Evolution of checkpoint inhibitors for the treatment of metastatic gastric cancers: Current status and future perspectives

Development and validation of a prognostic immunoinflammatory index for patients with gastric cancer

BACKGROUND

Studies have demonstrated the influence of immunity and inflammation on the development of tumors. Although single biomarkers of immunity and inflammation have been shown to be clinically predictive, the use of biomarkers integrating both to predict prognosis in patients with gastric cancer remains to be investigated.

AIM

To investigate the prognostic and clinical significance of inflammatory biomarkers and lymphocytes in patients undergoing surgical treatment for gastric cancer.

METHODS

Univariate COX regression analysis was performed to identify potential prognostic factors for patients with gastric cancer undergoing surgical treatment. Least absolute shrinkage and selection operator-COX (LASSO-COX) regression analysis was performed to integrate these factors and formulate a new prognostic immunoinflammatory index (PII). The correlation between PII and clinical characteristics was statistically analyzed. Nomograms incorporating the PII score were devised and validated based on the time-dependent area under the curve and decision curve analysis.

RESULTS

Patients exhibiting elevated neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and systemic immune inflammatory index displayed inferior progression-free survival (PFS) and overall survival (OS). Conversely, low levels of CD3(+), CD3(+) CD8(+), CD4(+)CD8(+), and CD3(+)CD16(+)CD56(+) T lymphocytes were associated with improved PFS and OS, while high CD19(+) T lymphocyte levels were linked to worse PFS and OS. The PII score demonstrated associations with tumor characteristics (primary tumor site and tumor size), establishing itself as an independent prognostic factor for both PFS and OS. Time-dependent area under the curve and decision curve analysis affirmed the effectiveness of the PII-based nomogram as a robust prognostic predictive model.

CONCLUSION

PII may be a reliable predictor of prognosis in patients with gastric cancer undergoing surgical treatment, and it offers insights into cancer-related immune-inflammatory responses, with potential significance in clinical practice.

Immunotherapy Based on Immune Checkpoint Molecules and Immune Checkpoint Inhibitors in Gastric Cancer-Narrative Review

Due to its rapid progression to advanced stages and highly metastatic properties, gastric cancer (GC) is one of the most aggressive malignancies and the fourth leading cause of cancer-related deaths worldwide. The metastatic process includes local invasion, metastasis initiation, migration with colonisation at distant sites, and evasion of the immune response. Tumour growth involves the activation of inhibitory signals associated with the immune response, also known as immune checkpoints, including PD-1/PD-L1 (programmed death 1/programmed death ligand 1), CTLA-4 (cytotoxic T cell antigen 4), TIGIT (T cell immunoreceptor with Ig and ITIM domains), and others. Immune checkpoint molecules (ICPMs) are proteins that modulate the innate and adaptive immune responses. While their expression is prominent on immune cells, mainly antigen-presenting cells (APC) and other types of cells, they are also expressed on tumour cells. The engagement of the receptor by the ligand is crucial for inhibiting or stimulating the immune cell, which is an extremely important aspect of cancer immunotherapy. This narrative review explores immunotherapy, focusing on ICPMs and immune checkpoint inhibitors in GC. We also summarise the current clinical trials that are evaluating ICPMs as a target for GC treatment.

Clinical outcomes and biomarker exploration of first-line PD-1 inhibitors plus chemotherapy in patients with low PD-L1-expressing of gastric or gastroesophageal junction adenocarcinoma

BACKGROUND

The beneficial effects of first-line programmed death-1 (PD-1) inhibitors plus chemotherapy in patients with low programmed death-ligand 1 (PD-L1)-expressing advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma are controversial.

METHODS

We conducted a retrospective analysis of patients with G/GEJ adenocarcinoma who had undergone first-line treatment with PD-1 inhibitors plus chemotherapy between October 2017 and May 2022. The primary outcomes were objective response rate (ORR) and progression-free survival (PFS). SPSS software V27.0 was used for data analysis.

RESULTS

Of 345 enrolled patients, 290 had measurable lesions. The overall ORR was 59.3%. PD-L1 status was available in 171 patients, and 67.8% of them were considered as low PD-L1 expression level (combined positive score (CPS) < 5). Patients with PD-L1 CPS < 5 showed a lower response rate (51.1% vs 70.8%, P = 0.024) and a worse PFS (P = 0.009) compared to those with PD-L1 CPS ≥ 5. In the PD-L1 low-expression cohort, patients with non-diffuse type, GEJ cancer, synchronous metastasis, distant lymph node metastasis, liver metastasis, non-peritoneal metastasis, and HER2 positive were significantly associated with higher response rates to PD-1 inhibitors plus chemotherapy (P < 0.05). The presence of peritoneal metastasis (P = 0.028) and diffuse type (P = 0.046) were identified as independent predictors of poor PFS in multivariate analysis of the PD-L1 CPS < 5 subgroup. When evaluated for correlation with overall survival (OS) in the PD-L1 low-expression subgroup, peritoneal metastasis was found to be the only independent prognostic factor of an increased risk of death (hazard ratio: 2.31, 95% CI 1.09-4.90; P = 0.029).

CONCLUSIONS

PD-L1 CPS ≥ 5 is significantly associated with improved response and extended PFS in G/GEJ cancer patients treated with a combination of PD-1 inhibitors and chemotherapy. Specific subgroups within the low PD-L1-expressing population, such as those with non-diffuse-type tumors and without peritoneal metastases, may also benefit from immunotherapy combined with chemotherapy.

Identification of the exosomal PD-L1 inhibitor to promote the PD-1 targeting therapy of gastric cancer

Programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) targeting therapy is widely applied in clinics for gastric cancer treatment. Nevertheless, the clinical response is not well acceptable due to the exosomal PD-L1. Hence, abrogation of the exosomal PD-L1 may be a strategy to sensitize the gastric cancer cell to PD-1 targeting therapy. With the aid of CD63 targeting antibody and PD-L1 targeting aptamer, HTRF based assay was established to quantify the exosomal PD-L1, and applied to our in-house compound library, resulting in the identification of moclobemide. Further optimization of moclobemide lead to EP16, which can inhibit the generation of exosomal PD-L1 with IC50 = 0.108 μM. By applying EP16 to gastric cancer cell line coupled with T-cell activity related experiment, it was validated to activate T-cell and can promote the response of PD-1 targeting therapy for gastric cancer treatment in vitro and in vivo. Collectively, our findings give a promising tool to promote the sensitivity of anti-PD-1 for gastric cancer treatment, and EP16 can serve as a leading compound for exosomal PD-L1 abrogation.

Survival after Trastuzumab Therapy in Patients with Locally Advanced or Metastatic HER2-Positive Gastric or Gastroesophageal Junction Cancer: A Meta-Analysis of Randomized Controlled Trials

Background

In the Trastuzumab for Gastric Cancer study, it was found that trastuzumab combined with doublet chemotherapy (fluoropyrimidine and platinum) was the gold-standard treatment for gastroesophageal adenocarcinoma (GEA) that was locally advanced, unresectable, or metastatic (HER2+).

Materials and Methods

We performed a meta-analysis of randomized phase II/III studies testing trastuzumab in combination or alone.

Results

This meta-analysis's findings involved 2048 patients in total. The treatment arm and hormone receptor status were used to stratify the combined HR. Overall, the PFS (Random model) HR [0.80] and 95% confidence intervals (CI) [0.68-0.95] were significantly higher for regimens containing trastuzumab, fluoropyrimidine, and platinum compared to regimens containing fluoropyrimidine and platinum.

Conclusions

The results of this meta-analysis provide additional support for trastuzumab's use in treating HER2-positive GEA, particularly in cases where the disease lacks a HER2+ receptor.

A machine learning-based radiomics model for prediction of tumor mutation burden in gastric cancer

Purpose: To evaluate the potential of machine learning (ML)-based radiomics approach for predicting tumor mutation burden (TMB) in gastric cancer (GC). Methods: The contrast enhanced CT (CECT) images with corresponding clinical information of 256 GC patients were retrospectively collected. Patients were separated into training set (n = 180) and validation set (n = 76). A total of 3,390 radiomics features were extracted from three phases images of CECT. The least absolute shrinkage and selection operator (LASSO) model was used for feature screening. Seven machine learning (ML) algorithms were employed to find the optimal classifier. The predictive ability of radiomics model (RM) was evaluated with receiver operating characteristic. The correlation between RM and TMB values was evaluated using Spearman's correlation coefficient. The explainability of RM was assessed by the Shapley Additive explanations (SHAP) method. Results: Logistic regression algorithm was chosen for model construction. The RM showed good predictive ability of TMB status with AUCs of 0.89 [95% confidence interval (CI): 0.85-0.94] and 0.86 (95% CI: 0.74-0.98) in the training and validation sets. The correlation analysis revealed a good correlation between RM and TMB levels (correlation coefficient: 0.62, p < 0.001). The RM also showed favorable and stable predictive accuracy within the cutoff value range 6-16 mut/Mb in both sets. Conclusion: The ML-based RM offered a promising image biomarker for predicting TMB status in GC patients.

