Immunotherapy of hepatocellular carcinoma

Gene therapy for people with hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma is the most common type of liver cancer, accounting for 70% to 85% of individuals with primary liver cancer. Gene therapy, which uses genes to treat or prevent diseases, holds potential for treatment, especially for tumours. Trials on the effects of gene therapy in people with hepatocellular carcinoma have been published or are ongoing.

OBJECTIVES

To evaluate the benefits and harms of gene therapy in people with hepatocellular carcinoma, irrespective of sex, administered dose, and type of formulation.

SEARCH METHODS

We identified randomised clinical trials through electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, LILACS, Science Citation Index Expanded, and Conference Proceedings Citation Index-Science. We searched five online clinical trial registries to identify unpublished or ongoing trials. We checked reference lists of the retrieved studies for further trials. The date of last search was 20 January 2023.

SELECTION CRITERIA

We aimed to include randomised clinical trials assessing any type of gene therapy in people diagnosed with hepatocellular carcinoma, irrespective of year, language of publication, format, or outcomes reported.

DATA COLLECTION AND ANALYSIS

We followed Cochrane methodology and used Review Manager to prepare the review. The primary outcomes were all-cause mortality/overall survival (whatever data were provided), serious adverse events during treatment, and health-related quality of life. The secondary outcomes were proportion of people with disease progression, adverse events considered non-serious, and proportion of people without improvement in liver function tests. We assessed risk of bias of the included trials using RoB 2 and the certainty of evidence using GRADE. We presented the results of time-to-event outcomes as hazard ratios (HR), dichotomous outcomes as risk ratios (RR), and continuous outcomes as mean difference (MD) with their 95% confidence intervals (CI). Our primary analyses were based on intention-to-treat and outcome data at the longest follow-up.

MAIN RESULTS

We included six randomised clinical trials with 364 participants. The participants had unresectable (i.e. advanced inoperable) hepatocellular carcinoma. We found no trials assessing the effects of gene therapy in people with operable hepatocellular carcinoma. Four trials were conducted in China, one in several countries (from North America, Asia, and Europe), and one in Egypt. The number of participants in the six trials ranged from 10 to 129 (median 47), median age was 55.2 years, and the mean proportion of males was 72.7%. The follow-up duration ranged from six months to five years. As the trials compared different types of gene therapy and had different controls, we could not perform meta-analyses. Five of the six trials administered co-interventions equally to the experimental and control groups. All trials assessed one or more outcomes of interest in this review. The certainty of evidence was very low in five of the six comparisons and low in the double-dose gene therapy comparison. Below, we reported the results of the primary outcomes only. Pexastimogene devacirepvec (Pexa-Vec) plus best supportive care versus best supportive care alone There is uncertainty about whether there may be little to no difference between the effect of Pexa-Vec plus best supportive care compared with best supportive care alone on overall survival (HR 1.19, 95% CI 0.78 to 1.82; 1 trial (censored observation at 20-month follow-up), 129 participants; very low-certainty evidence) and on serious adverse events (RR 1.42, 95% CI 0.60 to 3.33; 1 trial at 20 months after treatment, 129 participants; very low-certainty evidence). The trial reported quality of life narratively as "assessment of quality of life and time to symptomatic progression was confounded by the high patient dropout rate." Adenovirus-thymidine kinase with ganciclovir (ADV-TK/GCV) plus liver transplantation versus liver transplantation alone There is uncertainty about whether ADV-TK/GCV plus liver transplantation may benefit all-cause mortality at the two-year follow-up (RR 0.39, 95% CI 0.20 to 0.76; 1 trial, 45 participants; very low-certainty evidence). The trial did not report serious adverse events other than mortality or quality of life. Double-dose ADV-TK/GCV plus liver transplantation versus liver transplantation alone There is uncertainty about whether double-dose ADV-TK/GCV plus liver transplantation versus liver transplantation may benefit all-cause mortality at five-year follow-up (RR 0.40, 95% CI 0.22 to 0.73; 1 trial, 86 participants; low-certainty evidence). The trial did not report serious adverse events other than mortality or quality of life. Recombinant human adenovirus-p53 with hydroxycamptothecin (rAd-p53/HCT) versus hydroxycamptothecin alone There is uncertainty about whether there may be little to no difference between the effect of rAd-p53/HCT versus hydroxycamptothecin alone on the overall survival at 12-month follow-up (RR 3.06, 95% CI 0.16 to 60.47; 1 trial, 48 participants; very low-certainty evidence). The trial did not report serious adverse events or quality of life. rAd-p53/5-Fu (5-fluorouracil) plus transarterial chemoembolisation versus transarterial chemoembolisation alone The trial included 46 participants. We had insufficient data to assess overall survival. The trial did not report serious adverse events or quality of life. E1B-deleted (dl1520) adenovirus versus percutaneous ethanol injection The trial included 10 participants. It did not report data on overall survival, serious adverse events, or health-related quality of life. One trial did not provide any information on sponsorship; one trial received a national research grant, one trial by the Pedersen foundation, and three were industry-funded trials. We found five ongoing randomised clinical trials.

