Predictive biomarkers for the efficacy of cetuximab combined with cisplatin and capecitabine in advanced gastric or esophagogastric junction adenocarcinoma: a prospective multicenter phase 2 trial

Targeted therapy and immunotherapy for gastric cancer: rational strategies, novel advancements, challenges, and future perspectives

Gastric cancer (GC) is one of the most common malignant tumors worldwide, and its treatment has been a focus of medical research. Herein we systematically review the current status of and advancements in targeted therapy and immunotherapy for GC, which have emerged as important treatment strategies in recent years with great potential, and summarize the efficacy and safety of such treatments. Targeted therapies against key targets in GC, including epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR), have shown remarkable therapeutic efficacies by inhibiting tumor progression and/or blood supply. In particular, markable breakthroughs have been made in HER2-targeting drugs for HER2-positive GC patients. To address intrinsic and acquired resistances to HER2-targeting drugs, novel therapeutic agents including bispecific antibodies and antibody-drug conjugates (ADC) targeting HER2 have been developed. Immunotherapy enhances the recognition and elimination of cancer cells by activating body anticancer immune system. Programmed cell death protein 1 (PD-1) and programmed cell death-ligand 1 (PD-L1) antibodies are the most commonly used immunotherapeutic agents and have been used with some success in GC treatment. Innovative immunotherapy modalities, including adoptive immune cell therapy, tumor vaccines, and non-specific immunomodulators therapy, and oncolytic viruses have shown promise in early-stage clinical trials for GC. Clinical trials have supported that targeted therapy and immunotherapy can significantly improve the survival and quality of life of GC patients. However, the effects of such therapies need to be further improved and more personalized, with advancement in researches on tumor immune microenvironment. Further studies remain needed to address the issues of drug resistance and adverse events pertaining to such therapies for GC. The combined application of such therapies and individualized treatment strategies should be further explored with novel drugs developed, to provide more effective treatments for GC patients.

Potential diagnostic, prognostic, and predictive biomarkers of gastric cancer

Background

Gastric cancer (GC), a malignant epithelial tumor, is the fourth leading cause of cancer-related death worldwide. Therapeutic strategies for GC, despite the biggest challenges, can significantly improve survival rates through early detection and effective screening methods.

Aim

To provide brief information on the necessity of multiple specific diagnostic, prognostic, and predictive markers for GC.

Methods

This review was conducted using a variety of search engines, including PubMed Central, Scopus, Web of Science, Google Scholar, and others.

Results

Some potential biomarkers that provide essential information include circulating tumor cells (CTCs), DNA methylation, claudin 18.2, fibroblast growth factor receptor 2 (FGFR2), long noncoding RNAs (lncRNAs), cell-free DNA (cfDNA), microRNAs, and serum pepsinogens.

Conclusion

Multiple tumor markers are essential for screening, tumor identification, staging, prognostic assessment, and monitoring recurrence after therapy due to the absence of a single tumor indicator for diagnosing, prognosticating, and predicting GC.

Regulation of regulatory T cells and tumor-associated macrophages in gastric cancer tumor microenvironment

INTRODUCTION

Despite advancements in the methods for prevention and early diagnosis of gastric cancer (GC), GC continues to be the fifth in incidence among major cancers and the third most common cause of cancer-related death. The therapeutic effects of surgery and drug treatment are still unsatisfied and show notable differences according to the tumor microenvironment (TME) of GC.

METHODS

Through screening Pubmed, Embase, and Web of Science, we identified and summarized the content of recent studies that focus on the investigation of Helicobacter pylori (Hp) infection, regulatory T cells (Tregs), and tumor-associated macrophages (TAMs) in the TME of GC. Furthermore, we searched and outlined the clinical research progress of various targeted drugs in GC treatment including CTLA-4, PD-1\PD-L1, and VEGF/VEGFR.

RESULTS

In this review, the findings indicate that Hp infection causes local inflammation and leads to immunosuppressive environment. High Tregs infiltration in the TME of GC is associated with increased induction and recruitment; the exact function of infiltrated Tregs in GC was also affected by phenotypes and immunosuppressive molecules. TAMs promote the development and metastasis of tumors, the induction, recruitment, and function of TAMs in the TME of gastric cancer are also regulated by various factors.

CONCLUSION

Discussing the distinct tumor immune microenvironment (TIME) of GC can deepen our understanding on the mechanism of cancer immune evasion, invasion, and metastasis, help us to reduce the incidence of GC, and guide the innovation of new therapeutic targets for GC eventually.

