Mechanisms of Primary and Acquired Resistance to Immune Checkpoint Inhibitors in Patients with Hepatocellular Carcinoma

Efficacy of immunotherapy in hepatocellular carcinoma: Does liver disease etiology have a role?

The systemic treatment of hepatocellular carcinoma (HCC) is changing rapidly. After a decade of tyrosine kinase inhibitors (TKIs), as the only therapeutic option for the treatment of advanced HCC, in the last few years several phase III trials demonstrated the efficacy of immune checkpoint inhibitors (ICIs). The combination of the anti-PD-L1 atezolizumab and the anti-vascular endothelial growth factor (VEGF) bevacizumab demonstrated the superiority over sorafenib and currently represents the standard of care treatment for advanced HCC. In addition, the combination of durvalumab (an anti-PD-L1) and tremelimumab (an anti-CTLA4) proved to be superior to sorafenib, and in the same trial durvalumab monotherapy showed non-inferiority compared to sorafenib. However, early reports suggest an influence of HCC etiology in modulating the response to these drugs. In particular, a lower effectiveness of ICIs has been suggested in patients with non-viral HCC (in particular non-alcoholic fatty liver disease). Nevertheless, randomized controlled trials available to date have not been stratified for etiology and data suggesting a possible impact of etiology in the outcome of patients managed with ICIs derive from subgroup not pre-specified analyses. In this review, we aim to examine the potential impact of HCC etiology on the response to immunotherapy regimens for HCC.

Sorafenib and Metronomic Capecitabine in Child-Pugh B patients with advanced HCC: A real-life comparison with best supportive care

BACKGROUND AND AIMS

The efficacy of systemic therapy for unresectable advanced hepatocellular carcinoma (aHCC) has not been proven in patients with Child-Pugh (C-P) B cirrhosis. Nevertheless, in real-world these patients are treated both with tyrosine kinase inhibitors (TKIs) and with metronomic capecitabine (MC). This study aimed to compare sorafenib and MC outcomes versus best supportive care (BSC) in C-P B patients.

METHOD

Between 2008 and 2020, among 774 C-P B patients with aHCC not amenable/responsive to locoregional treatments, 410 underwent sorafenib, 62 MC, and 302 BSC. The propensity score matching method was used to correct the baseline unbalanced prognostic factors.

RESULTS

In the unmatched population, median OS was 9.7 months in patients treated with sorafenib, 8.0 with MC, and 3.9 months with BSC. In sorafenib vs. BSC-matched patients (135 couples), median OS was 7.3 (4.9-9.6) vs. 3.9 (2.6-5.2) months (p<0.001). ECOG-Performance Status, tumor size, macrovascular invasion, AFP, treatment-naive, and sorafenib were independent predictors of survival. In MC vs. BSC-matched patients (40 couples), median OS was 9.0 (0.2-17.8) vs.3.0 (2.2-3.8) months (p<0.001). Median OS did not differ (p = 0.283) in sorafenib vs. MC-matched patients (55 couples).

CONCLUSION

C-P B patients with aHCC undergoing BSC have poor survival. Both Sorafenib and MC treatment improve their prognosis.

Emerging strategy for the treatment of urothelial carcinoma: Advances in antibody-drug conjugates combination therapy

Urothelial carcinoma (UC) is a prevalent malignant tumor involving the urinary system. Although there are various treatment modalities, including surgery, chemotherapy, and immune checkpoint inhibitor (ICI) therapy, some patients experience disease recurrence and metastasis with poor prognosis and dismal long-term survival. Antibody-drug conjugates (ADCs), which combine the targeting ability of antibody drugs with the cytotoxicity of chemotherapeutic drugs, have recently emerged as a prominent research focus in the development of individualized precision cancer therapy. Although ADCs have improved the overall response rate in patients with UC, their effectiveness remains limited. Currently, ADC-based combination therapies, particularly ADC combined with ICIs, have demonstrated promising efficacy. This combination approach has advanced the treatment of UC, exhibiting the potential to become the standard first-line therapy for advanced UC in the future. This article reviewed clinical trials involving ADC-based combination therapy for UC and discussed the possible challenges and future perspectives to provide guidance for the clinical treatment of UC.