Immune checkpoint inhibitors plus chemotherapy for HER2-negative advanced gastric/gastroesophageal junction cancer: a cost-effectiveness analysis

Background

Nivolumab plus chemotherapy (NC) was recently approved as the first-line intervention for human epidermal growth factor receptor 2-negative advanced gastric/gastroesophageal junction cancer (GC/GEJC). Moreover, in the latest KEYNOTE-859 (NCT03675737), pembrolizumab plus chemotherapy (PC) was demonstrated to produce remarkable patient survival outcomes.

Objectives

The clinicians and patients need to assess NC and PC preference for cancer drugs.

Design

The cost-effective analysis.

Methods

In an economic assessment of the United States, United Kingdom, and Chinese healthcare systems using a Markov model simulated patients with GC/GEJC, two treatment decision branches with three health states and a tracked time horizon of 15 years were developed. The overall cost and efficacy outcomes of first-line strategies PC and NC were evaluated at willingness-to-pay (WTP) thresholds of different national, including life-years (LYs), quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios (ICERs), and incremental net-health benefit (INHB). Sensitivity and subgroup analyses were considered.

Results

Given a WTP threshold of $150,000, $60,161, and $37,653 per QALY in the United States, United Kingdom, and China, respectively, both PC and NC achieved QALYs of 1.67 and 1.65 (2.51 and 2.48 LYs), 1.65 and 1.63 (2.48 and 2.45 LYs), and 1.60 and 1.58 (2.40 and 2.37 LYs), with total costs of $242,444 and $232,617, $148,367 and $127,737, and $16,693 and $24,016, respectively. Based on our sensitivity analysis, the programmed death-1 inhibitors cost produced the largest impact on the outcome. In addition, the cost-effectiveness probabilities of PC were 38.3%, 4.1%, and 100% in the three aforementioned countries, respectively.

Conclusion

In the case of the Chinese payers' perspective, PC appeared more dominant as first-line therapy for advanced GC/GEJC patients, whereas NC was preferred in the United States and United Kingdom.

Rheumatological adverse events secondary to immune checkpoint inhibitors

The first experiences with a group of drugs called immune checkpoint inhibitors for the treatment of cancer were described in 2010. They are currently used in many tumours, with successful survival outcomes but a new profile of adverse events. This new spectrum of immune-mediated toxicities includes an exaggerated inflammatory response of T lymphocyte and the development of autoimmune diseases or similar pathologies. Of these, of particular note are the rheumatological toxicities. This review aims to alert internists and rheumatologists to their recognition and clinical management.

PIK3CA somatic mutations as potential biomarker for immunotherapy in elder or TP53 mutated gastric cancer patients

Immune checkpoint inhibitors (ICIs) improve overall survival in patients with advanced gastric cancer (GC). However, the molecular characterization of GC in ICIs responders is unclear. A total of 288 advanced GC patients were included in this study. Next-generation sequencing analysis was performed on tumor tissue and paired blood to screen for somatic mutants in 639 tumor-associated genes. We demonstrated that ARID1A, HER2/3/4, KMT2C/2D, LRP1B, PIK3CA, SPTA1, and TP53 mutations were significantly correlated with high tumor mutation burden (TMB) score, as well as HER2 amplification. For HER2 and PIK3CA mutations types, this relationship was statistically significant with age and TP53 mutation status, which was also found in the CDH1 gene. These results were confirmed by sequencing 873 GC cases in the cBioPortal database. PIK3CA mutations appear to be associated with longer survival in elderly population and TP53 mutant subtypes. For the first time, we found that GC patients ≥60 years old or with TP53 mutated type and PIK3CA mutations were associated with higher TMB and better ICI response. Building upon the age and TP53 mutation status, this study suggested a novel stratification approach to GC patients and explored the correlations between genetic somatic mutations and TMB score.

Combining neoadjuvant chemotherapy with PD-1/PD-L1 inhibitors for locally advanced, resectable gastric or gastroesophageal junction adenocarcinoma: A systematic review and meta-analysis

Background

Immune checkpoint inhibitors (ICIs) have shown promising prospects in locally advanced, resectable gastric or gastroesophageal junction adenocarcinoma (GC/GEJC) immunotherapy, but their efficacy in neoadjuvant settings remains unclear. This study aimed to assess the efficacy and safety of integrating programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors into neoadjuvant chemotherapy (NACT) of GC/GEJC treatment.

Methods

PubMed, Cochrane Library, Embase, ClinicalTrials.gov, and main oncology conference databases were systematically searched up to 19 November 2022, and randomized controlled trials (RCTs) and cohort studies that evaluated the efficacy and safety of PD-1/PD-L1 inhibitors plus NACT were included. The main outcomes were pathological complete response (pCR), major pathological response (MPR), R0 resection rate, and treatment-related adverse events (TRAEs).

Results

A total of 753 patients from 20 prospective studies were included in this meta-analysis. The pooled pCR and MPR rates from studies reporting were 21.7% [95% confidence interval (CI), 18.1%-25.5%] and 44.0% (95% CI, 34.1%-53.8%), respectively. The pooled incidence rate of total TRAEs was 89.1% (95% CI, 82.7%-94.3%), and the incidence rate of grade 3 to 4 TRAEs was 34.4% (95% CI, 17.8%-66.5%). The pooled R0 resection rate was reported to be 98.9% (95% CI, 97.0%-99.9%). Subgroup analysis has not found significant differences in efficacy and safety among different PD-1/PD-L1 inhibitors. Moreover, the efficacy in patients with positive PD-L1 expression (combined positive score ≥1) was comparable with that in the entire study population [pCR, 22.5% vs. 21.2% (p > 0.05); MPR, 48.6% vs. 43.7% (p > 0.05)].

Conclusion

This systematic review and meta-analysis found that PD-1/PD-L1 inhibitors combined with NACT for locally advanced GC/GEJC were well tolerated and may confer therapeutic advantages. The integration of ICIs into NACT has shown the potential for application in any PD-L1 expression population.

Unexpected curative effect of PD-1 inhibitor in gastric cancer with brain metastasis: A case report

Background

Gastric cancer (GC) is the third most common cause of cancer-related death in the world. Several clinical trials have proven that the use of PD-1/PD-L1 inhibitors can improve the survival of late-stage GC patients and is suggested in NCCN and CSCO guidelines. However, the correlation between PD-L1 expression and the response to PD-1/PD-L1 inhibitors is still controversial. GC rarely develops brain metastasis (BrM) and currently there is no therapeutic protocol for GC BrMs.

Case presentation

We report a case of a 46-year-old male suffering from GC with PD-L1 negative BrMs 12 years after GC resection and 5 cycles of chemotherapy. We treated the patient with the immune checkpoint inhibitor (ICI) pembrolizumab and all metastatic tumors achieved a complete response (CR). A durable remission of the tumors is confirmed after 4 years of follow-up.

Conclusion

We shared a rare case with PD-L1 negative GC BrM responsive to PD-1/PD-L1 inhibitors, the mechanism of which is still unclear. The protocol of therapeutic choice for late-stage GC with BrM is urgently needed. And we are expecting biomarkers other than PD-L1 expressions to predict the efficacy of ICI treatment.

Relationship and prognostic significance of IL-33, PD-1/PD-L1, and tertiary lymphoid structures in cervical cancer

IL-33, an epithelial-derived cytokine, functions as an alarmin for the immune system in the tumor microenvironment (TME). However, the expression and role of IL-33 on cervical cancer remain unclear. The aim of this study was to investigate the expression of IL-33 and its relationship with clinicopathologic features, tertiary lymphoid structures (TLS), and programmed cell death 1 (PD-1)/programmed cell death 1 ligand (PD-L1) immune checkpoints by immunohistochemistry in 93 cervical cancer patient specimens. Down-regulation of IL-33 expression was observed in tumor tissues compared with adjacent tissues. More importantly, IL-33 was detected in the cytoplasm of tumor fraction. IL-33 expression in tumor cytoplasm was associated with tumor size and the invasive depth of tumors (p < 0.05). Meanwhile, IL-33 expression in tumor cytoplasm was positively correlated with infiltration of CD3⁺ T cells, CD8⁺ T cells, and PD-L1 expression in tumor tissues (p < 0.05). The number of TLS strongly correlated with the depth of tumor invasion, preoperative chemotherapy, human papillomavirus infection, and high level of PD-1 (p < 0.05). However, there was no significant relationship between IL-33 and TLS. Kaplan-Meier survival curves showed that the formation of TLS was associated with a better prognosis (p = 0.008). In multivariable Cox regression modeling, high expression of PD-L1 in tumor tissues was correlated with poor prognosis (HR = 0.128; 95% CI: 0.026-0.646; p = 0.013), whereas the high expression of IL-33 in tumor tissues was associated with better prognosis (HR = 5.097; 95% CI:1.050-24.755; p = 0.043). These results indicate that IL-33, TLS, and PD-L1 are potentially valuable prognostic predictor for cervical cancer. IL-33 has potential for combination with PD-L1-related antitumor therapy.

