Margetuximab plus pembrolizumab in patients with previously treated, HER2-positive gastro-oesophageal adenocarcinoma (CP-MGAH22-05): a single-arm, phase 1b-2 trial

Progress of PD-1/PD-L1 inhibitor combination therapy in immune treatment for HER2-positive tumors

BACKGROUND

Patients with HER2-positive cancers often face a poor prognosis, and treatment regimens containing anti-HER2 have become the first-line treatment options for breast and gastric cancers. However, these approaches are faced with significant challenges in terms of drug resistance. Hence, it is crucial to explore precise treatment strategies aimed at improving survival outcomes.

ADVANCEMENTS IN TREATMENT

Over the past few years, there has been rapid advancement in the realm of tumor therapy, particularly with the swift progress of immune checkpoint inhibitors, including PD-1/PD-L1 inhibitors. They exert anti-tumor effects by disrupting immune-suppressive factors within the tumor microenvironment. However, monotherapy with PD-1/PD-L1 inhibitors has several limitations. Consequently, numerous studies have explored combinatorial immunotherapeutic strategies and demonstrated highly promising avenues of development.

OBJECTIVE

This article aims to review the clinical trials investigating PD-1/PD-L1 inhibitor combination therapy for HER2-positive tumors. Additionally, it provides a summary of ongoing trials evaluating the efficacy and safety of these combined treatments, with the intention of furnishing valuable insights for the clinical management of HER2-positive cancer.

CONCLUSION

Combinatorial immunotherapeutic strategies involving PD-1/PD-L1 inhibitors hold considerable promise in the treatment of HER2-positive tumors. Continued research efforts and clinical trials are warranted to elucidate optimal treatment regimens that maximize therapeutic benefits while minimizing adverse effects.

Efficacy and safety of bispecific antibodies vs. immune checkpoint blockade combination therapy in cancer: a real-world comparison

Emerging tumor immunotherapy methods encompass bispecific antibodies (BSABs), immune checkpoint inhibitors (ICIs), and adoptive cell immunotherapy. BSABs belong to the antibody family that can specifically recognize two different antigens or epitopes on the same antigen. These antibodies demonstrate superior clinical efficacy than monoclonal antibodies, indicating their role as a promising tumor immunotherapy option. Immune checkpoints are also important in tumor immunotherapy. Programmed cell death protein-1 (PD-1) is a widely acknowledged immune checkpoint target with effective anti-tumor activity. PD-1 inhibitors have demonstrated notable therapeutic efficacy in treating hematological and solid tumors; however, more than 50% of patients undergoing this treatment exhibit a poor response. However, ICI-based combination therapies (ICI combination therapies) have been demonstrated to synergistically increase anti-tumor effects and immune response rates. In this review, we compare the clinical efficacy and side effects of BSABs and ICI combination therapies in real-world tumor immunotherapy, aiming to provide evidence-based approaches for clinical research and personalized tumor diagnosis and treatment.

Targeting HER2 in Gastroesophageal Adenocarcinoma: Molecular Features and Updates in Clinical Practice

Gastroesophageal adenocarcinoma (GEA) is one of the principal causes of death related to cancer globally. Human epidermal growth factor receptor 2 (HER2) is a tyrosine kinase receptor which is found to be overexpressed or amplified in approximately 20% of GEA cases. In GEA, the identification of HER2-positive status is crucial to activate a specific anti-HER2 targeted therapy. The landmark ToGA trial demonstrated the superiority of adding trastuzumab to platinum-based chemotherapy, becoming the first-line standard of treatment. However, unlike breast cancer, the efficacy of other anti-HER2 drugs, such as lapatinib, pertuzumab, and T-DM1, has failed to improve outcomes in advanced and locally advanced resectable GEA. Recently, the combination of trastuzumab with pembrolizumab, along with chemotherapy, and the development of trastuzumab deruxtecan, with its specific bystander activity, demonstrated improved outcomes, renewing attention in the treatment of this disease. This review will summarise historical and emerging therapies for the treatment of HER2-positive GEA, with a section dedicated to the HER2 molecular pathway and the use of novel blood biomarkers, such as circulating tumour DNA and circulating tumour cells, which may be helpful in the future to guide treatment decisions.

Advances in Human Epidermal Growth Factor Receptor 2-Targeted Therapy in Upper Gastrointestinal Cancers

The Trastuzumab for Gastric Cancer (ToGA) trial marked a pivotal moment in the adoption of trastuzumab for treating advanced human epidermal growth factor receptor 2 (HER2)-positive esophagogastric (EG) cancer. The KEYNOTE-811 trial brought to light the synergistic effect of immune modulation and HER2 targeting. Additionally, the emergence of trastuzumab deruxtecan (T-DXd) highlighted the potential of new pharmaceutical technologies to extend response, particularly for patients who have advanced beyond initial HER2-targeted therapies. This review aims to navigate through both the successes and challenges encountered historically, as well as promising current trials on innovative and transformative therapeutic strategies, including promising first-in-class and novel first-in-human agents.

Gastric cancer with brain metastasis: from molecular characteristics and treatment

Gastric cancer is one of the cancers with increasing incidence and ranks fourth globally among the most frequent causes of cancer-related mortality. Early gastric cancer is often asymptomatic or presents with atypical symptoms, and the majority of patients present with advanced disease upon diagnosis. Brain metastases are present in approximately 1% of gastric cancer patients at the time of diagnosis, which significantly contributed to the overall mortality of the disease worldwide. Conventional therapies for patients with brain metastases remain limited and the median overall survival of patients is only 8 months in advanced cases. Recent studies have improved our understanding of the molecular mechanisms underlying gastric cancer brain metastases, and immunotherapy has become an important treatment option in combination with radiotherapy, chemotherapy, targeted therapy and surgery. This review aims to provide insight into the cellular processes involved in gastric cancer brain metastases, discuss diagnostic approaches, evaluate the integration of immune checkpoint inhibitors into treatment and prognosis, and explore the predictive value of biomarkers in immunotherapy.

Expression and correlation of PD-L1 and HER2 in oesophageal squamous cell carcinoma

AIMS

In recent years, patients with programmed cell death-Ligand 1 (PD-L1)-positive oesophageal squamous cell carcinoma (OSCC) have been able to benefit from immunotherapy. However, method for improving the treatment efficacy of PD-L1-positive patients is a problem that needs further consideration. Studies on the relationship between human epidermal growth factor receptor 2 (HER2) and PD-L1 expression have recently been reported in certain cancers, but the relationship between PD-L1 and HER2 expression in OSCC is still unclear.

METHODS

A total of 263 patients with OSCC were included in the study. PD-L1 protein expression and HER2 protein expression were analysed by immunohistochemistry (IHC), and fluorescence in situ hybridisation (FISH) was performed to assess HER2 gene amplification. The significance of differences between HER2 status, PD-L1 status and clinicopathological parameters was assessed. The relationship between PD-L1 status and HER2 status was examined.

RESULTS

Of the 263 OSCC cases, the PD-L1-positive expression rates were 39.2% and 77.2% in OSCC for Tumour Proportion Score (TPS) and Combined Positive Score (CPS), respectively, and PD-L1 expression was associated with the degree of tumour differentiation. The HER2 expression was positive in 24% (63/263) of cases based on IHC and FISH. HER2 expression was not significantly associated with clinicopathological characteristics. PD-L1 TPS expression and CPS expression were significantly positively correlated with HER2 expression in OSCC.