AUTHORS' CONCLUSIONS

The evidence is very uncertain about the effects of gene therapy on the studied outcomes because of high risk of bias and imprecision of outcome results. The trials were underpowered and lacked trial data on clinically important outcomes. There was only one trial per comparison, and we could not perform meta-analyses. Therefore, we do not know if gene therapy may reduce, increase, or have little to no effect on all-cause mortality or overall survival, or serious adverse events in adults with unresectable hepatocellular carcinoma. The impact of gene therapy on adverse events needs to be investigated further. Evidence on the effect of gene therapy on health-related quality of life is lacking.

New Therapeutics for HCC: Does Tumor Immune Microenvironment Matter?

The incidence of liver cancer is continuously rising where hepatocellular carcinoma (HCC) remains the most common form of liver cancer accounting for approximately 80-90% of the cases. HCC is strongly prejudiced by the tumor microenvironment and being an inflammation-associated condition, the contribution of various immune mechanisms is critical in its development, progression, and metastasis. The tumor immune microenvironment is initially inflammatory which is subsequently replenished by the immunosuppressive cells contributing to tumor immune escape. Regardless of substantial advancement in systemic therapy, HCC has poor prognosis and outcomes attributed to the drug resistance, recurrence, and its metastatic behavior. Therefore, currently, new immunotherapeutic strategies are extensively targeted in preclinical and clinical settings in order to elicit robust HCC-specific immune responses and appear to be quite effective, extending current treatment alternatives. Understanding the complex interplay between the tumor and the immune cells and its microenvironment will provide new insights into designing novel immunotherapeutics to overcome existing treatment hurdles. In this review, we have provided a recent update on immunological mechanisms associated with HCC and discussed potential advancement in immunotherapies for HCC treatment.

Immunotherapy for hepatocellular carcinoma: A review of potential new drugs based on ongoing clinical studies as of 2019

In the latest years, antineoplastic immunotherapy revolutionised the therapeutic landscape in oncology. First shown to be effective in melanoma and non-small cell lung carcinoma, immune checkpoint inhibitors are now being tested for the treatment of hepatocellular carcinoma (HCC). Preliminary results have been particularly promising. As a consequence, an increasing number of clinical trials are underway. The role of the immune system in carcinogenesis (with particular reference to tumour escape immune mechanisms), as well as the current immunotherapy trials for HCC in its different clinical scenarios, are the subject of this review. In particular, we aim to provide fresh updates about these novel therapeutic agents which promise to shape the future therapeutic scenario of HCC.

Controversies in the management of hepatocellular carcinoma

The management of hepatocellular carcinoma (HCC) has evolved considerably over the last decade. Surveillance of cirrhotic patients and refinements to imaging techniques have enabled a relevant proportion of patients to be diagnosed at an early stage, when effective therapies are feasible. Resection, transplantation and ablation are all options in patients with early stage HCC. Thus, there is some controversy regarding which is the best treatment approach in challenging scenarios. There have also been major developments in locoregional therapies, particularly in intra-arterial approaches. Finally, the systemic treatment for HCC has changed dramatically following the demonstration of a survival benefit with sorafenib; there are currently several first-line (sorafenib and lenvatinib) and second-line (regorafenib, cabozantinib and ramucirumab) treatments that have shown a survival benefit. Expectations for immune checkpoint inhibitors are high, with the results of the ongoing phase III trials eagerly awaited. In this review we discuss some of the controversies in the management of HCC, focussing in particular on systemic therapy.