Research progress in targeted therapy and immunotherapy for gastric cancer

ABSTRACT

Gastric cancer (GC) is one of the most common malignant tumors worldwide. Its incidence ranks the 5th among all malignant tumors globally, and it is the 3rd leading cause of death among patients with cancer. Surgical treatment is the first choice in clinical practice. However, targeted therapy, immunotherapy, and other treatment methods have also become research hotspots at home and abroad with the development of individualized precision therapy in recent years, besides traditional radiotherapy and chemotherapy. At present, targeted therapy and immunotherapy are methods used for treating GC, and they have important clinical application value and prospects. This study aimed to review the research progress of targeted therapy and immunotherapy for GC, focusing on its mechanism of action and related important clinical trials, hoping to provide references for the clinical treatment of GC.

Novel Biomarkers of Gastric Adenocarcinoma: Current Research and Future Perspectives

Simple Summary

Gastric cancer is characterized by poor survival rates despite surgery and chemotherapy. Current research focuses on biomarkers to improve diagnosis and prognosis, and to enable targeted treatment strategies. The aim of our review was to give an overview over the wide range of novel biomarkers in gastric cancer. These biomarkers are targets of a specific treatment, such as antibodies against human epidermal growth factor receptor 2. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are vascular endothelial growth factor, programmed cell death protein 1, and Claudin 18.2. There is a vast number of biomarkers based on DNA, RNA, and protein expression, as well as detection of circulating tumor cells and the immune tumor microenvironment.

Abstract

Overall survival of gastric cancer remains low, as patients are often diagnosed with advanced stage disease. In this review, we give an overview of current research on biomarkers in gastric cancer and their implementation in treatment strategies. The HER2-targeting trastuzumab is the first molecular targeted agent approved for gastric cancer treatment. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are VEGF and Claudin 18.2. Expression of MET has been shown to be a negative prognostic factor in gastric cancer. Targeting the PD-1/PD-L1 pathway with immune checkpoint inhibitors has proven efficacy in advanced gastric cancer. Recent technology advances allow the detection of circulating tumor cells that may be used as diagnostic and prognostic indicators and for therapy monitoring in gastric cancer patients. Prognostic molecular subtypes of gastric cancer have been identified using genomic data. In addition, transcriptome profiling has allowed a comprehensive characterization of the immune and stromal microenvironment in gastric cancer and development of novel risk scores. These prognostic and predictive markers highlight the rapidly evolving field of research in gastric cancer, promising improved treatment stratification and identification of molecular targets for individualized treatment in gastric cancer.

The design, analysis and application of mouse clinical trials in oncology drug development

Background

Mouse clinical trials (MCTs) are becoming wildly used in pre-clinical oncology drug development, but a statistical framework is yet to be developed. In this study, we establish such as framework and provide general guidelines on the design, analysis and application of MCTs.

Methods

We systematically analyzed tumor growth data from a large collection of PDX, CDX and syngeneic mouse tumor models to evaluate multiple efficacy end points, and to introduce statistical methods for modeling MCTs.

Results

We established empirical quantitative relationships between mouse number and measurement accuracy for categorical and continuous efficacy endpoints, and showed that more mice are needed to achieve given accuracy for syngeneic models than for PDXs and CDXs. There is considerable disagreement between methods on calling drug responses as objective response. We then introduced linear mixed models (LMMs) to describe MCTs as clustered longitudinal studies, which explicitly model growth and drug response heterogeneities across mouse models and among mice within a mouse model. Case studies were used to demonstrate the advantages of LMMs in discovering biomarkers and exploring drug’s mechanisms of action. We introduced additive frailty models to perform survival analysis on MCTs, which more accurately estimate hazard ratios by modeling the clustered mouse population. We performed computational simulations for LMMs and frailty models to generate statistical power curves, and showed that power is close for designs with similar total number of mice. Finally, we showed that MCTs can explain discrepant results in clinical trials.

Conclusions

Methods proposed in this study can make the design and analysis of MCTs more rational, flexible and powerful, make MCTs a better tool in oncology research and drug development.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5907-7) contains supplementary material, which is available to authorized users.