CONCLUSIONS

PD-L1 expression was significantly positively correlated with HER2 expression in OSCC. The results provide valuable insight for the future application of HER2-targeted therapy combined with immunotherapy in OSCC.

New clinical trial design in precision medicine: discovery, development and direction

In the era of precision medicine, it has been increasingly recognized that individuals with a certain disease are complex and different from each other. Due to the underestimation of the significant heterogeneity across participants in traditional "one-size-fits-all" trials, patient-centered trials that could provide optimal therapy customization to individuals with specific biomarkers were developed including the basket, umbrella, and platform trial designs under the master protocol framework. In recent years, the successive FDA approval of indications based on biomarker-guided master protocol designs has demonstrated that these new clinical trials are ushering in tremendous opportunities. Despite the rapid increase in the number of basket, umbrella, and platform trials, the current clinical and research understanding of these new trial designs, as compared with traditional trial designs, remains limited. The majority of the research focuses on methodologies, and there is a lack of in-depth insight concerning the underlying biological logic of these new clinical trial designs. Therefore, we provide this comprehensive review of the discovery and development of basket, umbrella, and platform trials and their underlying logic from the perspective of precision medicine. Meanwhile, we discuss future directions on the potential development of these new clinical design in view of the "Precision Pro", "Dynamic Precision", and "Intelligent Precision". This review would assist trial-related researchers to enhance the innovation and feasibility of clinical trial designs by expounding the underlying logic, which be essential to accelerate the progression of precision medicine.

Targeting HER2-positive breast cancer cells by a combination of dasatinib and BMS-202: Insight into the molecular pathways

BACKGROUND

Recent investigations have reported the benefits of using a tyrosine kinase inhibitor, dasatinib (DA), as well as programmed death-ligand 1 (PD-L1) inhibitors in the management of several solid tumors, including breast cancer. Nevertheless, the outcome of the combination of these inhibitors on HER2-positive breast cancer is not explored yet.

METHODS

Herein, we investigated the impact of DA and PD-L1 inhibitor (BMS-202) combination on HER2-positive breast cancer cell lines, SKBR3 and ZR75.

RESULTS

Our data reveal that the combination significantly inhibits cell viability of both cancer cell lines as compared to monotreatment. Moreover, the combination inhibits epithelial-mesenchymal transition (EMT) progression and reduces cancer cell invasion by restoring E-cadherin and β-catenin expressions and loss of vimentin, major biomarkers of EMT. Additionally, the combination reduces the colony formation of both cell lines in comparison with their matched control. Also, the combination considerably inhibits the angiogenesis of the chorioallantoic membrane model compared with monotreatment. Molecular pathway analysis of treated cells shows that this combination blocks HER2, AKT, β-catenin, and JNK1/2/3 activities.

CONCLUSION

Our findings implicate that a combination of DA and BMS-202 could have a significant impact on the management of HER2-positive breast cancer.

HER2-targeted therapies in cancer: a systematic review

Abnormal alterations in human epidermal growth factor receptor 2 (HER2, neu, and erbB2) are associated with the development of many tumors. It is currently a crucial treatment for multiple cancers. Advanced in molecular biology and further exploration of the HER2-mediated pathway have promoted the development of medicine design and combination drug regimens. An increasing number of HER2-targeted drugs including specific monoclonal antibodies, tyrosine kinase inhibitors (TKIs), and antibody-drug conjugates (ADCs) have been approved by the U.S. Food and Drug Administration. The emergence of ADCs, has significantly transformed the treatment landscape for various tumors, such as breast, gastric, and bladder cancer. Classic monoclonal antibodies and novel TKIs have not only demonstrated remarkable efficacy, but also expanded their indications, with ADCs in particular exhibiting profound clinical applications. Moreover the concept of low HER2 expression signifies a breakthrough in HER2-targeted therapy, indicating that an increasing number of tumors and patients will benefit from this approach. This article, provides a comprehensive review of the underlying mechanism of action, representative drugs, corresponding clinical trials, recent advancements, and future research directions pertaining to HER2-targeted therapy.

Ubiquilin-4 induces immune escape in gastric cancer by activating the notch signaling pathway

PURPOSE

We aimed to investigate the role of ubiquilin-4 in predicting the immunotherapy response in gastric cancer.

METHODS

Retrospective RNA-sequencing and immunohistochemical analysis were performed for patients with gastric cancer who received programmed death-1 blockade therapy after recurrence. Multiplex immunohistochemistry identified immune cell types in gastric cancer tissues. We used immunocompetent 615 mice and immunodeficient nude mice to perform tumorigenic experiments.

RESULTS

Ubiquilin-4 expression was significantly higher in responders (p < 0.05, false discovery rate > 2.5) and showed slight superiority over programmed death ligand 1 in predicting programmed death-1 inhibitor therapy response (area under the curve: 87.08 vs. 72.50). Ubiquilin-4-high patients exhibited increased CD4+ and CD8+ T cells, T follicular helper cells, monocytes, and macrophages. Ubiquilin-4-overexpressed mouse forestomach carcinoma cells showed significantly enhanced growth in immunocompetent mice but not in immunodeficient mice. Upregulation or downregulation of ubiquilin-4 synergistically affected programmed death ligand 1 at the protein and messenger RNA levels. Functional enrichment analysis revealed significant enrichment of the Notch, JAK-STAT, and WNT signaling pathways in ubiquilin-4-high gastric cancers. Ubiquilin-4 promoted Numb degaration, activating the Notch signaling pathway and upregulating programmed death ligand 1.

CONCLUSIONS

Ubiquilin-4 may contribute to immune escape in gastric cancer by upregulating programmed death ligand 1 expression in tumor cells through Notch signaling activation. Thus, ubiquilin-4 could serve as a predictive marker for programmed death ligand 1 inhibitor therapy response in gastric cancer.

Emerging Targets for Systemic Treatment of Gastric Cancer: HER2 and Beyond

In recent years, remarkable progress has been made in the molecular profiling of gastric cancer. This progress has led to the development of various molecular classifications to uncover subtype-specific dependencies that can be targeted for therapeutic interventions. Human epidermal growth factor receptor 2 (HER2) is a crucial biomarker for advanced gastric cancer. The recent promising results of novel approaches, including combination therapies or newer potent agents such as antibody-drug conjugates, have once again brought attention to anti-HER2 targeted treatments. In HER2-negative diseases, the combination of cytotoxic chemotherapy and programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) inhibitors has become the established standard of care in first-line settings. In the context of gastric cancer, potential biomarkers such as PD-L1 expression, Epstein-Barr virus, microsatellite instability, and tumor mutational burden are being considered for immunotherapy. Recently, promising results have been reported in studies on anti-Claudin18.2 and fibroblast growth factor receptor 2 treatments. Currently, many ongoing trials are aimed at identifying potential targets using novel approaches. Further investigations will be conducted to enhance the progress of these therapies, addressing challenges such as primary and acquired resistance, tumor heterogeneity, and clonal evolution. We believe that these efforts will improve patient prognoses. Herein, we discuss the current evidence of potential targets for systemic treatment, clinical considerations, and future perspectives.