Significance of PD-L1 clones and C-MET expression in hepatocellular carcinoma

Programmed cell death ligand 1 (PD-L1) is an essential immune checkpoint protein implicated in immune evasion by malignant tumors. Overexpression of programmed cell death protein 1 (PD-1) and its ligand PD-L1 is associated with poor prognosis in various types of cancer. Recently, multiple advances have occurred in the area of cancer immunotherapy. Inhibiting the ligation of PD-1 by PD-L1 has been the major focus of anti-tumor immunotherapy. In diagnostic pathology, it has become crucial to detect PD-L1⁺ tumor cases using a validated immunohistochemistry (IHC) approach. Preliminary data demonstrate that C-MET promotes survival of some (e.g., renal) cancer types through regulation of PD-L1. However, C-MET expression, and its association with PD-L1, has not been well-characterized in the context of hepatocellular carcinoma (HCC), and no anti-HCC immunotherapy is currently available in Korea. Therefore, it is crucial to investigate the expression of C-MET and PD-L1, and their association with clinicopathologic factors, to facilitate the development of targeted treatments for HCC. PD-L1 expression was examined in tumor cells (TC) and immune cells (IC) of 70 patient-derived HCC specimens using IHC. Two anti-PD-L1 monoclonal antibodies (MAbs), SP263 and SP142, were utilized. Additionally, TC C-MET expression was assessed. Correlations between PD-L1 expression (as identified by both MAbs), C-MET expression and clinicopathologic factors were assessed. More PD-L1⁺ cases were identified via SP263 than via SP142 when assessing both TC and IC; in the former group, SP236 identified 14/70 positive cases, while SP142 identified only 2/70. In the latter group, SP236 identified 49/70 positive cases, while SP142 identified 30/70. Both MAbs demonstrated a higher frequency of PD-L1 expression by IC than TC. The Edmondson-Steiner grade statistically correlated with a higher frequency of SP236-detected TC PD-L1 expression. C-MET was significantly associated with advanced tumor size and was positively correlated with SP263-detected PD-L1 expression in TC. These results suggest that C-MET may serve a role in regulating PD-L1 expression in HCC. Furthermore, while SP263 generally exhibited a higher sensitivity for PD-L1 detection, concordance in PD-L1⁺ case detection between the two different MAbs was generally good. These background data may be helpful in the development of targeted anti-HCC immunotherapy focused on PD-L1 or C-MET, and in evaluating selection criteria for target populations best suited to such treatments.

Overexpression of PD-L1 and PD-L2 Is Associated with Poor Prognosis in Patients with Hepatocellular Carcinoma

Purpose

Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Recently, the overexpression of programmed cell death 1 (PD-1) and PD-1 ligand 1 (PD-L1) has been shown to correlate with poor prognosis in many cancers. However, the expression of PD-L1 or PD-1 ligand 2 (PD-L2) and clinical outcomes have not been fully investigated in HCC.

Materials and Methods

Formalin-fixed paraffin-embedded samples were obtained from 85 patients with HCC who underwent surgery. The expression of PD-Ls (PD-L1, PD-L2) was evaluated by immunohistochemical analysis.

Results

The proportion of high expression groups of PD-L1 and PD-L2 was 27.1% and 23.5%, respectively. Univariate analysis revealed that tumor size (p < 0.001), histological differentiation (p=0.010), PD-L1 expression (p < 0.001), and PD-L2 expression (p=0.039) were significant prognostic factors of overall survival in patients with HCC. Multivariate analysis revealed that overall tumor size (hazard ratio [HR], 4.131; 95% confidence interval [CI], 2.233 to 7.643; p < 0.001 and HR, 3.455; 95% CI, 1.967 to 6.067; p < 0.001) and PD-L1 expression (HR, 5.172; 95% CI, 2.661 to 10.054; p < 0.001 and HR, 3.730; 95% CI, 1.453 to 9.574; p=0.006) were independent prognostic values for overall and disease-free survival. Patients with high expression of PD-Ls had a significantly poorer survival than those with low expression (p < 0.001, p=0.034).

Conclusion

The overexpression of PD-Ls in HCC patients is correlated with survival and tumor recurrence. Further evaluation of PD-1 and PD-Ls as therapeutic targets and predictive biomarkers for HCC is warranted.