HER2-targeted advanced metastatic gastric/gastroesophageal junction adenocarcinoma: treatment landscape and future perspectives

Recently, the global incidence of gastric/gastroesophageal junction (G/GEJ) cancer has remained high. China is also a large country with a high gastric cancer (GC) incidence rate, where the cases of GC account for 40% of all cases worldwide. More than 90% of GEJ cancers are the adenocarcinoma pathological type. Patients with early-stage G/GEJ adenocarcinoma may have a better prognosis after surgery. In contrast, patients with advanced metastatic G/GEJ adenocarcinoma usually choose comprehensive treatment based on systemic pharmacotherapy, but the subsequent long-term survival is not optimistic. The discovery of various biomarkers, especially microsatellite instability (MSI), programmed cell death-ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2), tumor mutational burden (TMB) and Epstein-Barr virus (EBV), has led to the identification of an increasing number of targeted populations and has greatly improved the clinical efficacy of treatments for G/GEJ adenocarcinoma. The ToGA trial added trastuzumab to standard chemotherapy, showed improved survival of patients with HER2-positive advanced G/GEJ adenocarcinoma and brought these patients into a new era of HER2-targeted therapy. Moreover, many HER2-targeted agents have been developed and studied in patients with advanced HER2-positive G/GEJ adenocarcinoma who have demonstrated excellent clinical outcomes. However, many patients experience disease progression with HER2-targeted therapy; hence, new anti-HER2 drugs keep being developed, significantly reducing HER2 resistance. This paper reviews HER2-targeted drugs for advanced metastatic G/GEJ adenocarcinoma, potential resistance mechanisms and future directions.

HER2 Inhibition in Gastric Cancer-Novel Therapeutic Approaches for an Established Target

Gastric cancer is a leading cause of cancer-related deaths globally. Human epidermal growth receptor 2 (HER2) overexpression of HER2 gene amplification is present in 20% of gastric cancers and defines a subset amenable to HER2-directed therapeutics. The seminal ToGA study led to routine use of the monoclonal antibody trastuzumab in conjunction to platinum-fluoropyridimine first-line chemotherapy for HER2-positive gastric cancers as standard-of-care. Although limited progress was made in the decade following ToGA, there is now an abundance of novel therapeutic approaches undergoing investigation in parallel. Additionally, new data from randomised trials have indicated efficacy of the antibody-drug conjugate trastuzumab deruxtecan in chemorefractory patients and increased responses with the addition of first-line immune checkpoint blockade to trastuzumab and chemotherapy. This review will outline the data supporting HER2 targeting in gastric cancers, discuss mechanisms of response and resistance to HER2-directed therapies and summarise the emerging therapies under clinical evaluation that may evolve the way we manage this subset of gastric cancers in the future.

Evolution of predictive and prognostic biomarkers in the treatment of advanced gastric cancer

Despite new therapeutic options, advanced gastric cancer remains associated with a poor prognosis compared with other cancers. Recent gains in the treatment of gastric cancer were accompanied by the identification of novel biomarkers associated with various cellular pathways and corresponding diagnostic technologies. It is expected that the standardization of clinical workflow and technological refinements in biomarker assessment will support greater personalization and further improve treatment outcomes. In this article, we review the current state of prognostic and predictive biomarkers in gastric cancer.

Association of ERBB2 Copy Number and Gene Coalterations With Trastuzumab Efficacy and Resistance in Human Epidermal Growth Factor Receptor 2-Positive Esophagogastric and Gastric Cancer

ERBB2 copy number (CN), measured using next-generation sequencing, is a predictive biomarker for trastuzumab efficacy in human epidermal growth factor receptor 2 (HER2)–positive advanced esophagogastric and gastric cancer (AGC). We aimed to investigate the association of ERBB2 amplification and gene coalterations with response and resistance to trastuzumab-combined chemotherapy.

The Durable Effect of Pyrotinib Plus Trastuzumab and Chemotherapy in HER2-Positive Gastric Cancer With Brain Metastases: A Case Report and Literature Review

Gastric cancer (GC) is a disease with macromolecular phenotypic heterogeneity and poor prognosis, especially for metastatic GC (mGC). Chemotherapy is the first choice for second-line treatment. However, the benefits of second-line chemotherapy are limited, so there is an urgent need for new treatment regimens to improve patient outcomes. A 65-year-old man with mGC was HER-2 positive. Standard trastuzumab, combined with chemotherapy, was given in the first-line therapy and progression-free survival (PFS) was 8 months. Second-line treatment with pyrotinib in combination with trastuzumab and chemotherapy yielded a PFS of 20 months, in sharp contrast to a median survival of 2.9-6.2 months for a majority of advanced GC patients. This case provides a meaningful reference for the second-line treatment of mGC patients with HER-2 positive. This case also provides valuable information on the response to pyrotinib plus trastuzumab of patients with brain metastases and a better understanding of dual target combination therapy applications in the future.

The clinical position of ramucirumab-containing regimens for advanced gastric cancer: a review of clinical trial data

Despite the availability of multiple treatment options, the prognosis for advanced gastric cancer (AGC) remains poor and more effective treatment options are needed. Ramucirumab is an established and recommended second-line treatment for AGC. In recently completed and ongoing clinical trials, ramucirumab has been investigated in combination with new therapeutics and in new clinical settings to address the unmet treatment needs of AGC. In this review, the findings of recent clinical trials are discussed. The aims of this review are to present the current picture of ramucirumab-containing regimens in AGC and offer practical guidance on the clinical position and target populations of ramucirumab-containing regimens in light of emerging therapeutic developments.

Cross-Resistance Among Sequential Cancer Therapeutics: An Emerging Issue

Over the past two decades, cancer treatment has benefited from having a significant increase in the number of targeted drugs approved by the United States Food and Drug Administration. With the introduction of targeted therapy, a great shift towards a new era has taken place that is characterized by reduced cytotoxicity and improved clinical outcomes compared to traditional chemotherapeutic drugs. At present, targeted therapies and other systemic anti-cancer therapies available (immunotherapy, cytotoxic, endocrine therapies and others) are used alone or in combination in different settings (neoadjuvant, adjuvant, and metastatic). As a result, it is not uncommon for patients affected by an advanced malignancy to receive subsequent anti-cancer therapies. In this challenging complexity of cancer treatment, the clinical pathways of real-life patients are often not as direct as predicted by standard guidelines and clinical trials, and cross-resistance among sequential anti-cancer therapies represents an emerging issue. In this review, we summarize the main cross-resistance events described in the diverse tumor types and provide insight into the molecular mechanisms involved in this process. We also discuss the current challenges and provide perspectives for the research and development of strategies to overcome cross-resistance and proceed towards a personalized approach.

Molecular pathogenesis and emerging targets of gastric adenocarcinoma

Gastric adenocarcinoma (GC) is a devastating disease and is the third leading cause of cancer deaths worldwide. This heterogeneous disease has several different classification systems that consider histological appearance and genomic alterations. Understanding the etiology of GC, including infection, hereditary conditions, and environmental factors, is of particular importance and is discussed in this review. To improve survival in GC, we also must improve our therapeutic strategies. Here, we discuss new targets that warrant further exploration.

Ramucirumab plus paclitaxel as a second-line treatment in HER2-positive gastric cancer: subgroup analysis of a nationwide, real-world study in Korea (KCSG-ST19-16)

BACKGROUND

A subgroup analysis of data from a nationwide study (KCSG-ST19-16) was performed to evaluate the efficacy and safety of second-line ramucirumab plus paclitaxel treatment in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastro-esophageal junction (GEJ) adenocarcinoma.

METHODS

The KCSG-ST19-16 study enrolled a total of 1063 patients from 56 hospitals in South Korea with advanced gastric or GEJ adenocarcinoma, who had received second-line treatment with ramucirumab plus paclitaxel. HER2 status was known for 994 (93.5%) of these patients, who were thus included in the subgroup analysis.