Recent Progress in Systemic Therapy for Advanced Hepatocellular Carcinoma

Patients with advanced hepatocellular carcinoma (HCC) have several systemic treatment options. There are many known risk factors for HCC, and although some, such as hepatitis C, are now treatable, others are not. For example, metabolic dysfunction-related chronic liver disease is increasing in incidence and has no specific treatment. Underlying liver disease, drug resistance, and an increasing number of treatment options without specific biomarkers are all challenges in selecting the best treatment for each patient. Conventional chemotherapy is almost never used for advanced-stage disease, which instead is treated with immunotherapy, tyrosine kinase inhibitors, and VEGF inhibitors. Immune checkpoint inhibitors targeting various receptors have been or are currently undergoing clinical evaluation. Ongoing trials with three-drug regimens may be the future of advanced-stage HCC treatment. Other immune-modulatory approaches of chimeric antigen receptor-modified T cells, bispecific antibodies, cytokine-induced killer cells, natural killer cells, and vaccines are in early-stage clinical trials. Targeted therapies remain limited for HCC but represent an area of potential growth. As we shift away from first-line sorafenib for advanced HCC, clinical trial control arms should comprise a standard treatment other than sorafenib, one that is a better comparator for advancing therapies.

Efficacy and safety of subsequent radiotherapy in patients with advanced-stage hepatocellular carcinoma treated with immune checkpoint inhibitors

Background

The development of immunotherapy resistance is associated with a poor prognosis in patients diagnosed with hepatocellular carcinoma (HCC) who are undergoing treatment with immune checkpoint inhibitors (ICI). This study aimed to evaluate the efficacy and safety of subsequent radiotherapy (RT) for patients with advanced-stage HCC who had lesion enlargement or new lesions (NLs) during ICI therapy.

Methods

This retrospective observational study enrolled 36 patients with advanced-stage HCC who underwent subsequent RT for lesion enlargement or NLs during ICI therapy from two centers. The primary endpoints were progression-free survival (PFS) and overall survival (OS). The secondary endpoints included objective response rate (ORR), disease control rate (DCR), 1- and 2-year local control (LC) rates, in-field PFS (IFPFS), out-field PFS (OFPFS), and safety.

Results

The median follow-up time was 15.3 months. The median PFS was 7.4 months [95% confidence interval (CI): 3.1-11.7 months], and the median OS was 18.8 months (95% CI: 17.1-20.5 months). ORR and DCR were 38.9% and 72.2%, respectively. In addition, the median IFPFS was 17.8 months (95% CI: 11.5-24.2 months), median OFPFS was 7.9 months (95% CI: 3.4-12.5 months), and estimated 1- and 2-year LC rates were 67.1% and 31.9%, respectively. The most common treatment-related adverse events (all grades) were diarrhea (33.3%), rash (30.6%), and malaise (27.8%); a total of 14 (38.9%) patients developed grade 3-4 AEs.

Conclusions

Subsequent RT showed reliable antitumor effects and an acceptable safety profile in patients with advanced-stage HCC who had unsatisfactory response to ICI therapy; therefore, it could serve as an optional salvage strategy.

Advances in Immunotherapy for Hepatocellular Carcinoma (HCC)

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related deaths in the world. More than half of patients with HCC present with advanced stage, and highly active systemic therapies are crucial for improving outcomes. Immune checkpoint inhibitor (ICI)-based therapies have emerged as novel therapy options for advanced HCC. Only one third of patients achieve an objective response with ICI-based therapies due to primary resistance or acquired resistance. The liver tumor microenvironment is naturally immunosuppressive, and specific mutations in cell signaling pathways allow the tumor to evade the immune response. Next, gene sequencing of the tumor tissue or circulating tumor DNA may delineate resistance mechanisms to ICI-based therapy and provide a rationale for novel combination therapies. In this review, we discuss the results of key clinical trials that have led to approval of ICI-based therapy options in advanced HCC and summarize the ongoing clinical trials. We review resistance mechanisms to ICIs and discuss how immunotherapies may be optimized based on the emerging research of tumor biomarkers and genomic alterations.

