
==== Front
JHEP Rep
JHEP Rep
JHEP Reports
2589-5559
Elsevier

S2589-5559(24)00134-4
10.1016/j.jhepr.2024.101130
101130
Review
Immunotherapy for hepatocellular carcinoma
Childs Alexa 12
Aidoo-Micah Gloryanne 12
Maini Mala K. 2
Meyer Tim t.meyer@ucl.ac.uk
13⁎
1 Department of Medical Oncology, Royal Free Hospital, London, UK
2 Division of Infection and Immunity, Institute of Immunity and Transplantation, University College London, London, UK
3 UCL Cancer Institute, University College London, UK
⁎ Corresponding author. Address: Department of Medical Oncology, Royal Free Hospital, London, NW3 2QG, UK. t.meyer@ucl.ac.uk
09 6 2024
10 2024
09 6 2024
6 10 10113010 4 2024
19 5 2024
28 5 2024
© 2024 The Authors
2024
https://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Summary

Hepatocellular carcinoma (HCC) is a major global healthcare challenge, with >1 million patients predicted to be affected annually by 2025. In contrast to other cancers, both incidence and mortality rates continue to rise, and HCC is now the third leading cause of cancer-related death worldwide. Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape for advanced HCC, with trials demonstrating a superior overall survival benefit compared to sorafenib in the first-line setting. Combination therapy with either atezolizumab (anti-PD-L1) and bevacizumab (anti-VEGF) or durvalumab (anti-PD-L1) and tremelimumab (anti-CTLA-4) is now recognised as standard of care for advanced HCC. More recently, two phase III studies of ICI-based combination therapy in the early and intermediate disease settings have successfully met their primary end points of improved recurrence- and progression-free survival, respectively. Despite these advances, and in contrast to other tumour types, there remain no validated predictive biomarkers of response to ICIs in HCC. Ongoing research efforts are focused on further characterising the tumour microenvironment in order to select patients most likely to benefit from ICI and identify novel therapeutic targets. Herein, we review the current understanding of the immune landscape in which HCC develops and the evidence for ICI-based therapeutic strategies in HCC. Additionally, we describe the state of biomarker development and novel immunotherapy approaches in HCC which have progressed beyond the pre-clinical stage and into early-phase trials.

Keywords:

hepatocellular carcinoma
immunotherapy
checkpoint inhibitors
tumour microenvironment
biomarkers
adoptive cell therapy
==== Body
pmc Key points

• Hepatocellular carcinoma (HCC) arises in a highly tolerogenic organ, on a background of chronic inflammation +/- fibrotic scarring; these influences compound the tolerogenic tumour niche.

• Further research is needed to fully characterise the range of potential therapeutic targets on immune effectors and immune suppressors in early vs. advanced HCC.

• Combination therapy with an anti-PD-L1 backbone and either an anti-CTLA-4 immune checkpoint inhibitor (ICI) or anti-VEGF therapy remains standard of care in the first-line setting for advanced HCC.

• Recent phase III trials suggest that anti-PD-L1 in combination with bevacizumab may be effective in intermediate-stage disease when combined with transarterial chemoembolisation, and as adjuvant therapy following resection.

• To date, no predictive biomarkers have been prospectively validated or approved for ICIs in HCC.

• Strategies in development including alternative ICIs, bispecific antibodies and adoptive cell therapies are likely to further re-shape the treatment landscape of HCC.

Introduction

Hepatocellular carcinoma (HCC) constitutes >90% of primary liver cancers and represents an increasing global health challenge, with over one million individuals predicted to be affected annually by 2025.1 The majority of HCC arises in the context of chronic liver disease and geographical incidence varies according to the prevalence of well-described viral and non-viral risk factors. Within Europe there has been a 70% increase in liver cancer-related mortality between 1990 and 2019, partly attributable to the rise in cirrhosis secondary to MASLD (metabolic dysfunction-associated steatotic liver disease).2 Late presentation with advanced disease and high recurrence rates or progression following surgical resection or locoregional therapy mean that approximately 50-60% of all patients will ultimately go on to receive systemic therapy for HCC.3 The therapeutic landscape of advanced HCC has changed significantly in recent years, with five tyrosine kinase inhibitors (TKIs) and an anti-vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) monoclonal antibody now approved across both the first- and second-line settings. However, the advent of immunotherapy, and more specifically immune checkpoint inhibitors (ICIs), has transformed the management of advanced HCC and become the backbone of current drug development strategies. First-line treatment with the combination of atezolizumab (anti-programmed death ligand 1 [PD-L1] antibody) and bevacizumab (anti-VEGF antibody) in advanced disease is associated with median survival of approximately 19 months and an objective response rate (ORR) of 30%, thus representing the standard of care to which new regimens are compared.4 Research efforts are now focused on improving the survival benefit seen with ICI-based therapy, investigating whether outcomes can also be improved in earlier disease settings and identifying predictive biomarkers of response. In this review, we provide an overview of the immune microenvironment of HCC and the current evidence base for ICI across all clinical stages of HCC. We end by discussing whether predictive biomarkers can help in selecting those patients most likely to benefit from treatment, and novel directions for future immunotherapy-based treatment in HCC.

The immune landscape of HCC

HCC differs from other cancers in that the majority of cases arise on the background of a diseased organ, with chronic necro-inflammation, often accompanied by fibrosis or cirrhosis, therefore likely to be dominant influences on tumour immunity.5 Chronic inflammation is itself indicative of a sub-optimal immune response and a harbinger for tumour initiation, proliferation and progression.6,7 Moreover, the liver has a constitutively tolerogenic immune milieu, mediated by a variety of mechanisms that may be co-opted to further compound the typical immunosuppressive niche found in tumours.8,9 This immunotolerance limits the induction of immunity against innocuous antigens but predisposes the liver to immune evasion by hepatotropic carcinogenic viruses (such as HBV and HCV) and cancer cells alike. In HCC, transformed hepatocytes can therefore avoid immune clearance through complex mechanisms of augmented immune suppression.

The immune system plays a dual role in cancer; suppression of tumour growth (by effector cells) and promotion of tumour progression (by immunosuppressive cells) (Fig. 1); thorough assessment of these should help guide prognostic and immunotherapeutic targets.[7], [10] The balance between immune activation and evasion is determined by the opposing action of these cellular components and their soluble mediators, and their relative composition within the tumour microenvironment (TME) has been used to define four subclasses of HCC with distinct clinical outcomes.11 There have been significant advances in understanding the full range of HCC immune effectors and inhibitors, particularly by single-cell transcriptomic studies,[12], [13], [14] but these need to be complemented by proteomic and spatial analyses, and improved access to tumour tissue from advanced disease, in addition to early, resectable disease.[15], [16], [17]Fig. 1 The local HCC immune landscape can be divided into immune effectors and immune regulators.

The local HCC immune landscape can be divided into immune effectors that can respond to HCC by producing a variety of mediators with anti-tumour potential (e.g. tissue-resident T cells, left top and middle panel) and immune regulators that suppress and/or exclude these immune effectors through membrane-bound checkpoint inhibitors (e.g. PD-L1) and soluble mediators (e.g. TGF-b, right top and middle panel). The balance of these opposing activities results in tumour control or growth, respectively. The goal of immunotherapies is to overcome immune exclusion/cold tumours (right bottom panel) and block negative immune regulators to allow influx and function of immune effectors for tumour shrinkage (bottom left panel). Key cellular subsets, soluble mediators and structural elements contributing to these processes are shown. Immune hot tumour – red tumour, immune cold/excluded tumour – blue (bottom panels). CAF, cancer-associated fibroblast; DC, dendritic cell; gMDSC, granulocytic myeloid derived suppressor cell; IL-, interleukin; IDO, idoleamine 2,3 dioxygenase; IFN-y, interferon γ; MAIT cell, mucosal-associated invariant T cell; mMDSC, monocytic myeloid derived suppressor cell; NK cell, natural killer cell; TAM, tumour associated macrophage; TGFβ, transforming growth factor-β; TLS, tertiary lymphoid structure; TNF-α, tumour necrosis factor-α; Treg, regulatory T cell; TRM, tissue resident memory; VEGF, vascular endothelial growth factor.

Fig. 1

Immune suppressors of the antitumour response

Conventional regulatory subsets including regulatory T cells (Tregs), tumour-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) are abundant in HCC and cooperate with stromal cells to preserve an immunosuppressive TME. Tregs can promote self-tolerance and suppress excessive immune activation via mechanisms including the production of inhibitory cytokines (e.g. interleukin [IL]-10, IL-35 and transforming growth factor-β [TGFβ]), direct cytolysis and metabolic disruption.18 Tregs are present in higher numbers within the peripheral blood and TME of HCC compared to normal liver, and higher infiltration corresponds with higher grade tumours, lower disease-free and overall survival (OS).[11], [19], [20]

TAMs cooperate with cancer-associated fibroblasts to form an immune barrier exclusionary to effector cells.21 They can additionally recruit Tregs via production of chemokines and further promote immune evasion via the production of immunosuppressive cytokines such as IL-10, expression of the inhibitory checkpoint ligand PD-L1, and downregulation of MHC II/costimulatory molecules required for successful CD8+ T-cell activation.[9], [10], [22] The presence of TAMs correlates with a worse prognosis in HCC, especially if skewed toward an M2 phenotype.[14], [21], [23]

MDSCs are a heterogeneous population of immunosuppressive immature myeloid cells (monocytic or granulocytic), which are abundant in the liver and increased in the peripheral blood of patients with HCC.[24], [25], [26] They promote local Treg differentiation from CD4+ T cells and suppress CD8+ T cell and natural killer (NK) cell activation through mediators such as TGFβ and arginase.27 Granulocytic MDSCs overlap with immunosuppressive neutrophils that also accumulate in HCC and represent novel immunotherapy targets.28 Other immunosuppressive cell types that have been described in HCC include a subset of B cells that express PD1 and have regulatory functions, CCR4- and CCR6-expressing T helper 17 cells, and tolerogenic dendritic cells expressing high levels of CTLA-4 and PD1.[29], [30], [31], [32]