RESULTS

In total, 163 of 994 patients (16.4%), had HER2-positive gastric or GEJ adenocarcinoma. The objective response rate to ramucirumab plus paclitaxel treatment was significantly higher in patients with HER2-positive disease compared to those with HER2-negative disease (23.0% [95% confidence interval (CI), 15.9-30.1] vs. 15.1% [95% CI, 12.3-17.9], p = 0.025). The median progression-free survival was longer in patients with HER2-positive versus HER2-negative disease, but the difference was not statistically significant (4.3 months [95% CI, 3.7-5.3] vs 3.7 months [95% CI, 3.4-4.0], p = 0.054). There was no statistically significant difference in median overall survival (OS) between the groups (9.8 months [95% CI, 8.9-12.3] vs 10.1 months [95% CI, 9.2-10.9], p = 0.564).

CONCLUSIONS

In patients with HER2-positive gastric or GEJ adenocarcinoma, the objective response rate to second-line treatment with ramucirumab plus paclitaxel was significantly higher compared to patients with HER2-negative disease. However, an increased response to treatment was not associated with an improvement in OS.

Comparative effectiveness and tolerability of targeted agents combined with chemotherapy in patients with HER2-positive gastroesophageal cancer: A network meta-analysis

Background

Gastric cancer (GC) or gastroesophageal junction (GEJ) cancer with HER2 overexpression is highly invasive, with a poor prognosis. With the development of new targeted agents, which agents have ideal therapeutic effects must be determined. This network meta-analysis analyzed the effectiveness and tolerability of targeted agents combined with chemotherapy in HER2-positive GC/GEJ cancer.

Methods

Public databases were searched from the date of inception to October 22, 2020. Randomized controlled trials (RCTs) on targeted agent-related regimens for HER2-positive advanced GC or GEJ cancer were included. Subgroup analyses based on publication language, first-line treatment, second/third-line treatment, and HER2 staining intensity were performed.

Results

In total, 13 articles were included. The trastuzumabderuxtecan (TraD) and pertuzumab plus trastuzumab and chemotherapy (PerTraChemo) regimens were considered to have high effectiveness but low tolerability. In the subgroup analysis, PerTraChemo still had high effectiveness with low tolerability as the first-line therapy. As the second- or third-line therapy, TraD and lapatinib plus chemotherapy (LapChemo) had high effectiveness and moderate tolerability. In terms of overall survival (OS) time, PerTraChemo had a relative advantage in the immunohistochemistry (IHC) 2+/in situ hybridization (ISH)+ population, whereas TraD, PerTraChemo, and trastuzumab plus chemotherapy (TraChemo) had a relative advantage in the IHC3+ population.

Conclusion

TraD had relative advantages as the second- or third-line therapy and in the IHC3 + population. PerTraChemo is a potential first-line therapy, but it requires further confirmation because the JACOB phase III clinical trial failed to confirm the superiority of PerTraChemo over TraChemo with regard to OS.

Therapeutic Advances and Challenges in the Management of HER2-Positive Gastroesophageal Cancers

Gastroesophageal cancer is one of the most common cancers in the world, with a high rate of mortality. While there has been significant progress over the past decade, particularly with the addition of anti-HER2 therapies to platinum-based chemotherapy agents in the advanced setting, the prognosis remains poor and the treatment options for this disease entity remain limited. In this review, we discuss the current therapeutic landscape for HER2-positive gastroesphageal cancer and the seminal clinical trials that have shaped our approach to this disease entity. In addition, we highlight some of the challenges to the understanding and management of this disease, specifically discussing the breadth of molecular diversity and intratumoral heterogeneity of HER2 expression that impact the clinical efficacy and prognosis. Furthermore, we discuss the potential role of next-generation sequencing (NGS) and circulating-tumor DNA (ctDNA) as complementary tools to immunohistochemistry (IHC) and fluorescent in-situ hybridization (FISH) to guiding clinical decision making. Finally, we highlight promising clinical trials of new treatment regimens that will likely reshape the therapeutic approach to this disease entity.

Real-World Data of Trastuzumab Deruxtecan for Advanced Gastric Cancer: A Multi-Institutional Retrospective Study

Simple Summary

Gastric cancer has the fifth highest incidence among cancers in the world, and it causes the third most cancer-related deaths. In this study, data from patients with HER2-positive advanced gastric cancer who received trastuzumab deruxtecan (T-DXd) were analyzed. Pre-administration of immune checkpoint inhibitors and a sufficiently long trastuzumab-free interval may be predictive factors of T-DXd efficacy.

Abstract

Trastuzumab deruxtecan (T-DXd) has shown promising efficacy against HER2-positive advanced gastric cancer (AGC). However, data on its real-world efficacy in AGC patients are insufficient, and the predictive marker of T-DXd is unclear. In this multi-center retrospective study, we collected clinical information of 18 patients with HER2-positive AGC who received T-DXd after intolerant or refractory responses to at least two prior regimens and analyzed predictive factors. The median age was 71 years (range: 51–85), 13 men were included, and ECOG performance status (PS): 0/1/2/3 was 9/6/2/1. A total of 11 patients (61%) received prior immune checkpoint inhibitors (ICIs), 14 patients were HER2 3+, and 4 patients were HER2 2+/FISH positive. The median trastuzumab (Tmab)-free interval was 7.7 months (range: 2.8–28.6). The overall response rate was 41%, and the disease control rate was 76%. Median progression-free survival (PFS) was 3.9 months (95% CI: 2.6–6.5), and median overall survival (OS) was 6.1 months (95% CI: 3.7–9.4). PFS (6.5 vs. 2.9 months, p = 0.0292) and OS (9.2 vs. 3.7 months, p = 0.0819) were longer in patients who received prior ICIs than in those who had not. PFS (6.5 vs. 3.4 months, p = 0.0249) and OS (9.4 vs. 5.7 months, p = 0.0426) were longer in patients with an 8 month or longer Tmab-free interval. In patients with ascites, PFS (6.5 vs. 2.75 months, p = 0.0139) and OS (9.4 vs. 3.9 months, p = 0.0460) were shorter. T-DXd showed promising efficacy in HER2-positive AGC patients in a real-world setting. Pre-administration of ICIs and a sufficient Tmab-free interval may be predictive factors of T-DXd efficacy.

Disrupting Circadian Rhythm via the PER1-HK2 Axis Reverses Trastuzumab Resistance in Gastric Cancer

Trastuzumab is the only approved targeted drug for first-line treatment of HER2-positive advanced gastric cancer, but the high rate of primary resistance and rapid emergence of secondary resistance limit its clinical benefits. We found that trastuzumab-resistant (TR) gastric cancer cells exhibited high glycolytic activity, which was controlled by hexokinase 2 (HK2)-dependent glycolysis with a circadian pattern [higher at zeitgeber time (ZT) 6, lower at ZT18]. Mechanistically, HK2 circadian oscillation was regulated by a transcriptional complex composed of PPARγ and the core clock gene PER1. In vivo and in vitro experiments demonstrated that silencing PER1 disrupted the circadian rhythm of PER1-HK2 and reversed trastuzumab resistance. Moreover, metformin, which inhibits glycolysis and PER1, combined with trastuzumab at ZT6, significantly improved trastuzumab efficacy in gastric cancer. Collectively, these data introduce the circadian clock into trastuzumab therapy and propose a potentially effective chronotherapy strategy to reverse trastuzumab resistance in gastric cancer.

SIGNIFICANCE

In trastuzumab-resistant HER2-positive gastric cancer, glycolysis fluctuates with a circadian oscillation regulated by the BMAL1-CLOCK-PER1-HK2 axis, which can be disrupted with a metformin-based chronotherapy to overcome trastuzumab resistance.

