Immunomodulatory Precision: A Narrative Review Exploring the Critical Role of Immune Checkpoint Inhibitors in Cancer Treatment

An immune checkpoint is a signaling pathway that regulates the recognition of antigens by T-cell receptors (TCRs) during an immune response. These checkpoints play a pivotal role in suppressing excessive immune responses and maintaining immune homeostasis against viral or microbial infections. There are several FDA-approved immune checkpoint inhibitors (ICIs), including ipilimumab, pembrolizumab, and avelumab. These ICIs target cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed death ligand 1 (PD-L1). Furthermore, ongoing efforts are focused on developing new ICIs with emerging potential. In comparison to conventional treatments, ICIs offer the advantages of reduced side effects and durable responses. There is growing interest in the potential of combining different ICIs with chemotherapy, radiation therapy, or targeted therapies. This article comprehensively reviews the classification, mechanism of action, application, and combination strategies of ICIs in various cancers and discusses their current limitations. Our objective is to contribute to the future development of more effective anticancer drugs targeting immune checkpoints.

Efficacy and Safety of PD-1/PD-L1 Inhibitors in Advanced Hepatocellular Carcinoma: A Systematic Review and Meta-analysis

INTRODUCTION

Programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors have been increasingly employed for the treatment of various cancers in clinical practice. This study aimed to systematically evaluate the efficacy and safety of PD-1/PD-L1 inhibitors for advanced hepatocellular carcinoma (HCC).

METHODS

PubMed, EMBASE, Cochrane library, Web of Science, and Abstracts of American Society of Clinical Oncology proceedings databases were searched. Objective response rate (ORR), disease control rate (DCR), median progression-free survival (PFS), median overall survival (OS), and incidence of adverse events (AEs) and drug withdrawal were pooled. Odds ratio (OR) and hazard ratio (HR) were calculated to analyze the difference in the ORR, DCR, PFS, and OS between groups.

RESULTS

Among the 14,902 initially identified papers, 98 studies regarding use of PD-1/PD-L1 inhibitors in advanced HCC were included. Based on different criteria of response in solid tumors, the pooled ORR, DCR, and median PFS was 16-36%, 54-74%, and 4.5-6.8 months, respectively. The pooled median OS was 11.9 months. Compared to multitarget tyrosine kinase inhibitors (TKIs), PD-1/PD-L1 inhibitors monotherapy significantly increased ORR (OR 2.73, P < 0.00001) and OS (HR 0.97, P = 0.05), and PD-1/PD-L1 inhibitors combined with TKIs significantly increased ORR (OR 3.17, P < 0.00001), DCR (OR 2.44, P < 0.00001), PFS (HR 0.58, P < 0.00001), and OS (HR 0.58, P < 0.00001). The pooled incidence of all-grade AEs, grade ≥ 3 AEs, and drug withdrawal was 71%, 25%, and 7%, respectively.

CONCLUSION

On the basis of the present systematic review and meta-analysis, PD-1/PD-L1 inhibitors should be the preferred treatment choice for advanced HCC owing to their higher antitumor effect and improved outcomes.

First-line immune checkpoint inhibitor-based combinations in unresectable hepatocellular carcinoma: current management and future challenges

INTRODUCTION

Immunotherapy has recently taken on an extremely important role in medical oncology, as first- or later-line treatment in several tumor types, and recent years have seen the emerging of clinical trials assessing immune checkpoint inhibitors (ICIs) in unresectable hepatocellular carcinoma (HCC).

AREAS COVERED

Herein, we provide an overview of recently published studies exploring the dual immune checkpoint blockade or the combination of ICIs plus biological treatments as first-line treatment in HCC patients with advanced disease, especially focusing on the biological rationale behind these therapeutic strategies, and ongoing active and recruiting clinical trials.

EXPERT OPINION

Results of studies on monotherapy with ICIs have suggested that this strategy could be beneficial only in a minority of patients; conversely, the recently published IMbrave150 study has reported an overall survival benefit in HCC receiving the combination of atezolizumab plus bevacizumab compared to sorafenib as first-line treatment. A wide number of clinical trials is evaluating ICI-based combinations in advanced HCC, a strategy which is supported by robust preclinical and early-phase clinical data, and results of these studies are highly awaited.

Immune checkpoint inhibition for the treatment of cancers: An update and critical review of ongoing clinical trials

Advances in Cancer immunotherapy in the past few years include the development of medications that modulate immune checkpoint proteins. Cytotoxic T-lymphocyte antigen 4 (CTLA4), programmed cell death protein 1 (PD1), and programmed cell death ligand 1 (PD-L1) are three co-inhibitory receptors that are expressed in the tumor microenvironment. Immune checkpoint inhibitors (ICI) that target these biomarkers unleash the properties of effector T cells that are licensed to kill cancer cells. Immune checkpoint blockade has dramatically changed the treatment landscape of many cancers. In this Review, we describe the current data regarding clinical trials of ICIs in six important cancers, including hepatocellular carcinoma (HCC), renal cell cancer (RCC), hodgkin lymphoma (HL), non-hodgkin lymphoma (NHL), non-small cell lung cancer (NSCLC), and head and neck cancer carcinoma (HNSCC).

Concurrent Sorafenib and Radiotherapy versus Radiotherapy Alone for Locally Advanced Hepatocellular Carcinoma: A Propensity-Matched Analysis

Purpose

Evidence is lacking concerning the benefit of the combination of sorafenib and radiotherapy to treat advanced hepatocellular carcinoma (HCC). To date, no publication has reported the outcomes of radiotherapy alone versus concurrent therapy. We aimed to compare the effectiveness of radiotherapy alone versus concurrent radiotherapy and sorafenib for locally advanced hepatocellular carcinoma.