Immune effectors of the antitumour response

Infiltrating and tissue-resident CD8+ T cells are the primary effectors of the antitumour immune response, and their presence correlates with improved prognosis and response to treatment.[33], [34], [35] However, CD8+ T cells are often highly dysfunctional within the HCC TME and thus ineffective at tumour clearance. Single-cell studies have shown both a reduction in the number of effector CD8+ cells, as well as a more pronounced “exhaustion” phenotype;12 enrichment of exhausted CD8+ T cells at the expense of tissue-resident memory cells is linked to poor survival.34

Exhausted CD8+ T cells can express multiple inhibitory receptors such as programmed death 1 (PD-1), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), TIM-3 (also known as HAVCR2), lymphocyte-activating 3 (LAG3) and T cell immunoreceptor with Ig and ITIM domains (TIGIT), which serve as targets for immune checkpoint blockade.[36], [37] Improved understanding of their hierarchical expression by tumour sampling could direct personalised ICI selection in the future. Other key anti-tumour effectors, such as NK cells and γδ T cells, also display an exhausted phenotype, including an exhausted functional and metabolic profile,[37], [38], [39], [40], [41] and represent potential targets for future HCC immunotherapy. A potential contribution of B cells and tertiary lymphoid structures to HCC outcomes is also emerging (Fig. 1).[42], [43]

Influence of cytokines and other soluble mediators

The HCC TME is enriched in cytokines and other soluble mediators that pleiotropically modulate the composition and function of the immune cells present in HCC. TGFβ, IL-10, IL-6, indoleamine 2,3-dioxygenase and arginase secreted by various cell types in the TME promote immunosuppression. For example, TGFβ produced by tumour cells, macrophages, cancer-associated fibroblasts and Tregs downregulates the antitumour response at different levels, including activation of tolerogenic dendritic cells, M2 polarisation of TAMs, suppression of CD8+ T and NK cells, and generation of Tregs.44 High tissue expression of TGFβ is associated with poor prognosis in HCC, and high circulating levels correlate with poorer response to sorafenib and pembrolizumab.[45], [46], [47] Conversely, pro-inflammatory cytokines such as IL-2, interferon (IFN)-y, chemokine C-X-C motif ligand (CXCL)10 and CXCL9 attract effector cells to mount an antitumour response, with IFN-y driving PD-L1, and activation of these pathways has been shown to predict a favourable response to immune checkpoint inhibition.[9], [48], [49] Hence, the interplay of these mediators shapes the immune composition and its ensuing response.

Impact of aetiology

Diverse immune mechanisms have been implicated in driving liver damage and/or immunosuppression according to the underlying aetiology,[10], [50], [51], [52] but to what extent these are specifically co-opted when tumours arise in these diverse backgrounds is not yet clear. For example, CXCR6+ CD8 T cells implicated in MASH (metabolic dysfunction-associated steatohepatitis)-related immunopathology53 and potential resistance to PD-1 blockade50 can also mediate bystander damage in HBV.54 Similarly, the efficacy of aspirin in HCC prevention55 may be underpinned by common or distinct immunological roles for platelets described in HCC arising in HBV56 and MASLD.57 Direct comparative studies will be needed to determine the contribution of distinct aetiology-driven immune mechanisms to HCC immunopathogenesis and immunotherapy.37

Antigenicity of HCC

Anti-HCC T-cell immunity may be elicited via the abnormal expression of oncofetal and cancer testis antigen genes (AFP, GPC3, MAGE-1 and NYESO1), viral peptide, or tumour-specific neoantigens. CD8+ T cells specific for alpha-fetoprotein (AFP), glypican 3 (GPC3), MAGE-1 (melanoma associated gene 1) and NYESO1 (New York oesophageal squamous cell carcinoma 1) can be detected in the blood and tumours of patients with HCC, and positively correlate with patient survival.[33], [58] In HBV/HCV-associated tumours, neoantigens can be generated by virally encoded open reading frames.[59], [60] Alternatively, genomic mutations may produce tumour-specific neoantigens that can induce naturally occurring anti-tumour T-cell responses. In HCC, circulating CD8 T cells targeting neoantigens are only detected in ∼15% of patients,[33], [59] stimulating interest in developing gene-modified cell therapies directed at HCC neoantigens.

Immune checkpoint inhibition in HCC

Advanced-stage HCC

Single agent

In both the first- and second-line setting, single-agent immune checkpoint inhibition focuses predominantly on the therapeutic targeting of PD-(L)1 to restore effector CD8+ T-cell function. Initial phase II data for pembrolizumab and nivolumab following first-line sorafenib demonstrated encouraging response rates of 18% and 14% (per RECIST v1.1 criteria) with a prolonged median duration of response (DOR) of 21 and 39.7 months, respectively.[61], [62], [63], [64] The subsequent phase III studies of nivolumab (CheckMate 459) and pembrolizumab (KEYNOTE-240) confirmed the activity and safety of these drugs in the first- and second-line setting, respectively (Table 1), but failed to demonstrate an OS benefit according to pre-defined statistical thresholds when compared to sorafenib or placebo.[65], [66] In contrast, the phase III KEYNOTE-394 study, conducted in an Asian population, demonstrated a statistically significant improvement in both median OS (14.6 vs. 13 months; hazard ratio [HR] 0.79; 95% CI 0.63-0.99; p = 0.018) and ORR (12.7 vs. 1.3%) for pembrolizumab vs. placebo in the second line.67 A subsequent meta-analysis showed consistent outcomes between the two KEYNOTE studies [41], and it is likely that the statistical design of KEYNOTE 240, including the use of dual primary endpoints of progression-free survival (PFS) and OS and two interim analyses, contributed to its failure to meet the pre-defined criteria for positivity.68 Further evidence for the efficacy and safety of single-agent ICI comes from the phase III HIMALAYA trial, in which OS with durvalumab monotherapy was shown to be non-inferior to sorafenib (HR 0.86, 95% CI 0.73-1.03, non-inferiority margin, 1.08) with an improved toxicity profile.69 Similarly, the RATIONALE-301 study demonstrated the non-inferiority of tislelizumab with sorafenib in the first-line setting (HR 0.85, 95% CI 0.71–1.02).70 This study, in keeping with other ICI studies, demonstrated a higher ORR rate (14.3 vs. 5.4%) and median DOR for the immunotherapy arm (36.1 months, 95% CI 18.8 to not evaluable, vs. 11 months, 95% CI 6.2-14.7).Table 1 Phase III trials evaluating ICI across HCC stages.

Table 1Trial (Ref)	No patients	mRFS (months)	HR RFS	ORR%	mDOR (months)	mPFS (months)	HR PFS	mOS (months)	HR OS	TRAE leading to discontinuation % (% discontinuing ICI alone)	
Adjuvant	
IMbrave 05079	
 Atezolizumab/bevacizumab	334	NE	0.72	NE	NE	NE	NE	NE	NE	9	
 Surveillance	334	NE									
Intermediate stage	
EMERALD-189	
 TACE + durvalumab + bevacizumab	204			43.6	NE	15	0.77	NE	NE	8.4	
 TACE + durvalumab	207			41		10	0.94			4.3	
 TACE	205			29.6		8.2				3.5	
Advanced disease	
IMbrave1504	
 Atezolizumab/bevacizumab	336			30	NE	6.9	0.65	19.2	0.66	22 (10)	
 Sorafenib	165			11	NE	4.3		13.4		12	
ORIENT-3272	
 Sintilimab/bevacizumab biosimilar	380			21	NE	4.6	0.56	NR	0.57	14	
 Sorafenib	191			4	9.8	2.8		10.5		6	
HIMALAYA69	
 Tremelimumab/durvalumab	393			21.1	22.3	5.4	0.9	16.4	0.78	14	
 Durvalumab	389			17	16.8	3.8	1.02	16.6	0.86	8	
 Sorafenib	389			5	18.4	5.6		13.7		17	
COSMIC-31273	
 Atezolizumab/cabozantanib	432			11	12.4	6.8	0.63	15.4	0.9	14 (6)	
 Sorafenib	217			4	8.4	4.2		15.5		8	
LEAP-00274	
 Pembrolizumab/lenvatinib	395			26	16.6	8.2	0.87	21.2	0.84	18 (6)	
 Lenvatinib	399			17	10.4	8		19		11(5)	
RATIONALE -30170	
 Tislelizumab	342			14.3	36.1	2.1	1.11	15.9	0.85	10.9	
 Sorafenib	332			5.4	11	3.4		14.1		18.5	
CheckMate 45965	
 Nivolumab	371			15	23.3	3.7	0.93	16.4	0.85	7	
 Sorafenib	372			7	23.4	3.8		14.7		11	
CARES-31075	
 Camrelizumab/rivoceranib	272			25	14.8	5.6	0.52	22.1	0.62	24 (4)	
 Sorafenib	271			6	9.2	3.7		15.2		4	
(m)DOR, (median) duration of response; HCC, hepatocellular carcinoma; HR, hazard ratio; ICI, immune checkpoint inhibitor; NE, not evaluable; NR, not reached; ORR, objective response rate; (m)OS, (median) overall survival; (m)PFS, (median) progression-free survival; (m)RFS, (median) recurrence-free survival; TACE, transarterial chemoembolisation; TRAE, treatment-related adverse event.