EPHA2 blockade reverses acquired resistance to afatinib induced by EPHA2-mediated MAPK pathway activation in gastric cancer cells and avatar mice

Afatinib is a pan-HER inhibitor approved for specific types of lung cancer. We explored antitumor activity, predictive biomarkers and the potential mechanisms underlying antitumor effect and acquired resistance of afatinib in gastric cancer (GC) in vitro and in vivo. Five human GC cell lines and eight patient-derived xenograft (PDX) models with clear molecular profiling were used to evaluate the antitumor activity and mechanisms of afatinib. The ErbB family and downstream PI3K/AKT/mTOR and mitogen-activated protein kinase (MAPK) pathways were evaluated before and after afatinib treatment. An afatinib-resistant PDX model was established to explore both the potential mechanisms of drug resistance and reversal strategies. We found that afatinib exerted a strong tumor suppression in EGFR/HER2 highly amplified (copy number >6) or overexpressed (IHC 3+) PDX models and a moderate tumor suppression in EGFR/HER2 moderately expressed (IHC 2+) PDX models. Afatinib selectively inhibited the proliferation of HER2 highly amplified GC cells in a dose-dependent manner in vitro. Afatinib also exerted its antitumor effect by inducing cell apoptosis and cell arrest at G1 phase. Diminished activation of the ErbB family and downstream PI3K/AKT/mTOR and MAPK pathways was also observed. Erythropoietin-producing hepatocellular receptor A2 (EPHA2) upregulation and phosphorylation might be involved in afatinib-acquired resistance, and EPHA2 blockade could restore afatinib sensitivity. GC patients with amplification (copy number >6) or overexpression (IHC 3+) of EGFR/HER2 were most likely to benefit from afatinib treatment and EPHA2 blockade reversed acquired resistance to afatinib treatment, which could provide solid evidences for future clinical trials.

Panitumumab in combination with modified docetaxel/cisplatin/5-fluorouracil as first-line treatment in gastric and gastroesophageal junction adenocarcinomas: a multicenter phase II study by the Hellenic Oncology Research Group

Background

A phase I/II study to define the maximum tolerated dose (MTD) of biweekly docetaxel/cisplatin/5-fluorouracil (DCF) plus panitumumab (P), its efficacy, and tolerability as first-line treatment in advanced gastroesophageal cancer.

Methods

In phase I part, patients with unresectable locally advanced or metastatic adenocarcinomas of the stomach or the gastroesophageal junction received cisplatin (40 mg/m² on day 1), leucovorin (400 mg/m² on day 1), 5-fluorouracil (400 mg/m² bolus on day 1), 5-fluorouracil (1000 mg/m²/daycontinuous infusion on days 1-2), and escalated doses of docetaxel (on day 1) plus P (6 mg/kg on day 1) every 2 weeks. In phase II part, patients were treated with DCF/P at the MTD and the primary endpoint was response rate. The expected response rate was set at >40%.

Results

The MTD for docetaxel in the mDCF/P was defined at 40 mg/m² and a total of 40 evaluable patients were enrolled in phase II study. One (2.5%) complete and 13 (32.5%) partial responses (overall response rate: 35%), as well as 16 (40%) disease stabilizations were documented. The median progression-free survival was 6.9 months (95% confidence interval [CI] 3.5-10.3) and the median overall survival was 11.3 months (95%CI 7.7-14.8). Grade 3-4 neutropenia occurred in 10 patients (25%) and febrile neutropenia in 2 (5%). Allergic reactions (grade 1-4) occurred in 9 patients (22.5%). There was 1 treatment-related death.

Conclusions

mDCF/P combination was feasible, though associated with a poor toxicity profile. However, the study failed to meet its primary endpoint and was terminated prematurely due to futility.

New therapeutic options opened by the molecular classification of gastric cancer

Gastric cancer (GC) is one of the most lethal and aggressive cancers, being the third cause of cancer related death worldwide. Even with radical gastrectomy and the latest generation of molecular chemotherapeutics, the numbers of recurrence and mortality remains high. This is due to its biological heterogeneity based on the interaction between multiple factors, from genomic to environmental factors, diet or infections with various pathogens. Therefore, understanding the molecular characteristics at a genomic level is critical to develop new treatment strategies. Recent advances in GC molecular classification provide the unique opportunity to improve GC therapy by exploiting the biomarkers and developing novel targeted therapy specific to each subtype. This article highlights the molecular characteristics of each subtype of gastric cancer that could be considered in shaping a therapeutic decision, and also presents the completed and ongoing clinical trials addressed to those targets. The implementation of the novel molecular classification system will allow a preliminary patient selection for clinical trials, a mandatory issue if it is desired to test the efficacy of a certain inhibitor to the given target. This will represent a substantial advance as well as a powerful tool for targeted therapy. Nevertheless, translating the scientific results into new personalized treatment opportunities is needed in order to improve clinical care, the survival and quality of life of patients with GC.