Programmed death-ligand 1 expression in the immune compartment of colon carcinoma

Programmed cell death ligand 1 (PD-L1) on tumor cells is a significant prognostic biomarker for a number of malignancies, although less is known about the significance of PD-L1 positive immune cells in colon carcinoma. The purpose of this study is to evaluate the role of PD-L1 in a large cohort of colon carcinomas to identify patterns of PD-L1 expression in the tumor microenvironment and its correlation with other key immune subsets to better understand the impact of these immune cells. We assessed 1218 colon carcinomas on representative tissue microarray sections, gathered relevant clinicopathologic information, and performed immunohistochemical staining for mismatch repair proteins, CD8, CD163, LAG3, PD-L1, FoxP3, and BRAF V600E. We then performed automated quantification; manual quantification was used for PD-L1 tumor cells and immune cells. Dual PD-L1/PU.1 immunostain was also performed. The majority of PD-L1 positive cells expressed PU.1 thus representing tumor-associated macrophages. Based on the median number of PD-L1 positive immune cells (7.6/mm²), we classified tumors into two classes: (1) PD-L1 immune cell low and (2) PD-L1 immune cell high. PD-L1 immune cell high colon carcinomas showed favorable prognostic pathologic features including less frequent extramural venous invasion (p = 0.0001) and lower AJCC stage (p = 0.0001); they were also more commonly associated with deficient mismatch repair (dMMR) (p = 0.0001) and BRAF V600E reactivity. PD-LI immune cell high tumors were associated with high CD8, CD163, and FoxP3 positive cells (p = 0.0001, respectively). PD-L1 immune cell high and LAG3 high colon carcinomas were associated with improved disease-specific survival (p = 0.0001 and 0.001, respectively). PD-L1 expression on tumor cells was not associated with disease-specific survival. On multivariate analysis of chemotherapy naïve stage 2 colon carcinomas, only extramural venous invasion (p = 0.002), perineural invasion (p = 0.001) and PD-L1 immune cell expression (p = 0.032) correlated with disease-specific survival. Resected colonic carcinomas with high expression of PD-L1 and LAG3 proteins on immune cells were associated with improved prognosis in colon carcinoma. The mechanism underlying the improved prognosis of colon carcinomas bearing high numbers of immunoregulatory cells needs further investigation.

A novel prognostic index of stomach adenocarcinoma based on immunogenomic landscape analysis and immunotherapy options

Stomach adenocarcinoma (STAD) is one of the most common malignant tumors worldwide. In this study, we attempted to construct a valid immune-associated gene prognostic index risk model that can predict the survival of patients with STAD and the efficacy of immune checkpoint inhibitors (ICIs) treatment. Transcriptome, clinical, and gene mutational data were obtained from the TCGA database. Immune-related genes were downloaded from the ImmPort and InnateDB databases. A total of 493 immune-related genes were identified to be enriched in functions associated with immune response, as well as in immune and tumor-related pathways. Further, 36 candidate genes related to the overall survival (OS) of STAD were obtained by weighted gene co-expression network analysis (WGCNA). Next, based on a Cox regression analysis, we constructed an immune-associated gene prognostic index (IAGPI) risk model based on eight genes, which was verified using the GEO STAD cohort. The patients were divided into two subsets according to their risk score. Patients in the low-risk group had better OS than those in the high-risk group. In the low-risk group, there were more CD8, activated memory CD4, and follicular helper T cells, and M1 macrophages, whereas monocytes, M2 macrophages, eosinophils, and neutrophils were more abundant in the high-risk group. The patients in the low-risk group were more sensitive to ICIs therapy. The IAGPI risk model can precisely predict the prognosis, reflect the tumor immune microenvironment, and predict the efficacy of ICIs therapy in patients with STAD.

An Immune-Related Prognostic Signature Predicts Overall Survival in Stomach Adenocarcinomas

This study aimed to explore an immune response-related gene signature to predict the clinical prognosis and tumor immunity of stomach adenocarcinomas (STAD). Based on the expression and clinical data of STAD in the TCGA database, the immune cell infiltration status was evaluated using CIBERSORT and ESTIMATE methods. Samples were grouped into “hot” and “cold” tumors based on immune cell infiltration status and consensus clustering. The infiltration abundance of activated memory CD4 T cells and CD8 T cells had a significant effect on the overall survival of STAD patients. Among the three clusters, cluster 2 had a higher immune score and a significantly higher abundance of CD8 T cells and activated memory CD4 T cells were assigned as a hot tumor, while cluster 1 and 3 were assigned as a cold tumor. DEGs between hot and cold tumors were mainly enriched in immune-related biological processes and pathways. Total of 13 DEGs were related to the overall survival (OS). After the univariate and multivariable Cox regression analysis, three signature genes (PEG10, DKK1, and RGS1) was identified to establish a prognostic model. Patients with the high-risk score were associated with worse survival, and the risk score had an independent prognostic value. Based on TIMER online tool, the infiltration levels of six immune cell types showed significant differences among different copy number statuses of PEG10, DKK1, and RGS1. In this study, an immune-related prognostic model containing three genes was established to predict survival for STAD patients.

Perioperative treatment in resectable gastric cancer with spartalizumab in combination with fluorouracil, leucovorin, oxaliplatin and docetaxel (FLOT): a phase II study (GASPAR)

Background

Perioperative chemotherapy and surgery are a standard of care for patients with resectable gastric or gastroesophageal junction (GEJ) adenocarcinoma. However, the prognosis remains poor for this population. The FLOT (fluorouracil, leucovorin, oxaliplatin, and docetaxel) regimen is considered as the new standard chemotherapy regimen for perioperative strategy, despite associated with a 5-year overall survival rate (OS) amounting 45% following radical surgery.

Immunotherapy with antibodies that inhibit PD-1/ PD-L1 interaction has recently emerged as a new treatment option with promising and encouraging early trial results for patients with advanced or metastatic gastric or GEJ adenocarcinoma. Currently, no trials have investigated the impact of perioperative immunotherapy in combination with chemotherapy for resectable gastric or GEJ adenocarcinoma.

Methods

GASPAR trial is a multicenter open-label, nonrandomized, phase II trial to evaluate the efficacy and safety of Spartalizumab in combination with the FLOT regimen as perioperative treatment for resectable gastric or GEJ adenocarcinoma. The main endpoint is the proportion of patients with pathological complete regression (pCR) in the primary tumour after preoperative treatment.

Systemic treatment will include a pre-operative neoadjuvant and a post-operative adjuvant treatment, during which FLOT regimen will be administered every two weeks for 4 cycles and Spartalizumab every four weeks for 2 cycles.

For patients with confirmed tumor resectability on imaging assessment, surgery will be realized within 4–6 weeks after the last dose of preoperative chemotherapy. Post-operative systemic treatment will then be initiated within 4–10 weeks after surgery.

Using a Simon’s two-stage design, up to 67 patients will be enrolled, including 23 in the first stage.

Discussion

Currently, no trials have investigated the impact of immunotherapy in combination with FLOT chemotherapy as perioperative treatment for resectable gastric or GEJ adenocarcinoma. Some studies have suggested a change in the tumor immune micro-environment following neoadjuvant chemotherapy in this setting, reinforcing the relevance to propose a phase II trial evaluating efficacy and safety of Spartalizumab in combination with perioperative chemotherapy, with the aim of improving treatment efficacy and survival outcomes.

Trial registration

NCT04736485, registered February, 3, 2021.

Plasma extracellular vesicle derived protein profile predicting and monitoring immunotherapeutic outcomes of gastric cancer

Immune checkpoint inhibitor (ICI)‐based immunotherapy brought new hope for gastric cancer (GC) treatment. However, due to the lack of proper biomarkers, patient selection and outcome prediction for GC's immunotherapy remain unsatisfying. In this study, through applying an extracellular vesicle (EV) protein expression array, we assessed the correlation of plasma EV‐derived protein spectrum with outcomes of ICI‐related therapeutic combinations. Plasma from 112 GC patients received ICI‐related therapies were investigated retrospectively/prospectively as three cohorts. We identified four plasma EV‐derived proteins (ARG1/CD3/PD‐L1/PD‐L2) from 42 crucial candidate proteins and combined them as an EV‐score that robustly predicting immunotherapeutic outcomes at baseline and dynamically monitoring disease progression along with treatment. High EV‐score reflected microenvironmental features of stronger antitumour immunity, characterized by more activated CD8⁺ T/NK cells, higher TH1/TH2 ratio and higher expressions of IFN‐γ/perforin/granzymes in paired peripheral blood, which were verified by dataset analysis and in vivo experiments. EV‐score≥1 GC received more therapeutic benefits from ICIs, while EV‐score < 1 GC potentially benefited more from ICIs combining HER2‐targeted therapies. Collectively, through proposing a plasma EV‐score on protein level that powerfully predicting and monitoring GC's immunotherapeutic outcomes, our work facilitated clinical patient selection and decision‐makings, and provided mechanistical insights for immunotherapy‐related microenvironmental changes and improvements for current ICI‐regimens.