Materials and Methods

We conducted a propensity score matching (PSM) cohort study comparing the effectiveness of the concurrent use of sorafenib and external beam radiotherapy versus radiotherapy alone in Barcelona Clinic Liver Cancer (BCLC) stage B or C, nonsurgically managed, nonmetastatic patients with HCC. Two subpopulations were matched based on baseline characteristics. Stratified analysis was also performed to assess the heterogeneous effects of the two arms. Overall survival (OS) was compared. Radiation-induced liver disease (RILD) and overt gastrointestinal (GI) bleeding events were also recorded.

Results

Seven hundred thirty-one BCLC stage B or C nonmetastatic HCC patients were identified from 2007 to 2017. Of these, 347 patients met the inclusion criteria (Radiotherapy alone: 269 patients; concurrent therapy: 78 patients). Propensity score matching yielded 73 patients each in the radiotherapy and concurrent groups. The median OS was 9.6 months in the radiotherapy-alone group and 9.9 months in the concurrent group (hazard ratio (HR): 1.12; 95% CI=0.78–1.62; p=0.544). Posttreatment toxicities, including radiation-induced liver disease and overt gastrointestinal bleeding, showed no significant differences between the groups.

Conclusion

In our study, the concurrent use of sorafenib and conventional external beam radiotherapy shows no survival benefit over radiotherapy alone for locally advanced hepatocellular carcinoma.

Lenvatinib: established and promising drug for the treatment of advanced hepatocellular carcinoma

INTRODUCTION

: The evolving therapeutic landscape of advanced hepatocellular carcinoma (HCC) includes the increasing implementation of target-therapy and immunotherapy. Lenvatinib, a multi-target tyrosine kinase inhibitor (TKI), is an emerging first-line therapy for hepatocellular carcinoma. Its approval has changed the scenario of first-line therapies for advanced HCC, where just sorafenib proved clinical efficacy for over a decade.

AREAS COVERED

: The current evidence on the role of lenvatinib for patients with advanced HCC is reviewed in this article. Particularly, therapeutic mechanisms and clinical efficacy of lenvatinib are summarized and the management of adverse events is discussed. In addition, future perspectives on the emerging role of combine therapy for HCC are highlighted.

EXPERT OPINION

In the first line, lenvatinib was found to be non-inferior to sorafenib for overall survival, with significantly better progression-free survival and objective response rate. Immune checkpoint inhibitors (ICIs) are now part of HCC treatment, and recently the combination of atezolizumab plus bevacizumab has become the recommended standard of care first-line therapy for selected patients. The antitumor and immunomodulatory activities that lenvatinib shows in preclinical studies, and the positive outcomes achieved using a combination of lenvatinib plus ICIs, open new perspectives for advanced HCC treatment.

Hepatocellular Carcinoma Immunotherapy and the Potential Influence of Gut Microbiome

Disruptions in the human gut microbiome have been associated with a cycle of hepatocyte injury and regeneration characteristic of chronic liver disease. Evidence suggests that the gut microbiota can promote the development of hepatocellular carcinoma through the persistence of this inflammation by inducing genetic and epigenetic changes leading to cancer. As the gut microbiome is known for its effect on host metabolism and immune response, it comes as no surprise that the gut microbiome may have a role in the response to therapeutic strategies such as immunotherapy and chemotherapy for liver cancer. Gut microbiota may influence the efficacy of immunotherapy by regulating the responses to immune checkpoint inhibitors in patients with hepatocellular carcinoma. Here, we review the mechanisms by which gut microbiota influences hepatic carcinogenesis, the immune checkpoint inhibitors currently being used to treat hepatocellular carcinoma, as well as summarize the current findings to support the potential critical role of gut microbiome in hepatocellular carcinoma (HCC) immunotherapy.

Sintilimab plus a bevacizumab biosimilar (IBI305) versus sorafenib in unresectable hepatocellular carcinoma (ORIENT-32): a randomised, open-label, phase 2-3 study

BACKGROUND

China has a high burden of hepatocellular carcinoma, and hepatitis B virus (HBV) infection is the main causative factor. Patients with hepatocellular carcinoma have a poor prognosis and a substantial unmet clinical need. The phase 2-3 ORIENT-32 study aimed to assess sintilimab (a PD-1 inhibitor) plus IBI305, a bevacizumab biosimilar, versus sorafenib as a first-line treatment for unresectable HBV-associated hepatocellular carcinoma.

METHODS

This randomised, open-label, phase 2-3 study was done at 50 clinical sites in China. Patients aged 18 years or older with histologically or cytologically diagnosed or clinically confirmed unresectable or metastatic hepatocellular carcinoma, no previous systemic treatment, and a baseline Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 were eligible for inclusion. In the phase 2 part of the study, patients received intravenous sintilimab (200 mg every 3 weeks) plus intravenous IBI305 (15 mg/kg every 3 weeks). In the phase 3 part, patients were randomly assigned (2:1) to receive either sintilimab plus IBI305 (sintilimab-bevacizumab biosimilar group) or sorafenib (400 mg orally twice daily; sorafenib group), until disease progression or unacceptable toxicity. Randomisation was done using permuted block randomisation, with a block size of six, via an interactive web response system, and stratified by macrovascular invasion or extrahepatic metastasis, baseline α-fetoprotein, and ECOG performance status. The primary endpoint of the phase 2 part of the study was safety, assessed in all patients who received at least one dose of study drug. The co-primary endpoints of the phase 3 part of the study were overall survival and independent radiological review committee (IRRC)-assessed progression-free survival according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 in the intention-to-treat population. The study is registered with ClinicalTrials.gov, NCT03794440. The study is closed to new participants and follow-up is ongoing for long-term outcomes.

