synergistically in clinical trials. Recently, the combination of atezolizumab and bevacizumab evaluated in a phase III clinical trial has demonstrated survival superiority in the first-line treatment; it is the new considered standard of care. In this manuscript, we aimed to review the latest advances in the systemic treatment of advanced hepatocellular carcinoma focusing on immunotherapy and targeted therapies.

Immunotherapy for Hepatocellular Carcinoma: A 2021 Update

Hepatocellular carcinoma (HCC) is one of one of the most frequent liver cancers and the fourth leading cause of cancer-related mortality worldwide. Current treatment options such as surgery, neoadjuvant chemoradiotherapy, liver transplantation, and radiofrequency ablation will benefit only a very small percentage of patients. Immunotherapy is a novel treatment approach representing an effective and promising option against several types of cancer. The aim of our study is to present the currently ongoing clinical trials and to evaluate the efficacy of immunotherapy in HCC. In this paper, we demonstrate that combination of different immunotherapies or immunotherapy with other modalities results in better overall survival (OS) and progression-free survival (PFS) compared to single immunotherapy agent. Another objective of this paper is to demonstrate and highlight the importance of tumor microenvironment as a predictive and prognostic marker and its clinical implications in immunotherapy response.

Current progress and prospect of immune checkpoint inhibitors in hepatocellular carcinoma

In recent years, the incidence of liver cancer has increased and is currently the sixth most common tumor and the second leading cause of cancer-associated mortality worldwide. Most cases of liver cancer are hepatocellular carcinoma (HCC). Surgery, including liver transplantation or resection, and radiofrequency ablation therapies are all considered to be the curative treatment options for early-stage HCC. However, most patients have advanced HCC at the time of diagnosis, contributing to a poor prognosis. Therefore, improved treatment for late-stage HCC is needed. Immune checkpoint inhibitors (ICIs), among which programmed death receptor 1 (PD-1)/PD-ligand 1 and cytotoxic T lymphocyte-associated protein 4 are the representative immunological checkpoints, have shown great promise and progress for HCC treatment. The present review summarizes recent studies that have focused on ICIs and discusses the present limitations affecting the development of new therapeutic strategies.

Immune Phenotype and Immune Checkpoint Inhibitors for the Treatment of Human Hepatocellular Carcinoma

Immunotherapies are promising approaches for treating hepatocellular carcinomas (HCCs) refractory to conventional therapies. However, a recent clinical trial of immune checkpoint inhibitors (ICIs) revealed that anti-tumor responses to ICIs are not satisfactory in HCC cases. Therefore, it is critical to identify molecular markers to predict outcome and develop novel combination therapies that enhance the efficacy of ICIs. Recently, several attempts have been made to classify HCC based on genome, epigenome, and transcriptome analyses. These molecular classifications are characterized by unique clinical and histological features of HCC, as well immune phenotype. For example, HCCs exhibiting gene expression patterns with proliferation signals and stem cell markers are associated with the enrichment of immune infiltrates in tumors, suggesting immune-proficient characteristics for this type of HCC. However, the presence of activating mutations in β-catenin represents a lack of immune infiltrates and refractoriness to ICIs. Although the precise mechanism that links the immunological phenotype with molecular features remains controversial, it is conceivable that alterations of oncogenic cellular signaling in cancer may lead to the expression of immune-regulatory molecules and result in the acquisition of specific immunological microenvironments for each case of HCC. Therefore, these molecular and immune characteristics should be considered for the management of HCC using immunotherapy.