Pulmonary Resection after Radiosurgery and Neoadjuvant Immunochemotherapy for NSCLC Patients with Synchronous Brain Metastasis—A Case Series of Three Patients

Simple Summary

In this short communication, we present three cases of patients with symptomatic, synchronous brain metastases of otherwise locally limited non-small cell lung cancer. The patients received local ablative treatment of the brain metastases followed by neoadjuvant immunochemotherapy with pemetrexed, cisplatin, and pembrolizumab, and resection of the pulmonary lesion with curative intent. With two of the patients still alive and maintaining a good quality of life with a progression-free survival and overall survival of 28 and 35 months, respectively, this case series illustrates the potential of novel combinatorial treatment approaches.

Abstract

Brain metastases are a common finding upon initial diagnosis of otherwise locally limited non-small cell lung cancer. We present a retrospective case series describing three cases of patients with symptomatic, synchronous brain metastases and resectable lung tumors. The patients received local ablative treatment of the brain metastases followed by neoadjuvant immunochemotherapy with pemetrexed, cisplatin, and pembrolizumab. Afterwards, resection of the pulmonary lesion with curative intent was performed. One patient showed progressive disease 12 months after initial diagnosis, and passed away 31 months after initial diagnosis. Two of the patients are still alive and maintain a good quality of life with a progression-free survival and overall survival of 28 and 35 months, respectively, illustrating the potential of novel combinatorial treatment approaches.

Safety and efficacy of HER2 blockade by trastuzumab-based chemotherapy-containing combination strategies in HER2+ gastroesophageal adenocarcinoma

Since completion of the Trastuzumab for Gastric Cancer study, trastuzumab with doublet chemotherapy (a fluoropyrimidine and a platinum) has been the gold-standard first-line therapy for patients with locally advanced unresectable or metastatic human epidermal growth factor receptor 2-positive (HER2+) gastroesophageal adenocarcinoma (GEA). The safety and efficacy of 23 studies of first-line trastuzumab plus doublet chemotherapy, without checkpoint inhibitors (n = 19) or with checkpoint inhibitors (n = 4), conducted in patients with locally advanced unresectable or metastatic HER2+ GEA, including phase II/III, prospective, and retrospective observational studies, were summarized. In studies without checkpoint inhibitors, the median duration of trastuzumab treatment ranged from 19.5 to 39.0 weeks and from 15.3 to 30.0 weeks for chemotherapy. In studies with checkpoint inhibitors, the median duration of pembrolizumab/trastuzumab/chemotherapy was 30 weeks, and 18 weeks for chemotherapy. In studies without checkpoint inhibitors, treatment-emergent adverse events (TEAEs) of grade ≥3 ranged from 32% to 84%. Serious adverse events (SAEs) ranged from 15% to 39%. Adverse events resulting in discontinuation ranged from 0% to 30%. Treatment-related deaths occurred in 0%-9% of patients. In studies with checkpoint inhibitors, TEAEs of grade ≥3 were 57%. SAEs ranged from 31% to 38%. Adverse events resulting in discontinuation ranged from 5% to 24%. Treatment-related deaths occurred in 0%-3% of patients. In studies without checkpoint inhibitors, objective response rate (ORR) ranged from 39% to 82%, median progression-free survival (PFS) from 5.7 to 11.6 months, and median overall survival (OS) from 11.2 to 27.6 months. In studies with checkpoint inhibitors, ORR ranged from 39% to 86%, median PFS from 8.0 to 13.0 months, and median OS from 19.3 to 27.3 months. This review provides a historical benchmark on safety and efficacy of available first-line chemotherapy-based standard of care for patients with locally advanced unresectable or metastatic HER2+ GEA.

Immune-Checkpoint Inhibition in the Treatment of Gastro-Esophageal Cancer: A Closer Look at the Emerging Evidence

To date, several trials have evaluated the safety and efficacy of immune-checkpoint inhibitors (ICI) for the treatment of gastroesophageal cancers (GEC). In the US, ICIs have established indications for second-line treatment of microsatellite unstable tumors, while their use in third-line settings was recently withdrawn. Notably, the use of ICIs for first-line therapy of GEC is rapidly evolving, which currently includes high PD-L1 expressing tumors, irrespective of HER2 status, and in the adjuvant setting after neoadjuvant chemoradiotherapy in select patients. In this article, we review the results of studies that have evaluated the utility of ICI in the third-line, second-line, first-line, and peri-operative treatment settings of GECs. Considerations should be made before making any cross-trial comparisons since these trials vary in chemotherapy backbone, anatomical and histological eligibility, biomarker assessment, PD-L1 diagnostic antibodies, and definition of PD-L1 positivity. Regardless, the totality of the data suggest that first-line ICI use may most benefit GEC patients with high PD-L1 combined positivity score (CPS) ≥5 or ≥10, irrespective of histology or anatomy. Moreover, although PD-L1 by CPS has a good negative predictive value for significant benefit from ICIs, it has a low positive predictive value. Therefore, there is a pressing need to identify better biomarkers to predict benefit from ICIs among these patients.

Immune infiltration profiling in gastric cancer and their clinical implications

The abundance and type of immune cells in the tumor microenvironment (TME) significantly influence immunotherapy and tumor progression. However, the role of immune cells in the TME of gastric cancer (GC) is poorly understood. We studied the correlations, proportion, and infiltration of immune and stromal cells in GC tumors. Data analyses showed a significant association of infiltration levels of specific immune cells with the pathological characteristics and clinical outcomes of GC. Furthermore, based on the difference in infiltration levels of immune and stromal cells, GC patients were divided into two categories, those with "immunologically hot" (hot) tumors and those with "immunologically cold" (cold) tumors. The assay for transposase-accessible chromatin using sequencing and RNA sequencing analyses revealed that the hot and cold tumors had altered epigenomic and transcriptional profiles. Claudin-3 (CLDN3) was found to have high expression in the cold tumors and negatively correlated with CD8⁺ T cells in GC. Overexpression of CLDN3 in GC cells inhibited the expression of MHC-I and CXCL9. Finally, the differentially expressed genes between hot and cold tumors were utilized to generate a prognostic model, which predicted the overall survival of GC as well as patients with immunotherapy. Overall, we undertook a comprehensive analysis of the immune cell infiltration pattern in GC and provided an accurate model for predicting the prognosis of GC patients.

Identification and Validation of the Immune Regulator CXCR4 as a Novel Promising Target for Gastric Cancer

Immune checkpoint blockade has attracted a lot of attention in the treatment of human malignant tumors. We are trying to establish a prognostic model of gastric cancer (GC) based on the expression profile of immunoregulatory factor-related genes. Based on the TCGA database, we identified 234 differentially expressed immunoregulatory factors. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) conducted enrichment analysis to clarify the biological functions of differential expression of immunoregulatory factors. STRING database predicted the interaction network between 234 differently expressed immune regulatory factors. The expression of 11 immunoregulatory factors was significantly related to the overall survival of gastric cancer patients. Univariate Cox regression analysis, Kaplan–Meier analysis and multivariate Cox regression analysis found that immunomodulatory factors were involved in the progression of gastric cancer and promising biomarkers for predicting prognosis. Among them, CXCR4 was related to the low survival of GC patients and a key immunomodulatory factor in GC. Based on TCGA data, the high expression of CXCR4 in GC was positively correlated with the advanced stage and grade of gastric cancer and related to poor prognosis. Univariate analysis and multivariate analysis indicated that CXCR4 was an independent prognostic indicator for TCGA gastric cancer patients. In vitro functional studies had shown that CXCR4 promoted the proliferation, migration, and invasion of gastric cancer cells. In summary, this study has determined the prognostic value of 11 immunomodulatory factors in gastric cancer. CXCR4 is an independent prognostic indicator for gastric cancer patients, which may help to improve the individualized prognostic prediction of GC and provide candidates for the diagnosis and treatment of GC.

Multistage-responsive nanovehicle to improve tumor penetration for dual-modality imaging-guided photodynamic-immunotherapy

The exploration of an intelligent multifunctional imaging-guided therapeutic platform is of great significance because of its ideal delivery efficiency and controlled release. In this work, a tumor microenvironment (TME)-responsive nanocarrier (denoted as MB@MSP) is designed for on-demand, sequentially release of a short D-peptide antagonist of programmed cell death-ligand 1 (named as P^DPPA-1) and a photosensitizer methylene blue (MB). Fe₃O₄-Au located in the core of MB@MSP is used as a magnetic resonance imaging and micro-computed tomography imaging contrast agent for noninvasive diagnosis of solid tumors and simultaneous monitoring of drug delivery. The P^DPPA-1 coated on MB@MSP can be shed due to the cleavage of the peptide substrate by matrix metalloproteinase-2 (MMP-2) that is highly expressed in the tumor stroma, and disulfide bonding is further broken when it encounters high levels of glutathione (GSH) in TME, which finally leads to significant size reduction and charge-reversal. These transitions facilitate penetration and uptake of nanocarriers against tumors. Noticeably, the released P^DPPA-1 can block the immune checkpoint to create an environment that favors the activation of cytotoxic T lymphocytes and augment the antitumor immune response elicited by photodynamic therapy, thus significantly improving therapeutic outcomes. Studies of the underlying mechanisms suggest that the designed MMP-2 and GSH-sensitive delivery system not only induce apoptosis of tumor cells but also modulate the immunosuppressive tumor microenvironment to eventually augment the suppression tumor metastasis effect of CD8⁺ cytotoxic T cells. Overall, the visualization of the therapeutic processes with comprehensive information renders MB@MSP an intriguing platform to realize the combined treatment of metastatic tumors.