FINDINGS

Between Feb 11, 2019 and Jan 15, 2020, we enrolled 595 patients: 24 were enrolled directly into the phase 2 safety run-in and 571 were randomly assigned to sintilimab-bevacizumab biosimilar (n=380) or sorafenib (n=191). In the phase 2 part of the trial, 24 patients received at least one dose of the study drug, with an objective response rate of 25·0% (95% CI 9·8-46·7). Based on the preliminary safety and activity data of the phase 2 part, in which grade 3 or worse treatment-related adverse events occurred in seven (29%) of 24 patients, the randomised phase 3 part was started. At data cutoff (Aug 15, 2020), the median follow-up was 10·0 months (IQR 8·5-11·7) in the sintilimab-bevacizumab biosimilar group and 10·0 months (8·4-11·7) in the sorafenib group. Patients in the sintilimab-bevacizumab biosimilar group had a significantly longer IRRC-assessed median progression-free survival (4·6 months [95% CI 4·1-5·7]) than did patients in the sorafenib group (2·8 months [2·7-3·2]; stratified hazard ratio [HR] 0·56, 95% CI 0·46-0·70; p<0·0001). In the first interim analysis of overall survival, sintilimab-bevacizumab biosimilar showed a significantly longer overall survival than did sorafenib (median not reached [95% CI not reached-not reached] vs 10·4 months [8·5-not reached]; HR 0·57, 95% CI 0·43-0·75; p<0·0001). The most common grade 3-4 treatment-emergent adverse events were hypertension (55 [14%] of 380 patients in the sintilimab-bevacizumab biosimilar group vs 11 [6%] of 185 patients in the sorafenib group) and palmar-plantar erythrodysaesthesia syndrome (none vs 22 [12%]). 123 (32%) patients in the sintilimab-bevacizumab biosimilar group and 36 (19%) patients in the sorafenib group had serious adverse events. Treatment-related adverse events that led to death occurred in six (2%) patients in the sintilimab-bevacizumab biosimilar group (one patient with abnormal liver function, one patient with both hepatic failure and gastrointestinal haemorrhage, one patient with interstitial lung disease, one patient with both hepatic faliure and hyperkalemia, one patient with upper gastrointestinal haemorrhage, and one patient with intestinal volvulus) and two (1%) patients in the sorafenib group (one patient with gastrointestinal haemorrhage and one patient with death of unknown cause).

INTERPRETATION

Sintilimab plus IBI305 showed a significant overall survival and progression-free survival benefit versus sorafenib in the first-line setting for Chinese patients with unresectable, HBV-associated hepatocellular carcinoma, with an acceptable safety profile. This combination regimen could provide a novel treatment option for such patients.

FUNDING

Innovent Biologics.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Research Progresses of Targeted Therapy and Immunotherapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, with nearly one million new cases and deaths every year. Owing to the complex pathogenesis, hidden early symptoms, rapidly developing processes, and poor prognosis, the morbidity and mortality of HCC are increasing yearly. With the progress being made in modern medicine, the treatment of HCC is no longer limited to traditional methods. Targeted therapy and immunotherapy have emerged to treat advanced and metastatic HCC in recent years. Since Sorafenib is the first molecular targeting drug against angiogenesis, targeted drugs for HCC are continually emerging. Moreover, immunotherapy plays a vital role in clinical trials. In particular, the application of immune checkpoint inhibitors, which have received increasing attention in the field of cancer treatment, is a possible research path. Interestingly, these two therapies generally complement each other at some stages of HCC, bringing new hope for patients with advanced HCC. In this paper, we discuss the research progress of targeted therapy and immunotherapy for HCC in recent years, which will provide a reference for the further development of drugs for HCC.

Advances in Targeting Cutaneous Melanoma

Simple Summary

Cutaneous Melanoma (CM), arising from pigment-producing melanocytes in the skin, is an aggressive cancer with high metastatic potential. While cutaneous melanoma represents only a fraction of all skin cancers (<5%), it accounts for most skin-cancer-related deaths worldwide. Immune checkpoint inhibition has been the first therapeutic approach to significantly benefit patient survival after treatment. Nevertheless, the immunosuppressive tumor microenvironment and the intrinsic and acquired treatment resistance of melanoma remain crucial challenges. Combining local and systemic treatment offers the potential to augment therapeutic response and overcome resistance, although, complex drug combinations can harbor an increased risk of immune-related adverse events. The aim of this review is to give current insight into studies combining systemic and local therapeutic approaches to overcome drug resistance, prime melanoma cells for therapy, and improve overall treatment response in CM patients.

Abstract

To date, the skin remains the most common cancer site among Caucasians in the western world. The complex, layered structure of human skin harbors a heterogenous population of specialized cells. Each cell type residing in the skin potentially gives rise to a variety of cancers, including non-melanoma skin cancer, sarcoma, and cutaneous melanoma. Cutaneous melanoma is known to exacerbate and metastasize if not detected at an early stage, with mutant melanomas tending to acquire treatment resistance over time. The intricacy of melanoma thus necessitates diverse and patient-centered targeted treatment options. In addition to classical treatment through surgical intervention and radio- or chemotherapy, several systemic and intratumoral immunomodulators, pharmacological agents (e.g., targeted therapies), and oncolytic viruses are trialed or have been recently approved. Moreover, utilizing combinations of immune checkpoint blockade with targeted, oncolytic, or anti-angiogenic approaches for patients with advanced disease progression are promising approaches currently under pre-clinical and clinical investigation. In this review, we summarize the current ‘state-of-the-art’ as well as discuss emerging agents and regimens in cutaneous melanoma treatment.