Optimizing the Continuum of Care in Gastric Cancer

Gastric cancer (GC) still ranks as the fifth most common malignancy and the fourth leading cause of cancer-related death worldwide. Despite the recent progress in the therapeutic algorithm of the advanced disease with the advent of immune checkpoint inhibitors (ICIs) and next-generation HER2-directed therapies, survival rates remain poor, with a median survival hardly exceeding 12 months. Furthermore, only 40% of patients remain eligible for second- and later-line treatments due to the aggressiveness of the disease and the rapid deterioration of performance status (PS). Thus, current research is focusing either on the identification of novel treatment options or the development of personalized strategies to optimize the continuum of care and ultimately improve patients' outcome. In this article, we provide an overview of the current treatment landscape for advanced GC with a particular emphasis on later-line treatments and outline novel perspectives on the horizon.

Immune checkpoint inhibitors and cellular immunotherapy for advanced gastric, gastroesophageal cancer: a long pathway

Although the incidence rate and mortality of gastric/gastroesophageal cancer (G/GEJC) are declining globally, G/GEJC remains a health issue in East Asia. When diagnosed as advanced stage, treatment after serial lines of chemotherapy is limited, with a median overall survival of less than 1 year. Immunotherapy, including immune checkpoint inhibitors (ICIs) and cellular immunotherapy, has changed the prospects of cancer therapy by reversing immune suppression in the tumor microenvironment. As part of this review, we enumerated the clinical uses of ICIs related to the immunosuppressive signaling axis PD-1/PD-L1 and CTLA-4/B7. ICIs were initially approved as a secondary treatment option for patients with severe pretreating advanced gastric and gastroesophageal cancer (AG/GEJC). Till now, it has become the mainstream therapy in combination with chemotherapy and targeted therapy for patients identified by biomarkers. Numerous evidence showed microsatellite instability (MSI), programmed cell death ligand 1 (PD-L1) expression, tumor mutation burden (TMB) and Epstein-Barr virus (EBV) status might be indicative to the use of ICIs. In addition, we discussed the current limitations and prospects of ICIs in AG/GGEJC, as well as the first clinical application of novel CAR-T cell therapies.

Immunology and immunotherapy in gastric cancer

Gastric cancer is the fifth leading cause of cancer-related deaths worldwide. As the diagnosis of early gastric cancer is difficult, most patients are at a late stage of cancer progression when diagnosed. The current therapeutic approaches based on surgical or endoscopic resection and chemotherapy indeed improve patients' outcomes. Immunotherapy based on immune checkpoint inhibitors has opened a new era for cancer treatment, and the immune system of the host is reshaped to combat tumor cells and the strategy differs according to the patient's immune system. Thus, an in-depth understanding of the roles of various immune cells in the progression of gastric cancer is beneficial to application for immunotherapy and the discovery of new therapeutic targets. This review describes the functions of different immune cells in gastric cancer development, mainly focusing on T cells, B cells, macrophages, natural killer cells, dendritic cells, neutrophils as well as chemokines or cytokines secreted by tumor cells. And this review also discusses the latest advances in immune-related therapeutic approaches such as immune checkpoint inhibitors, CAR-T or vaccine, to reveal potential and promising strategies for gastric cancer treatment.

Human Epidermal Growth Factor Receptor-2 Gastric Adenocarcinoma: Expanding Therapy of a Recognized Target

Human epidermal growth factor receptor-2 (HER2) is a well-known cancer target. Many HER2-targeted agents are marketed and being investigated. Unfortunately, these therapies lack consistent responses and outcomes amongst different tumors. Questions remain as to why HER2 biology is different in different tumor types. Gastric adenocarcinomas (GACs) demonstrate both intra- and inter-tumor HER2 expression heterogeneity and show discordance amongst primary and metastatic disease sites. This creates barriers in determining HER2 agents' effectiveness and contributes to the failure of some HER2-targeted agents in the treatment of HER2-positive advanced GACs. Trastuzumab deruxtecan, an antibody drug conjugate of trastuzumab with a topoisomerase inhibitor, was recently approved for the treatment of refractory HER2-positive advanced GAC patients. There are exciting and newer therapies under investigation. Examining resistance patterns (both adaptive and acquired) along with establishing a better understanding of the intra- and inter-tumor heterogeneity is necessary to ensure successful progress. Here we review the current status of HER2-targeted therapy in GACs. We additionally review newer therapies under investigation and their potential role in HER2 GACs.

Predictive Biomarkers for Immunotherapy in Gastric Cancer: Current Status and Emerging Prospects

Gastric cancer presents substantial management challenges, and the advent of immunotherapy has ignited renewed hope among patients. Nevertheless, a significant proportion of patients do not respond to immunotherapy, and adverse events associated with immunotherapy also occur on occasion, underscoring the imperative to identify suitable candidates for treatment. Several biomarkers, including programmed death ligand-1 expression, tumor mutation burden, mismatch repair status, Epstein-Barr Virus infection, circulating tumor DNA, and tumor-infiltrating lymphocytes, have demonstrated potential in predicting the effectiveness of immunotherapy in gastric cancer. However, the quest for the optimal predictive biomarker for gastric cancer immunotherapy remains challenging, as each biomarker carries its own limitations. Recently, multi-omics technologies have emerged as promising platforms for discovering novel biomarkers that may help in selecting gastric cancer patients likely to respond to immunotherapy. The identification of reliable predictive biomarkers for immunotherapy in gastric cancer holds the promise of enhancing patient selection and improving treatment outcomes. In this review, we aim to provide an overview of clinically established biomarkers of immunotherapy in gastric cancer. Additionally, we introduce newly reported biomarkers based on multi-omics studies in the context of gastric cancer immunotherapy, thereby contributing to the ongoing efforts to refine patient stratification and treatment strategies.

The History and Development of HER2 Inhibitors

HER2 is highly expressed in a variety of malignant tumors and affects the prognosis of patients, making it a highly sensitive target for cancer therapy. Since the approval of the first HER2 inhibitor, trastuzumab, in 1998, HER2-targeted drugs have rapidly evolved. Currently, targeting HER2 drugs mainly include monoclonal antibodies (mAbs), tyrosine kinase inhibitors (TKIs), and antibody-drug conjugates (ADCs). This article reviews the development of HER2 inhibitors for various tumors over the past 20 years.

Immunotherapeutic strategy in the management of gastric cancer: molecular profiles, current practice, and ongoing trials

Gastric cancer (GC) is the one of the most commonly solid cancer worldwide. Although under the aggressive treatment, the poor clinical outcomes of patients with GCs have not been improved. Current studies emphasized that targeting therapies or immune response-based therapeutic strategy may be a potential approach to improve the clinical outcomes. Moreover, accumulative evidence has reported the increasing expression of PD-L1 expression in GC cells and highlighted its role in the tumor progression. Currently, great development has been established in the immune checkpoint inhibitors (ICIs) and further changed the clinical practice of GC treatment and prognosis. In addition, the combination therapies with targeting therapy or traditional therapies are expected to push the development of immunotherapies. In our present review, we predominantly focus on the biomarkers and molecular profiles for immunotherapies in GCs and highlight the role and administration of ICIs-based immunotherapeutic strategies against the GCs.