Influence of the HER receptor ligand system on sensitivity to cetuximab and trastuzumab in gastric cancer cell lines

Purpose

Gastric cancer remains a major health concern, and improvement of the therapeutic options is crucial. Treatment with targeted therapeutics such as the EGFR-targeting antibody cetuximab or the HER2-targeting antibody trastuzumab is either ineffective or moderately effective in this disease, respectively. In this study, we analysed the involvement of the HER receptor ligands amphiregulin (AREG), epidermal growth factor (EGF), heparin-binding epidermal growth factor (HB-EGF) and transforming growth factor alpha (TGFα) in the responsiveness of gastric cancer cell lines to cetuximab and trastuzumab.

Methods

A panel of 11 gastric cancer cell lines was characterized for cetuximab and trastuzumab sensitivity, ligand secretion and expression and activation of the HER receptors using WST-1 cell proliferation assays, ELISAs and Western blot analyses. We further investigated the effects of an exogenous ligand application on the cetuximab and trastuzumab sensitivity.

Results

We found no correlation between TGFα secretion and the sensitivity to cetuximab or trastuzumab. For AREG, we confirmed previous results indicating that this ligand is a positive predictor of cetuximab sensitivity. Exogenous HB-EGF was effective in rescuing sensitive cell lines from inhibition of cell proliferation by both, cetuximab and trastuzumab.

Conclusions

Our data indicate that HB-EGF may be a useful marker for the prediction of trastuzumab sensitivity in gastric cancer.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-016-2308-z) contains supplementary material, which is available to authorized users.

Predictive biomarkers for targeted and cytotoxic agents in gastric cancer for personalized medicine

Gastric cancer (GC) is the fourth most common cancer and the second leading cause of cancer. The treatment of GC remains challenging as the outcomes achieved with surgery alone or adjuvant or neoadjuvant chemotherapy and radiotherapy are relatively poor. New treatment strategies are emerging and are being tested in solid tumors including GC. Over the past few years, the treatment of metastatic colorectal cancer (CRC) has made great advances, but strategies to manage GC have improved little. Multiple drug resistance is common in GC chemotherapy and targeted therapy; some patients appear to receive treatment that is suboptimal or even inefficacious. Unfortunately, there are few validated predictive biomarkers to guide the tailored treatment of GC. ToGA and AVAGAST are two phase III trials that tested the efficacy and safety of targeted agents in advanced gastric cancer (AGC), and results clearly indicated that patients need to be selected and that targeted agents are the best hope for better results. This review aims to provide an overview of potential predictive biomarkers for cytotoxic and targeted agents in GC.

Targeted therapy for gastric cancer: Current status and future directions (Review)

According to the 2012 statistics of the International Agency for Research on Cancer (IARC), gastric cancer is the fifth most common malignancy, and the third leading cause of cancer-related deaths worldwide. Conventional chemotherapy and radiation have shown limited efficacy for advanced gastric cancer, showing an overall survival (OS) rate of ~10 months. Trastuzumab, a monoclonal antibody against human epidermal growth factor receptor 2 (HER2), is the first approved molecularly targeted agent for HER2-overexpressing gastric cancer, which was found to prolong the OS and the progression-free survival (PFS) of patients. However, HER2 overexpression is present only in a minority of patients with gastric cancer. Hence, other targeted agents are urgently needed. Ramucirumab, a novel human IgG1 monoclonal antibody that selectively targets the extracellular domain of VEGF receptor 2 (VEGFR2), is regarded as a new standard second-line treatment for patients with advanced gastric cancer. The combination of two or more targeted agents directed against two different molecular targets may improve the survival of patients with advanced gastric cancer. Although great efforts have been made, the effect of targeted therapy for gastric cancer is limited. One key reason is that participants in clinical trials for new targeted agents were not selected by detection of the targeted molecule. Here, we review clinical trials related to molecular targets such as anti-epidermal growth factor receptor signaling including anti-HER2 and anti-EGFR1, anti-VEGF signaling, anti-mammalian target of rapamycin (mTOR), tyrosine kinase inhibitors (TKIs) and anti-MET.