Peretinoin, an Acyclic Retinoid, for the Secondary Prevention of Hepatocellular Carcinoma

The high rates of hepatocellular carcinoma (HCC) recurrence after initially successful curative therapy emphasize ongoing unmet needs to prevent or reduce HCC recurrence. Retinoid acid (RA), a metabolite of vitamin A and its related analogues (termed retinoids) has been suggested as a promising chemotherapeutic agent in cancer treatment. The synthetic oral retinoid peretinoin is the only agent for the secondary chemoprevention of HCC after curative therapy that is currently well applied into clinical development. Here we present an updated summary of the molecular pathogenesis of HCC and of preclinical and clinical findings with peretinoin, including its clinical characteristics, safety and tolerability profile and future perspectives for clinical use.

Immunotherapy for advanced hepatocellular carcinoma: a focus on special subgroups

Following the success of immune checkpoint blockers (ICBs) in different cancer types, a large number of studies are currently investigating ICBs in patients with hepatocellular carcinoma (HCC), alone or in combination with other treatments. Both nivolumab and pembrolizumab, as well as the combination of nivolumab plus ipilimumab have been granted accelerated approval by the United States Food and Drug Administration for sorafenib-pretreated patients. While nivolumab and pembrolizumab both failed to meet their primary endpoints in phase III trials, the combination of atezolizumab plus bevacizumab eventually improved overall and progression-free survival compared with sorafenib in a front-line phase III trial, and thus, will become the new standard of care in this setting. Despite this breakthrough, there are patient populations with certain underlying conditions that may not be ideal candidates for this new treatment either due to safety concerns or potential lack of efficacy. In this review, we discuss the safety of ICBs in patients with pre-existing autoimmune disease, IBD or a history of solid organ transplantation. Moreover, we summarise emerging preclinical and clinical data suggesting that ICBs may be less efficacious in patients with underlying non-alcoholic steatohepatitis or HCCs with activated Wnt/β-catenin signalling.

Augmenting Anticancer Immunity Through Combined Targeting of Angiogenic and PD-1/PD-L1 Pathways: Challenges and Opportunities

Cancer immunotherapy (CIT) with antibodies targeting the programmed cell death 1 protein (PD-1)/programmed cell death 1 ligand 1 (PD-L1) axis have changed the standard of care in multiple cancers. However, durable antitumor responses have been observed in only a minority of patients, indicating the presence of other inhibitory mechanisms that act to restrain anticancer immunity. Therefore, new therapeutic strategies targeted against other immune suppressive mechanisms are needed to enhance anticancer immunity and maximize the clinical benefit of CIT in patients who are resistant to immune checkpoint inhibition. Preclinical and clinical studies have identified abnormalities in the tumor microenvironment (TME) that can negatively impact the efficacy of PD-1/PD-L1 blockade. Angiogenic factors such as vascular endothelial growth factor (VEGF) drive immunosuppression in the TME by inducing vascular abnormalities, suppressing antigen presentation and immune effector cells, or augmenting the immune suppressive activity of regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages. In turn, immunosuppressive cells can drive angiogenesis, thereby creating a vicious cycle of suppressed antitumor immunity. VEGF-mediated immune suppression in the TME and its negative impact on the efficacy of CIT provide a therapeutic rationale to combine PD-1/PD-L1 antibodies with anti-VEGF drugs in order to normalize the TME. A multitude of clinical trials have been initiated to evaluate combinations of a PD-1/PD-L1 antibody with an anti-VEGF in a variety of cancers. Recently, the positive results from five Phase III studies in non-small cell lung cancer (adenocarcinoma), renal cell carcinoma, and hepatocellular carcinoma have shown that combinations of PD-1/PD-L1 antibodies and anti-VEGF agents significantly improved clinical outcomes compared with respective standards of care. Such combinations have been approved by health authorities and are now standard treatment options for renal cell carcinoma, non-small cell lung cancer, and hepatocellular carcinoma. A plethora of other randomized studies of similar combinations are currently ongoing. Here, we discuss the principle mechanisms of VEGF-mediated immunosuppression studied in preclinical models or as part of translational clinical studies. We also discuss data from recently reported randomized clinical trials. Finally, we discuss how these concepts and approaches can be further incorporated into clinical practice to improve immunotherapy outcomes for patients with cancer.

Immune Checkpoint Inhibitors in Hepatocellular Carcinoma: Current Status and Novel Perspectives

Immune checkpoint inhibitors (ICIs) represent a promising treatment for many kinds of cancers, including hepatocellular carcinoma (HCC). The rationale for using ICIs in HCC is based on the immunogenic background of hepatitis and cirrhosis and on the observation of high programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes in this cancer. Promising data from phase I/II studies in advanced HCC, showing durable objective response rates (~20% in first- and second-line settings) and good safety profile, have led to phase III studies with ICIs as single agents or in combination therapy, both in first and second line setting. While the activity of immunotherapy agents as single agents seems to be limited to an "ill-defined" small subset of patients, the combination of the anti PD-L1 atezolizumab and anti-vascular endothelial growth factor bevacizumab revealed a benefit in the outcomes when compared to sorafenib in the first line. In addition, the activity and efficacy of the combinations between anti-PD-1/anti-PD-L1 antibody and other ICIs, tyrosine kinase inhibitors, or surgical and locoregional therapies, has also been investigated in clinical trials. In this review, we provide an overview of the role of ICIs in the management of HCC with a critical evaluation of the current status and future directions.