Combination therapy

Whilst ICI monotherapy in advanced HCC has shown encouraging response rates, it has failed to consistently translate into significant improvements in OS. To address this, efforts have focused on developing novel combinations consisting of an anti-PD-(L)1 backbone and (a) monoclonal antibody/multikinase inhibitors with activity against VEGF(R) or (b) additional immune checkpoint inhibition (Table 1). There is a good rationale for combining VEGF/PD-(L)1 blockade in HCC, given the pre-existing evidence of anti-angiogenic efficacy in HCC and the role of VEGF(R) in maintaining an immunosuppressive TME. The phase III IMbrave-150 study of atezolizumab (anti-PD-L1) and bevacizumab (anti-VEGF) therapy was the first to demonstrate a survival benefit over sorafenib in the first-line setting and has become the standard of care in advanced HCC.4 Updated efficacy data has shown a median OS of 19.2 months (95% CI 17-23.7) in the atezolizumab/bevacizumab arm compared to 13.4 months (95% CI 11.4-16.9; stratified HR 0.66, 95% CI 0.52-0.85, p <0.001) in the sorafenib arm.71 Furthermore, the ORR was significantly improved with this combination (30% vs. 11%, p <0.001) with a median DOR of 18.1 months (95% CI 14.6-not evaluable) for atezolizumab/bevacizumab and 14.9 months (95% CI 4.9-17.0) for sorafenib. Consistent with this, the phase III ORIENT-32 study, which compared the combination of sintilimab (PD-L1 inhibitor) and IBI305 (a bevacizumab biosimilar) to sorafenib in a Chinese patient population, demonstrated an OS benefit for combination therapy (HR 0.57, 95% CI 0.43-0.75).72 In contrast, phase III studies evaluating PD-(L)1 with TKI therapy have shown variable results to date. The combination of cabozantinib plus atezolizumab failed to show an OS benefit in the first-line setting compared with sorafenib (15.4 months, 96% CI 13.7–17.7, vs. 15.5 months, 96% CI 12.1–not estimable) and reported disappointing response rates of 11% for the combination therapy.73 LEAP-002 also failed to meet prespecified significance for improved OS when evaluating lenvatinib and pembrolizumab in combination vs. lenvatinib alone (21.2 vs. 19.0 months, HR 0.84, 95% CI 0.71-1.00, stratified log-rank p = 0.023), in part explained by the unexpectedly long survival of patients in the lenvatinib arm.74 However, the combination of camrelizumab (anti-PD-1) and rivoceranib in the first-line setting was recently reported to be associated with a median OS of 22.1 months, the longest observed for any systemic therapy in the first-line setting for advanced HCC, and statistically superior to sorafenib (22.1 months, 95% CI 19.1-27.2, vs. 15.2 months, 95% CI 13.0-18.5; HR 0.62, 95% CI 0.49-0.80, one-sided p <0.0001).75 The study was conducted in a predominantly Asian population, with over 70% of patients having HBV-related liver disease and the outcome of global regulatory review is awaited.

Combining different ICIs has also been explored. The first study to provide evidence of the efficacy of targeting both CTLA-4 (ipilimumab) and PD-1 (nivolumab) in advanced HCC was the phase I/II CheckMate 040.76 This demonstrated a promising response rate of 32% in arm A (nivolumab 1 mg/kg plus ipilimumab 3 mg/kg once every 3 weeks) in the second-line setting and the phase III CheckMate 9DW has recently reported meeting its primary endpoint of OS benefit compared to sorafenib or lenvatinib in the first-line setting (NCT04039607). Combined blockade of CTLA-4 and PD-L1 in the STRIDE regimen (tremelimumab and durvalumab, respectively) has also shown benefit over sorafenib in the first-line setting.69 In the phase III HIMALAYA study, median OS in the STRIDE arm was 16.4 months (95% CI 14.1-19.5) vs. 13.7 months (95% CI 12.2-16.1) for sorafenib, with a superior ORR of 20.1% vs. 5.1%. Recently, longer term follow-up data has been reported for the HIMALAYA trial and this has confirmed a durable survival benefit of 25.2% at 4 years vs.15.1% for sorafenib.77

Early-stage disease

Adjuvant setting

Following the success of the atezolizumab/bevacizumab regimen in advanced HCC, interest has extended to the application of ICI in restoring anti-tumour cellular immune function in the adjuvant setting and four global phase III trials investigating this concept opened in parallel.78 IMbrave-050 is the first trial to have reported and demonstrated an improved RFS with atezolizumab/bevacizumab therapy, with a hazard ratio of 0.72 (adjusted 95% CI 0.53–0.98, p = 0.012) at the first pre-determined interim analysis, amounting to an absolute risk reduction of 12.5% (95% CI 5.6-19.5) at 12 months.79 Eligible patients were classified as high risk for recurrence according to criteria incorporating the number and size of tumours, as well as histological criteria such as the presence of microvascular invasion or poorly differentiated tumours. The event to patient ratio for survival was only 7% and further follow-up will be required in order to address the secondary endpoint of OS. Of note, 61% of the surveillance group who met the RFS event had already crossed over to atezolizumab and bevacizumab at the time of publication. Recently, in an open label phase II trial conducted in six centres in China, sintilimab (anti-PD-1) was also shown to prolong RFS in patients with microvascular invasion when compared to active surveillance after hepatic resection (median RFS, 27.7 vs. 15.5 months; hazard ratio 0.534, 95% CI 0.360–0.792; p = 0.002).80 Notably, adjuvant therapy was given for 6 months compared to 12 months in IMbrave-050. The shorter duration of therapy could offer financial and quality of life benefits to patients and extend therapy to those with contraindications to bevacizumab. However, in both studies the majority or entirety of patients were Asian and most had hepatitis B-related liver disease. There are outstanding questions as to how this result can be applied to a Western population. The results reported to date demonstrate an early efficacy signal for ICIs as adjuvant therapy, but further follow-up and additional trial readouts (NCT03383458, NCT03867084 and NCT03847428) will reveal the extent and durability of the benefit.

Neoadjuvant and perioperative setting

Neoadjuvant or perioperative immunotherapy strategies are particularly attractive in HCC, where up to 70% of patients with early-stage disease amenable to surgical resection recur within 5 years and adjuvant sorafenib therapy has failed to show any benefit.[81], [82] There is a biological rationale for immunotherapy in this setting, where increased exposure to tumour-specific neoantigens whilst the disease remains in situ may enhance development of anti-tumour immunity. Critically, preoperative therapy also allows for an assessment of drug sensitivity, which may inform the selection of post-operative therapy. Several early-phase trials predominantly targeting patients with upfront resectable disease have been reported to date, with major pathological response rates varying between 17.6% and 33%.[13], [83], [84] A meta-analysis of nine studies (including 193 patients) demonstrated a median major pathological response rate of 27.3% with no single ICI identified as superior in subgroup analysis.85 In a phase II study of neoadjuvant nivolumab or ipilimumab-nivolumab, 6 of the 20 patients who underwent resection had a major pathological response, defined as ≥70% necrosis, and importantly none had recurred at 26.8 months of follow-up.83 As predicted from data in the advanced setting, the rate of Grade 3/4 immunotherapy-related adverse events was significantly higher in the combination arm (6 [43%] of 14 patients) than in the nivolumab alone arm (3 [23%] of 13; difference 20%, 95% CI −14.7% to 38.7, p = 0.69); however, no patients had surgery delayed due to this. Across early phase trials, the incidence of grade ≥3 treatment-related adverse events has varied from 10-30%, with a low surgical delay rate of 1.7% (95% CI 0–4.1%).85 However, it is important to note that, in several studies, a significant proportion of patients did not proceed to surgery due to disease progression or other factors, thus the reported pathological response rate is in the per protocol rather than the intention to treat population. There are several ongoing early phase trials investigating ICIs for resectable or borderline resectable HCC. Beyond PD-1 and CTLA-4 blockade, combination strategies incorporating antibodies or TKIs targeting VEGFRs are also being explored. An example of this is the multi-centre PRIMER-1 study, where participants are randomised to 6 weeks of neoadjuvant therapy consisting of pembrolizumab, lenvatinib or pembrolizumab/lenvatinib, followed by a year of adjuvant pembolizumab post-operatively (NCT05185739). These studies will further define the role of immunotherapy in the neoadjuvant or perioperative setting.

Intermediate-stage disease

Locoregional therapies remain the mainstay of treatment for those with intermediate-stage HCC, or early disease not suitable for surgery or ablation. In view of the prolonged OS benefit seen in the advanced setting, combination therapies targeting both PD(L)1 and VEGFR are now also being investigated in multinodular intermediate-stage disease, with locoregional therapies as the control arm (NCT04803994, NCT04777852). There is also a good biological rationale for combining immunotherapy with locoregional treatment, as embolisation can induce tumour necrosis and enhance tumour antigen presentation.[86], [87], [88] There are several ongoing studies investigating whether clinical outcomes with locoregional therapy can be improved upon by combining with immunotherapy, either as a monotherapy (NCT04268888, NCT04340193) or in combination with anti-VEGF(R)-directed therapy including bevacizumab, lenvatinib and regorafenib (NCT04712643, NCT04340193, NCT04246177). To date, the only study to have reported is EMERALD-1, a global double-blind, randomised, placebo-controlled phase III trial of durvalumab plus transarterial chemoembolisation (TACE) concurrently, followed by durvalumab with or without bevacizumab vs. TACE plus placebo(s) in 616 patients with unresectable HCC eligible for embolisation. The study met its primary endpoint, with a significant PFS benefit for TACE plus durvalumab and bevacizumab vs. the TACE control (median PFS 15.0 vs. 8.2 months; HR 0.77, 95% CI 0.61–0.98, p = 0.032).89 The full results are awaited and further follow-up will be required to address the secondary endpoint of OS; however, these initial results may indicate a new role for immunotherapy in intermediate-stage disease, whilst also raising questions about the implications for first-line treatment options in the advanced-stage setting.

Biomarkers

Despite improved clinical outcomes in advanced HCC following the introduction of ICIs, only 30% of patients achieve an objective response and the majority progress. Consequently, there have been intensive efforts to define predictive biomarkers that could inform clinical decision making, reduce unnecessary toxicity and improve overall cost benefit at a population level. For this purpose, it is important to distinguish biomarkers that are merely prognostic, while the methodology for validation of predictive markers has been clearly defined.90 Similarly, those biomarkers which are merely associated with response, such as fall in AFP, are less valuable since they can only be measured after a treatment decision has been made. To date, the only predictive biomarker that has been validated in a prospective randomised trial is baseline AFP for the use of ramucirumab.91 However, a range of potential biomarkers have been evaluated in retrospective series and as exploratory endpoints in the context of prospective clinical trials.