Advances in targeted therapy and immunotherapy for esophageal cancer

ABSTRACT

Esophageal cancer (EC) is one of the most common aggressive malignant tumors in the digestive system with a severe epidemiological situation and poor prognosis. The early diagnostic rate of EC is low, and most EC patients are diagnosed at an advanced stage. Multiple multimodality treatments have gradually evolved into the main treatment for advanced EC, including surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy. And the emergence of targeted therapy and immunotherapy has greatly improved the survival of EC patients. This review highlights the latest advances in targeted therapy and immunotherapy for EC, discusses the efficacy and safety of relevant drugs, summarizes related important clinical trials, and tries to provide references for therapeutic strategy of EC.

Targeted and Immunotherapy Approaches in HER2-Positive Gastric and Gastroesophageal Junction Adenocarcinoma: A New Era

HER2-targeted therapy with the HER2 monoclonal antibody trastuzumab has achieved impressive outcomes in the first-line settings of patients with advanced gastric and gastroesophageal junction (GEJ) adenocarcinoma overexpressing HER2. However, considering that a substantial proportion of those patients eventually relapses, as well as the relatively limited performance of those agents in second-line settings, a deeper understanding of resistance mechanisms is needed for enhanced guidance for patients' therapeutic selection in the second-line setting and beyond. In this review, we highlight trastuzumab's (HER2-targeting agent) performance in patients with gastric or GEJ cancer, with insight into mechanisms of resistance. We also discuss the new integration of PD-1 inhibitor pembrolizumab into the trastuzumab for gastric cancer frontline regimen, the latest addition of trastuzumab deruxtecan to the treatment armamentarium, and the potential of pipeline HER2-targeting approaches and combinations in patients with gastric or GEJ adenocarcinoma.

Novel Biomarkers of Gastric Cancer: Current Research and Future Perspectives

Gastric cancer is a heterogeneous disease with diverse histological and genomic subtypes, making it difficult to demonstrate treatment efficacy in clinical trials. However, recent efforts have been made to identify molecular biomarkers with prognostic and predictive implications to better understand the broad heterogeneity of gastric cancer and develop effective targeted therapies for it. HER2 overexpression, HER2/neu amplification, MSI-H, and PD-L1+ are predictive biomarkers in gastric cancer, and a growing number of clinical trials based on novel biomarkers have demonstrated the efficacy of targeted therapies alone or in combination with conventional chemotherapy. Enrichment design clinical trials of targeted therapies against FGFR2b and claudin 18.2 have demonstrated efficacy in unresectable advanced gastric cancer. Nonetheless, it is essential to continuously validate promising molecular biomarkers and introduce them into clinical practice to optimize treatment selection and improve patient outcomes. In this review, we focused on established (PD-L1, HER2, MSI) and emerging biomarkers (FGFR2, CLDN18.2) in gastric cancer, their clinical significance, detection methods, limitations, and molecular agents that target these biomarkers.

Targeted Therapies and Developing Precision Medicine in Gastric Cancer

Gastric cancer is an aggressive disease with survival remaining poor in the advanced setting. More than a decade after the first targeted treatment was approved, still only HER2, MSI and PDL-1 status have reached everyday practice in terms of guiding treatment options for these patients. However, various new targets and novel treatments have recently been investigated and have shown promise in improving survival outcomes. In this review, we will summarise previous and currently ongoing studies on predictive biomarkers, possible new targeted treatments, potential reasons for conflicting trial results and hope for the future of precision medicine in gastric cancer.

Gastric cancer treatment: recent progress and future perspectives

Gastric cancer (GC) is one of the most common malignancies worldwide. Most patients are diagnosed at advanced stages due to the subtle symptoms of earlier disease and the low rate of regular screening. Systemic therapies for GC, including chemotherapy, targeted therapy and immunotherapy, have evolved significantly in the past few years. For resectable GC, perioperative chemotherapy has become the standard treatment. Ongoing investigations are exploring the potential benefits of targeted therapy or immunotherapy in the perioperative or adjuvant setting. For metastatic disease, there have been notable advancements in immunotherapy and biomarker-directed therapies recently. Classification based on molecular biomarkers, such as programmed cell death ligand 1 (PD-L1), microsatellite instability (MSI), and human epidermal growth factor receptor 2 (HER2), provides an opportunity to differentiate patients who may benefit from immunotherapy or targeted therapy. Molecular diagnostic techniques have facilitated the characterization of GC genetic profiles and the identification of new potential molecular targets. This review systematically summarizes the main research progress in systemic treatment for GC, discusses current individualized strategies and presents future perspectives.

Immune Checkpoint Inhibitors Combined with Targeted Therapy: The Recent Advances and Future Potentials

Immune checkpoint inhibitors (ICIs) have revolutionized the therapeutic landscape of cancer and have been widely approved for use in the treatment of diverse solid tumors. Targeted therapy has been an essential part of cancer treatment for decades, and in most cases, a special drug target is required. Numerous studies have confirmed the synergistic effect of combining ICIs with targeted therapy. For example, triple therapy of PD-L1 inhibitor atezolizumab plus BRAF inhibitor vemurafenib and MEK inhibitor cobimetinib has been approved as the first-line treatment in advanced melanoma patients with BRAF^V600 mutations. However, not all combinations of ICIs and targeted therapy work. Combining ICIs with EGFR inhibitors in non-small-cell lung cancer (NSCLC) with EGFR mutations only triggered toxicities and did not improve efficacy. Therefore, the efficacies of combinations of ICIs and different targeted agents are distinct. This review firstly and comprehensively covered the current status of studies on the combination of ICIs mainly referring to PD-1 and PD-L1 inhibitors and targeted drugs, including angiogenesis inhibitors, EGFR/HER2 inhibitors, PARP inhibitors and MAPK/ERK signaling pathway inhibitors, in the treatment of solid tumors. We discussed the underlying mechanisms, clinical efficacies, side effects, and potential predictive biomarkers to give an integrated view of the combination strategy and provide perspectives for future directions in solid tumors.

Efficacy and survival of anti-PD-1 antibody in combination with trastuzumab and chemotherapy versus trastuzumab and chemotherapy as first-line treatment of HER2-positive metastasis gastric adenocarcinoma: a retrospective study

Background

The KEYNOTE-811 study exhibited promising preliminary results for HER2-positive metastasis gastric adenocarcinoma; however, long-term survival benefit remains to be determined.

Methods

In this single-center, controlled, retrospective study, patients with histologically confirmed HER2-positive unresectable or metastatic gastric/gastroesophageal adenocarcinoma received either anti-PD-1 antibody combined with trastuzumab and chemotherapy (cohort A) or trastuzumab and chemotherapy treatment (cohort B). The primary end points were progression-free survival (PFS) and overall survival (OS). The secondary end points were objective response rate (ORR), disease control rate (DCR), and duration of response (DoR).