Current Translational and Clinical Challenges in Advanced Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a frequent and increasing cause of cancerrelated deaths worldwide. Reversing this trend is complicated by the varied aetiological factors leading to liver cirrhosis resulting in molecular genetic and clinical heterogeneity, combined with frequent presentation at advanced stage. Large-scale genomic studies have identified alterations in key signalling pathways for HCC development and progression, but these findings have not yet directly influenced patient management in the clinical setting. Despite these translational challenges, a small number of anti-angiogenic systemic therapy agents have succeeded in recent randomized trials enriching the repertoire of available treatments for advanced HCC. In addition, the early promise of immune checkpoint inhibition is now on the cusp of delivering changes to standard systemic therapy algorithms. This review focuses on recent translational and clinical developments that have advanced. current practice and explores the challenges encountered in attempting to improve the outcomes and experience of patients diagnosed with advanced HCC.

Translational Considerations to Improve Response and Overcome Therapy Resistance in Immunotherapy for Hepatocellular Carcinoma

Over the last decade, progress in systemic therapies significantly improved the outcome of primary liver cancer. More recently, precision oncological and immunotherapeutic approaches became the focus of intense scientific and clinical research. Herein, preclinical studies showed promising results with high response rates and improvement of overall survival. However, results of phase III clinical trials revealed that only a subfraction of hepatocellular carcinoma (HCC) patients respond to therapy and display only moderate objective response rates. Further, predictive molecular characteristics are largely missing. In consequence, suitable trial design has emerged as a crucial factor for the success of a novel compound. In addition, increasing knowledge from translational studies indicate the importance of targeting the tumor immune environment to overcome resistance to immunotherapy. Thus, combination of different immunotherapies with other treatment modalities including antibodies, tyrosine kinase inhibitors, or local therapies is highly promising. However, the mechanisms of failure to respond to immunotherapy in liver cancer are still not fully understood and the modulation of the immune system and cellular tumor composition is particularly relevant in this context. Altogether, it is increasingly clear that tailoring of immunotherapy and individualized approaches are required to improve efficacy and patient outcome in liver cancer. This review provides an overview of the current knowledge as well as translational considerations to overcome therapy resistance in immunotherapy of primary liver cancer.

Overview of Current Progress in Immune Checkpoint Inhibitor Therapy for Advanced Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains to a common cause of tumor mortality worldwide and represents the most common type of lethal hepatic malignancy. The incidence of HCC is swiftly increasing in western countries and southeast Asia. Despite poor prognosis, traditional treatments for advanced HCC appear to be minimally effective or even useless since patients are usually diagnosed in the advanced stage of disease. In recent years, immune checkpoint blockade has shown promising results in multiple pre-clinical and clinical trials of different solid tumors, including advanced HCC. Novel drugs targeting immune checkpoints, such as nivolumab (anti-PD-1), durvalumab (anti-PD-L1), and tremelimumab (anti-CTLA-4) have been shown to be highly effective and relatively safe in monotherapy or in combination treatment of advanced liver cancer. Unlike other immunotherapies, this approach can rouse human anti-tumor immunity by relieving T-cell exhaustion and inhibiting the evasion of HCC by blocking co-inhibitory signaling transduction accurately. In this review, we will provide current knowledge of several major immune checkpoints and summarize recent data from clinical trials that applied immune checkpoint inhibitors alone or in combination. In addition, this review will discuss the limitations and future prospective of immune checkpoint-targeted therapy for advanced HCC.

Lenvatinib for hepatocellular carcinoma: From preclinical mechanisms to anti-cancer therapy

Lenvatinib, a multi-target tyrosine kinase inhibitor (TKI), is an emerging first-line therapy for hepatocellular carcinoma (HCC). Its application has changed the status of sorafenib as the only first-line TKI treatment for HCC for more than a decade. Evidence has shown that lenvatinib possesses antitumor proliferation and immunomodulatory activity in preclinical studies. In comparison, lenvatinib was non-inferior to sorafenib in overall survival (OS), and even shows superiority with regard to all the secondary efficacy endpoints. Immune-checkpoint inhibitors(ICIs)are now being incorporated into HCC treatment. Positive outcomes have been achieved in the combination of lenvatinib plus ICIs, bringing broader prospects for HCC. This review presents an overview on the therapeutic mechanisms and clinical efficacy of lenvatinib in HCC, and we discuss the future perspectives of lenvatinib in HCC management with focus on biomarker-guided precision medicine.