Interest of the Addition of Taxanes to Standard Treatment in First-Line Advanced HER2 Positive Gastroesophageal Adenocarcinoma in Selective Patients

Background

Studies have reported a beneficial role of the addition of trastuzumab to platin-5-FU based chemotherapy in first-line advanced HER2 positive gastroesophageal adenocarcinoma (GEA). However, the effect of taxanes combined with platin-5FU + trastuzumab (PFT) is understudied.

Methods

We performed a retrospective cohort study to evaluate the interest of taxanes among HER2-positive advanced GEA patients treated with PFT. We enrolled HER2-positive advanced GEA patients who underwent treatment between January 2009 to March 2021 in seven hospitals centers in France, treated with PFT alone (S group) or with taxanes + PFT regimen (T group). The primary outcome was progression-free survival (PFS). Also, overall survival (OS), response rate, conversion surgery rate, and safety were evaluated.

Results

Overall, 65 patients received PFT-based therapy, 24 patients in the T group, and 41 patients in the S group. To avoid the selection bias, only those patients presenting an ECOG-PS of 0-1 and synchronous metastasis (21 patients in the T group and 19 patients in the S group) were included for analysis. The median PFS was 9.3 months (95%CI 7.0 to 17.2) in the T group and 5.9 months (95%CI 3.7 to 9.6) in the S group (log-rank p=0.038). Treatment by taxanes was significantly associated with a better PFS in univariate (HR 0.49; 95%CI 0.25 to 0.98, p=0.042) and multivariate Cox regression analysis (HR 0.44; 95%CI 0.21 to 0.94, p=0.033), and IPTW method (HR 0.56; 95% CI 0.34 to 0.91, p=0.019). OS was prolonged (19.0 months (95%CI 7.8 to 45.2) vs 13.0 months (95%CI 5.5 to 14.8), log-rank p=0.033) in favor of the T group. Treatment by taxanes was significantly associated with a better OS in univariate Cox regression analysis (HR 0.49; 95%CI 0.21 to 0.96, p=0.038) and IPTW method (HR 0.49; 95% CI 0.29 to 0.84, p=0.009). The response rate was higher in the T group, with conversion surgery in five patients. No treatment-related death was observed in both groups.

Conclusions

Given the improvement in PFS and OS, the addition of taxanes to standard chemotherapy could be considered as a promising treatment for selected HER2-positive advanced GEA patients, with PS 0-1 and synchronous metastasis (NCT04920747).

Phase II Study of Continued Trastuzumab Plus Irinotecan in Patients with HER2-positive Gastric Cancer Previously Treated with Trastuzumab (HGCSG 1201)

Background

The efficacy of irinotecan plus continuous trastuzumab beyond progression in patients with gastric cancer previously treated with trastuzumab plus standard first-line chemotherapy has not been reported.

Methods

Patients with human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer who were previously treated with trastuzumab received trastuzumab every 3 weeks and irinotecan every 2 weeks. The primary endpoint was the overall response rate (ORR), and the secondary endpoints included progression-free survival (PFS), 6-month survival rates, safety, and subgroup analysis by HER2 status.

Results

Sixteen patients were enrolled in a 3-year pre-planned registration period. This study was prematurely closed due to poor patient accrual. The ORR and disease control rate were 6.7% (95% CI, 0.2-32.0) and 53.3% (95% CI, 26.6-78.7). The median PFS and overall survival (OS) were 2.4 months (95% CI, 0.0-5.2) and 9.7 months (95% CI, 8.2-11.2), respectively. The most frequently reported grades 3-4 adverse events were neutropenia (40%), anemia (27%), anorexia (33%), and fatigue (33%).

Conclusion

With only 16 patients enrolled, the present study has very low power to detect any clinical benefit of trastuzumab plus irinotecan beyond disease progression in patients with HER2-positive advanced gastric cancer who previously received trastuzumab.

Trial Identifier: UMIN000007636.

Systemic therapy for gastric cancer: Perioperative strategies and beyond

Each year, gastric cancer claims the lives of hundreds of thousands of patients worldwide. Despite surgical resection, the risk of residual disease, micrometastatic disease, and disease recurrence remain elevated. Herein, we review systemic therapy strategies in the neoadjuvant, adjuvant, and metastatic settings, including novel uses of immunotherapy, targeted therapies and cytotoxic chemotherapies, for the treatment of gastric cancer.

Multimodal treatment in oligometastatic gastric cancer

Gastric cancer is generally diagnosed at an advanced stage, especially in countries without screening programs. Previously, the metastatic stage was synonymous with palliative management, and surgical indications were only for symptomatic relief. However, this therapeutic option is associated with poor prognosis. A subgroup of patients with limited metastatic disease could benefit from intensive treatment. A combination of chemotherapy, immunotherapy, and targeted therapy could help either maintain a resectable state for oligometastatic disease or diminish the metastasis size to obtain a complete resection configuration. This latter strategy is known as conversion therapy and has growing evidence with favorable outcomes. Oncosurgical approach of metastatic disease could prolong survival in selected patients. The challenge for the surgeon and oncologist is to identify these specific patients to offer the best multimodal management. We review in this article the actual evidence for the treatment of oligometastatic gastric cancer with curative intent.

Gastric Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Gastric cancer is the third leading cause of cancer-related deaths worldwide. Over 95% of gastric cancers are adenocarcinomas, which are typically classified based on anatomic location and histologic type. Gastric cancer generally carries a poor prognosis because it is often diagnosed at an advanced stage. Systemic therapy can provide palliation, improved survival, and enhanced quality of life in patients with locally advanced or metastatic disease. The implementation of biomarker testing, especially analysis of HER2 status, microsatellite instability (MSI) status, and the expression of programmed death-ligand 1 (PD-L1), has had a significant impact on clinical practice and patient care. Targeted therapies including trastuzumab, nivolumab, and pembrolizumab have produced encouraging results in clinical trials for the treatment of patients with locally advanced or metastatic disease. Palliative management, which may include systemic therapy, chemoradiation, and/or best supportive care, is recommended for all patients with unresectable or metastatic cancer. Multidisciplinary team management is essential for all patients with localized gastric cancer. This selection from the NCCN Guidelines for Gastric Cancer focuses on the management of unresectable locally advanced, recurrent, or metastatic disease.

Emerging HER2-directed therapeutic agents for gastric cancer in early phase clinical trials

INTRODUCTION

HER2 positive gastric cancer is a distinct subgroup overexpressing the HER2 receptor. For a decade, first-line Trastuzumab was the only licensed HER2-directed therapy for HER2 positive advanced gastric cancer following results from the ToGA trial in 2010 demonstrating a survival benefit when added to chemotherapy. Within the last year, significant advances have taken place in the field of HER2-directed gastric cancer therapy.

AREAS COVERED

This review discusses pivotal clinical trial results and summarises current clinical trials of HER2-directed therapy in gastric cancer. Evidence for HER2-directed antibodies, immunotherapy, immune stimulating antibody conjugates, antibody-drug conjugates (including DESTINY trial results) and tyrosine kinase inhibitors are placed into clinical context. Key challenges including resistance mechanisms and drug toxicities are outlined. Search terms 'HER2' and 'gastric cancer' were entered into ClinicalTrials.gov, Pubmed and Google. Only English-language studies were included.

EXPERT OPINION

Clinical management of HER2 positive gastric cancer patients is likely to change significantly over the next 5 years. Checkpoint inhibition is likely to be used alongside HER2-directed therapy and chemotherapy first-line in advanced disease. Trastuzumab deruxtecan is likely to be offered second-line and beyond. The sheer number of clinical trials of HER2-directed therapy in gastric cancer are testament to progress and potential.

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.