Results

A total of 56 patients were eligible to join the study, with 30 patients in cohort A and 26 patients in cohort B. The median PFS (mPFS) was 16.2 months (95% CI, 15.093-17.307) in cohort A versus 14.5 months (95% CI, 9.491-19.509) in cohort B (p = 0.58). The median OS in cohort A was 28.1 months (95% CI, 17.625-38.575) versus 31.6 months (95% CI, 13.757-49.443) in cohort B (p = 0.534). ORRs were 66.7% and 50% in the two groups, respectively. DCRs were 90% and 84.6% in the two groups. Median DoR was not reached in cohort A and it was 16.3 (95% CI, 8.453-24.207) months in cohort B (p = 0.141). The most common irAEs were grade 1 hypothyroidism (33.3%) in cohort A. No treatment-related deaths occurred in this study.

Conclusions

This retrospective cohort study provided a preliminary picture on the long-term follow-up of combining anti-PD-1 antibody with trastuzumab and chemotherapy in HER2-positive GC, and a trend with longer DoR and ORR was identified. Further studies with larger sample sizes and more in-depth molecular investigation are needed.

History and Future of HER2-Targeted Therapy for Advanced Gastric Cancer

Human epidermal growth factor receptor 2 (HER2) is a receptor tyrosine kinase that belongs to the human epidermal growth factor receptor family. It is overexpressed/amplified in approximately 20% of gastric or gastroesophageal junction cancers. HER2 is being developed as a therapeutic target in a variety of cancers, and several agents have been shown to be effective in breast cancer. The development of HER2-targeted therapy for gastric cancer successfully began with trastuzumab. However, while effective in breast cancer, the successive anti-HER2 agents lapatinib, T-DM1, and pertuzumab failed to demonstrate benefits regarding survival in gastric cancer compared with the existing standard therapies. Intrinsic differences lie between gastric and breast cancer in terms of HER2-positive tumor biology, which may make development difficult. Recently, a novel anti-HER2 agent, trastuzumab deruxtecan, was introduced, and the development of HER2-positive gastric cancer agents has been moving to the next stage. This review summarizes the current HER2-targeted therapy for gastric or gastroesophageal cancer in chronological order and describes the promising future of HER2-targeted therapy.

Can Patients with HER2-Low Breast Cancer Benefit from Anti-HER2 Therapies? A Review

Breast cancer (BC) poses a severe threat to the health of women worldwide. Currently, different therapeutic regimens are used for BC according to the pathological classification of HER2-positive or HER2-negative. Clinical reports of HER2-low expression indicate that the condition is HER2-negative, which was ineligible for HER2-targeted therapy. In contrast to HER2-zero tumors, however, HER2-low BC is a heterogeneous disease with unique genetic characteristics, prognoses, and different therapeutic responses. Clinical efficacy has been demonstrated by numerous potent and innovative anti-HER2 medications, particularly antibody-drug conjugates (ADCs). Certain ADCs, including T-DXd, have demonstrated good efficacy in some trials either used alone or in conjunction with other medications. To enhance outcomes in individuals with HER2-low BC, immunotherapy and other treatments are frequently combined with HER2-targeted therapy. There are also alternative strategies that target both HER2 and HER3 or other antigenic sites. We hope more individuals with HER2-low BC will benefit from more precise treatment regimens in the future. This article provides a review of existing research and clinical trials.

Updated Immunotherapy for Gastric Cancer

Gastric cancer treatments are evolving rapidly. For example, immune checkpoint inhibitors, especially those that target PD-1 or PD-L1, have long-term efficacy in a subset of gastric cancer patients, and are currently the first-line therapy. Immunotherapies approved for use in untreated gastric cancer patients include monotherapy and chemotherapy-immunotherapy combinations. Major clinical trials have reported efficacy and safety data suggesting that PD-L1 expression is important for regimen selection, although other biomarkers, clinicopathologic factors, and patient preference might also be relevant in other situations. Currently, several novel biomarkers and therapeutic strategies are being assessed, which might refine the current treatment paradigm. In this review, we describe the current treatment regimens for patients with gastric cancer and detail the approach we use for the selection of first-line immunotherapy regimens.

Recent advances in immunotherapy and molecular targeted therapy for gastric cancer

Our increasing understanding of the molecular biological characteristics of cancer and of cancer genomics is facilitating the development of immunotherapy and molecular targeted drugs for gastric cancer. After the approval of immune checkpoint inhibitors (ICIs) for melanoma in 2010, many different cancers have been shown to respond to such treatments. Thus, the anti-PD-1 antibody nivolumab was reported to prolong survival in 2017, and ICIs have become the mainstay of treatment development. Many clinical trials of combination therapies with cytotoxic agents and molecular-targeted agents, as well as combinations of immunotherapeutic agents acting via different mechanisms, are currently underway for each treatment line. As a result, further improvements in therapeutic outcomes for gastric cancer are anticipated in the near future.

Current developments in gastric cancer: from molecular profiling to treatment strategy

Gastric cancer and gastro-oesophageal junction cancer represent a global health-care challenge. Despite the efficacy of improved chemotherapy and surgical options, these patients still have a poor prognosis. In advanced disease, only trastuzumab and some immune checkpoint inhibitors, such as nivolumab and pembrolizumab in addition to chemotherapy, have demonstrated consistent and reliable efficacy in patients with HER2-positive and PDL1-positive tumours, respectively. In this Review, we discuss the intrinsic characteristics of gastric and gastro-oesophageal cancer from the molecular and clinical perspectives and provide a comprehensive review of previously reported and ongoing phase II and III clinical trials with targeted agents and immunotherapy in advanced and localized settings. Finally, we suggest alternative strategies to help overcome current challenges in precision medicine and to improve outcomes for these patients.

Challenges and future of HER2-positive gastric cancer therapy

Gastric cancer is the fifth most common cancer worldwide, and the treatment of advanced gastric cancer has relatively little progress. With the continuous development of molecularly targeted therapy for tumors, it has been discovered that human epidermal growth factor receptor 2 (HER2) contributes to the poor prognosis and pathogenesis of various cancers. In order to treat HER2-positive advanced gastric cancer, Trastuzumab has emerged as the first first-line targeted medication used in conjunction with chemotherapy. The consequent trastuzumab resistance has become an important issue, and various new HER2-targeted gastric cancer drugs are emerging to address this challenge. This review's primary concern is the drug mechanism of various HER2-positive gastric cancer targeted therapy and fresh techniques of detection.

Application of immune checkpoint inhibitors in immunotherapy for gastric cancer

Gastric cancer is the fifth most common cancer worldwide. With the development of immunotherapy, especially the application of immune checkpoint inhibitors (ICIs), the prognosis of advanced gastric cancer has improved. At present, ICIs combined with other therapies or dual ICI strategies in the treatment of advanced gastric cancer have shown clinical effectiveness and controllable safety. In addition, predictive biomarkers facilitate the precise selection of patients. Therefore, it is crucial to explore rational combinations and reliable predictive biomarkers for ICI therapy. This article reviews the recent advances in ICIs and relevant predictive biomarkers in the treatment of gastric cancer.

Short-term efficacy and influencing factors of conventional chemotherapy combined with irinotecan in patients with advanced gastric cancer

BACKGROUND

Gastric cancer is one of the most common cancers worldwide, with a 5-year survival rate of only 20%. The age of onset of gastric cancer is in line with the general rule of cancer. Most of them occur after middle age, mostly between 40 and 60 years old, with an average age of about 50 years old, and only 5% of patients are under 30 years old. The incidence of male is higher than that of female.