Clinical factors

Subgroup analysis of IMbrave-150 trial suggested that patients with non-virally associated HCC did not have the same survival benefit with ICIs as those with HBV/HCV-associated HCC.4 Additionally, studies using preclinical models of MASH-induced HCC showed lack of response to anti-PD-1 therapy and, when used prophylactically, led to an increased incidence of HCC associated with an increase in hepatic CD8+PD-1+CXCR6+ T cells.50 However, data from numerous trials including IMbrave-150 demonstrate a similar radiological response between viral and non-viral HCC.[4], [61], [92] Moreover, a recent meta-analysis of eight randomised phase III trials confirmed survival benefit for patients treated with ICI-based therapy compared with TKI controls. Based on current data there is insufficient evidence that background liver disease aetiology can be used to predict response to ICIs.93

The CRAFITY score has been proposed as a predictive biomarker for responses to ICI treatment in HCC. Using baseline AFP and C-reactive protein, three categories are defined which correlated with survival in patients with HCC treated with anti-PD-(L)1 therapy in both a training and validation cohort.94 However, the score was similarly correlated with survival in a sorafenib-treated cohort suggesting that it is generally prognostic. There was some association with radiological response rate, which ranged from 29% in CRAFITY-low to 17% in CRAFITY-high, but this is not sufficient basis on which to make a treatment decision and the score requires prospective validation.

Tumour mutational burden and PD-L1 expression

Tumour mutational burden (TMB) quantifies the number of mutations per megabase (Mb) in the tumour genome, and those with a high TMB (TMB-H) tend to have more immunogenic neoantigens and greater sensitivity to anti-PD-(L)1 therapy. In 2020, based on a single arm trial in lung cancer, the FDA approved pembrolizumab for tumours with TMB ≥10 mutations/Mb using the FoundationOne CDx assay. HCC tends to be on the lower end of the spectrum with values ranging from 0.42 to 65.6 Mut/Mb and medians ranging from 2.56 to 5 Mut/Mb.95 Analysis of the atezolizumab plus bevacizumab-treated patients in IMbrave 150 showed no relationship between TMB and response.35 Similarly, in CheckMate 459, there was no significant difference in OS between those patients with high or low TMB treated with nivolumab. Only 3% had microsatellite instability-high tumours and none of these 12 patients showed a response in either treatment arm.96

Tumour cell PD-L1 expression by immunohistochemistry is an established predictive biomarker for PD-(L)1 treatment of non-small cell lung cancer97 but does not appear to consistently correlate with response in many other tumours including HCC. In the single-arm CheckMate 040 trial, ORR and OS were higher in patients with tumour PD-L1 expression ≥1%, particularly in the sorafenib-experienced group [110] but in randomised trials, including CheckMate 459, IMbrave 150 and HIMALAYA,[71], [77], [96] there was no additional survival benefit for those with tumour PD-L1 expression ≥1%. A more extensive analysis of IMbrave 150 showed no difference in response based on immune cell or tumour cell PD-L1 expression unless expression was ≥10%.35 But high expression was only recorded in 14 patients treated with atezolizumab and bevacizumab. Overall, the current data do not support the use of PD-L1 expression as a predictive biomarker.

Mutations and gene signatures

Mutations in CTNNB1 resulting in activation of the Wnt/β-catenin pathway are present in around one-third of patients with HCC and are associated with the immune exclusion sub-class.98 Initial pre-clinical and patient cohort studies suggested that alterations in Wnt/β-catenin signalling were associated with resistance to ICIs,[99], [100] but subsequent randomised trials have failed to confirm these observations. In both the Checkmate 459 and IMbrave 150 trials, no significant difference in survival was identified in the ICI-containing arms based on CTNNB1 mutations or Wnt/β-catenin pathway activity.[4], [96] Interestingly, both studies demonstrated that patients treated with sorafenib had improved outcomes in the presence of CTNNB1 mutations.

Many inflammatory gene signatures have been reported and their association with response and survival has been evaluated in exploratory analyses of prospective trials. In a post hoc analysis of 37 patients from the CheckMate 040 trial, several signatures were associated with both response and OS.49 The so called atezolizumab plus bevacizumab response signature (ABRS) was derived from the top 10 genes obtained from differentially expressed gene analysis and curated gene signatures using data from the GO30140 study.35 The ABRS and inflammatory signature genes, including CD274 and an effector T cell signature (CXCL9, PRF1 and GZMB), were higher in those achieving a complete/partial response in the IMbrave150 atezolizumab plus bevacizumab-treated group. PFS and OS was also improved in multivariate analysis. Artificial intelligence has been used to impute the presence of the ABRS in histological specimens and this may provide a cheaper and clinically applicable method to select patients in the future.101 More recently, an 11-gene signature (IFNAP) defined by upregulation of IFN-γ signalling and MHC II-related antigen presentation was derived from a cohort of patients treated with anti-PD-1 monotherapy.102 This signature appears to be associated with outcome in patients treated with anti-PD-1 therapy in the front-line. However, all these studies should be considered as hypothesis generating and require prospective validation in order to qualify them as clinically valuable predictive biomarkers that can be used for clinical decision making.

The role of biopsy

Tissue-based biomarker research in HCC has been severely limited in the past by reliance on radiological diagnostic criteria. However, the limitations of non-invasive diagnostic criteria in the setting of advanced disease have been clearly demonstrated103 and diagnostic tissue biopsy is increasingly routine. It is clearly important that routinely collected tissue is associated with consent for research and linked to well annotated clinical data. Whilst circulating tumour DNA will become an important resource in the future, detailed interrogation of the TME will remain dependent on tissue-based analysis.

New immunotherapy approaches in clinical trials

The approval of immunotherapy-based therapies in HCC has significantly altered the prognosis for patients with advanced HCC and become the new benchmark for drug development strategies. Current research efforts focus on expanding existing combination therapies and developing novel immunotherapy strategies beyond ICI. Whilst many new immunotherapeutic targets are being explored in pre-clinical studies, herein we will briefly review those that have progressed to clinical trials.

Novel ICIs

Beyond CTLA-4 and PD-(L)1 blockade, there is interest in targeting alternative immune-checkpoints in HCC to build on the success of combination therapy and overcome resistance mechanisms to ICI-based regimens. The combination of TIM-3 and PD-1 blockade with cobolimab and dostarlimab is currently under evaluation in a single-arm phase II study of treatment-naive patients with advanced HCC.104 Interim results have shown encouraging signs of efficacy, with an ORR of 46% and acceptable safety profile. There are also ongoing trials investigating dual LAG3 and PD-1 blockade in HCC. RELATIVITY-073 is a randomised phase II study investigating relatinib (anti-LAG3) and nivolumab vs. nivolumab monotherapy in patients with advanced HCC who have progressed on first-line TKI therapy and are immunotherapy-naive (NCT04567615). Unlike many other ICI studies, this trial aims to enrich for those patients most likely to benefit from this combination, with LAG3 expression mandatory for inclusion. Additionally, RELATIVITY-106 (phase I/II) will evaluate the combination of nivolumab, relatinib and bevacizumab compared to nivolumab and bevacizumab alone in the first-line setting (NCT05337137). Finally, use of anti-TIGIT-directed therapy is also being explored in advanced HCC. The three-drug combination of ociperlimab (anti-TIGIT), tislelizumab (anti-PD1) and BAT 1706 (bevacizumab biosimilar) did not improve ORR compared to tislelizumab and BAT1706 alone in a Chinese patient population, although survival data is immature.105 In contrast to this, the MORPHEUS-liver study (phase Ib/II) demonstrated a promising ORR of 43.5% when investigating the anti-TIGIT therapy tiragolumab in combination with atezolizumab and bevacizumab,106 and this combination has been taken forward into the phase III IMbrave 152 study which commenced recruitment earlier this year (NCT05904886).

Bispecific antibodies

Unlike monoclonal antibodies, bispecifics are engineered to allow precise binding to two antigens or epitopes, either on the same or different cell types. Bispecific antibodies targeting two different immune checkpoints on T cells (anti-PD-1/CTLA-4 and anti-PD-1/TIGIT) are currently being evaluated in patients with advanced HCC in a phase II study, combining the potential benefits of two drugs in a single molecule (NCT05775159). Alternatively, bispecifics can act as a bridge between effector T cells and tumour cells in order to improve the specificity and effectiveness of cell killing. Application of this technology in HCC remains in its infancy, but a bispecific antibody for GPC3 and the T cell-specific antigen CD3 has been shown to enhance T-cell activation and tumour cell death in HCC cell lines.107

Adoptive cell therapy

Following the success of cell-based immune therapies in haematological malignancies,[108], [109] there has been increasing interest in applying this technology to solid tumours including HCC. Early phase trials have investigated using both gene-modified (e.g. chimeric antigen receptor T [CAR-T] cells and T-cell receptor modified T [TCR-T] cells) and non-gene modified adoptive cell therapy (cytokine induced killer [CIK] cells, NK cells and tumour-infiltrating lymphocytes [TILs]).

(i) Non-gene-modified cell therapy

CIK cells are CD3+CD56+ NK-like T cells expanded from peripheral blood that have potential as an “off the shelf” allogeneic therapy. They have shown efficacy in the adjuvant setting in a Korean phase III trial in which patients with early-stage disease treated with resection or ablation were randomised to multiple infusions of autologous CIKs or standard of care.110 Allogeneic NK cells have also been investigated in combination with cryoablation in advanced-stage HCC111 and in an ongoing phase II trial in combination with targeted therapy (NCT04162158). In contrast, TILs are polyclonal tumour-targeting T cells which are expanded for use as an autologous therapy and have recently gained FDA approval for advanced melanoma. HCC TILs are phenotypically exhausted with high expression of inhibitory immune checkpoints, such as TIM-3 and LAG3,112 suggesting that combination therapy with ICIs may be required to maximise their utility in HCC. However, there is a scarcity of clinical trials in this area, with only two studies investigating autologous TILs as an adjuvant therapy after tumour resection.[113], [114] These demonstrated an acceptable toxicity profile, but no further studies of TIL therapy are currently in progress in HCC.