Toward a Treatment Sequencing Strategy: A Systematic Review of Treatment Regimens in Advanced Gastric Cancer/Gastroesophageal Junction Adenocarcinoma

BACKGROUND

Platinum and fluoropyrimidine combinations typically comprise first-line (1L) therapy in advanced gastric cancer or gastroesophageal junction adenocarcinoma (G/GEA), although controversy exists regarding the use of 5doublet versus triplet cytotoxic regimens. Historically, second-line (2L) and third-line or later (3L+) therapy has been fragmented. Recent trials have increased the need for optimal treatment sequencing in advanced G/GEA.

MATERIALS AND METHODS

We conducted a systematic search of peer-reviewed manuscripts of randomized clinical trials examining 1L, 2L, and 3L+ therapy for advanced G/GEA published from 2009 through November 19, 2019. When available, overall survival, progression-free survival, time to progression, overall response rate, and toxicity were extracted from each and compared descriptively.

RESULTS

In 1L therapy, chemotherapy triplets demonstrated variable efficacy improvements with invariable increased toxicity compared with platinum/fluoropyrimidine doublets. Currently, the only published report of positive outcomes using biologics in 1L describes adding trastuzumab in HER2-overexpressing advanced G/GEA. In 2L, doublet chemotherapy regimens are not uniformly more efficacious than single-agent taxanes or irinotecan, and ramucirumab has demonstrated improved outcomes both as monotherapy and in combination.

CONCLUSION

For advanced G/GEA, review of trial results from 2009-2019 support 1L therapy with platinum and fluoropyrimidine and sequencing with taxanes or irinotecan in combination with biologics as effective 2L options. Escalating to a triplet may add some efficacy at the expense of added toxicity.

IMPLICATIONS FOR PRACTICE

The rapidly changing treatment landscape for advanced gastric cancer includes increasing options for refractory disease. With multiple first-line platinum-based regimens, identification of those with the best benefit-to-risk ratio may provide guidance on treatment sequencing strategies. This article presents findings from the published literature of randomized controlled trials that included a first-line platinum/fluoropyrimidine combination and, for second-line trials, patients with platinum/fluoropyrimidine-refractory disease. This guiding summary could be a tool for clinicians to identify the optimal first-line regimen(s) followed by a strategy for subsequent regimens.

Trastuzumab deruxtecan and other HER2-targeting agents for the treatment of HER2-positive gastric cancer

INTRODUCTION

Although various new drugs have been developed, the prognosis of therapeutic advances for metastatic gastric cancer is insufficient. Trastuzumab deruxtecan (T-DXd), a new human epidermal growth factor receptor 2 (HER2)-targeting antibody-drug conjugate (ADC), has demonstrated promising results in clinical trials.

AREAS COVERED

In this article, we review the history of anti-HER2 ADCs and focus on the efficacy and safety of T-DXd and describe the development of new anti-HER2 drugs.

EXPERT OPINION

So far, no other anti-HER2 ADCs have demonstrated efficacy in patients with HER2-positive advanced gastric cancer with two or more previous lines of chemotherapy, including trastuzumab. However, a new drug, T-DXd, has shown a significantly higher objective response rate and a longer overall survival and, thus, was approved in Japan. In the future, new anti-HER2 drugs and/or treatment strategies including T-DXd along with cytotoxic chemotherapy or immune checkpoint inhibitors will be developed.

HER2-Directed Therapy in Advanced Gastric and Gastroesophageal Adenocarcinoma: Triumphs and Troubles

OPINION STATEMENT

Gastric and gastroesophageal junction (GEJ) cancers represent the third leading cause of malignancy-associated death worldwide. Approximately 15-20% of these adenocarcinomas overexpress the human epidermal growth factor receptor 2 (HER2), a pro-proliferative receptor tyrosine kinase that has been therapeutically exploited in other disease contexts. The landmark ToGA trial demonstrated that trastuzumab, an anti-HER2 antibody, could improve overall survival for patients with HER2 overexpressing advanced gastric and GEJ adenocarcinomas. In the ensuing decade, great effort has been made to refine and expand this therapeutic strategy through a variety of avenues including optimization of chemotherapy backbones, identifying potential synergy with immune checkpoint inhibition, deployment of alternative HER2-targeted antibodies, use of small molecule inhibitors, and development of HER2-directed antibody drug conjugates. While the results of these efforts have had variable success, they have led to a greater understanding of the mechanisms of both primary and acquired resistance to HER2-directed therapies, laying the groundwork for future investigations. Recently, KEYNOTE-811 and DESTINY-Gastric01 have led to the FDA approvals of pembrolizumab in combination with trastuzumab and chemotherapy in the 1st-line advanced setting and trastuzumab deruxtecan (fam-trastuzumab deruxtecan-nxki) in the 2nd-line setting, respectively. Herein, we review these significant works as well as discuss the ongoing investigations they have inspired, which aim to find and utilize additional means for targeting HER2 in gastric and GEJ cancers.

ctDNA analysis in the personalized clinical management of gastroesophageal adenocarcinoma: turning hope into reality

Gastroesophageal adenocarcinoma (GEA) is a global health issue with a high fatality-to-case ratio and a 5-year overall survival that has only slightly improved. High-throughput molecular profiling has uncovered a profound complexity and heterogeneity in GEA biology, which limits considerably the treatment advances. Liquid biopsy with circulating tumor (ct)DNA analysis could elucidate GEA molecular heterogeneity and provide diagnostic, prognostic and predictive information to guide clinical decision-making. However, only a handful of studies have shown positive results for the application of ctDNA analysis in GEA clinical management. As a result, no comprehensive information is available to date on this continuously evolving topic. Here, we discuss the current state of knowledge, along with promises and challenges related to ctDNA analysis in GEA.

Advanced Gastric Cancer: Current Treatment Landscape and a Future Outlook for Sequential and Personalized Guide: Swiss Expert Statement Article

BACKGROUND

Gastric cancer is a leading cause of cancer-related deaths worldwide. Several treatment possibilities have been investigated, but only a few show clinically meaningful results.

SUMMARY

Systemic treatment options for advanced gastric cancer (aGC) have evolved over the recent years, implementing the growing molecular knowledge of this heterogeneous disease. Molecular profiling (at least for HER-2-expression, microsatellite instability status, Epstein-Barr virus expression, and programmed death ligand-1 expression/combined positive score [CPS]) is recommended for all therapy-fit patients prior to the start of a systemic treatment and is crucial for decisions on treatment strategy and drug selection. Various examples like the application of trastuzumab in the HER-2-positive subgroup underline the benefits of this approach starting from the first-line setting. A combination of platinum and fluoropyrimidine remains the first-line chemotherapy backbone in the treatment of advanced gastric cancer. Triplet combinations adding taxanes to the doublet regimen are reserved for certain scenarios. Unfortunately, almost all patients who receive first-line treatment (with or without anti-HER-2 blockade) progress and <70% are eligible for a second-line therapy. The addition of monoclonal antibodies has substantially improved outcomes in this setting. As such, ramucirumab has led to significant and clinically meaningful advancements in the second-line treatment. Furthermore, immuno-oncology with checkpoint inhibition and immune stimulation has evolved in the field of aGC. Recent first-line data show a significant survival benefit in aGC patients with a CPS ≥ 5 under immunochemotherapy. Nonetheless, the impact of immunotherapy combinations and immunochemotherapy remains an area of investigation. Key Message: In this review, we highlight recent improvements in the treatment landscape of advanced gastric cancer, the heterogeneity of this disease, and possible personalized targets.

How May Ramucirumab Help Improve Treatment Outcome for Patients with Gastrointestinal Cancers?