Myeloid-Derived Suppressor Cells in Immune Microenvironment Promote Progression of Esophagogastric Junction Adenocarcinoma

Adenocarcinoma of the esophagogastric junction (AEG) is a fatal disease. Accumulating evidence indicates that, for a comprehensive understanding of AEG, studies should be conducted not only to investigate tumor cells, but also the tumor microenvironment (TME). In this study, we collected AEG patient data from The Cancer Genome Atlas, and used the CIBERSORT algorithm to analyze tumor-infiltrating immune cell profiles. The levels of CD8⁺ T cells and M0 and M2 macrophages were relatively high in AEG tissues. M2 macrophages were abundant in G3 tumors, and neutrophils were associated with poor prognosis. Myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of immunosuppressive cells which share a similar origin to neutrophils and macrophages. We further analyzed the levels of MDSCs in AEG patients and healthy donors (HD) using flow cytometry. MDSC levels were elevated at tumor sites, with polymorphonuclear MDSCs (PMN-MDSCs) being the predominant subtype. Circulating MDSCs partly represented cells at the tumor site. We observed that PMN-MDSC levels at tumor sites were positively correlated with advanced staging, low grade, lymph node metastasis, and HER2⁻ status. Immunohistochemistry and immunofluorescence analyses indicated that activation of the STAT3 and NF-κB pathways in MDSCs may be a potential mechanism for cancer progression. Our studies provided a comprehensive perspective involving tumor-infiltrating immune cells, and detailed insights into the proportion of MDSCs in AEG and their clinical significance. Together, these findings may improve our current understanding of cancer progression involving tumor-infiltrating immune cells in the TME.

Immune Checkpoint Inhibition in Oesophago-Gastric Carcinoma

Immune checkpoint inhibitors enrich the therapeutic landscape in oesophago-gastric carcinoma. With regard to oesophageal squamous cell carcinoma (ESCC), the selective PD-1 (programmed cell death receptor 1)-inhibitor nivolumab improves disease-free survival in the adjuvant therapy setting (CHECKMATE-577). In first-line treatment, ESCC patients (pts) benefit in overall survival (OS) from the PD-1-inhibitor pembrolizumab in combination with chemotherapy (KEYNOTE-590). In the second-line setting, nivolumab (ATTRACTION-03) and pembrolizumab (KEYNOTE-181) demonstrate a benefit in OS compared with chemotherapy. These data resulted in the approval of nivolumab for the second-line treatment of advanced ESCC pts regardless of PD-L1 (programmed cell death ligand 1) status in Europe, Asia, and the USA, and pembrolizumab for pts with PD-L1 CPS (combined positivity score) ≥ 10 in Asia and the USA. Further approvals can be expected. In gastro-oesophageal junction and gastric cancer, the addition of nivolumab to chemotherapy in first-line treatment improves OS in pts with advanced disease with PD-L1 CPS ≥ 5 (CHECKMATE-649). Additionally, pembrolizumab was non-inferior to chemotherapy for OS in PD-L1 CPS ≥ 1 pts (KEYNOTE-062). In third-line treatment, nivolumab shows benefits in OS regardless of PD-L1 expression (ATTRACTION-02) with approval in Asia, and pembrolizumab prolonged the duration of response in PD-L1 positive pts (KEYNOTE-059) with approval in the USA. We discuss the recent results of the completed phase II and III clinical trials.

Efficacy and safety of immune checkpoint inhibitors in gastric cancer: a network meta-analysis of well-designed randomized controlled trials

Background

Immune checkpoint inhibitors (ICIs) that inhibit the programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) interactions have shown promising prospects as treatment options for advanced gastric cancer (AGC). This manuscript analyzed well designed clinical trials to evaluate the efficacy and safety of immunotherapy in AGC.

Methods

PubMed, Embase, the Cochrane Library, and Medline were searched for randomized controlled trials (RCTs) of AGC treatments that were published before April 2020. Progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and treatment-related adverse events (TRAEs) were evaluated to determine the efficacy and safety of ICIs. Network meta-analysis was performed using a random-effects model under the Bayesian framework. The ability of each treatment was ranked using the surface under the cumulative ranking (SUCRA) curve.

Results

Our analysis included five studies having seven immunotherapy regimens and 1,730 patients. The network meta-analysis showed that nivolumab 1 mg/kg every 3 weeks plus ipilimumab 3 mg/kg every 3 weeks (88.369%) was the regimen most likely to improve PFS. Nivolumab 3 mg/kg every 3 weeks (84.563%) and nivolumab 1 mg/kg every 3 weeks plus ipilimumab 3 mg/kg every 3 weeks (84.556%) were similarly best for OS outcome with excellent tolerance. The regimen of avelumab 10 mg/kg every 2 weeks (91.167%) had the lowest TRAEs. All immunotherapies had similar response rates.

Conclusions

We recommend nivolumab 3 mg/kg every 2 weeks or nivolumab 1 mg/kg every 3 weeks plus ipilimumab 3 mg/kg every 3 weeks as the preferred regimen due to their high efficacies.

A Systematic Review and Meta-analysis of PD-1 and PD-L1 Inhibitors Monotherapy in Metastatic Gastric and Gastroesophageal Junction Adenocarcinoma

Immune checkpoint inhibitors are new targeted treatments that harness the body's immune system to attack cancers. Drugs that are most extensively used among checkpoint inhibitors inhibit the PD-L1 or PD-1 (programmed death 1) ligand or receptor pair and are currently approved for many cancer indications. In gastric or gastroesophageal junction adenocarcinomas one inhibitor, pembrolizumab has regulatory approval for PD-L1 positive carcinomas. This meta-analysis investigates available data on the efficacy of PD-L1 or PD-1 inhibitors as a class in gastric or gastroesophageal junction adenocarcinomas. The literature was reviewed to identify clinical studies that included arms with PD-L1 or PD-1 inhibitors as monotherapy in gastric or gastroesophageal junction adenocarcinomas. Relevant patient characteristics, outcomes, and adverse effects were recorded. Summary estimates of response rates (RR) and survival were calculated using a random or fixed effect model, depending on heterogeneity. Six studies with a total of 1068 patients were included in the analysis. The summary RR was 10.63% (95% confidence interval (CI) 5.36–15.89%). The summary disease control rate (DCR) was 28.11% (95% CI 24.60–31.63%). Summary progression-free survival (PFS) was 1.59 months (95% CI 1.24–1.94 months). Summary overall survival (OS) was 5.72 months (95% CI 0–12.19 months). A subset of patients derived long-term benefits as seen in other cancer locations. The adverse effect rate was low and consistent with that in other disease locations. Low efficacy of immune checkpoint inhibitors as a class in gastric or gastroesophageal junction adenocarcinomas is observed in this analysis and stresses the need for effective biomarker use for the identification of most probable responders.

How to cite this article: Voutsadakis IA. A Systematic Review and Meta-analysis of PD-1 and PD-L1 Inhibitors Monotherapy in Metastatic Gastric and Gastroesophageal Junction Adenocarcinoma. Euroasian J Hepato-Gastroenterol 2020;10(2):56–63.

Single-cell dissection of intratumoral heterogeneity and lineage diversity in metastatic gastric adenocarcinoma

Intratumoral heterogeneity (ITH) is a fundamental property of cancer; however, the origins of ITH remain poorly understood. We performed single-cell transcriptome profiling of peritoneal carcinomatosis (PC) from 15 patients with gastric adenocarcinoma (GAC), constructed a map of 45,048 PC cells, profiled the transcriptome states of tumor cell populations, incisively explored ITH of malignant PC cells and identified significant correlates with patient survival. The links between tumor cell lineage/state compositions and ITH were illustrated at transcriptomic, genotypic, molecular and phenotypic levels. We uncovered the diversity in tumor cell lineage/state compositions in PC specimens and defined it as a key contributor to ITH. Single-cell analysis of ITH classified PC specimens into two subtypes that were prognostically independent of clinical variables, and a 12-gene prognostic signature was derived and validated in multiple large-scale GAC cohorts. The prognostic signature appears fundamental to GAC carcinogenesis and progression and could be practical for patient stratification.

Clinical implications of plasma ctDNA features and dynamics in gastric cancer treated with HER2-targeted therapies

BACKGROUND

Gastric cancer (GC) is confronted with limited options for precision medicine. Human epidermal growth factor receptor 2 (HER2) is the principal druggable target of GC, yet proper biomarkers for response/resistance prediction remain unveiled.