Management and Treatment of Hepatocellular Carcinoma with Immunotherapy: A Review of Current and Future Options

With mortality rates of liver cancer doubling in the last 20 years, this disease is on the rise and has become the fifth most common cancer in men and the seventh most common cancer in women. Hepatocellular carcinoma (HCC) represents approximately 90% of all primary liver cancers and is a major global health concern. Patients with HCC can be managed curatively with surgical resection or with liver transplantation, if they are diagnosed at an early stage. Unfortunately, most patients with HCC present with advanced stages of the disease and have underlying liver dysfunction, which allows only 15% of patients to be eligible for curative treatment. Several different treatment modalities are available, including locoregional therapy radiofrequency ablation, microwave ablation, percutaneous ethanol injection, trans-arterial chemoembolization, transarterial radio-embolization, cryoablation, radiation therapy, stereotactic radiotherapy, systemic chemotherapy, molecularly targeted therapies, and immunotherapy. Immunotherapy has recently become a promising method for inhibiting HCC tumor progression, recurrence, and metastasis. The term "Immunotherapy" is a catch-all, encompassing a wide range of applications and targets, including HCC vaccines, adoptive cell therapy, immune checkpoint inhibitors, and use of oncolytic viruses to treat HCC. Immunotherapy in HCC is a relatively safe option for treating patients with advanced disease in the USA who are either unable to receive or failed sorafenib/lenvatinib therapy and thus may offer an additional survival benefit for these patients. The purpose of this review is to elaborate on some of the most recent advancements in immunotherapy.

Effectiveness of nivolumab versus regorafenib in hepatocellular carcinoma patients who failed sorafenib treatment

Background/Aims

Several treatment options are currently available for patients with hepatocellular carcinoma (HCC) failing previous sorafenib treatment. We aimed to compare the effectiveness of regorafenib and nivolumab in these patients.

Methods

Consecutive HCC patients who received regorafenib or nivolumab after failure of sorafenib treatment were included. Primary endpoint was overall survival (OS) and secondary endpoints were time to progression, tumor response rate, and adverse events. Inverse probability of treatment weighting (IPTW) using the propensity score was conducted to reduce treatment selection bias.

Results

Among 150 study patients, 102 patients received regorafenib and 48 patients received nivolumab. Median OS was 6.9 (95% confidence interval [CI], 3.0–10.8) months for regorafenib and 5.9 (95% CI, 3.7–8.1) months for nivolumab (P=0.77 by log-rank test). In multivariable analysis, nivolumab was associated with prolonged OS (vs. regorafenib: adjusted hazard ratio [aHR], 0.54; 95% CI, 0.30–0.96; P=0.04). Time to progression was not significantly different between groups (nivolumab vs. regorafenib: aHR, 0.82; 95% CI, 0.51–1.30; P=0.48). HRs were maintained after IPTW. Objective response rates were 5.9% and 16.7% in patients treated with regorafenib and nivolumab, respectively (P=0.04).

Conclusions

After sorafenib failure, the use of nivolumab may be associated with improved OS and better objective response rate as compared to using regorafenib.

The hypoxic tumour microenvironment: A safe haven for immunosuppressive cells and a therapeutic barrier to overcome

Dating back to the seminal work of Paul Ehrlich, the idea of harnessing our immune system to eliminate cancerous cells is now over a century old. In the presence of a functional immune system that so efficiently guards the host against developing neoplasms, tumour cells must evolve sophisticated strategies to escape immune destruction in order to give rise to clinically detectable cancers. A new way of treating cancer would thus be to target the immune system itself rather than the tumour, and extensive studies in randomised trials have cemented the possibility of using immunotherapy for treating advanced-stage cancers. Immunotherapy, however, is only tolerated in a minority of patients and in many cases, patients suffer from adverse immune-related reactions when the immune system goes into overdrive. A primary barrier thwarting the development of effective immunotherapy seems to coalesce into the peculiarities of the tumour microenvironment for which hypoxia is a key feature. Here, we review emerging themes on how hypoxia contributes to immune suppression and obstructs anti-tumour effector cell functions. We discuss the challenges and opportunities relating to the potential for dually targeting hypoxia and the immune system to promote durable and favourable responses in cancer patients.

Immune-based therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third most frequent cause of cancer-related death. The immune-rich contexture of the HCC microenvironment makes this tumour an appealing target for immune-based therapies. Here, we discuss how the functional characteristics of the liver microenvironment can potentially be harnessed for the treatment of HCC. We will review the evidence supporting a therapeutic role for vaccines, cell-based therapies and immune-checkpoint inhibitors and discuss the potential for patient stratification in an attempt to overcome the series of failures that has characterised drug development in this disease area.

Molecular therapies for HCC: Looking outside the box

Over the past decade, sorafenib has been the only systemic agent with proven clinical efficacy for patients with unresectable hepatocellular carcinoma (HCC). Recently, lenvatinib was shown to be non-inferior to sorafenib, while regorafenib, cabozantinib, and ramucirumab were shown to be superior to placebo in patients failing sorafenib. In addition, trials of immune checkpoint inhibitors reported encouraging efficacy signals. However, apart from alpha-fetoprotein, which is used to select patients for ramucirumab, no biomarkers are available to identify patients that may respond to a specific treatment. Different synergisms have been postulated based on the potential interplay between antiangiogenic drugs and immunotherapy, with several clinical trials currently testing this hypothesis. Indeed, encouraging preliminary results of phase I studies of bevacizumab plus atezolizumab and lenvatinib plus pembrolizumab have led to the design of ongoing phase III trials, including both antiangiogenics and immune checkpoint inhibitors in the front-line setting. Other important phase II studies have tested molecular therapies directed against different novel targets, such as transforming growth factor-beta, MET (hepatocyte growth factor receptor), and fibroblast growth factor receptor 4. These studies integrated translational research with the aim of better defining the biological tumour profile and identifying tumour and blood biomarkers that select patients who may really benefit from a specific molecular therapy. Importantly, good safety profiles make these drugs suitable for future combinations. In this review, we discuss the most recent data on novel combination strategies and targets, as well as looking ahead to the future role of molecular therapies in the treatment of patients with advanced HCC.