GI cancers are characterized by high recurrence rates and a dismal prognosis and there is an urgent need for new therapeutic approaches. This is a narrative review designed to provide a summary of the efficacy as measured by overall survival, progression free survival, and safety data from phase 3 randomized controlled GI clinical trials of ramucirumab including those from important pre-specified patient subgroups and evidence from real clinical practice worldwide. Quality of life (QOL) is discussed where data are available. Our aim was to summarize the efficacy and safety of ramucirumab in the treatment of GI cancers using these existing published data with a view to demonstrating how ramucirumab may help improve treatment outcome for patients with GI cancers. The data indicate that ramucirumab is efficacious, safe, and tolerable across the intent-to-treat patient populations as a whole and across several pre-specified subgroups, even those whose disease is traditionally more difficult to treat. Furthermore, survival outcomes observed in real-world clinical practice demonstrate similar data from phase 3 clinical trials even in patients with complications, suggesting that the benefits of ramucirumab translate in actual clinical practice.

Recent Advances in Systemic Treatments for HER-2 Positive Advanced Gastric Cancer

Gastric cancer (GC) is the fifth most common cancer worldwide. Despite recent improvements in treatment quality and options, advanced gastric cancer remains one of the hardest to cure cancers, with a median overall survival (OS) of 10–12 months and a 5-year OS of approximately 5–20%. There is an unmet need for further efforts to palliate disease-related symptoms, improve quality of life, increase tumor response rate, and prolong progression free and overall survival while balancing the toxicities of therapy. The most common type of GC is adenocarcinoma, which demonstrates morphological, biological, and clinical heterogeneity. A plethora of genomic alterations and the activation of numerous molecular pathways including human epidermal growth receptor 2 (HER2), epidermal growth factor receptor (EGFR), fibroblast growth factor receptor-2 (FGFR2), mesenchymal epidermal transforming factor receptor (MET), and the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) are responsible for the complex heterogeneity of GC. Efforts to validate the therapeutic effects of inhibiting some of these aberrantly expressed pathways have failed to lead to a clinically meaningful outcome apart from the overexpression/amplification of the HER2 gene, inhibition of which has had a significant impact on clinical practice. The only available biomarkers to guide the effective treatment of patients with advanced GC are HER2 overexpression, MSI/PD-L1 status, and FGFR alterations. Various anti-HER2 agents have been evaluated after the success of the ToGA trial, but none led to a significant enough clinical improvement to be considered a viable alternative for HER2-targeted therapy in advanced GC until the global Keynote-811 trial, which added pembrolizumab to trastuzumab in combination with chemotherapy. This combination demonstrated a survival advantage for the first time in the 11 years since ToGA. Trastuzumab deruxtecan (T-DXd) was also found to be effective in patients who had already received >2 previous lines of treatment. Despite these promising avenues, the optimal management of HER-2 positive GC still requires further development.

Harnessing biomarkers of response to improve therapy selection in esophago-gastric adenocarcinoma

Advanced esophago-gastric (OG) adenocarcinomas have a high mortality rate and new therapeutic options are urgently required. Despite recent advances in understanding the molecular characteristics of OG cancers, tumor heterogeneity poses a challenge in developing new therapeutics capable of improving patient outcomes. Consequently, chemotherapy remains the mainstay of systemic treatment, with the HER2 being the only predictive biomarker routinely targeted in clinical practice. Recent data indicate that immunotherapy will be incorporated into first-line chemotherapy, but further research is required to refine patient selection. This review will summarize the clinical strategies being evaluated to utilize our knowledge of predictive biomarkers with reference to novel therapeutics, and discuss the barriers to implementing precision oncology in OG adenocarcinoma.

Trastuzumab deruxtecan for the treatment of HER2-positive advanced gastric cancer: a clinical perspective

Human epidermal growth factor receptor 2 (HER2)-positive gastric cancer is a subtype for which new drugs and specific treatment strategies should be developed. Trastuzumab deruxtecan (T-DXd) is a novel HER2-targeted antibody-drug conjugate containing topoisomerase I inhibitor as a payload. In the randomized phase 2 study (DESTINY-Gastric01) for HER2-positive advanced gastric or gastroesophageal junction cancer (AGC), patients treated with T-DXd showed a significantly higher response rate compared with the chemotherapy of physician's choice, associated with remarkably prolonged progression-free and overall survival. T-DXd also exhibits anti-tumor activity to HER2-negative tumor cells close to HER2-positive cells (so-called bystander killing effect). T-DXd was effective even for HER2-low expressing breast and gastric cancer in several clinical studies. Taking advantage of these strong points and synergism with other cytotoxic, molecular-targeted and immunological agents, it is expected that T-DXd will bring further progression in treatment both for strongly and weakly HER2 positive AGC in various treatment settings including perioperative chemotherapy.

Current treatment and recent progress in gastric cancer

Gastric cancer is not a top-10 malignancy in the United States but represents one of the most common causes of cancer death worldwide. Biological differences between tumors from Eastern and Western countries add to the complexity of identifying standard-of-care therapy based on international trials. Systemic chemotherapy, radiotherapy, surgery, immunotherapy, and targeted therapy all have proven efficacy in gastric adenocarcinoma; therefore, multidisciplinary treatment is paramount to treatment selection. Triplet chemotherapy for resectable gastric cancer is now accepted and could represent a plateau of standard cytotoxic chemotherapy for localized disease. Classification of gastric cancer based on molecular subtypes is providing an opportunity for personalized therapy. Biomarkers, in particular microsatellite instability (MSI), programmed cell death ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2), tumor mutation burden, and Epstein-Barr virus, are increasingly driving systemic therapy approaches and allowing for the identification of populations most likely to benefit from immunotherapy and targeted therapy. Significant research opportunities remain for the less differentiated histologic subtypes of gastric adenocarcinoma and those without markers of immunotherapy activity.

HER2 Splice Site Mutation c.1899-1G>A as the Potential Acquired Resistance to Trastuzumab in a Patient with HER2-Positive Gastric Adenocarcinoma

The addition of trastuzumab to chemotherapy regimen is the standard of care for human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer; however, most patients eventually acquire trastuzumab resistance. Although some resistance mechanisms to trastuzumab-based regimens have been proposed, further understanding is required for developing therapeutic strategies to overcome the resistance. In the present work, we attempted to determine the possible resistance mechanism to trastuzumab in a patient with HER2-positive stage IV gastric adenocarcinoma. In this study, we first report the nucleotide change c.1899-1G>A at the intron 15 acceptor splice site promoting exon 16 deletion of HER2 as the potential mechanism of trastuzumab resistance in HER2-positive gastric adenocarcinoma. KEY POINTS: The combination of trastuzumab with chemotherapy is considered to be the standard therapy for HER2-positive advanced gastric cancer (GC), but most of the patients eventually acquire trastuzumab resistance. The mechanisms of resistance to trastuzumab in GC are poorly characterized. To the best of the authors' knowledge, this study is the first to implicate HER2 c.1899-1G>A, which results in exon 16 skpping, as the acquired resistance mechanism to trastuzumab in HER2-positive gastric adenocarcinoma. This work provides insights into the potential molecular mechanism of trastuzumab resistance, which is crucial in developing effective therapeutic strategies for HER2-positive GC patients refractory to trastuzumab.

HER2-targeted therapies in gastric cancer

Molecular targeted therapy of cancer has always been the focus of clinicians. Among those therapeutic targets, the human epidermal growth factor receptor-2 (HER-2) signaling pathway is one of the most popular targets for translational research in cancer. However, unlike prospect in breast cancer, HER-2 inhibitor trastuzumab is the only molecular targeted drug approved by US Food and Drug Administration (FDA) for the first-line treatment of HER-2 positive advanced gastric cancer. On this basis, a variety of novel HER2- targeted drugs for gastric cancer are under development, and related clinical researches are in full swing, including small molecular kinase inhibitors (e.g., afatinib, neratinib, pyrotinib), antibody-drug conjugates (e.g., DS-8201a, RC48-ADC) and other novel therapies (e.g., ZW25, CAR-T, BVAC-B). In this study, we will summarize the recent advances in anti-HER-2 agents, potential mechanisms of resistance to HER2-targeted therapy in HER2-positive gastric cancer. We will also discuss the future prospects of potential strategies to overcome anti-HER-2 resistance and development of novel anti-HER-2 approaches for the treatment of HER2-positive gastric cancer patients.