METHODS

From 40 GC patients received HER2-targeted therapy, a total of 327 peripheral blood plasma specimens was collected including baseline and treatment time points. Circulating tumor DNA (ctDNA) was extracted and sequenced with a target panel of 425 genes. Experimental validation of resistant mutations was carried out in NIH-3T3 cell line.

RESULTS

Genomic features, including ERBB2 copy number variation (CNV), total copy number load, and tumor mutation burdens (TMBs), dynamically changed along with the treatment process and correlated with disease progression. Plasma ctDNA-based diagnosis was more sensitive than conventional computed tomography scanning in 40% of investigated patients, gaining additional time for clinical management. Compared to baseline, new gene alterations were emerged in 12 patients who developed drug resistance during treatment. ERBB2 mutations potentially related to Pyrotinib resistance were identified in plasma ctDNA of one patient and functional analysis of their downstream signaling pathways was carried out in NIH-3T3 cell line. TMB exhibited more power than ERBB2 CNV in predicting treatment responses and prognosis for HER2-targeted therapy in GC patients. Interestingly, survival analysis indicated that patients harboring both HER2 (ERBB2) positivity and high TMB might gain more therapeutic benefits from immune checkpoint inhibitors instead of HER2-targeted regimens that required further studies and validations CONCLUSIONS: Our work showed that the dynamic surveillance of plasma ctDNA genomic features provided instructive information for the precision medication of GC patients.

HX008, an anti-PD1 antibody, plus irinotecan as second-line treatment for advanced gastric or gastroesophageal junction cancer: a multicenter, single-arm phase II trial

BACKGROUND

Irinotecan is used as second-line treatment in advanced gastric or gastroesophageal junction (G/GEJ) cancer. The role of anti-programmed death-1 (PD-1) antibody plus irinotecan, in this setting and population is unclear.

METHODS

This multicenter, open-label, single-arm, phase II trial was conducted in 11 Chinese hospitals. Eligible patients had histologically confirmed advanced G/GEJ cancer that refractory to, or intolerant of, first-line chemotherapy with a platinum and/or fluoropyrimidine. Subjects received HX008 200 mg intravenously every 3 weeks plus irinotecan 160 mg/m² intravenously every 2 weeks until disease progression or unacceptable toxicity. The primary end point was objective response rate (ORR) as assessed according to Response Evaluation Criteria In Solid Tumors V.1.1.

RESULTS

Between October 2018 and September 2019, a total of 58 patients with advanced G/GEJ cancer were enrolled in this study. Median follow-up was 10.5 months (range 7.4-18.9) months. Confirmed ORR was observed in 16 patients, for an ORR of 27.6% (95% CI 16.1% to 39.1%); 19 patients experienced stable disease, leading to a disease control rate of 60.3% (95% CI 46.4% to 73.0%). ORR in patients with PD-ligand 1 (L1) positive (Combined Positive Score (CPS) ≥1) and negative (CPS＜1) tumors was 38.5% (5/13) and 37.5% (3/8), respectively. Median duration of response was 8.0 months (range 1.5-12.5), 6 of 16 (37.5%) responses were ongoing. Median progression-free survival (PFS) was 4.2 months (95% CI 2.2 to 5.5). Median overall survival (OS) was not reached (NR) (95% CI 8.7 to NR). Patients with PD-L1 positive tumors tended to have longer OS than those with PD-L1 negative tumors, but the difference was not statistically significant (NR vs 8.7 months, p=0.1858).The most common treatment-related adverse events of grade 3 or 4 included neutropenia (32.8%), leukopenia (31.0%), anemia (17.2%), decreased appetite (8.6%), vomit (6.9%), nausea (6.9%) and fatigue (5.2%). There were no treatment-related deaths.

CONCLUSION

The combination of HX008 and irinotecan demonstrated promising activity and manageable safety as second-line treatment in patients with advanced G/GEJ cancer, which warrants further study.

TRIAL REGISTRATION NUMBER

NCT03704246.

Chimeric Antigen Receptor T Cell Therapy Targeting ICAM-1 in Gastric Cancer

Cancer therapy utilizing adoptive transfer of chimeric antigen receptor (CAR) T cells has demonstrated remarkable clinical outcomes in hematologic malignancies. However, CAR T cell application to solid tumors has had limited success, partly due to the lack of tumor-specific antigens and an immune-suppressive tumor microenvironment. From the tumor tissues of gastric cancer patients, we found that intercellular adhesion molecule 1 (ICAM-1) expression is significantly associated with advanced stage and shorter survival. In this study, we report a proof-of-concept study using ICAM-1-targeting CAR T cells against gastric cancer. The efficacy of ICAM-1 CAR T cells showed a significant correlation with the level of ICAM-1 expression in target cells in vitro. In animal models of human gastric cancer, ICAM-1-targeting CAR T cells potently eliminated tumors that developed in the lungs, while their efficacy was more limited against the tumors in the peritoneum. To augment CAR T cell activity against intraperitoneal tumors, combinations with paclitaxel or CAR activation-dependent interleukin (IL)-12 release were explored and found to significantly increase anti-tumor activity and survival benefit. Collectively, ICAM-1-targeting CAR T cells alone or in combination with chemotherapy represent a promising strategy to treat patients with ICAM-1+ advanced gastric cancer.

Role of Immunotherapy in Advanced Gastroesophageal Cancer

PURPOSE OF REVIEW

Immunotherapy and tumor microenvironment have been at the forefront of cancer research over the past several decades. Here, we will review the role of immunotherapy in advanced gastroesophageal cancers including targeted antibodies, immunomodulating agents, vaccines, oncolytic virus therapy, and adoptive immunotherapy, and discuss the future direction for immunotherapy in this population.

RECENT FINDINGS

Targeted antibodies are already standard-of-care. An anti-PD-1 monoclonal antibody is currently FDA approved for second-line treatment of locally advanced or metastatic ESCC, as well as beyond second-line treatment of advanced G/GEJ cancers, and recent data suggests it may be considered in first-line treatment of advanced G/GEJ cancers. Combination therapies such as immunotherapy plus chemotherapy and/or radiotherapy, vaccines, oncolytic viral therapy, and adoptive immunotherapy in varying combinations are currently under active investigation. Several trials are ongoing and are hoped to reach more efficacious and individualized treatment options in advanced gastroesophageal cancer, where novel treatment options are desperately needed.

Aurora A Inhibitor TAS-119 Enhances Antitumor Efficacy of Taxanes In Vitro and In Vivo: Preclinical Studies as Guidance for Clinical Development and Trial Design

TAS-119 is a novel orally active, selective inhibitor of Aurora kinase A identified as a clinical candidate for efficacy testing in combination with taxanes. In vitro, TAS-119 enhanced cell growth inhibition of paclitaxel in multiple human cancer cell lines derived from various tissues, including paclitaxel-resistant cell lines. Interestingly, TAS-119 did not enhance paclitaxel antitumor activity in normal lung diploid fibroblast cell lines WI-38 and MRC5. In vivo, TAS-119 enhanced the antitumor efficacy of paclitaxel and docetaxel in multiple models at doses inhibitory to Aurora A in tumors. Moreover, the drug combination was well tolerated, and TAS-119 did not exaggerate clinically documented side effects of taxanes, neutropenia and neurotoxicity, in rats. The same TAS-119 concentration enhanced the cell growth inhibitory activity of three clinically approved taxanes, paclitaxel, docetaxel, and cabazitaxel. The degree of enhancement calculated as fold of change of the IC₅₀ value for each taxane was almost the same among the three taxanes. We conducted in vitro and in vivo experiments to develop an optimized combination therapy regimen for TAS-119 with paclitaxel/docetaxel. Using in vitro and in vivo models, we tested the drug administration order for TAS-119 combined with paclitaxel and the TAS-119 treatment duration. The best regimen in preclinical models was combining paclitaxel or docetaxel treatment with 4 days of TAS-119 dosing, which was initiated on the same day as the paclitaxel or docetaxel administration or one day later. This information provided guidance for the design of a clinical trial of TAS-119 and paclitaxel or docetaxel combination.

From Interconnection between Genes and Microenvironment to Novel Immunotherapeutic Approaches in Upper Gastro-Intestinal Cancers-A Multidisciplinary Perspective

Despite the progress during the last decade, patients with advanced gastric and esophageal cancers still have poor prognosis. Finding optimal therapeutic strategies represents an unmet need in this field. Several prognostic and predictive factors have been evaluated and may guide clinicians in choosing a tailored treatment. Data from large studies investigating the role of immunotherapy in gastrointestinal cancers are promising but further investigations are necessary to better select those patients who can mostly benefit from these novel therapies. This review will focus on the treatment of metastatic esophageal and gastric cancer. We will review the standard of care and the role of novel therapies such as immunotherapies and CAR-T. Moreover, we will focus on the analysis of potential predictive biomarkers such as Modify as: Microsatellite Instability (MSI) and PD-L1, which may lead to treatment personalization and improved treatment outcomes. A multidisciplinary point of view is mandatory to generate an integrated approach to properly exploit these novel antiproliferative agents.