The immunobiology of hepatocellular carcinoma in humans and mice: Basic concepts and therapeutic implications

Basic and clinical studies have demonstrated the efficacy of immunotherapy, a technical and conceptual breakthrough that has revolutionised cancer treatment. Hepatocellular carcinoma (HCC), a deadly malignancy with aetiologic diversity and a chronic course, is strongly influenced by the immune system, and was recently found to partially benefit from immune-checkpoint inhibitor therapy. Notably, HCC onco-immunology depends on diverse genetic and environmental factors that together shape cancer-promoting inflammation and immune dysfunction - critical processes that control HCC malignant progression and response to therapy. Herein, we summarise the current understanding of liver and HCC onco-immunology obtained through basic studies with mouse models and clinical practice in humans. In particular, we discuss preclinical and clinical findings that implicate immunomodulation as a major factor in HCC development and explain the basis for HCC-targeting immunotherapy.

Emerging agents and regimens for hepatocellular carcinoma

Liver cancer, mostly hepatocellular carcinoma (HCC), is the second leading cause of cancer mortality globally. Most patients need at least one systemic therapy at different phases of their treatment for HCC. Sorafenib was the first agent shown to improve the survival of patients with advanced HCC. A decade after the approval of sorafenib, most agents failed to improve patient survival more than sorafenib. In recent years, treatment practices have changed, with lenvatinib as another first-line treatment choice and regorafenib, ramucirumab, and cabozantinib as second-line treatment options. Anti-PD-1 antibodies, including nivolumab, pembrolizumab, and camrelizumab, have demonstrated promising anti-tumor effects as monotherapy for advanced HCC in phase II clinical trials. The combination of an anti-PD-1 antibody and an anti-angiogenesis agent has shown more potent anti-tumor effects in early phase clinical trials and is now the hotspot in clinical studies. Furthermore, these agents are investigated in combination treatment with surgery or other loco-regional therapies in patients with early or intermediate-stage HCC.

Immune checkpoint inhibitors for hepatocellular carcinoma

The position of immunotherapy as a pillar of systemic cancer treatment has been firmly established over the past decade. Immune checkpoint inhibitors are a welcome option for patients with different malignancies. This is in part because they offer the possibility of durable benefit, even for patients who have failed other treatment modalities. The recent demonstration that immunotherapy is effective for patients with hepatocellular carcinoma (HCC) is a milestone in the history of this recalcitrant disease. The treatment of HCC has been a challenge, and for many years was limited to the tyrosine kinase inhibitor sorafenib and to several novel tyrosine kinase inhibitors that have shown efficacy and have been approved. The current role of immune checkpoint inhibitors in the management of HCC, and how this role is likely to evolve in the years ahead, are key. Other than efforts evaluating single checkpoint inhibitors, potential combination strategies, including combinations with existing local and systemic approaches, including novel therapies are evolving. This is understandably of special interest considering the potential unique immune system of the liver, which may impact the use of immunotherapy in patients with HCC going forward, and how can it be enhanced further.

Insights into the success and failure of systemic therapy for hepatocellular carcinoma

Systemic treatment for hepatocellular carcinoma (HCC) has been boosted by the incorporation of new agents after many negative phase III trials in the decade since the approval of sorafenib. Sorafenib introduced the concept that targeting specific hallmarks of hepatocarcinogenesis could modify the dismal prognosis of this disease, with the drug remaining a cornerstone in the upfront therapy for advanced HCC. The design of clinical trials in this malignancy is complicated by important obstacles related to patient selection, prognostic assessment and the need for endpoints that correlate with improvement in survival outcomes. In addition, the currently used criteria to determine treatment response or progression might prevent physicians from making appropriate clinical judgements and interpreting evidence arising from trials. In this Review, we discuss the advances in systemic therapy for HCC and critically review trial designs in HCC. Although novel therapies, such as new targeted agents and immunotherapies, are being rapidly incorporated, it is paramount to design future clinical trials based on the lessons learned from past failures and successes.

Immunotherapy for hepatocellular carcinoma: recent advances and future perspectives

The introduction of immunotherapies has been a major development in the treatment of many advanced cancers, including hepatocellular carcinoma (HCC). We are entering a new era of systemic therapy for advanced HCC associated with an explosion of clinical trial activity. Data from phase I/II studies of checkpoint inhibitors in advanced HCC have been promising, with durable objective response rates of approximately 20% seen (in both first- and second-line settings) and acceptable safety profiles (including immune-mediated hepatitis). Phase III studies evaluating anti-programmed cell death protein 1 (anti-PD-1) and anti-programmed cell death ligand 1 (anti-PD-L1) antibodies compared with sorafenib are already underway. The potential synergistic effects of anti-PD-1/anti-PD-L1 when used in combination with agents against other checkpoint molecules, systemic therapies, as well as conventional surgical and locoregional therapies are also being explored in upcoming clinical trials. Aside from this, other strategies to harness the immune system, including chimeric antigen receptor-engineered T cells, natural killer cell therapies, and peptide vaccines directed against HCC antigens have entered phase I/II studies. Current limitations of immunotherapies and areas of future research include the accurate assessment and prediction of tumor response, overcoming the immunosuppressive effects of a hypoxic microenvironment, and the management of immune-related hepatitis in patients who already have limited liver reserve.