Trastuzumab deruxtecan for the treatment of HER2-positive gastric cancer

Introduction: Trastuzumab deruxtecan (T-DXd) is a novel human epidermal growth factor receptor 2 (HER2)-targeted antibody-drug conjugate with a humanized anti-HER2 antibody, cleavable peptide-based linker, and topoisomerase I inhibitor payload. The phase II trial DESTINY-Gastric01 has demonstrated that T-DXd exhibits antitumor activity in patients with HER2-positive advanced gastric cancer (AGC) who had received at least two previous therapies, including trastuzumab.Area covered: T-DXd was approved for previously treated HER2-positive AGC in Japan. The US Food and Drug Administration also approved on 15 January 2021. In this article, we review the development of T-DXd, its pharmacology, and its safety profile in patients with HER2-positive AGC.Expert opinion: T-DXd has demonstrated a significantly higher objective response rate and a longer overall survival in HER2-positive AGC patients with two or more previous lines of systemic chemotherapy, including trastuzumab. Safety profile was acceptable. Currently, there are several ongoing clinical trials of T-DXd in combination with cytotoxic chemotherapy or an immune checkpoint inhibitor.

Trastuzumab deruxtecan in HER2-positive metastatic breast cancer and beyond

INTRODUCTION

Despite the substantial improvements made in human epidermal growth factor receptor 2 (HER2)-targeted therapies since the approval of trastuzumab more than 20 years ago, there is still considerable unmet need in patients with HER2-expressing breast cancer (BC) and other solid tumors. Trastuzumab deruxtecan (T-DXd) is a newer antibody-drug conjugate approved for the treatment of metastatic breast cancer (BC) and gastric cancer (GC) and is under active investigation in other solid tumors, including non-small cell lung cancer, colorectal cancer, and HER2-low tumors.

AREAS COVERED

The current treatment and investigational landscape of HER2-positive and HER2-low metastatic BC (mBC) and the preclinical and clinical trials investigating T-DXd. To identify relevant literature, a search was performed on English-language publications and congress abstracts.

EXPERT OPINION

T-DXd is likely to become the standard of care for second-line treatment of HER2-positive mBC, and it may play a role in the treatment of hormone receptor-positive and triple-negative mBC with HER2-low expression. Because it was recently approved in the United States and Japan to treat HER2-positive metastatic GC, it holds promise for the treatment of other HER2-positive solid tumors, including colorectal cancer, non-small cell lung cancer, and HER2-low BC.

Dual HER2 blockade with lapatinib and trastuzumab in combination with chemotherapy in metastatic gastroesophageal adenocarcinoma

The development of resistance to trastuzumab in HER2-positive gastroesophageal cancer remains a problem. The use of dual HER2 blockade to overcome this is a therapeutic strategy that should be researched more extensively.

Novel HER2-Directed Treatments in Advanced Gastric Carcinoma: AnotHER Paradigm Shift?

Human epidermal growth factor receptor 2 (HER2) is overexpressed and/or amplified in approximately 15-20% of gastric adenocarcinoma (GC) patients. In 2010, the landmark ToGA trial established the combination of trastuzumab plus chemotherapy as the first-line standard of care for HER2-positive GC patients with advanced disease. However, subsequent studies on HER2 targeted therapies in this setting failed to meet their primary endpoints, and not all HER2-positive GC patients benefit from targeted approaches. More recently, novel HER2-directed treatments have been investigated, including trastuzumab deruxtecan (T-Dxd); following the results of the DESTINY-Gastric01 study, T-Dxd received its first U.S. Food and Drug Administration (FDA) approval on 15 January 2021 for the treatment of adults with unresectable, locally advanced, or metastatic GC who have received a prior trastuzumab-based regimen. In this review, we discuss the current HER2-targeted treatments for GC in the advanced disease setting, mainly focusing on emerging new treatments and future research directions.

Where to Start and What to Do Next: The Sequencing of Treatments in Metastatic Esophagogastric Cancer

Esophagogastric cancer is associated with rising incidence and high mortality. Nearly 40% of patients have metastatic disease at the time of diagnosis with poor 5-year overall survival. The treatment of squamous cell carcinoma of the esophagus and gastroesophageal adenocarcinoma has started to bifurcate in recent years, owing to the evolving understanding of the biologic and genomic characteristics of these tumors. Incorporation of HER2-directed therapy in the form of monoclonal antibody and antibody-drug conjugate is now standard of care for patients with HER2-positive disease. The addition of immune checkpoint inhibitors to the therapeutic landscape of metastatic esophagogastric cancer is associated with modest improvement in overall survival, and definition of predictive biomarkers of response to checkpoint inhibition remains imprecise. A number of therapeutic targets including FGFR2b, Claudin 18.2, DKK-1, and DNA repair defects are being explored in clinical trials. Similarly, combination immunotherapy and novel HER2-targeting agents, such as bispecific antibody and small-molecule inhibitors, are at various stages of clinical development. Despite the progress made in the field of targeted therapies and checkpoint inhibition, chemotherapy remains an integral part of treatment of metastatic esophagogastric cancer but is associated with considerable toxicity. Clinical trials focusing on minimizing toxicity of currently available therapeutic agents, development of novel biomarker-driven treatment strategies, and overcoming resistance to immune checkpoint inhibition will define the future of this traditionally indelible disease.

HER2 Expression, Test Deviations, and Their Impact on Survival in Metastatic Gastric Cancer: Results From the Prospective Multicenter VARIANZ Study

Trastuzumab is the only approved targeted drug for first-line treatment of human epidermal growth factor receptor 2–positive (HER2+) metastatic gastric cancer (mGC). However, not all patients respond and most eventually progress. The multicenter VARIANZ study aimed to investigate the background of response and resistance to trastuzumab in mGC.

Beyond the Guidelines: The Grey Zones of the Management of Gastric Cancer. Consensus Statements from the Gastric Cancer Italian Network (GAIN)

BACKGROUND

Management of gastric and gastroesophageal junction (GEJ) adenocarcinoma remains challenging, because of the heterogeneity in tumor biology within the upper gastrointestinal tract. Daily clinical practice is full of grey areas regarding the complexity of diagnostic, staging, and therapeutic procedures. The aim of this paper is to provide a guide for clinicians facing challenging situations in routine practice, taking a multidisciplinary consensus approach based on available literature.

METHODS

The GAIN (GAstric cancer Italian Network) group was established with the aims of reviewing literature evidence, discussing key issues in prevention, diagnosis, and management of gastric and GEJ adenocarcinoma, and offering a summary of statements. A Delphi consensus method was used to obtain opinions from the expert panel of specialists.

RESULTS

Forty-nine clinical questions were identified in six areas of interest: role of multidisciplinary team; risk factors; diagnosis; management of early gastric cancer and multimodal approach to localized gastric cancer; treatment of elderly patients with locally advanced resectable disease; and treatment of locally advanced and metastatic cancer.

CONCLUSIONS

The statements presented may guide clinicians in practical management of this disease.

Targeted and immunotherapy in the era of personalised gastric cancer treatment

Gastric cancer is a major cause of cancer-related morbidity and mortality worldwide. Advances in targeted medical treatment were scarce in the past and challenged by the marked spatial and temporal biological heterogeneity of gastric cancer. Recent molecular profiling studies have increased our understanding of genetic and epigenetic drivers, leading to better patient selection for drug development. Beyond that, immune-related biomarkers were identified, paving the way for future effective immunotherapy. We systematically reviewed articles from PubMed of the past 10 years, and abstracts from annual meetings of ESMO, ASCO and AACR to summarise the current knowledge about targeted and immunotherapy and outline pathways to future personalised therapy of gastric cancer.