AIM

To investigate the short-term efficacy and influencing factors of chemotherapy combined with irinotecan in patients with advanced gastric cancer.

METHODS

Eighty patients with advanced gastric cancer who were treated in our hospital from January 2019 to January 2022 were selected. The patients were divided into an observation group (n = 40) and control group (n = 40) by the envelope method. The control group was given preoperative routine chemotherapy. The observation group was treated with irinotecan in addition to the chemotherapy given to the control group. The short-term efficacy of treatment in the two groups, as well as tumor marker levels and quality of life before and after treatment were evaluated.

RESULTS

The short-term treatment effect in the observation group was better than that in the control group (P < 0.05), and the total effective rate was 57.50%. The age and proportion of tumor node metastasis (TNM) stage IV patients with ineffective chemotherapy in the observation group were (65.12 ± 5.71) years and 52.94%, respectively, which were notably higher than those of patients with effective chemotherapy (P < 0.05), while the Karnofsky Performance Scale score was (67.70 ± 3.83) points, which was apparently lower than that of patients with effective chemotherapy (P < 0.05). After 3 mo of treatment, the SF-36 scale scores of physiological function, energy, emotional function, and mental health in the observation group were 65.12 ± 8.14, 54.76 ± 6.70, 47.58 ± 7.22, and 66.16 ± 8.11 points, respectively, which were considerably higher than those in the control group (P < 0.05). The incidence rates of grade III-IV diarrhea and grade III-IV thrombocytopenia in the observation group were 32.50% and 25.00%, respectively, which were markedly higher than those in the control group (P < 0.05).

CONCLUSION

Chemotherapy combined with irinotecan in patients with advanced gastric cancer has a good short-term efficacy and can significantly reduce serum tumor markers and improve the quality of life of patients. The efficacy may be affected by the age and TNM stage of the patients, and its long-term efficacy needs further study.

Adding of apatinib and camrelizumab to overcome de novo trastuzumab resistance of HER2-positive gastric cancer: A case report and literature review

Background: Studies confirmed that trastuzumab plus fluorouracil-based chemotherapy improves the survival to more than 1 year in human with human epidermal growth factor receptor-2 (HER2)-positive advanced gastric cancer. However, there are still a small proportion of patients who do not benefit from trastuzumab treatment. Case summary: Here, we described a case report of de novo trastuzumab resistance in HER2-positive gastric cancer. Concomitant cyclin-E1 (CCNE1) and HER2 amplification are associated with de novo trastuzumab resistance. Genomic analysis demonstrated CCNE1 amplification and TP53 mutation in a HER2-positive gastric cancer patient. This patient achieved significant survival benefit and good safety when the patient received triple regimens consisting of trastuzumab, apatinib, and camrelizumab. Conclusion: Trastuzumab plus camrelizumab plus apatinib has the potential efficacy in HER2-positive gastric cancer patients who were previously treated with trastuzumab plus chemotherapy. This may lead to a new solution to trastuzumab resistance.

Effectiveness and safety of anti-PD-1 monotherapy or combination therapy in Chinese advanced gastric cancer: A real-world study

Purpose

Gastric cancer (GC) is one of the most frequently diagnosed cancers and one of the leading causes of cancer deaths worldwide, especially in eastern Asia and China. Anti-PD-1 immune checkpoint inhibitors, Pembrolizumab and Nivolumab, have been approved for the treatment of locally advanced or metastatic gastric or gastroesophageal junction cancer (GC/GEJC). Our study evaluated the effectiveness and safety of anti-PD-1-based treatment (monotherapy or combination therapy) in Chinese patients with advanced or metastatic GC/GEJCs in a real-world setting.

Methods

A retrospective cohort study was conducted, and 54 patients from May 31, 2015, to May 31, 2021, were included in our analysis, including 19 patients treated with anti-PD-1 monotherapy and 35 patients treated with anti-PD-1 combination therapy. Demographic and clinical information were evaluated. Clinical response, survival outcomes, and safety profile were measured and analyzed.

Results

Overall, the median overall survival (mOS) was 11.10 months (95% CI, 7.05-15.15), and the median progression-free survival (mPFS) was 3.93 months (95% CI, 2.47-5.39). Of the patients, 16.7% achieved a clinical response, and 72.2% achieved disease control. Prolonged overall survival (OS) and progression-free survival (PFS) and increased clinical response were observed in the combination group compared with the monotherapy group, although statistical significance was not reached. In subgroups with live metastases or elevated baseline neutrophil-to-lymphocyte ratio (NLR) levels, combination therapy outperformed anti-PD-1 alone in survival outcomes. Patients treated with anti-PD-1 monotherapy (n = 5, 26.3%) had fewer treatment-related adverse events (TRAEs) than those in the combination group (n = 22, 62.9%). There were also fewer patients with TRAEs of grades 3-5 with monotherapy (n = 2, 10.5%) than with combination therapy (n = 7, 20.0%). Pneumonitis in three patients was the only potential immune-related adverse event reported.

Conclusions

Anti-PD-1-based monotherapy and combination therapy showed favorable survival outcomes and manageable safety profiles in advanced or metastatic GC/GEJCs. In clinical treatment, immunotherapy should be an indispensable choice in the treatment strategy for GC/GEJC. Patients with a heavy tumor burden and more metastatic sites might benefit more from combination therapy. Elderly patients and patients with more treatment lines or high Eastern Cooperative Oncology Group (ECOG) performance scores might be more suitable for immune monotherapy, and some clinical benefits have been observed.

Turning Tertiary Lymphoid Structures (TLS) into Hot Spots: Values of TLS in Gastrointestinal Tumors

Tertiary lymphoid structures (TLSs) are ectopic lymphocyte aggregation structures found in the tumor microenvironment (TME). Emerging evidence shows that TLSs are significantly correlated with the progression of gastrointestinal tumors, patients' prognosis, and the efficacy of adjuvant therapy. Besides, there are still some immunosuppressive factors in the TLSs that may affect the anti-tumor responses of TLSs, including negative regulators of anti-tumor immune responses, the immune checkpoint molecules, and inappropriate tumor metabolism. Therefore, a more comprehensive understanding of TLSs' responses in gastrointestinal tumors is essential to fully understand how TLSs can fully exert their anti-tumor responses. In addition, targeting TLSs with immune checkpoint inhibitors and vaccines to establish mature TLSs is currently being developed to reprogram the TME, further benefiting cancer immunotherapies. This review summarizes recent findings on the formation of TLSs, the mechanisms of their anti-tumor immune responses, and the association between therapeutic strategies and TLSs, providing a novel perspective on tumor-associated TLSs in gastrointestinal tumors.