Overall survival of patients with hepatocellular carcinoma treated with sintilimab and disease outcome after treatment discontinuation

BACKGROUND

The use of Anti-PD-1 therapy has yielded promising outcomes in hepatocellular carcinoma (HCC). However, limited research has been conducted on the overall survival (OS) of patients with varying tumor responses and treatment duration.

METHODS

This retrospective study analyzed HCC patients who received sintilimab between January 2019 and December 2020 at four centers in China. The evaluation of tumor progression was based on Response Evaluation Criteria in Solid Tumors version 1.1. The study investigated the correlation between tumor response and OS, and the impact of drug use on OS following progressive disease (PD).

RESULTS

Out of 441 treated patients, 159 patients satisfied the inclusion criteria. Among them, 77 patients with disease control exhibited a significantly longer OS compared to the 82 patients with PD (median OS 26.0 vs. 11.3 months, P < 0.001). Additionally, the OS of patients with objective response (OR) was better than that of patients with stable disease (P = 0.002). Among the 47 patients with PD who continued taking sintilimab, the OS was better than the 35 patients who discontinued treatment (median OS 11.4 vs. 6.9 months, P = 0.042).

CONCLUSIONS

In conclusion, the tumor response in HCC patients who received sintilimab affects OS, and patients with PD may benefit from continued use of sintilimab.

Outcomes of Patients with Advanced Hepatocellular Carcinoma Receiving Lenvatinib following Immunotherapy: A Real World Evidence Study

BACKGROUND

Lenvatinib, a multikinase inhibitor, is an FDA-approved treatment for advanced hepatocellular carcinoma (HCC) in the first-line setting. Recent trial data have established atezolizumab plus bevacizumab as well as tremelimumab plus durvalumab as preferred first-line treatment options for advanced HCC. The role of lenvatinib following progression on immunotherapy in patients with advanced HCC remains unclear.

METHODS

We conducted a multicentric, retrospective analysis of patients with advanced HCC diagnosed between 2010 and 2021 at the Mayo Clinic in Minnesota, Arizona, and Florida who received immunotherapy followed by lenvatinib. Median overall survival and progression-free survival analyses were performed using the Kaplan-Meier method, and responses were determined using RECIST 1.1. Adverse events were determined using CTCAE v 4.0.

RESULTS

We identified 53 patients with advanced HCC who received lenvatinib following progression on immunotherapy. Forty five (85%) patients had a Child Pugh class A at diagnosis, while 30 (58%) patients were still Child Pugh A at time of lenvatinib initiation. Lenvatinib was administered as a second-line treatment in 85% of the patients. The median PFS was 3.7 months (95% CI: 3.2-6.6), and the median OS from the time of lenvatinib initiation was 12.8 months (95% CI: 6.7-19.5). In patients with Child Pugh class A, the median OS and PFS was 14 and 5.2 months, respectively. Race, gender, and Child Pugh class was associated with OS on multivariate analysis.

DISCUSSION

Our study, using real-world data, suggests that patients benefit from treatment with lenvatinib following progression on immunotherapy in advanced HCC. The optimal sequencing of therapy for patients with advanced HCC following progression on immunotherapy remains unknown, and these results need to be validated in a clinical trial.

Recent progress in the immunotherapy of hepatocellular carcinoma: Non-coding RNA-based immunotherapy may improve the outcome