Mechanisms of Pharmaceutical Therapy and Drug Resistance in Esophageal Cancer

Pharmaceutical therapies are essential for esophageal cancer (EC). For the advanced EC, the neoadjuvant therapy regimen, including chemotherapy plus radiotherapy and/or immunotherapy, is effective to achieve clinical benefit, even pathological complete response. For the unresectable, recurrent, and metastatic EC, the pharmaceutical therapy is the limited effective regimen to alleviate the disease and prolong the progression-free survival and overall survival. In this review, we focus on the pharmaceutical applications in EC treatment including cytotoxic agents, molecular targeted antibodies, and immune checkpoint inhibitors (ICIs). The chemotherapy regimen is based on cytotoxic agents such as platinum-based complexes, fluorinated pyrimidines and taxenes. Although the cytotoxic agents have been developed in past decades, the standard chemotherapy regimen is still the cisplatin and 5-FU or paclitaxel because the derived drugs have no significant advantages of overcoming the shortcomings of side effects and drug resistance. The targeted molecular therapy is an essential supplement for chemotherapy; however, there are only a few targeted therapies available in clinical practice. Trastuzumab and ramucirumab are the only two molecular therapy drugs which are approved by the US Food and Drug Administration to treat advanced and/or metastatic EC. Although the targeted therapy usually achieves effective benefits in the early stage therapy of EC, the patients will always develop drug resistance during treatment. ICIs have had a significant impact on routine clinical practice in cancer treatment. The anti-programmed cell death-1 monoclonal antibodies pembrolizumab and nivolumab, as the ICIs, are recommended for advanced EC by several clinical trials. However, the significant issues of pharmaceutical treatment are still the dose-limiting side effects and primary or secondary drug resistance. These defects of pharmaceutical therapy restrain the clinical application and diminish the effectiveness of treatment.

Phase II Study of the Reuse of Trastuzumab with Docetaxel beyond Progression after First-Line Treatment in Second-Line Treatment for Unresectable, Metastatic Gastric Cancer (T-CORE1203)

Whether trastuzumab use beyond disease progression is beneficial in second-line treatment for patients with unresectable human epidermal growth factor receptor 2 (HER2)-positive gastric cancer remains to be elucidated. We conducted this phase II study to assess whether trastuzumab plus docetaxel was effective for patients with previously treated advanced HER2-positive gastric cancer. This trial was a single-arm, open-label, multicenter, phase II study, conducted by Tohoku Clinical Oncology Research and Education Society (T-CORE). Patients aged 20 years or older who had advanced HER2-positive gastric cancer and were refractory to trastuzumab, fluoropyrimidine, and cisplatin were enrolled. Patients were treated with 6 mg/kg trastuzumab and 60 mg/m² docetaxel every 3 weeks. The primary endpoint was the overall response rate. The threshold overall response rate was estimated to be at 15%. Secondary endpoints were progression-free survival, 6-month survival rate, overall survival, and toxicities. A total of 27 patients were enrolled from 7 hospitals. The median age was 67 years. Partial response was seen in 3 patients among the 26 evaluated patients. The overall response rate was at 11.5% (90% confidence interval 1.2%-21.8%). The median progression-free survival was 3.2 months, the 6-month survival rate was 85%, and the median overall survival was 11.6 months. Febrile neutropenia was observed in 14.8%. The most frequently observed grade 3 non-hematologic toxicity was anorexia (14.8%). The primary endpoint was not achieved. The results support a current consensus that the continuation of trastuzumab in second-line therapy for gastric cancer is not a recommended option.

Phase I study of the recombinant humanized anti-HER2 monoclonal antibody-MMAE conjugate RC48-ADC in patients with HER2-positive advanced solid tumors

PURPOSE

RC48 contains the novel humanized anti-HER2 antibody hertuzumab conjugated to MMAE via a cleavable linker. A phase I study was initiated to evaluate the toxicity, MTD, PK, and antitumor activity of RC48 in patients with HER2-overexpressing locally advanced or metastatic solid carcinomas, particularly gastric cancer.

PATIENTS AND METHODS

This was a 2-part phase I study. Successive cohorts of patients received escalating doses of RC48 (0.1 mg/kg, 0.5 mg/kg, 1.0 mg/kg, 2.0 mg/kg, 2.5 mg/kg, and 3.0 mg/kg). Dose expansion proceeded at the dose of 2.0 mg/kg Q2W. The efficacy and safety set included all patients who received at least one dose of RC48.

RESULTS

Fifty-seven patients were enrolled, the MTD was unavailable due to termination of 3.0 mg/kg cohort; 2.5 mg/kg Q2W was declared the RP2D. RC48 was well tolerated, the most frequent grade 3 or worse TRAEs included neutropenia (19.3%), leukopenia (17.5%), hypoesthesia (14.0%), and increased conjugated blood bilirubin (8.8%). Four deaths occurred during the whole study, three of which were believed to be related to RC48. Overall, ORR and DCR were 21.0% (12/57) and 49.1% (28/57). Notably, patients who were HER2 IHC2+/FISH- responded similarly to those who were IHC2+/FISH+ and IHC3+, with ORRs of 35.7% (5/14), 20% (2/10), and 13.6% (3/22), respectively. In patients who were pretreated with HER2-targeted drugs, RC48 also showed promising efficacy, with ORR of 15.0% (3/20) and DCR of 45.0% (9/20).

CONCLUSION

RC48 was well tolerated and showed promising antitumor activity in HER2-positive solid tumors, including gastric cancer with HER2 IHC 2+/FISH- status.

CLINICAL TRIAL INFORMATION

NCT02881190.

Personalized Antibodies for Gastroesophageal Adenocarcinoma (PANGEA): A Phase II Study Evaluating an Individualized Treatment Strategy for Metastatic Disease

The one-year and median overall survival (mOS) rates of advanced gastroesophageal adenocarcinomas (GEA) are ∼50% and <12 months, respectively. Baseline spatial and temporal molecular heterogeneity of targetable alterations may be a cause of failure of targeted/immunooncologic therapies. This heterogeneity, coupled with infrequent incidence of some biomarkers, has resulted in stalled therapeutic progress. We hypothesized that a personalized treatment strategy, applied at first diagnosis then serially over up to three treatment lines using monoclonal antibodies combined with optimally sequenced chemotherapy, could contend with these hurdles. This was tested using a novel clinical expansion-platform type II design with a survival primary endpoint. Of 68 patients by intention-to-treat, the one-year survival rate was 66% and mOS was 15.7 months, meeting the primary efficacy endpoint (one-sided P = 0.0024). First-line response rate (74%), disease control rate (99%), and median progression-free survival (8.2 months) were superior to historical controls. The PANGEA strategy led to improved outcomes warranting a larger randomized study. SIGNIFICANCE: This study highlights excellent outcomes achieved by individually optimizing chemotherapy, biomarker profiling, and matching of targeted therapies at baseline and over time for GEA. Testing a predefined treatment strategy resulted in improved outcomes versus historical controls. Therapeutic resistance observed in correlative analyses suggests that dual targeted inhibition may be beneficial.This article is highlighted in the In This Issue feature, p. 211.

Advances in the treatment of gastric cancer

PURPOSE OF REVIEW

To provide an up-to-date review on the management of cancers of the stomach and esophagogastric junction (EGJ).