(ii) Gene-modified

Gene engineering approaches to cell therapy aim to modify immune cells with synthetic receptors in order to enhance recognition of tumour-specific antigens. CAR-T cells are engineered with synthetic cell surface receptors to enable tumour-specific cell killing in an MHC-independent manner. A growing number of clinical trials are demonstrating the value of CAR-T cells in solid tumours, and several promising targets for CAR-T therapy have been identified in HCC, including GPC3, AFP, NKG2DL (NK group 2 member D ligand), MUC1, CD147, HBV surface protein and c-MET.[115], [116], [117], [118], [119], [120] Currently, most CAR-T cell therapies for HCC are directed at GPC3, due to the favourable combination of high expression in HCC with limited expression in other tissues, including normal and cirrhotic liver. There are multiple ongoing phase I/II trials targeting GPC3 (Table 2) and two sequential phase I studies investigating autologous CAR-GPC3 T cells in advanced HCC have been reported to date.117 Although response rates were disappointing with 1/13 achieving a partial response, 2/13 maintaining stable disease and 8/13 progressing on treatment, the toxicity profile was broadly in keeping with published data for CAR-T therapy, with 9/13 (69%) patients experiencing any grade cytokine release syndrome and one death due to cytokine release syndrome (Grade 5). Optimised approaches using armoured CAR-T cell designs, combination therapy with TKIs, ICIs and radiotherapy, and intrahepatic targeted delivery are currently under investigation, with the aim of boosting efficacy. An alternative cell therapy approach in HCC is the use of TCR-T cells, where engineered TCRs are designed to recognise intracellular tumour antigens on HLA class I and II molecules. The advantage of this technique is the additional ability to target intracellular antigens like AFP, which is processed and presented on HLA, although this comes at the cost of limiting therapy to the most frequently shared HLA types. To date, early phase trials of TCR-T in HCC have mostly been directed at AFP or viral associated antigens (predominantly HBV; Table 3). In a phase I study with eight patients, HBV-specific TCR-expressing autologous T cells have demonstrated acceptable tolerability in patients with advanced HBV-related HCC not suitable for liver transplantation, with one patient achieving a durable partial response of 27.7 months.121 One concern with using HBV antigens as a target for TCR-T cell therapy is the potential for inducing liver damage due to the expression of viral antigens on non-malignant liver tissue. Potential strategies to circumvent this have utilised mRNA HBV-TCR-directed T cells that are functionally short lived due to the short half-life of mRNA.122 Finally, the specificity and high expression of AFP in HCC has been exploited in the development of AFP-directed autologous SPEAR T cells, which have been tested in HLA-A∗02-selected patients with AFP-overexpressing HCC in the phase I setting. Full results are pending, but the initial safety profile appeared favourable, with preliminary evidence of antitumour activity.123Table 2 Ongoing trials of CAR T cell therapies.

Table 2NCT number	Phase	Target (co-stimulator)	Planned enrolment	Patient population	Sponsor	Region/country	Preconditioning	Primary outcome	Status	
GCP3 based	
3884751	I	GPC3	15	Advanced HCC	CARsgen Therapeutics Co., Ltd.	China		Safety and tolerability	Completed	
3980288	I	GPC3	36	Advanced HCC	Zhejiang Universit	China	Flu + Cyclo	Safety and tolerability	Completed	
4121273	I	GPC3	14	Advanced HCC	Baylor College of Medicine	USA	Flu + Cyclo	DLT	Unknown	
2959151	I/II	GPC3	20	Advanced HCC	Shanghai GeneChem Co., Ltd	China		Adverse events	Unknown	
3146234	I	GPC3	20	Advanced HCC	RenJi Hospital	China	Flu + Cyclo	Safety and tolerability	Completed	
5652920	lb/ll	GPC3	105	Advanced HCC	OriCell Therapeutics Co., Ltd.	China		MTD	Recruiting	
2715362	l/ll	GPC3 (4-1BB)	30	Advanced HCC	Shanghai GeneChem Co., Ltd	China	Cylco	Safety and tolerability	Unknown	
5003895	l	GPC3	38	Advanced HCC	National Cancer Institute (NCI)	USA	Flu + Cyclo	Safety and feasibility	Recruiting	
5783570	l	GPC3	12	Advanced HCC	Eutilex	Korea		Adverse events	Recruiting	
5103631	l	GPC3 (IL-15)	27	Advanced HCC	Baylor College of Medicine	USA	Flu + Cyclo	DLT	Recruiting	
3302403	l	GPC3	48	Advanced HCC	Kang YU	China	Flu + Cyclo	Safety and tolerability	Unknown	
5070156	l	GPC3	3	Advanced HCC	Tongji University	China		Adverse events	Not recruiting	
6084884	l/ll	GPC3	84	Advanced HCC	AstraZeneca	Korea and USA	Flu + Cyclo	Safety and tolerability	Recruiting	
6198296	l	GCP3 (IL-15 and IL-21)	21	Multiple inc HCC	Baylor College of Medicine	USA	Flu + Cyclo	DLT	Not recruiting	
5620706	l	GPC3	20	Advanced HCC	Shenzhen University General Hospital	China		Adverse events	Recruiting	
5120271	l/ll	GPC3	110	Multiple inc HCC	Sotio Biotech Inc.	USA	Flu + Cyclo	Safety and tolerability	Recruiting	
3198546	l	GPC3+/-TGFβ (IL-7)	30	Advanced HCC	Second Affiliated Hospital of Guangzhou Medical University	China		DLT	Recruiting	
5155189	l	GPC3	44	Advanced HCC	Zhejiang University	China		Adverse events	Recruiting	
4951141	l	GPC3	10	Advanced HCC	Beijing Immunochina Medical Science & Technology Co., Ltd.	China		Adverse events	Unknown	
2395250	l	GPC3	10	Advanced HCC	RenJi Hospital	China		Adverse events	Completed	
3084380	l/ll	GPC3	20	Advanced HCC	Xinqiao Hospital of Chongqing	China	Flu + Cyclo	Safety	Unknown	
6144385	l	GPC3	20	Advanced HCC	Shanghai Ming Ju Biotechnology Co., Ltd.	China	Flu + Cyclo	Safety	Recruiting	
5926726		GPC3	12	Advanced HCC	RenJi Hospital	China	Flu + Cyclo	DLT and adverse events	Recruiting	
Non-GCP3 targets	
3672305	l	c-Met/PD-L1	50	Advanced HCC	The Second Hospital of Nanjing Medical University	China	Flu + Cyclo	Efficacy	Unknown	
5323201	l/ll	B7H3	15	Advanced HCC	The Affiliated Hospital of Xuzhou Medical University	China	Flu + Cyclo	Safety and response rate	Recruiting	
3013712	l/ll	EPCAM	60	Multiple inc HCC	First Affiliated Hospital of Chengdu Medical College	China		Toxicity	Unknown	
3993743	l	CD147	34	Advanced HCC	Xijing Hospital	China		Adverse events	Unknown	
5028933	l	EPCAM	48	Multiple inc HCC	Zhejiang University	China	Flu + Cyclo	PK and adverse events	Recruiting	
5131763	l	NKG2DL (4-1BB)	3	Multiple inc HCC	Fudan University	China		Adverse events	Unknown	
4550663	l	NKG2DL	10	Multiple inc HCC	The Affiliated Nanjing Drum Tower Hospital of Nanjing University	China		MTD and adverse events	Unknown	
2587689	l	MUC1	20	Multiple inc HCC	PersonGen BioTherapeutics (Suzhou) Co., Ltd.	China		Adverse events	Unknown	
3941626	l/ll	EGFRvIII/DR5	50	Multiple inc HCC	Shenzhen BinDeBio Ltd.	China	Flu + Cyclo	Adverse events	Unknown	
3638206	l/ll	EGFRvIII/DR5/C-met	73	Multiple inc HCC	Shenzhen BinDeBio Ltd.	China	Flu + Cyclo	Adverse events	Unknown	
Cyclo, cyclophosphamide; DLT, dose limiting toxicity; Flu, fludarabine; GPC3, glypican 3; MTD, maximum tolerated dose; NR, not reported.

Table 3 Ongoing genetically engineered TCR T-cell therapies in progress.

Table 3NCT number	Phase	Target	Planned enrolment	Patient population	HLA class (if stated)	Sponsor	Region/country	Primary outcome	Status	
4745403	l	HBV Ag	10	HBV Ag + advanced HCC	HLA-A∗02:01 or HLA-A∗24:02	Lion TCR Pte. Ltd.	Singapore	Safety	Recruiting	
3899415	l	HBV Ag	10	HBV Ag + advanced HCC		Beijing 302 Hospital	China	Safety	Recruiting	
4677088	l	HBV Ag	7	HBV Ag+ HCC post- transplant		Xiaoshun He	China	Safety	Unknown	
2686372	l	HBV Ag	13	HBV Ag+ HCC post -transplant		Lion TCR Pte. Ltd	China	Adverse events	Completed	
5339321	l	HBV Ag	36	HBV Ag + advanced HCC	HLA-A∗02:01	Peking Union Medical College Hospital	China	Adverse events	Unknown	
5195294	l/ll	HBV Ag	55	HBV Ag + advanced HCC		Lion TCR Pte. Ltd	NR	Adverse events	Not recruiting	
5417932	l/lla	HBV Ag	46	HBV Ag + advanced HCC	HLA-A∗02:01	SCG Cell Therapy Pte. Ltd	Hong Kong, Singapore, USA	Safety and response	Recruiting	
3971747	l	AFP	9	HCC serum AFP >200 ng/ml	HLA-A∗02:01	Cellular Biomedicine Group Ltd.	China	Adverse events	Unknown	
4368182	l	AFP	3	HCC serum AFP >200 ng/ml	HLA-A∗02:01	Zhejiang University	China	Safety	Unknown	
3132792	l	AFP	30	HCC serum AFP ≥100 ng/ml	HLA-A∗02:01	Adaptimmune	EU and USA	DLT and adverse events	Completed	
AFP, alpha-fetoprotein; HBV, hepatitis B virus; HCC, hepatocellular carcinoma.

Conclusion

Immune checkpoint inhibition has transformed the management of advanced HCC and emerging data suggest a possible role for its use in earlier disease stages. These data will require robust evaluation and have implications for subsequent treatment in the advanced setting, including sequencing of therapy and the role of continuing ICI beyond disease progression for patients with clinical benefit (as currently being evaluated in the phase III IMBRAVE 251 study [NCT04770896]). Despite these advances, there is currently insufficient evidence to guide selection of those patients most likely to benefit from ICIs and questions remain as to whether new ICI-based combinations will be able to overcome resistance to atezolizumab/bevacizumab treatment in the first-line setting. Ongoing studies evaluating novel combinations and alternative immunotherapeutic strategies are looking to answer these questions and improve the survival benefit already demonstrated in advanced disease. Recruitment to clinical trials with embedded translational research will be key in building upon the success seen to date and improving patient outcomes.