Hepatocellular carcinoma (HCC) is the second most lethal cancer and a leading cause of cancer-related mortality worldwide. Immune checkpoint inhibitors (ICIs) significantly improved the prognosis of HCC; however, the therapeutic response remains unsatisfactory in a substantial proportion of patients or needs to be further improved in responders. Herein, other methods of immunotherapy, including vaccine-based immunotherapy, adoptive cell therapy, cytokine delivery, kynurenine pathway inhibition, and gene delivery, have been adopted in clinical trials. Although the results were not encouraging enough to expedite their marketing. A major proportion of human genome is transcribed into non-coding RNAs (ncRNAs). Preclinical studies have extensively investigated the roles of ncRNAs in different aspects of HCC biology. HCC cells reprogram the expression pattern of numerous ncRNAs to decrease the immunogenicity of HCC, exhaust the cytotoxic and anti-cancer function of CD8 + T cells, natural killer (NK) cells, dendritic cells (DCs), and M1 macrophages, and promote the immunosuppressive function of T Reg cells, M2 macrophages, and myeloid-derived suppressor cells (MDSCs). Mechanistically, cancer cells recruit ncRNAs to interact with immune cells, thereby regulating the expression of immune checkpoints, functional receptors of immune cells, cytotoxic enzymes, and inflammatory and anti-inflammatory cytokines. Interestingly, prediction models based on the tissue expression or even serum levels of ncRNAs could predict response to immunotherapy in HCC. Moreover, ncRNAs markedly potentiated the efficacy of ICIs in murine models of HCC. This review article first discusses recent advances in the immunotherapy of HCC, then dissects the involvement and potential application of ncRNAs in the immunotherapy of HCC.

The effect of liver disease on hepatic microenvironment and implications for immune therapy

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the fourth leading cause of cancer-related death worldwide. HCC often occurs in the setting of chronic liver disease or cirrhosis. Recent evidence has highlighted the importance of the immune microenvironment in the development and progression of HCC, as well as its role in the potential response to therapy. Liver disease such as viral hepatitis, alcohol induced liver disease, and non-alcoholic fatty liver disease is a major risk factor for the development of HCC and has been demonstrated to alter the immune microenvironment. Alterations in the immune microenvironment may markedly influence the response to different therapeutic strategies. As such, research has focused on understanding the complex relationship among tumor cells, immune cells, and the surrounding liver parenchyma to treat HCC more effectively. We herein review the immune microenvironment, as well as the relative effect of liver disease on the immune microenvironment. In addition, we review how changes in the immune microenvironment can lead to therapeutic resistance, as well as highlight future strategies aimed at developing the next-generation of therapies for HCC.

Predicting Outcomes of Atezolizumab and Bevacizumab Treatment in Patients with Hepatocellular Carcinoma

A combination of atezolizumab with bevacizumab (AB) is the first regimen that has shown superiority compared to sorafenib and is now being used as the systemic treatment of choice for hepatocellular carcinoma (HCC) patients with Barcelona Liver Cancer Clinic stage C. However, a considerable number of patients do not achieve survival or significant responses, indicating the need to identify predictive biomarkers for initial and on-treatment decisions in HCC patients receiving AB. In this manuscript, we summarized the current data from both experimental and clinical studies. This review will be beneficial for both clinicians and researchers in clinical practice as well as those designing experimental, translational, or clinical studies.

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

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

Current Landscape of Immune Checkpoint Inhibitor Therapy for Hepatocellular Carcinoma

The liver maintains a balance between immune tolerance and activation in its role as a filtration system. Chronic inflammation disrupts this immune microenvironment, thereby allowing for the rise and progression of cancer. Hepatocellular carcinoma (HCC) is a liver tumor generally diagnosed in the setting of chronic liver disease. When diagnosed early, the primary treatment is surgical resection, liver transplantation, or liver directed therapies. Unfortunately, patients with HCC often present at an advanced stage or with poor liver function, thereby limiting options. To further complicate matters, most systemic therapies are relatively limited and ineffective among patients with advanced disease. Recently, the IMbrave150 trial demonstrated that the combination of atezolizumab and bevacizumab was associated with better survival compared to sorafenib among patients with advanced HCC. As such, atezolizumab and bevacizumab is now recommended first-line therapy for these patients. Tumor cells work to create an immunotolerant environment by preventing the activation of stimulatory immunoreceptors and upregulating expression of proteins that bind inhibitory immunoreceptors. ICIs work to block these interactions and bolster the anti-tumor function of the immune system. We herein provide an overview of the use of ICIs in the treatment of HCC.