RECENT FINDINGS

Microsatellite instable (MSI) high status in gastric cancer may portend a relatively good prognosis and indicate that adjuvant chemotherapy is of no added benefit to primary surgical management. In the preoperative treatment of HER2 (ErbB2)-positive EGJ adenocarcinoma with chemoradiotherapy, the addition of trastuzumab, a recombinant humanized mAb directed against the extracellular domain of Her2, failed to improve outcome over conventional chemoradiotherapy alone. Escalating the dose of radiation in combined chemoradiotherapy regimens did not improve survival over conventional dose radiotherapy in the nonoperative management of EGJ cancer. The use of proton vs. conventional external beam radiation therapy, although potentially less toxic, did not improve therapy outcome with preoperative or definitive chemoradiotherapy in EGJ cancer. In metastatic HER2-positive gastric cancer, after disease progression on trastuzumab, continuation of trastuzumab did not improve progression free or overall survival compared with second-line chemotherapy alone. However, in the setting or prior trastuzumab therapy in metastatic HER2-positive gastric cancer, the new agent trastuzumab deruxtecan achieved significant rates of response, progression free and overall survival compared with standard chemotherapy. After initial chemotherapy for metastatic esophagogastric cancer, maintenance therapy with the anti PDL-1 agent avelumab was no better than chemotherapy alone.

SUMMARY

MSI high gastric cancer has a better prognosis and may not require adjuvant chemotherapy. Trastuzumab, added to preoperative chemoradiotherapy in HER2-positive esophageal adenocarcinoma, does not improve outcome. Dose escalation of radiotherapy in the nonoperative management of EGJ cancer does not improve local control or survival, and proton therapy may not achieve superior outcomes compared with external beam radiotherapy. In metastatic HER2-positive gastric cancer, continuing trastuzumab into second-line chemotherapy does not add benefit; however, the novel agent trastuzumab deruxtecan has substantial activity after prior trastuzumab-based therapy.

Liquid biopsy as a perioperative biomarker of digestive tract cancers: review of the literature

Tissue biopsies are the gold-standard for investigating the molecular characterization of tumors. However, a "solid" biopsy is an invasive procedure that cannot capture real-time tumor dynamics and may yield inaccurate information because of intratumoral heterogeneity. In this review, we summarize the current state of knowledge about surgical treatment-associated "liquid" biopsy for patients with digestive organ tumors. A liquid biopsy is a technique involving the sampling and testing of non-solid biological materials, including blood, urine, saliva, and ascites. Previous studies have reported the potential value of blood-based biomarkers, circulating tumor cells, and cell-free nucleic acids as facilitators of cancer treatment. The applications of a liquid biopsy in a cancer treatment setting include screening and early diagnosis, prognostication, and outcome and recurrence monitoring of cancer. This technique has also been suggested as a useful tool in personalized medicine. The transition to precision medicine is still in its early stages. Soon, however, liquid biopsy is likely to form the basis of patient selection for molecular targeted therapies, predictions regarding chemotherapy sensitivity, and real-time evaluations of therapeutic effects.

Prognostic benefit of conversion surgery for HER2 positive stage IV gastric cancer; a case series study of eleven patients treated with trastuzumab-based chemotherapy

BACKGROUND

Since the ToGA trial, trastuzumab-based chemotherapy is the standard treatment for HER2 positive stage IV gastric cancer. However, it is not yet clear whether surgical resection after trastuzumab-based chemotherapy (conversion surgery) can improve survival of HER2 positive stage IV gastric cancer. The purpose of this study is to evaluate the prognostic benefit of conversion surgery in HER2 positive stage IV gastric cancer patients.

CASE PRESENTATION

We retrospectively investigated the medical records of the patients with HER2 positive (IHC3(+) or IHC2(+)/FISH(+)) stage IV gastric cancer treated with trastuzumab-based chemotherapy as the first line treatment. Overall survival (OS) was compared between patients with conversion surgery and without. Eleven HER2 positive stage IV gastric cancer patients treated with trastuzumab-based chemotherapy as the first line treatment were evaluated. Response rate was 63.6%, and 6 of 11 patients could receive conversion surgery. R0 resection was achieved in four patients. In Kaplan-Meier analysis, patients who received conversion surgery showed significantly better OS than those without surgery (3-year survival rate, 66.7% vs. 20%, P = 0.03). The median OS of patients who achieved R0 resection is 51.8 months.

CONCLUSIONS

Conversion surgery might have a survival benefit for HER2 positive stage IV gastric cancer patients. If curative surgery is technically possible, conversion surgery could be a treatment option for HER2 positive stage IV gastric cancer.

Precision Medicine to Treat Advanced Gastroesophageal Adenocarcinoma: A Work in Progress

Gastroesophageal adenocarcinoma (GEA) represents a heterogeneous disease and, when diagnosed as locally advanced or metastatic, it is characterized by poor prognosis. During the last few years, several molecular classifications have been proposed to try to personalize treatment for those patients diagnosed with advanced disease. Nevertheless, despite the great effort, precision medicine is still far from being a reality. The improvement in the molecular analysis due to the application of high throughput technologies based on DNA and RNA sequencing has opened a novel scenario leading to the personalization of treatment. The possibility to target epidermal growth factor receptor (HER)2, Claudine, Fibroblast Growth Factor Receptors (FGFR), and other alterations with a molecular matched therapy could significantly improve clinical outcomes over advanced gastric cancer patients. On the other hand, the development of immunotherapy could also represent a promising strategy in a selected population. In this review, we sought to describe the novel pathways implicated in GEA progression and the results of the molecular matched therapies.

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

BACKGROUND

Margetuximab, a novel, investigational, Fc-engineered, anti-HER2 monoclonal antibody, is designed to more effectively potentiate innate immunity than trastuzumab. We aimed to evaluate the safety, tolerability, and antitumour activity of margetuximab plus pembrolizumab (an anti-PD-1 monoclonal antibody) in previously treated patients with HER2-positive gastro-oesophageal adenocarcinoma.

METHODS

CP-MGAH22-05 was a single-arm, open-label, phase 1b-2 dose-escalation and cohort expansion study done at 11 academic centres in the USA and Canada and 15 centres in southeast Asia (Korea, Taiwan, and Singapore) that enrolled men and women aged 18 years or older with histologically proven, unresectable, locally advanced or metastatic, HER2-positive, PD-L1-unselected gastro-oesophageal adenocarcinoma, with an Eastern Cooperative Oncology Group performance status of 0 or 1, who had progressed after at least one previous line of therapy with trastuzumab plus chemotherapy in the locally advanced unresectable or metastatic setting. In the dose-escalation phase, nine patients were treated: three received margetuximab 10 mg/kg intravenously plus pembrolizumab 200 mg intravenously every 3 weeks and six received the recommended phase 2 dose of margetuximab 15 mg/kg plus pembrolizumab 200 mg intravenously every 3 weeks. An additional 86 patients were enrolled in the phase 2 cohort expansion and received the recommended phase 2 dose. The primary endpoints were safety and tolerability, assessed in the safety population (patients who received at least one dose of either margetuximab or pembrolizumab) and the objective response rate as assessed by the investigator according to both Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, in the response-evaluable population (patients with measurable disease at baseline and who received the recommended phase 2 dose of margetuximab and pembrolizumab). This trial is registered with ClinicalTrials.gov, NCT02689284. Recruitment for the trial has completed and follow-up is ongoing.

FINDINGS

Between Feb 11, 2016, and Oct 2, 2018, 95 patients were enrolled. Median follow-up was 19·9 months (IQR 10·7-23·1). The combination therapy showed acceptable safety and tolerability; there were no dose-limiting toxicities in the dose-escalation phase. The most common grade 3-4 treatment-related adverse events were anaemia (four [4%]) and infusion-related reactions (three [3%]). Serious treatment-related adverse events were reported in nine (9%) patients. No treatment-related deaths were reported. Objective responses were observed in 17 (18·48%; 95% CI 11·15-27·93) of 92 evaluable patients.

INTERPRETATION

These findings serve as proof of concept of synergistic antitumour activity with the combination of an Fc-optimised anti-HER2 agent (margetuximab) along with anti-PD-1 checkpoint blockade (pembrolizumab).

FUNDING

MacroGenics.