Abbreviations

ABRS, atezolizumab plus bevacizumab response signature; AFP, alpha-fetoprotein; CAR-T, chimeric antigen receptor-T; CIK, cytokine-induced killer; CTLA-4, cytotoxic T-lymphocyte associated protein 4; CXCL, chemokine C-X-C motif ligand; DOR, duration of response; GPC3, glypican 3; HR, hazard ratio; ICI, immune checkpoint inhibitor; IFN, interferon; IL-, interleukin-; LAG3, lymphocyte-activating 3; MDSCs, myeloid-derived suppressor cells; NK, natural killer; ORR, objective response rate; OS, overall survival; PD-1, programmed death 1; PD-L1, programmed death ligand 1; PFS, progression-free survival; TAMs, tumour-associated macrophages; TCR-T, T-cell receptor modified-T; TGFβ, transforming growth factor-β; TIL(s), tumour-infiltrating lymphocyte(s); TIGIT, T cell immunoreceptor with Ig and ITIM domains; TKI(s), tyrosine kinase inhibitor(s); TMB, tumour mutational burden; TME, tumour microenvironment; Tregs, regulatory T cells.

Financial support

The authors did not receive any financial support to produce this manuscript. GAM is funded by Cancer Research UK HUNTER, Ref. C9380/A26813. TM is funded by National Institute for Health Research (NIHR203950) and NIHR UCH Biomedical Research Facility.

Conflict of interests

T. Meyer reports Consultancy: Roche, Astra Zeneca, Signant Health, GreyWolf, Guerbet, Geneos, Eisai, Beigene, MSD. Research Funding: MSD, Bayer, Boston Scientific.

Please refer to the accompanying ICMJE disclosure forms for further details.

Authors’ contributions

1. Concept and design – All. 2. Drafting of manuscript- All. 3. Approval of final manuscript- All.

Supplementary data

The following are the supplementary data to this article:Multimedia component 1

Multimedia component 1

Supplementary data to this article can be found online at https://doi.org/10.1016/j.jhepr.2024.101130.
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References