Considerations of heterogeneity in clinical trials for hepatocellular carcinoma

Introduction: Clinical trials in hepatocellular carcinoma (HCC) exhibit a high degree of heterogeneity. These heterogeneities may lead to unexpected results among clinical trials. Area covered: In this review, we address the heterogeneity noted in early phase HCC trials, trials involving transarterial chemoembolization, and advanced HCC trials. Furthermore, we discuss possible methods to attenuate the detrimental effects of heterogeneity when conducting clinical trials. Expert opinion: Clinical trials in HCC exhibit an inherently high degree of heterogeneity because of various reasons: tumor heterogeneity, different cirrhotic backgrounds, various etiologies of cirrhosis, and geographical differences in practice and expertise. Such heterogeneity may cause imbalance among the enrolled patient population, premature withdrawal from the clinical trial, and variable response to the treatment. In addition, methodological heterogeneity also exists in designing trial protocol and response evaluation. All these factors may eventually lead to conflicting results among clinical trials. Accounting for these heterogeneities is important to foster the success of future trials. In recent years, significant progress with molecular targeted agents and immune checkpoint inhibitors was made in advanced HCC. These new agents are also being tested in clinical trials involving earlier stage HCC and will also face the challenge of these issues.

Enhancing Antitumor Immunity with Antiangiogenic Therapy: A Clinical Model in Renal Cell Carcinoma?

Combination therapies involving antiangiogenic agents plus immune checkpoint inhibitors have recently demonstrated clinical efficacy in advanced renal cell carcinoma (RCC). This commentary summarizes the clinical advances and reviews the potential implications for RCC and other advanced solid tumors.

Programmed cell death protein-1 (PD-1)-targeted immunotherapy in advanced hepatocellular carcinoma: efficacy and safety data from an international multicentre real-world cohort

BACKGROUND

Programmed cell death protein-1-targeted immunotherapy has shown promising results in phase II studies of hepatocellular carcinoma.

AIM

To evaluate safety and efficacy of nivolumab and pembrolizumab in an international, multicentre, real-world cohort of patients with advanced hepatocellular carcinoma.

METHODS

Sixty-five patients treated with nivolumab (n = 34) or pembrolizumab (n = 31) between July 10, 2015 and December 31, 2018 (data cut-off) across six centres in Austria and Germany were retrospectively analysed.

RESULTS

Child-Pugh class A/B/C was 32 (49%)/28 (43%)/5 (8%). Immunotherapy was used as systemic first-/second-/third-/fourth-line treatment in 9 (14%)/27 (42%)/26 (40%)/3 (5%) patients. Fifty-four patients had at least one follow-up imaging and were, therefore, available for radiological response assessment. The overall response and disease control rates were 12% and 49% respectively. Of 52 evaluable patients, four (8%) had hyperprogressive disease. Median time to progression was 5.5 (95% CI, 3.5-7.4) months, median progression-free survival was 4.6 (95% CI, 3.0-6.2) months, and median overall survival was 11.0 (95% CI, 8.2-13.8) months. Most common adverse events were infections (n = 7), rash (n = 6), pruritus (n = 3), fatigue (n = 3), diarrhoea (n = 3) and hepatitis (n = 3). Efficacy and safety results were comparable between Child-Pugh A and B patients; however, median overall survival (OS) was shorter in Child-Pugh B patients (16.7 vs 8.6 months; P = 0.065). There was no difference in terms of efficacy and adverse events between patients who received immunotherapy as first-/second-line and third-/fourth-line respectively.

CONCLUSIONS

Programmed cell death protein-1-targeted immunotherapy with nivolumab or pembrolizumab showed promising efficacy and safety in patients with advanced hepatocellular carcinoma, including subjects with Child-Pugh stage B and patients with intensive pretreatment.

[Treatment of the advanced HCC: A second revolution by using immunotherapy]

The treatment of advanced hepatocellular carcinoma has long been hopeless due to an absence of effective molecules and an underlying cirrhosis, compromising tolerance to conventional chemotherapy. A targeted anti-angiogenic therapy, sorafenib, has been the only option for a decade before new oral molecules have been finally validated. Immunotherapy, intended to correct the immunosuppressive context frequently associated with this tumor, has shown very promising results and could profoundly challenge the therapeutic algorithm of advanced hepatocellular carcinoma.

Targeted and immune therapies for hepatocellular carcinoma: Predictions for 2019 and beyond

Systemic therapy for hepatocellular carcinoma (HCC) has markedly advanced since the survival benefit of a molecular targeted agent, sorafenib, were demonstrated in the SHARP and Asia Pacific trials in 2007. Treatment options for patients with advanced HCC increased by sorafenib, and long-term survival for patients with advanced stage HCC has become possible to some extent. However, development of a more potent first-line novel molecular targeted agent replacing sorafenib and a potent second-line agent after disease progression on or intolerant to sorafenib has been warranted because sorafenib lacks tumor shrinking/necrotizing effects and induces relatively severe adverse events such as hand foot skin reaction. Many agents in the 1st line and 2nd line setting were attempted to develop between 2007 and 2016, but all of these clinical trials failed. On the other hand, clinical trials of 4 agents (regorafenib, lenvatinib, cabozantinib, and ramucirumab) succeeded in succession in 2017 and 2018, and their use in clinical practice is possible (regorafenib and lenvatinib) or underway (cabozantinib and ramucirumab). Furthermore, all of 5 clinical trials of combination therapy with transcatheter chemoembolization (TACE) plus a molecular targeted agent failed to date, however, the combination of TACE and sorafenib (TACTICS trials) was reported to be successful and presented at ASCO in 2018. Phase 3 clinical trials of immune checkpoint inhibitors and a combination therapy of immune checkpoint inhibitors and molecular targeted agents are also ongoing, which suggests treatment paradigm of HCC in all stages from early, intermediate and advanced stage, is expected to be changed drastically in the very near future.