Breakthroughs in the Systemic Treatment of HER2-Positive Advanced/Metastatic Gastric Cancer: From Singlet Chemotherapy to Triple Combination

Gastric cancer is heterogeneous in morphology, biology, genomics, and treatment response. Alterations in human epidermal growth factor receptor 2 (HER2) overexpression, microsatellite instability (MSI) status, programmed death-ligand 1 (PD-L1) levels, and fibroblast growth factor receptor 2 (FGFR2) can be used as biomarkers. Since the combination of fluoropyrimidine/platinum plus trastuzumab that was investigated in the ToGA trial was approved as a standard of care in HER2-positive patients in 2010, no other agents showed efficacy in the first- (HELOISE, LOGiC, JACOB trials) and second- (TyTAN, GATSBY, T-ACT trials) line treatments. Despite the success in treating breast cancer, various anti-HER2 agents, including a monoclonal antibody (pertuzumab), an antibody-drug conjugate (ADC; trastuzumab emtansine [T-DM1]), and a small molecule (lapatinib) failed to translate into clinical benefits until the KEYNOTE-811 (first-line) and DESTINY-Gastri01 (≥second-line) trials were conducted. The incorporation of HER2-directed treatment with immune checkpoint inhibitors in the form of a monoclonal antibody or ADC is now approved as a standard treatment. Despite the promising results of new agents (engineered monoclonal antibodies, bi-specific antibodies, fusion proteins, and small molecules) in the early phase of development, the management of HER2-positive gastric cancer requires further optimization to achieve precision medicine with a chemotherapeutic backbone. Treatment resistance is a complex process that can be overcome using a combination of chemotherapy, targeted agents, and immune checkpoint inhibitors, including novel agents. HER2 status must be reassessed in patients undergoing anti-HER2 treatment with disease progression after the first-line treatment. As a general guideline, patients who need systemic treatment should receive chemotherapy plus targeted agents, anti-angiogenic agents, immune checkpoint inhibitors, or their combinations.

Current molecular biomarkers evaluation in gastric/gastroesophageal junction adenocarcinoma: pathologist does matter

The comprehensive molecular characterization of gastric and gastroesophageal junction adenocarcinomas has led to the improvement of targeted and more effective treatments. As a result, several biomarkers have been introduced into clinical practice and the implementation of innovative diagnostic tools is under study. Such assessments are mainly based on the evaluation of limited biopsy material in clinical practice. In this setting, the pathologist represents a key player in the selection of patients facilitating precision medicine approaches.

A Review of Margetuximab-Based Therapies in Patients with HER2-Positive Metastatic Breast Cancer

Breast cancer (BC) is the most commonly diagnosed cancer globally, with high mortality rates. Targeted drug therapies have revolutionized cancer treatment. For example, treatment with human epidermal receptor 2 (HER2) antagonists has markedly improved the prognosis of patients with HER2-positive BC (HER2 + BC). However, HER2+ metastatic BC (MBC) remains prevalent owing to its resistance to conventional anti-HER2 drugs. Therefore, novel agents are needed to overcome the limitations of existing cancer treatments and to enhance the progression-free and overall survival rates. Progress has been made by optimizing the fragment crystallizable (Fc) domain of trastuzumab, an IgG1 monoclonal, chimeric anti-HER2 antibody, to develop margetuximab. The modified Fc domain of margetuximab enhances its binding affinity to CD16A and decreases its binding affinity to CD32B, thereby promoting its antitumor activity. This review summarizes studies on the efficacy of margetuximab, discusses its utility as an anti-HER2 monoclonal antibody drug for the treatment of HER2 + BC, and presents the latest advances in the treatment of BC. This review provides insights into the clinical implication of margetuximab in HER2 + MBC treatment.

Focusing on NK cells and ADCC: A promising immunotherapy approach in targeted therapy for HER2-positive breast cancer

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer has a high metastatic potential. Monoclonal antibodies (mAbs) that target HER2, such as trastuzumab and pertuzumab, are the cornerstone of adjuvant therapy for HER2-positive breast cancer. A growing body of preclinical and clinical evidence points to the importance of innate immunity mediated by antibody-dependent cellular cytotoxicity (ADCC) in the clinical effect of mAbs on the resulting anti-tumor response. In this review, we provide an overview of the role of natural killer (NK) cells and ADCC in targeted therapy of HER2-positive breast cancer, including the biological functions of NK cells and the role of NK cells and ADCC in anti-HER2 targeted drugs. We then discuss regulatory mechanisms and recent strategies to leverage our knowledge of NK cells and ADCC as an immunotherapy approach for HER2-positive breast cancer.

Immune-based combination therapy for esophageal cancer

Esophageal cancer (EC) is an aggressive malignancy raising a healthcare concern worldwide. Standard treatment options include surgical resection, chemotherapy, radiation therapy, and targeted molecular therapy. The five-year survival rate for all stages of EC is approximately 20%, ranging from 5% to 47%, with a high recurrence rate and poor prognosis after treatment. Immunotherapy has shown better efficacy and tolerance than conventional therapies for several malignancies. Immunotherapy of EC, including immune checkpoint inhibitors, cancer vaccines, and adoptive cell therapy, has shown clinical advantages. In particular, monoclonal antibodies against PD-1 have a satisfactory role in combination therapy and are recommended for first- or second-line treatments. Here, we present a systematic summary and analysis of immunotherapy-based combination therapies for EC.

Quantification of the growth suppression of HER2+ breast cancer colonies under the effect of trastuzumab and PD-1/PD-L1 inhibitor

Introduction

Immune checkpoint blockade (ICB)-based therapy is revolutionizing cancer treatment by fostering successful immune surveillance and effector cell responses against various types of cancers. However, patients with HER2+ cancers are yet to benefit from this therapeutic strategy. Precisely, several questions regarding the right combination of drugs, drug modality, and effective dose recommendations pertaining to the use of ICB-based therapy for HER2+ patients remain unanswered.

Methods

In this study, we use a mathematical modeling-based approach to quantify the growth inhibition of HER2+ breast cancer (BC) cell colonies (ZR75) when treated with anti-HER2; trastuzumab (TZ) and anti-PD-1/PD-L1 (BMS-202) agents.

Results and discussion

Our data show that a combination therapy of TZ and BMS-202 can significantly reduce the viability of ZR75 cells and trigger several morphological changes. The combination decreased the cell's invasiveness along with altering several key pathways, such as Akt/mTor and ErbB2 compared to monotherapy. In addition, BMS-202 causes dose-dependent growth inhibition of HER2+ BC cell colonies alone, while this effect is significantly improved when used in combination with TZ. Based on the in-vitro monoculture experiments conducted, we argue that BMS-202 can cause tumor growth suppression not only by mediating immune response but also by interfering with the growth signaling pathways of HER2+BC. Nevertheless, further studies are imperative to substantiate this argument and to uncover the potential crosstalk between PD-1/PD-L1 inhibitors and HER2 growth signaling pathways in breast cancer.