1 Dasgupta P. Henshaw C. Youlden D.R. Global trends in incidence rates of primary adult liver cancers: a systematic review and meta-analysis Front Oncol 10 2020 Feb 28 171 32185125
2 Vos T. Lim S.S. Abbafati C. Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019 The Lancet 396 10258 2020 Oct 1204 1222
3 Llovet J.M. Montal R. Sia D. Molecular therapies and precision medicine for hepatocellular carcinoma Nat Rev Clin Oncol 15 10 2018 Oct 30 599 616 30061739
4 Finn R.S. Qin S. Ikeda M. Atezolizumab plus bevacizumab in unresectable hepatocellular carcinoma New Engl J Med 382 20 2020 May 14 1894 1905 32402160
5 Park E.J. Lee J.H. Yu G.Y. Dietary and genetic obesity promote liver inflammation and tumorigenesis by enhancing IL-6 and TNF expression Cell 140 2 2010 Jan 197 208 20141834
6 Grivennikov S.I. Greten F.R. Karin M. Immunity, inflammation, and cancer Cell 140 6 2010 Mar 883 899 20303878
7 Schreiber R.D. Old L.J. Smyth M.J. Cancer immunoediting: integrating immunity’s roles in cancer suppression and promotion Science 331 6024 2011 Mar 25 1565 1570 21436444
8 Kubes P. Jenne C. Immune responses in the liver Annu Rev Immunol 36 1 2018 Apr 26 247 277 29328785
9 Ringelhan M. Pfister D. O’Connor T. The immunology of hepatocellular carcinoma Nat Immunol 19 3 2018 Mar 29 222 232 29379119
10 Llovet J.M. Castet F. Heikenwalder M. Immunotherapies for hepatocellular carcinoma Nat Rev Clin Oncol 19 3 2022 Mar 11 151 172 34764464
11 Gao Q. Qiu S.J. Fan J. Intratumoral balance of regulatory and cytotoxic T cells is associated with prognosis of hepatocellular carcinoma after resection J Clin Oncol 25 18 2007 Jun 20 2586 2593 17577038
12 Zheng C. Zheng L. Yoo J.K. Landscape of infiltrating T cells in liver cancer revealed by single-cell sequencing Cell 169 7 2017 Jun 1342 1356 28622514
13 Xia Y. Tang W. Qian X. Efficacy and safety of camrelizumab plus apatinib during the perioperative period in resectable hepatocellular carcinoma: a single-arm, open label, phase II clinical trial J ImmunoTherapy Cancer 10 4 2022 Apr 3 1136
14 Zhang Q. He Y. Luo N. Landscape and dynamics of single immune cells in hepatocellular carcinoma Cell 179 4 2019 Oct 829 845.e20 31675496
15 Nguyen P.H.D. Wasser M. Tan C.T. Trajectory of immune evasion and cancer progression in hepatocellular carcinoma Nat Commun 13 1 2022 Mar 17 1441 35301339
16 Chew V. Chuang C.H. Hsu C. Translational research on drug development and biomarker discovery for hepatocellular carcinoma J Biomed Sci 31 1 2024 Feb 17 22 38368324
17 Greten T.F. Villanueva A. Korangy F. Biomarkers for immunotherapy of hepatocellular carcinoma Nat Rev Clin Oncol 20 11 2023 Nov 780 798 37726418
18 Vignali D.A.A. Collison L.W. Workman C.J. How regulatory T cells work Nat Rev Immunol 8 7 2008 Jul 523 532 18566595
19 Schoenberg M.B. Li X. Li X. The predictive value of tumor infiltrating leukocytes in Hepatocellular Carcinoma: a systematic review and meta-analysis Eur J Surg Oncol 47 10 2021 Oct 2561 2570 33966947
20 Yu S. Wang Y. Hou J. Tumor-infiltrating immune cells in hepatocellular carcinoma: tregs is correlated with poor overall survival Wang E. PLoS ONE 15 4 2020 Apr 2 e0231003
21 Liu Y. Xun Z. Ma K. Identification of a tumour immune barrier in the HCC microenvironment that determines the efficacy of immunotherapy J Hepatol 78 4 2023 Apr 770 782 36708811
22 Heymann F. Peusquens J. Ludwig-Portugall I. Liver inflammation abrogates immunological tolerance induced by Kupffer cells Hepatology 62 1 2015 Jul 22 279 291 25810240
23 Yeung O.W.H. Lo C.M. Ling C.C. Alternatively activated (M2) macrophages promote tumour growth and invasiveness in hepatocellular carcinoma J Hepatol 62 3 2015 Mar 607 616 25450711
24 Schrader J. The role of MDSCs in hepatocellular carcinoma – in vivo veritas? J Hepatol 59 5 2013 Nov 921 923 23958935
25 Hoechst B. Ormandy L.A. Ballmaier M. A new population of myeloid-derived suppressor cells in hepatocellular carcinoma patients induces CD4+CD25+Foxp3+ T cells Gastroenterology 135 1 2008 Jul 234 243 18485901
26 Bayik D. Lauko A.J. Roversi G.A. Hepatobiliary malignancies have distinct peripheral myeloid-derived suppressor cell signatures and tumor myeloid cell profiles Scientific Rep 10 1 2020 Nov 2 18848
27 Veglia F. Sanseviero E. Gabrilovich D.I. Myeloid-derived suppressor cells in the era of increasing myeloid cell diversity Nat Rev Immunol 21 8 2021 Aug 485 498 33526920
28 Geh D. Leslie J. Rumney R. Neutrophils as potential therapeutic targets in hepatocellular carcinoma Nat Rev Gastroenterol Hepatol 19 4 2022 Apr 257 273 35022608
29 Greten T.F. Zhao F. Gamrekelashvili J. Human Th17 cells in patients with cancer: friends or foe? OncoImmunology 1 8 2012 Nov 1438 1439 23243621
30 Han Y. Chen Z. Yang Y. Human CD14 + CTLA-4 + regulatory dendritic cells suppress T-cell response by cytotoxic T-lymphocyte antigen-4-dependent IL-10 and indoleamine-2,3-dioxygenase production in hepatocellular carcinoma: hepatology, Vol. 00, NO. 0, 2013 Hepatology 59 2 2014 Feb 567 579 23960017
31 Zhang J.P. Yan J. Xu J. Increased intratumoral IL-17-producing cells correlate with poor survival in hepatocellular carcinoma patients J Hepatol 50 5 2009 May 980 989 19329213
32 Xiao X. Lao X.M. Chen M.M. PD-1hi identifies a novel regulatory B-cell population in human hepatoma that promotes disease progression Cancer Discov 6 5 2016 May 1 546 559 26928313
33 Flecken T. Schmidt N. Hild S. Immunodominance and functional alterations of tumor-associated antigen-specific CD8 + T-cell responses in hepatocellular carcinoma Hepatology 59 4 2014 Apr 20 1415 1426 24002931
34 Barsch M. Salié H. Schlaak A.E. T-cell exhaustion and residency dynamics inform clinical outcomes in hepatocellular carcinoma J Hepatol 77 2 2022 Aug 397 409 35367533
35 Zhu A.X. Abbas A.R. de Galarreta M.R. Molecular correlates of clinical response and resistance to atezolizumab in combination with bevacizumab in advanced hepatocellular carcinoma Nat Med 28 8 2022 Aug 23 1599 1611 35739268
36 Chew V. Lai L. Pan L. Delineation of an immunosuppressive gradient in hepatocellular carcinoma using high-dimensional proteomic and transcriptomic analyses Proc Natl Acad Sci 114 29 2017 Jul 18 E5900 E5909 28674001
37 Lim C.J. Lee Y.H. Pan L. Multidimensional analyses reveal distinct immune microenvironment in hepatitis B virus-related hepatocellular carcinoma Gut 68 5 2019 May 916 927 29970455
38 Cariani E. Pilli M. Zerbini A. HLA and killer immunoglobulin-like receptor genes as outcome predictors of hepatitis C virus–related hepatocellular carcinoma Clin Cancer Res 19 19 2013 Oct 1 5465 5473 23938290
39 Zecca A. Barili V. Canetti D. Energy metabolism and cell motility defect in NK-cells from patients with hepatocellular carcinoma Cancer Immunol Immunother 69 8 2020 Aug 19 1589 1603 32307580
40 Zakeri N. Hall A. Swadling L. Characterisation and induction of tissue-resident gamma delta T-cells to target hepatocellular carcinoma Nat Commun 13 1 2022 Mar 16 1372 35296658
41 Easom N.J.W. Stegmann K.A. Swadling L. IL-15 overcomes hepatocellular carcinoma-induced NK cell dysfunction Front Immunol 9 2018 May 9 1009 29867983
42 Calderaro J. Ziol M. Paradis V. Molecular and histological correlations in liver cancer J Hepatol 71 3 2019 Sep 616 630 31195064
43 Schumacher T.N. Thommen D.S. Tertiary lymphoid structures in cancer Science 375 6576 2022 Jan 7 eabf9419
44 David C.J. Massagué J. Contextual determinants of TGFβ action in development, immunity and cancer Nat Rev Mol Cell Biol 19 7 2018 Jul 419 435 29643418
45 Lin T.H. Shao Y.Y. Chan S.Y. High serum transforming growth factor-β1 levels predict outcome in hepatocellular carcinoma patients treated with sorafenib Clin Cancer Res 21 16 2015 Aug 15 3678 3684 25977342
46 Feun L.G. Li Y. Wu C. Phase 2 study of pembrolizumab and circulating biomarkers to predict anticancer response in advanced, unresectable hepatocellular carcinoma Cancer 125 20 2019 Oct 15 3603 3614 31251403
47 Jin X. Zhang S. Wang N. High expression of TGF-β1 contributes to hepatocellular carcinoma prognosis via regulating tumor immunity Front Oncol 12 2022 Apr 25 861601
48 Chew V. Chen J. Lee D. Chemokine-driven lymphocyte infiltration: an early intratumoural event determining long-term survival in resectable hepatocellular carcinoma Gut 61 3 2012 Mar 427 438 21930732
49 Sangro B. Melero I. Wadhawan S. Association of inflammatory biomarkers with clinical outcomes in nivolumab-treated patients with advanced hepatocellular carcinoma J Hepatol 73 6 2020 Dec 1460 1469 32710922
50 Pfister D. Núñez N.G. Pinyol R. NASH limits anti-tumour surveillance in immunotherapy-treated HCC Nature 592 7854 2021 Apr 450 456 33762733
51 Parlesak A. Schäfer C. Schütz T. Increased intestinal permeability to macromolecules and endotoxemia in patients with chronic alcohol abuse in different stages of alcohol-induced liver disease J Hepatol 32 5 2000 May 742 747 10845660
52 Yan G. Wang X. Sun C. Chronic alcohol consumption promotes diethylnitrosamine-induced hepatocarcinogenesis via immune disturbances Sci Rep 7 1 2017 May 31 2567 28566719
53 Dudek M. Pfister D. Donakonda S. Auto-aggressive CXCR6+ CD8 T cells cause liver immune pathology in NASH Nature 592 7854 2021 Apr 15 444 449 33762736
54 Nkongolo S. Mahamed D. Kuipery A. Longitudinal liver sampling in patients with chronic hepatitis B starting antiviral therapy reveals hepatotoxic CD8+ T cells J Clin Invest 133 1 2023 Jan 3 e158903
55 Simon T.G. Duberg A.S. Aleman S. Association of aspirin with hepatocellular carcinoma and liver-related mortality N Engl J Med 382 11 2020 Mar 12 1018 1028 32160663
56 Sitia G. Aiolfi R. Di Lucia P. Antiplatelet therapy prevents hepatocellular carcinoma and improves survival in a mouse model of chronic hepatitis B Proc Natl Acad Sci USA 109 32 2012 Aug 7 E2165 E2172 22753481
57 Ma C. Fu Q. Diggs L.P. Platelets control liver tumor growth through P2Y12-dependent CD40L release in NAFLD Cancer Cell 40 9 2022 Sep 986 998.e5 36055226
58 Sangro B. Sarobe P. Hervás-Stubbs S. Advances in immunotherapy for hepatocellular carcinoma Nat Rev Gastroenterol Hepatol 18 8 2021 Aug 13 525 543 33850328
59 Yarchoan M. Johnson B.A. Lutz E.R. Targeting neoantigens to augment antitumour immunity Nat Rev Cancer 17 4 2017 Apr 24 209 222 28233802
60 Efremova M. Finotello F. Rieder D. Neoantigens generated by individual mutations and their role in cancer immunity and immunotherapy Front Immunol 8 2017 Nov 28 01679
61 El-Khoueiry A.B. Sangro B. Yau T. Nivolumab in patients with advanced hepatocellular carcinoma (CheckMate 040): an open-label, non-comparative, phase 1/2 dose escalation and expansion trial Lancet (London, England) 389 10088 2017 Jun 24 2492 2502 28434648
62 Zhu A.X. Finn R.S. Edeline J. Pembrolizumab in patients with advanced hepatocellular carcinoma previously treated with sorafenib (KEYNOTE-224): a non-randomised, open-label phase 2 trial Lancet Oncol 19 7 2018 Jul 940 952 29875066
63 Kudo M. Finn R.S. Edeline J. Updated efficacy and safety of KEYNOTE-224: a phase II study of pembrolizumab in patients with advanced hepatocellular carcinoma previously treated with sorafenib Eur J Cancer 167 2022 May 1 12 35364421
64 El-Khoueiry A.B. Trojan J. Meyer T. Nivolumab in sorafenib-naive and sorafenib-experienced patients with advanced hepatocellular carcinoma: 5-year follow-up from CheckMate 040 Ann Oncol 2023 Dec 381 391 38151184
65 Yau T. Park J.W. Finn R.S. Nivolumab versus sorafenib in advanced hepatocellular carcinoma (CheckMate 459): a randomised, multicentre, open-label, phase 3 trial Lancet Oncol 23 1 2022 Jan 77 90 34914889
66 Finn R.S. Ryoo B.Y. Merle P. Pembrolizumab as second-line therapy in patients with advanced hepatocellular carcinoma in KEYNOTE-240: a randomized, double-blind, phase III trial J Clin Oncol 38 3 2020 Jan 20 193 202 31790344