The Role of Gastric Mucosal Immunity in Gastric Diseases

Gastric mucosa plays its immune function through innate and adaptive immunity by recruiting immune cells and releasing corresponding cytokines, which have an inseparable relationship with gastric diseases. Whether infective gastric diseases caused by Helicobacter pylori, Epstein-Barr virus or other microbe, noninfective gastric diseases, or gastric cancer, gastric mucosal immunity plays an important role in the occurrence and development of the disease. Understanding the unique immune-related tissue structure of the gastric mucosa and its role in immune responses can help prevent gastric diseases or treat them through immunotherapy. In this review, we summarize the basic feature of gastric mucosal immunity and its relationship with gastric diseases to track the latest progress of gastric mucosal immunity, update relevant knowledge and provide theoretical reference for the prevention and treatment of gastric diseases based on the gastric mucosal immunity.

Novel Frontiers of Treatment for Advanced Gastric or Gastroesophageal Junction Cancer (GC/GEJC): Will Immunotherapy Be a Future Direction?

Considering the limited progress of chemotherapy and targeted therapy in improving the generally disappointing outcomes of advanced gastric or gastroesophageal junction cancer (GC/GEJC), immunotherapies have been gradually developed and advanced into novel frontiers of treatment for advanced GC/GEJC. Nevertheless, the response to immunotherapy was not always satisfactory, and the emergence of resistance was unavoidable. These factors prompt the development of different combination therapies and predictive and prognostic biomarkers of efficacy to improve the outcomes of patients with advanced GC/GEJC and to overcome drug resistance. This article discusses the advances of immune monotherapy, multiple current and ongoing clinical trials of immune combination therapy, immune-related adverse events, and various biomarkers in GC/GEJC.

Research progress of PD-1/PD-L1 immunotherapy in gastrointestinal tumors

Gastrointestinal tumor (GIT) is a common malignant tumor of the digestive system, which seriously threatens people's health and life. With the deepening of the study on the mechanism of tumor immune escape, programmed death receptor ligand 1 (PD-L1) has been proved to interact with the tumor microenvironment to mediate tumor immune escape. PD-L1 inhibitor is a hot spot in tumor immunotherapy in recent years, which can restore the activity of T cells, enhance the body's ability of immune response, and ultimately enable the immune system to effectively identify and kill gastric cancer cells, then achieve long-term tumor remission in patients with GITs. At present, variety of PD-L1 inhibitors such as pembrolizumab, nivolumab and avelumab have been approved for the market, and they have achieved good results in clinical studies on the GIT. This paper reviews the progress of PD-1/PD-L1 immunotherapy in GITs which include gastric cancer, colon cancer and rectal cancer.

Integrated analysis identifies an immune-based prognostic signature for the mesenchymal identity in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) has been divided into 4 consensus molecular subtypes (CMSs), of which CMS4 has the mesenchymal identity and the highest relapse rate. Our goal is to develop a prognostic signature by integrating the immune system and mesenchymal modalities involved in CMS4.

METHODS

The gene expression profiles collected from 5 public datasets were applied to this study, including 1280 samples totally. Network analysis was applied to integrate the mesenchymal modalities and immune signature to establish an immune-based prognostic signature for CRC (IPSCRC).

RESULTS

We identified 6 immune genes as key factors of CMS4 and established the IPSCRC. The IPSCRC could significantly divide patients into high- and low- risk groups in terms of relapse-free survival (RFS) and overall survival (OS) and in discovery (RFS: P < .0001) and 4 independent validation sets (RFS range: P = .01 to <.0001; OS range: P = .02-.0004). After stage stratification, the IPSCRC could still distinguish poor prognosis patients in discovery (RFS: P = .04) and validation cohorts (RFS range: P = .04-.007) within stage II in terms of RFS. Further, in multivariate analysis, the IPSCRC remained an independent predictor of prognosis. Moreover, Macrophage M2 was significantly enriched in the high-risk group, while plasma cells enriched in the low-risk group.

CONCLUSION

We propose an immune-based signature identified by network analysis, which is a promising prognostic biomarker and help for the selection of CRC patients who might benefit from more rigorous therapies. Further prospective studies are warranted to test and validate its efficiency for clinical application.

Integrated Analysis Identifies an Immune-Based Prognostic Signature for the Mesenchymal Identity in Gastric Cancer

Background

Gastric cancer (GC) has been divided into four molecular subtypes, of which the mesenchymal subtype has the poorest survival. Our goal is to develop a prognostic signature by integrating the immune system and molecular modalities involved in the mesenchymal subtype.

Methods

The gene expression profiles collected from 6 public datasets were applied to this study, including 1,221 samples totally. Network analysis was applied to integrate the mesenchymal modalities and immune signature to establish an immune-based prognostic signature for GC (IPSGC).

Results

We identified six immune genes as key factors of the mesenchymal subtype and established the IPSGC. The IPSGC can significantly divide patients into high- and low-risk groups in terms of overall survival (OS) and relapse-free survival (RFS) in discovery (OS: P < 0.001) and 5 independent validation sets (OS range: P = 0.05 to P < 0.001; RFS range: P = 0.03 to P < 0.001). Further, in multivariate analysis, the IPSGC remained an independent predictor of prognosis and performed better efficiency compared to clinical characteristics. Moreover, macrophage M2 was significantly enriched in the high-risk group, while plasma cells were enriched in the low-risk group.

Conclusions

We propose an immune-based signature identified by network analysis, which is a promising prognostic biomarker and help for the selection of GC patients who might benefit from more rigorous therapies. Further prospective studies are warranted to test and validate its efficiency for clinical application.

Cancer Stem Cells and Combination Therapies to Eradicate Them

Cancer stem cells (CSCs) show self-renewal ability and multipotential differentiation, like normal stem or progenitor cells, and which proliferate uncontrollably and can escape the effects of drugs and phagocytosis by immune cells. Traditional monotherapies, such as surgical resection, radiotherapy and chemotherapy, cannot eradicate CSCs, however, combination therapy may be more effective at eliminating CSCs. The present review summarizes the characteristics of CSCs and several promising combination therapies to eradicate them.

Integrated immune gene expression signature and molecular classification in gastric cancer: New insights

Gastric cancer (GC) is characterized by extreme heterogeneity due to histopathological differences, molecular characteristics, and immune gene expression signature. Until recently, several targeted therapies failed due to this complexity. The recent immunotherapy resulted in more effective and safe approaches in several malignancies. All tumors could be considered potentially immunogenic and the new knowledge regarding the interactions among tumor cells, immune cells, and tumor microenvironment (TME) allowed to reverse possible immune resistance. The immune response is a complex multisteps process that finely regulates the balance between the recognition of non-self and the prevention of autoimmunity. Cancer cells can use these pathways to suppress tumor immunity as a major mechanism of immune resistance. The recent molecular classifications of GCs by The Cancer Genome Atlas (TCGA) and by the Asian Cancer Research (ACRG) networks, together with the identification of multiple biomarkers, open new perspectives for stratification of patients who might benefit from a long-term immune checkpoint therapy. One of the major processes that contribute to an immunosuppressive microenvironment is represented by tumor angiogenesis. The cellular mechanisms inducing both angiogenesis and immunosuppressive responses are often reached by the same cell types and soluble factors, such as vascular endothelial growth factor A (VEGFA). Recent studies point out that combinatorial strategies should be adapted as useful therapeutic approach to reverse the immunosuppressive status of microenvironment occurring in a relevant percentage of gastric tumors.

Immune classification for the PD-L1 expression and tumour-infiltrating lymphocytes in colorectal adenocarcinoma

Background

Colorectal adenocarcinoma is the third most common cancer worldwide and a leading cause of cancer-related death. The recent emergence of diverse immunotherapeutic agents has made it crucial to interpret a complex tumour microenvironment intermingled with tumour-infiltrating immune cells to predict the immunotherapeutic response rate. However, in colorectal adenocarcinoma, studies are lacking that provide detailed analyses of programmed death-ligand 1 (PD-L1) and tumour-infiltrating lymphocytes (TIL) to elucidate their prognostic values and to identify immunotherapy-targetable subgroups, preferably with multiple immune-related biomarkers. In the present study, we categorize colorectal adenocarcinomas into four types of tumour immune microenvironments according to PD-L1 expression and TIL, analyse their prognostic values, and propose an immunotherapy-targetable subgroup.

Methods

Formalin-fixed, paraffin-embedded tissue samples of surgically resected primary colorectal adenocarcinomas (n = 489) were obtained and arrayed on tissue microarray blocks. Immunohistochemical stains for PD-L1, programmed cell death protein 1 (PD-1), cluster of differentiation 8 (CD8), and deficient mismatch repair (dMMR) were performed and evaluated.

Results

Tumour microenvironment immune type (TMIT) I (PD-L1-positive tumour cells and CD8-high TIL) and type II (PD-L1-negative tumour cells and CD8-low TIL) showed the best and worst prognoses, respectively. PD-L1 overexpression was significantly associated with dMMR status. PD-L1 immunoreactivity was positively correlated with TIL having CD8 or PD-1 overexpression.