Long-term survival after immunotherapy and targeted therapy without chemotherapy in an elderly patient with HER2-positive gastroesophageal junction cancer: A case report

A 74-yr-old man underwent thoracic laparoscopy combined with radical gastrectomy, and the postoperative pathological diagnosis was esophageal and gastric cardia cancer pT3N1M0, pStage IIB. Immunohistochemical staining for HER2 (3+) and PD-L1 (<5%) was positive. Adjuvant chemotherapy was not performed because the patient developed severe thrombocytopenia (platelet counts <30 × 10⁹/L), which was never cured throughout the reporting period. At 10.7 months post-surgery, he suffered metastases in multiple organs, including the peritoneum, liver, lung, and bone. Following two cycles of first-line trastuzumab and pembrolizumab (200 mg), he developed immune-related myositis (G2), myocarditis (G2), and hepatitis (G1). Therefore, pembrolizumab was discontinued. Trastuzumab was administered as a monotherapy; meanwhile, adoptive cytokine-induced killer (CIK) cell infusions were initiated. Eight months after the initial immunotherapy, a solitary brain metastasis was detected, and the patient underwent CyberKnife radiosurgery. For second-line therapy, adoptive CIK cell immunotherapy plus trastuzumab was still used. At the time of reporting, the patient had achieved a complete response (CR) in the brain and liver and a partial response (PR) in the ilium, and he had been followed-up for 36.6 months, much longer than the median survival time for patients with advanced GEJ cancer. We suggest that HER2-targeted therapy and immunotherapy with pembrolizumab or CIK adoptive cell infusions prolonged the overall survival of an elderly patient with HER2-positive GEJ cancer with multiple metastases.

Recent advances in the progress of immune checkpoint inhibitors in the treatment of advanced gastric cancer: A review

Most patients with advanced gastric cancer were treated with palliative therapy, which had a poor curative effect and a short survival time. In recent years, the clinical research of immune checkpoint inhibitors in advanced gastric cancer has made a breakthrough and has become an important treatment for advanced gastric cancer. The modes of immune checkpoint inhibitors in the treatment of advanced gastric cancer include single drug, combined chemotherapy, radiotherapy, and multiple immune drug combination therapy, among which combination therapy shows better clinical efficacy, and a large number of trials are currently exploring more effective combination therapy programs. In this paper, the new clinical research progress of immune checkpoint inhibitors in the treatment of advanced gastric cancer is reviewed, with an emphasis on combination therapy.

Recent Trends and Advancements in the Diagnosis and Management of Gastric Cancer

Gastric cancer is an enigmatic malignancy that has recently been shown to be increasing in incidence globally. There has been recent progress in emerging technologies for the diagnosis and treatment of the disease. Improvements in non-invasive diagnostic techniques with serological tests and biomarkers have led to decreased use of invasive procedures such as endoscopy. A multidisciplinary approach is used to treat gastric cancer, with recent significant advancements in systemic therapies used in combination with cytotoxic chemotherapies. New therapeutic targets have been identified and clinical trials are taking place to assess their efficacy and safety. In this review, we provide an overview of the current and emerging treatment strategies and diagnostic techniques for gastric cancer.

Recent progress and current challenges of immunotherapy in advanced/metastatic esophagogastric adenocarcinoma

The new era of immunotherapy is successfully implemented in the treatment of metastatic/locally advanced esophagogastric adenocarcinoma (EGAC), as it has been investigated in combinations with/without chemotherapy in human epidermal growth factor receptor 2 (Her2)-positive and Her2-negative tumors. Recent approvals of immune checkpoint inhibitors (ICI) enrich the therapeutic landscape in nearly every therapeutic line. Based on CHECKMATE-649, the combination of nivolumab and chemotherapy in first-line therapy of programmed cell death protein 1 (PD-L1)-positive patients with advanced gastroesophageal junction cancer (GEJC), esophageal cancer (EC), and gastric cancer (GC) was approved in Europe for PD-L1 combined positivity score (CPS) ≥ 5 patients and independently from PD-L1 score in the USA and Asia. Based on KEYNOTE-590, patients with advanced GEJC and EC qualify for the combination of pembrolizumab plus chemotherapy in Europe (CPS ≥ 10) and the USA. For Her2-positive patients, trastuzumab with first-line chemotherapy plus pembrolizumab has beneficial response rates and resulted in approval in the USA (KEYNOTE-811). In third-line therapy, superior overall survival (OS) was achieved by the administration of nivolumab (approval in Japan, ATTRACTION-02), and pembrolizumab shows a positive effect on the duration of response (KEYNOTE-059). Questions of resistance to immunotherapy or the role of gender in response to ICI need to be clarified. This review provides an overview of the current approvals of ICI in advanced EGAC and reflects results of relevant phase II/III trials with focus on possible biomarkers, including PD-L1 CPS and microsatellite-instability (MSI) status.

Resistance to Trastuzumab

Simple Summary

Trastuzumab is a humanized antibody that has significantly improved the management and treatment outcomes of patients with cancers that overexpress HER2. Many research groups, both in academia and industry, have contributed towards understanding the various mechanisms engaged by trastuzumab to mediate its anti-tumor effects. Nevertheless, data from several clinical studies have indicated that a significant proportion of patients exhibit primary or acquired resistance to trastuzumab therapy. In this article, we discuss underlying mechanisms that contribute towards to resistance. Furthermore, we discuss the potential strategies to overcome some of the mechanisms of resistance to enhance the therapeutic efficacy of trastuzumab and other therapies based on it.

Abstract

One of the most impactful biologics for the treatment of breast cancer is the humanized monoclonal antibody, trastuzumab, which specifically recognizes the HER2/neu (HER2) protein encoded by the ERBB2 gene. Useful for both advanced and early breast cancers, trastuzumab has multiple mechanisms of action. Classical mechanisms attributed to trastuzumab action include cell cycle arrest, induction of apoptosis, and antibody-dependent cell-mediated cytotoxicity (ADCC). Recent studies have identified the role of the adaptive immune system in the clinical actions of trastuzumab. Despite the multiple mechanisms of action, many patients demonstrate resistance, primary or adaptive. Newly identified molecular and cellular mechanisms of trastuzumab resistance include induction of immune suppression, vascular mimicry, generation of breast cancer stem cells, deregulation of long non-coding RNAs, and metabolic escape. These newly identified mechanisms of resistance are discussed in detail in this review, particularly considering how they may lead to the development of well-rationalized, patient-tailored combinations that improve patient survival.

Common strategies for effective immunotherapy of gastroesophageal cancers using immune checkpoint inhibitors

Gastroesophageal cancers (GECs) are very prevalent around the world and rank as the second cause of all cancer-related deaths in men and women and demonstrate a very poor prognosis. Currently, the treatment options for these malignancies are very limited and the response rates are also very low. Recently, immune checkpoint inhibitors (ICIs) have been proposed for immunotherapy of GECs; although preliminary results obtained from the clinical trials of ICIs in GECs were promising, they have shown to be effective only in a few subsets of patients who had a previous immune response to the tumor. In order to maximize the efficacy of ICIs in GECs, as well as identify the patients who will likely benefit from ICIs, several predictive biomarkers, such as Programmed death-ligand 1 (PD-L1) have been developed and evaluated. Since the single ICI therapies resulted in poor treatment response, several clinical studies began to explore various combinations of one or two ICIs with other anti-cancer treatment approaches, including chemotherapy, radiotherapy, and anti-angiogenesis therapy. These combinations demonstrated a more effective response among the ICIs-responsive patients and even in some instances sensitized the non-responsive individuals. This review is aimed to summarize the efforts made so far for improving the effectiveness of ICIs in the treatment of patients with GECs. Furthermore, multiple aspects of translational medicine such as available biomarkers and interactions between tumor and the immune system, as well as clinical aspects regarding the combination therapies and results of clinical trials will be discussed.