Molecular and immune landscape of hepatocellular carcinoma to guide therapeutic decision-making

Liver cancer, primarily HCC, exhibits highly heterogeneous histological and molecular aberrations across tumors and within individual tumor nodules. Such intertumor and intratumor heterogeneities may lead to diversity in the natural history of disease progression and various clinical disparities across the patients. Recently developed multimodality, single-cell, and spatial omics profiling technologies have enabled interrogation of the intertumor/intratumor heterogeneity in the cancer cells and the tumor immune microenvironment. These features may influence the natural history and efficacy of emerging therapies targeting novel molecular and immune pathways, some of which had been deemed undruggable. Thus, comprehensive characterization of the heterogeneities at various levels may facilitate the discovery of biomarkers that enable personalized and rational treatment decisions, and optimize treatment efficacy while minimizing the risk of adverse effects. Such companion biomarkers will also refine HCC treatment algorithms across disease stages for cost-effective patient management by optimizing the allocation of limited medical resources. Despite this promise, the complexity of the intertumor/intratumor heterogeneity and ever-expanding inventory of therapeutic agents and regimens have made clinical evaluation and translation of biomarkers increasingly challenging. To address this issue, novel clinical trial designs have been proposed and incorporated into recent studies. In this review, we discuss the latest findings in the molecular and immune landscape of HCC for their potential and utility as biomarkers, the framework of evaluation and clinical application of predictive/prognostic biomarkers, and ongoing biomarker-guided therapeutic clinical trials. These new developments may revolutionize patient care and substantially impact the still dismal HCC mortality.

Immune Checkpoint Inhibitors in Hepatocellular Carcinoma: Current Strategies and Biomarkers Predicting Response and/or Resistance

In recent years, immune checkpoint inhibitors (ICIs) have revolutionized the treatment of patients with hepatocellular carcinoma (HCC). Following the positive results of the IMbrave150 trial, the combination of atezolizumab (an anti-PD-L1 antibody) and bevacizumab (an anti-VEGF antibody) became the standard of care frontline treatment for patients with advanced stage HCC. Several other trials evaluated immunotherapy in HCC, demonstrating that ICIs-based regimens are currently the most effective treatment strategies and expanding the therapeutic possibilities. Despite the unprecedent rates of objective tumor response, not all patients benefit from treatment with ICIs. Therefore, in order to select the appropriate therapy as well as to correctly allocate medical resources and avoid unnecessary treatment-related toxicities, there is great interest in identifying the predictive biomarkers of response or resistance to immunotherapy-based regimens. Immune classes of HCC, genomic signatures, anti-drug antibodies, and patient-related factors (e.g., etiology of liver disease, gut microbiota diversity) have been associated to the response to ICIs, but none of the proposed biomarkers have been translated into clinical practice so far. Considering the crucial importance of this topic, in this review we aim to summarize the available data on tumor and clinical features associated with the response or resistance of HCC to immunotherapies.

Resistance to Antiangiogenic Therapy in Hepatocellular Carcinoma: From Molecular Mechanisms to Clinical Impact

Antiangiogenic drugs were the only mainstay of advanced hepatocellular carcinoma (HCC) treatment from 2007 to 2017. However, primary or secondary resistance hampered their efficacy. Primary resistance could be due to different molecular and/or genetic characteristics of HCC and their knowledge would clarify the optimal treatment approach in each patient. Several molecular mechanisms responsible for secondary resistance have been discovered over the last few years; they represent potential targets for new specific drugs. In this light, the advent of checkpoint inhibitors (ICIs) has been a new opportunity; however, their use has highlighted other issues: the vascular normalization compared to a vessel pruning to promote the delivery of an active cancer immunotherapy and the development of resistance to immunotherapy which leads to a better selection of patients as candidates for ICIs. Nevertheless, the combination of antiangiogenic therapy plus ICIs represents an intriguing approach with high potential to improve the survival of these patients. Waiting for results from ongoing clinical trials, this review depicts the current knowledge about the resistance to antiangiogenic drugs in HCC. It could also provide updated information to clinicians focusing on the most effective combinations or sequential approaches in this regard, based on molecular mechanisms.