67 Qin S. Chen Z. Fang W. Pembrolizumab plus best supportive care versus placebo plus best supportive care as second-line therapy in patients in Asia with advanced hepatocellular carcinoma (HCC): phase 3 KEYNOTE-394 study J Clin Oncol 40 4_suppl 2022 Feb 1 383–383
68 Finn R.S. Gu K. Chen X. Abstract CT222: pembrolizumab (pembro) for previously treated advanced hepatocellular carcinoma (aHCC): meta-analysis of the phase 3 KEYNOTE-240 and KEYNOTE-394 studies Cancer Res 82 12_Supplement 2022 Jun 15 CT222–CT222
69 Abou-Alfa G.K. Lau G. Kudo M. Tremelimumab plus durvalumab in unresectable hepatocellular carcinoma NEJM Evid 1 8 2022 Jul 26
70 Qin S. Kudo M. Meyer T. Tislelizumab vs sorafenib as first-line treatment for unresectable hepatocellular carcinoma JAMA Oncol 2023 Oct 5 1651 1659 37796513
71 Cheng A.L. Qin S. Ikeda M. Updated efficacy and safety data from IMbrave150: atezolizumab plus bevacizumab vs. sorafenib for unresectable hepatocellular carcinoma J Hepatol 76 4 2022 Apr 862 873 34902530
72 Ren Z. Xu J. Bai Y. Sintilimab plus a bevacizumab biosimilar (IBI305) versus sorafenib in unresectable hepatocellular carcinoma (ORIENT-32): a randomised, open-label, phase 2–3 study Lancet Oncol 22 7 2021 Jul 977 990 34143971
73 Kelley R.K. Rimassa L. Cheng A.L. Cabozantinib plus atezolizumab versus sorafenib for advanced hepatocellular carcinoma (COSMIC-312): a multicentre, open-label, randomised, phase 3 trial Lancet Oncol 23 8 2022 Aug 1 995 1008 35798016
74 Llovet J.M. Kudo M. Merle P. Lenvatinib plus pembrolizumab versus lenvatinib plus placebo for advanced hepatocellular carcinoma (LEAP-002): a randomised, double-blind, phase 3 trial Lancet Oncol 24 12 2023 Dec 1 1399 1410 38039993
75 Qin S. Chan S.L. Gu S. Camrelizumab plus rivoceranib versus sorafenib as first-line therapy for unresectable hepatocellular carcinoma (CARES-310): a randomised, open-label, international phase 3 study The Lancet 402 10408 2023 Sep 30 1133 1146
76 Yau T. Kang Y.K. Kim T.Y. Efficacy and safety of nivolumab plus ipilimumab in patients with advanced hepatocellular carcinoma previously treated with sorafenib JAMA Oncol 6 11 2020 Nov 12 e204564
77 Sangro B. Chan S.L. Kelley R.K. Four-year overall survival update from the phase III HIMALAYA study of tremelimumab plus durvalumab in unresectable hepatocellular carcinoma Ann Oncol : official J Eur Soc Med Oncol 2024 Feb 19 448 457
78 Vogel A. Grant R.C. Meyer T. Adjuvant and neoadjuvant therapies for hepatocellular carcinoma Hepatology (Baltimore, Md) 10 2023 Dec 18 1097
79 Qin S. Chen M. Cheng A.L. Atezolizumab plus bevacizumab versus active surveillance in patients with resected or ablated high-risk hepatocellular carcinoma (IMbrave050): a randomised, open-label, multicentre, phase 3 trial The Lancet 402 10415 2023 Nov 1835 1847
80 Wang K. Xiang Y.J. Yu H.M. Adjuvant sintilimab in resected high-risk hepatocellular carcinoma: a randomized, controlled, phase 2 trial Nat Med 2024 Jan 19 708 715 38242982
81 Bruix J. Takayama T. Mazzaferro V. Adjuvant sorafenib for hepatocellular carcinoma after resection or ablation (STORM): a phase 3, randomised, double-blind, placebo-controlled trial Lancet Oncol 16 13 2015 1344 1354 26361969
82 Williet N. Dubreuil O. Boussaha T. Neoadjuvant sorafenib combined with gemcitabine plus oxaliplatin in advanced hepatocellular carcinoma World J Gastroenterol 17 17 2011 2255 2258 21633538
83 Kaseb A.O. Hasanov E. Cao H.S.T. Perioperative nivolumab monotherapy versus nivolumab plus ipilimumab in resectable hepatocellular carcinoma: a randomised, open-label, phase 2 trial Lancet Gastroenterol Hepatol 7 3 2022 Mar 208 218 35065057
84 Marron T.U. Fiel M.I. Hamon P. Neoadjuvant cemiplimab for resectable hepatocellular carcinoma: a single-arm, open-label, phase 2 trial Lancet Gastroenterol Hepatol 7 3 2022 Mar 219 229 35065058
85 Zhao M. Chen S. Li C. Neoadjuvant immune checkpoint inhibitors for resectable hepatocellular carcinoma: a systematic review and meta-analysis Cancers 15 3 2023 Jan 18 600 36765557
86 Chew V. Lee Y.H. Pan L. Immune activation underlies a sustained clinical response to Yttrium-90 radioembolisation in hepatocellular carcinoma Gut 68 2 2019 Feb 335 346 29440463
87 Llovet J.M. De Baere T. Kulik L. Locoregional therapies in the era of molecular and immune treatments for hepatocellular carcinoma Nat Rev Gastroenterol Hepatol 18 5 2021 May 28 293 313 33510460
88 Yang X. Guo Y. Guo Z. Cryoablation inhibition of distant untreated tumors (abscopal effect) is immune mediated Oncotarget 10 41 2019 Jun 25 4180 4191 31289616
89 Sangro B. Kudo M. Qin S. P-347 A phase 3, randomized, double-blind, placebo-controlled study of transarterial chemoembolization combined with durvalumab or durvalumab plus bevacizumab therapy in patients with locoregional hepatocellular carcinoma: EMERALD-1 Ann Oncol 31 2020 Jul S202 S203
90 Singal A.G. Hoshida Y. Pinato D.J. International liver cancer association (ILCA) white paper on biomarker development for hepatocellular carcinoma Gastroenterology 160 7 2021 Jun 2572 2584 33705745
91 Zhu A.X. Kang Y.K. Yen C.J. Ramucirumab after sorafenib in patients with advanced hepatocellular carcinoma and increased α-fetoprotein concentrations (REACH-2): a randomised, double-blind, placebo-controlled, phase 3 trial Lancet Oncol 20 2 2019 Feb 282 296 30665869
92 Merle P. Kudo M. Edeline J. Pembrolizumab as second-line therapy for advanced hepatocellular carcinoma: longer term follow-up from the phase 3 KEYNOTE-240 trial Liver Cancer 12 4 2023 Sep 309 320 37901200
93 Meyer T. Galani S. Lopes A. Aetiology of liver disease and response to immune checkpoint inhibitors: an updated meta-analysis confirms benefit in those with non-viral liver disease J Hepatol 79 2 2023 Aug e73 e76 37086920
94 Scheiner B. Pomej K. Kirstein M.M. Prognosis of patients with hepatocellular carcinoma treated with immunotherapy - development and validation of the CRAFITY score J Hepatol 76 2 2022 Feb 353 363 34648895
95 Wong M. Kim J.T. Cox B. Evaluation of tumor mutational burden in small early hepatocellular carcinoma and progressed hepatocellular carcinoma Hepatic Oncol 8 4 2021 Dec 39
96 Neely J. Yao J. Kudo M. Abstract 2145: genomic and transcriptomic analyses related to the clinical efficacy of first-line nivolumab in advanced hepatocellular carcinoma from the phase 3 CheckMate 459 trial Cancer Res 82 12_Supplement 2022 Jun 15 2145–2145
97 Reck M. Rodríguez-Abreu D. Robinson A.G. Pembrolizumab versus chemotherapy for PD-L1-positive non-small-cell lung cancer New Engl J Med 375 19 2016 Nov 10 1823 1833 27718847
98 Sia D. Jiao Y. Martinez-Quetglas I. Identification of an immune-specific class of hepatocellular carcinoma, based on molecular features Gastroenterology 153 3 2017 Sep 812 826 28624577
99 Harding J.J. Nandakumar S. Armenia J. Prospective genotyping of hepatocellular carcinoma: clinical implications of next-generation sequencing for matching patients to targeted and immune therapies Clin Cancer Res: Off J Am Assoc Cancer Res 25 7 2019 Apr 1 2116 2126
100 Ruiz de Galarreta M. Bresnahan E. Molina-Sánchez P. β-Catenin activation promotes immune escape and resistance to anti-PD-1 therapy in hepatocellular carcinoma Cancer Discov 9 8 2019 Aug 1124 1141 31186238
101 Zeng Q. Klein C. Caruso S. Artificial intelligence-based pathology as a biomarker of sensitivity to atezolizumab-bevacizumab in patients with hepatocellular carcinoma: a multicentre retrospective study Lancet Oncol 24 12 2023 Dec 1411 1422 37951222
102 Haber P.K. Castet F. Torres-Martin M. Molecular markers of response to anti-PD1 therapy in advanced hepatocellular carcinoma Gastroenterology 164 1 2023 Jan 72 88.e18 36108710
103 Childs A. Zakeri N. Ma Y.T. Biopsy for advanced hepatocellular carcinoma: results of a multicentre UK audit Br J Cancer 125 10 2021 Nov 1350 1355 34526664
104 Acoba J.D. Rho Y. Fukaya E. Phase II study of cobolimab in combination with dostarlimab for the treatment of advanced hepatocellular carcinoma J Clin Oncol 41 4_suppl 2023 Feb 1 580–580
105 Ren Z. Huang Y. Guo Y. 945MO AdvanTIG-206: phase II randomized open-label study of ociperlimab (OCI) + tislelizumab (TIS) + BAT1706 (bevacizumab biosimilar) versus TIS + BAT1706 in patients (pts) with advanced hepatocellular carcinoma (HCC) Ann Oncol 34 2023 Oct S594
106 Finn R.S. Ryoo B.Y. Hsu C.H. Results from the MORPHEUS-liver study: phase Ib/II randomized evaluation of tiragolumab (tira) in combination with atezolizumab (atezo) and bevacizumab (bev) in patients with unresectable, locally advanced or metastatic hepatocellular carcinoma (uHCC) J Clin Oncol 41 16_suppl 2023 Jun 1 4010–4010
107 Yu L. Yang X. Huang N. A novel targeted GPC3/CD3 bispecific antibody for the treatment hepatocellular carcinoma Cancer Biol Ther 21 7 2020 Jul 2 597 603 32240054
108 Anderson Jr LD. Idecabtagene vicleucel (ide-cel) CAR T-cell therapy for relapsed and refractory multiple myeloma Future Oncol 18 3 2022 Jan 277 289 34854741
109 Mullard A. FDA approves first CAR T therapy Nat Rev Drug Discov 16 10 2017 Oct 1 669–669
110 Lee J.H. Lee J.H. Lim Y.S. Adjuvant immunotherapy with autologous cytokine-induced killer cells for hepatocellular carcinoma Gastroenterology 148 7 2015 Jun 1383 1391.e6 25747273
111 Lin M. Liang S. Wang X. Cryoablation combined with allogenic natural killer cell immunotherapy improves the curative effect in patients with advanced hepatocellular cancer Oncotarget 8 47 2017 Oct 10 81967 81977 29137237
112 Gao F. Xie K. Xiang Q. The density of tumor-infiltrating lymphocytes and prognosis in resectable hepatocellular carcinoma: a two-phase study Aging 13 7 2021 Apr 15 9665 9678 33744864
113 Jiang S.S. Tang Y. Zhang Y.J. A phase I clinical trial utilizing autologous tumor-infiltrating lymphocytes in patients with primary hepatocellular carcinoma Oncotarget 6 38 2015 Dec 1 41339 41349 26515587
114 Takayama T. Sekine T. Makuuchi M. Adoptive immunotherapy to lower postsurgical recurrence rates of hepatocellular carcinoma: a randomised trial The Lancet 356 9232 2000 Sep 802 807
115 Jiang W. Li T. Guo J. Bispecific c-Met/PD-L1 CAR-T Cells have enhanced therapeutic effects on hepatocellular carcinoma Front Oncol 11 2021 Mar 10 546586
116 Liu H. Xu Y. Xiang J. Targeting alpha-fetoprotein (AFP)–MHC complex with CAR T-cell therapy for liver cancer Clin Cancer Res 23 2 2017 Jan 15 478 488 27535982
117 Shi D. Shi Y. Kaseb A.O. Chimeric antigen receptor-glypican-3 T-cell therapy for advanced hepatocellular carcinoma: results of phase I trials Clin Cancer Res 26 15 2020 Aug 1 3979 3989 32371538
118 Sideras K. Bots S.J. Biermann K. Tumour antigen expression in hepatocellular carcinoma in a low-endemic western area Br J Cancer 112 12 2015 Jun 9 1911 1920 26057582
119 Sun B. Yang D. Dai H. Eradication of hepatocellular carcinoma by NKG2D-based CAR-T cells Cancer Immunol Res 7 11 2019 Nov 1 1813 1823 31484657
120 Zhang R.Y. Wei D. Liu Z.K. Doxycycline inducible chimeric antigen receptor T cells targeting CD147 for hepatocellular carcinoma therapy Front Cell Dev Biol 7 2019 Oct 11 233 31681766
121 Meng F. Zhao J. Tan A.T. Immunotherapy of HBV-related advanced hepatocellular carcinoma with short-term HBV-specific TCR expressed T cells: results of dose escalation, phase I trial Hepatol Int 15 6 2021 Dec 30 1402 1412 34850325
122 Tan A.T. Meng F. Jin J. Immunological alterations after immunotherapy with short lived HBV-TCR T cells associates with long-term treatment response in HBV-HCC Hepatol Commun 6 4 2022 Apr 21 841 854 34935312
123 Goyal L. Frigault M. Meyer T. Abstract 3183: initial safety of AFP SPEAR T-cells in patients with advanced hepatocellular carcinoma Cancer Res 79 13_Supplement 2019 Jul 1 3183–3183