Conclusions

TMIT I subgroup showed stronger CD8/PD-L1/PD-1 signalling interaction compared to the other TMIT. Therefore, we propose that the TMIT I subgroup is a candidate TMIT to predict effective response rate for existing immune checkpoint inhibitors and determine targetable subgroups for emerging therapies.

Multiplex profiling of peritoneal metastases from gastric adenocarcinoma identified novel targets and molecular subtypes that predict treatment response

OBJECTIVE

Peritoneal carcinomatosis (PC) occurs frequently in patients with gastric adenocarcinoma (GAC) and confers a poor prognosis. Multiplex profiling of primary GACs has been insightful but the underpinnings of PC's development/progression remain largely unknown. We characterised exome/transcriptome/immune landscapes of PC cells from patients with GAC aiming to identify novel therapeutic targets.

DESIGN

We performed whole-exome sequencing (WES) and whole transcriptome sequencing (RNA-seq) on 44 PC specimens (43 patients with PC) including an integrative analysis of WES, RNA-seq, immune profile, clinical and pathological phenotypes to dissect the molecular pathogenesis, identifying actionable targets and/or biomarkers and comparison with TCGA primary GACs.

RESULTS

We identified distinct alterations in PC versus primary GACs, such as more frequent CDH1 and TAF1 mutations, 6q loss and chr19 gain. Alterations associated with aggressive PC phenotypes emerged with increased mutations in TP53, CDH1, TAF1 and KMT2C, higher level of 'clock-like' mutational signature, increase in whole-genome doublings, chromosomal instability (particularly, copy number losses), reprogrammed microenvironment, enriched cell cycle pathways, MYC activation and impaired immune response. Integrated analysis identified two main molecular subtypes: 'mesenchymal-like' and 'epithelial-like' with discriminating response to chemotherapy (31% vs 71%). Patients with the less responsive 'mesenchymal-like' subtype had high expression of immune checkpoint T-Cell Immunoglobulin And Mucin Domain-Containing Protein 3 (TIM-3), its ligand galectin-9, V-domain Ig suppressor of T cell activation (VISTA) and transforming growth factor-β as potential therapeutic immune targets.

CONCLUSIONS

We have uncovered the unique mutational landscape, copy number alteration and gene expression profile of PC cells and defined PC molecular subtypes, which correlated with PC therapy resistance/response. Novel targets and immune checkpoint proteins have been identified with a potential to be translated into clinics.

Thirty years of Epstein-Barr virus-associated gastric carcinoma

Thirty years have passed since a possible association of Epstein-Barr virus (EBV) with gastric carcinoma was reported. We now know EBV-associated gastric carcinoma to be a specific subtype of gastric carcinoma. Global epigenetic methylation and counteraction of the antitumour microenvironment are two major characteristics of this subtype of gastric carcinoma. Recent development of therapeutic modalities for gastric carcinoma, such as endoscopic mucosal dissection and immune checkpoint inhibitor therapy, has made the presence of EBV infection a biomarker for the treatment of gastric carcinoma. This review presents a portrait of EBV-associated gastric carcinoma from initiation to maturity that we define as the 'gastritis-infection-cancer sequence', followed by its molecular abnormalities and interactions with immune checkpoint molecules and the microenvironment. EBV non-coding RNAs (microRNA and circular RNA) and exosomes derived from EBV-infected cells that were previously behind the scenes are now recognized for their roles in EBV-associated gastric carcinoma. The virus utilizes cellular machinery skilfully to control infected cells and their microenvironment. We should thus strive to understand virus-host interactions more fully in the following years to overcome this virus-driven subtype of gastric carcinoma.

Combination of checkpoint inhibitors with radiotherapy in esophageal squamous cell carcinoma treatment: A novel strategy

Despite the rapid development of numerous types of treatment, including radiotherapy (RT) as the main strategy, esophageal squamous cell carcinoma (ESCC) has a poor prognosis. Recent studies demonstrated that immunotherapy can improve the survival of patients with locally advanced and metastatic ESCC. Furthermore, previous studies reported that the expression of programmed death-ligand 1 is significantly associated with esophageal cancer prognosis. At present, several ongoing clinical trials have extended the use of immunotherapy from palliative and salvage treatments to neoadjuvant treatment with concurrent chemoradiation. The first- or second-line treatments were used to explore antitumor efficacy with reduced adverse events. The combination of RT and immunotherapy can exert a local therapeutic effect and improve the function of the immune system, enhancing antitumor efficacy. This review investigated the role of immunotherapy and radiotherapy in ESCC and described the potential efficacy of combining immunotherapy with radiotherapy in ESCC.

Targeted and pH-facilitated theranostic of orthotopic gastric cancer via phase-transformation doxorubicin-encapsulated nanoparticles enhanced by low-intensity focused ultrasound (LIFU) with reduced side effect

Purpose

Focused ultrasound-mediated chemotherapy, as a non-invasive therapeutic modality, has been extensively explored in combating deep tumors for predominant penetration performance. However, the generally used high-intensity focused ultrasound (HIFU) inevitably jeopardizes normal tissue around the lesion for hyperthermal energy. To overcome this crucial issue, low-intensity focused ultrasound (LIFU) was introduced to fulfill precisely controlled imaging and therapy in lieu of HIFU. The objective of this study was to develop a facile and versatile nanoplatform (DPP-R) in response to LIFU and provide targeted drug delivery concurrently.

Methods

Multifunctional DPP-R was fabricated by double emulsion method and carbodiimide method. Physicochemical properties of DPP-R were detected respectively and the bio-compatibility and bio-safety were evaluated by CCK-8 assay, blood analysis, and histologic section. The targeted ability, imaging function, and anti-tumor effect were demonstrated in vitro and vivo.

Results

The synthetic DPP-R showed an average particle size at 367 nm, stable physical-chemical properties in different media, and high bio-compatibility and bio-safety. DPP-R was demonstrated to accumulate at the tumor site by active receptor/ligand reaction and passive EPR effect with intravenous administration. Stimulated by LIFU at the tumor site, phase-transformable PFH was vaporized in the core of the integration offering contrast-enhanced ultrasound imaging. The stimuli led to encapsulated DOX's initial burst release and subsequent sustained release for anti-tumor therapy which was verified to be more effective and have less adverse effects than free DOX.

Conclusion

DPP-R combined with LIFU provides a novel theranostic modality for GC treatment with potent therapeutic effect, including prominent performance of targeting, ultrasound imaging, and accurate drug release.

Transcriptome analysis reveals GPNMB as a potential therapeutic target for gastric cancer

Gastric cancer has the fifth highest incidence of disease and is the third leading cause of cancer-associated mortality in the world. The etiology of gastric cancer is complex and needs to be fully elucidated. Thus, it is necessary to explore potential pathogenic genes and pathways that contribute to gastric cancer. Gene expression profiles of the GSE33335 and GSE54129 datasets were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were compared and identified using R software. The DEGs were then subjected to gene set enrichment analysis and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Survival analyses based on The Cancer Genome Atlas database were used to further screen the essential DEGs. A knockdown assay was performed to determine the function of the candidate gene in gastric cancer. Finally, the association between the candidate gene and immune-related genes was investigated. We found that GPNMB serves as an essential gene, with a high expression level, and predicts a worse outcome of gastric cancer. Knockdown of GPNMB inhibited gastric cancer cell proliferation and migration. In addition, GPNMB may augment the immunosuppressive ability of gastric cancer by recruiting immunosuppressive cells and promoting immune cell exhaustion through PI3K/AKT/CCL4 signaling axis. Collectively, these data suggest that GPNMB acts as an important positive mediator of tumor progression in gastric cancer, and GPNMB could exert multimodality modulation of gastric cancer-mediated immune suppression.

Late-line treatment in metastatic gastric cancer: today and tomorrow

Survival for patients with unresectable advanced or recurrent gastric cancer (GC) remains poor and the historical lack of evidence-based therapeutic options after second-line therapy is reflected in current clinical guidelines for this condition. Despite uncertainty about optimal therapeutic strategies, further treatment is appropriate for some patients after failure of second line and may prolong survival. This approach has been reported in clinical trials and is becoming more common in real-world clinical settings. Several prognostic factors may increase the likelihood that a patient will be eligible for treatment in the third-line setting, including geographic location, status at diagnosis and response to treatment. There has been little progress over the last decade until the results from two large phase III randomized controlled trials completed in the last year: the ATTRACTION-2 trial with the programmed cell death-1 (PD-1) inhibitor, nivolumab, in an Asian population; and the TAGS trial with the oral chemotherapy trifluridine/tipiracil in a global population. Both ATTRACTION-2 and TAGS reported positive results in third-line treatment in advanced GC in specific patient groups. A further recently reported study, KEYNOTE-059, which was a single-arm phase II trial of the PD-1 inhibitor pembrolizumab in a mainly non-Asian population, has provided evidence supporting the use of this immunotherapy in patients with advanced GC. As further third-line options become available, more GC patients are expected to benefit from an individualized evidence-based approach to later-line therapy, with a common goal of extending survival and improving outcomes for their refractory disease.