Phase II trial of capecitabine and everolimus (RAD001) combination in refractory gastric cancer patients

Unique Genomic Alterations and Microbial Profiles Identified in Patients With Gastric Cancer of African, European, and Asian Ancestry: A Novel Path for Precision Oncology

OBJECTIVE

Here, we characterize differences in the genetic and microbial profiles of GC in patients of African (AFR), European, and Asian ancestry.

BACKGROUND

Gastric cancer (GC) is a heterogeneous disease with clinicopathologic variations due to a complex interplay of environmental and biological factors, which may affect disparities in oncologic outcomes..

METHODS

We identified 1042 patients with GC with next-generation sequencing data from an institutional Integrated Mutation Profiling of Actionable Cancer Targets assay and the Cancer Genomic Atlas group. Genetic ancestry was inferred from markers captured by the Integrated Mutation Profiling of Actionable Cancer Targets and the Cancer Genomic Atlas whole exome sequencing panels. Tumor microbial profiles were inferred from sequencing data using a validated microbiome bioinformatics pipeline. Genomic alterations and microbial profiles were compared among patients with GC of different ancestries.

RESULTS

We assessed 8023 genomic alterations. The most frequently altered genes were TP53 , ARID1A , KRAS , ERBB2 , and CDH1 . Patients of AFR ancestry had a significantly higher rate of CCNE1 alterations and a lower rate of KRAS alterations ( P < 0.05), and patients of East Asian ancestry had a significantly lower rate of PI3K pathway alterations ( P < 0.05) compared with other ancestries. Microbial diversity and enrichment did not differ significantly across ancestry groups ( P > 0.05).

CONCLUSIONS

Distinct patterns of genomic alterations and variations in microbial profiles were identified in patients with GC of AFR, European, and Asian ancestry. Our findings of variation in the prevalence of clinically actionable tumor alterations among ancestry groups suggest that precision medicine can mitigate oncologic disparities.

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.

PI3K/Akt/mTOR Signaling Pathway: Role in Esophageal Squamous Cell Carcinoma, Regulatory Mechanisms and Opportunities for Targeted Therapy

Esophageal squamous cell carcinoma (ESCC), is the most common type of esophageal cancer worldwide, mainly occurring in the Asian esophageal cancer belt, including northern China, Iran, and parts of Africa. Phosphatidlinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway is one of the most important cellular signaling pathways, which plays a crucial role in the regulation of cell growth, differentiation, migration, metabolism and proliferation. In addition, mutations in some molecules of PI3K/Akt/mTOR pathway are closely associated with survival and prognosis in ESCC patients. A large number of studies have found that there are many molecules in ESCC that can regulate the PI3K/Akt/mTOR pathway. Overexpression of these molecules often causes aberrant activation of PI3K/Akt/mTOR pathway. Currently, several effective PI3K/Akt/mTOR pathway inhibitors have been developed, which can play anticancer roles either alone or in combination with other inhibitors. This review mainly introduces the general situation of ESCC, the composition and function of PI3K/Akt/mTOR pathway, and regulatory factors that interact with PI3K/Akt/mTOR signaling pathway. Meanwhile, mutations and inhibitors of PI3K/Akt/mTOR pathway in ESCC are also elucidated.

Synergistic anticancer effects of everolimus (RAD001) and Rhein on gastric cancer cells via phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway

Everolimus (RAD001) is a mTOR inhibitor and is widely used for the treatment of gastric cancer (GC). Evidence suggests that Rhein has anticancer effect on GC. But the synergistic effect and mechanism of RAD001 and Rhein combination on GC is not clear. The current study aims to clarify the combination of RAD001 and Rhein in GC treatment. We found Rhein dose-dependently repressed MGC-803 cell viability (50% inhibition concentration (IC50) value = 94.26 μM). Rhein (80 μM) significantly suppressed GC cell proliferation and invasion. RAD001 dose-dependently repressed MGC-803 cells viability (IC50 value = 45.41 nM). The combination of Rhein and RAD001 repressed MGC-803 cells viability, invasion, and proliferation compared to the administration of Rhein or RAD001 alone. Protein levels of epithelial-mesenchymal transition (EMT)-related molecules E-cadherin, N-cadherin and Vimentin expressions were significantly affected by the combination of Rhein and RAD001. The combination of Rhein and RAD001 significantly facilitated cell apoptosis and up-regulated expressions of cell apoptosis and cycle-related protein p53, cyclin-dependent kinase 4 (CDK4) and cyclin D1 compared to the administration of Rhein or RAD001 alone. Moreover, the combination of Rhein and RAD001 repressed the expressions of phosphorylation-phosphoinositide-3-kinase (p-PI3K), p-protein kinase B (p-AKT) and p-mammalian target of rapamycin (p-mTOR). Finally, the combination of RAD001 and Rhein significantly decreased tumor weight and volume, suppressed the expressions of p-PI3K, p-Akt and p-mTOR, and repressed cell proliferation marker Ki-67 expression, which exerted synergistic cancer prevention in GC in vivo. Overall, the combination of Rhein and RAD001 exert synergistic cancer prevention in GC via PI3K/Akt/mTOR pathway.

The PI3K/Akt/mTOR signaling pathway in gastric cancer; from oncogenic variations to the possibilities for pharmacologic interventions

Genetic and epigenetic alterations have been under concentrated investigations for many years in order to unearth the molecules regulating human cancer pathogenesis. However, the identification of a wide range of dysregulated genes and their protein products has raised a question regarding how the results of this large collection of alterations could converge into a formation of one malignancy. The answer may be found in the signaling cascades that regulate the survival and metabolism of the cells. Aberrancies of each participant molecule of such cascades may well result in augmented viability and unlimited proliferation of cancer cells. Among various signaling pathways, the phosphatidylinositol-3-kinase (PI3K) axis has been shown to be activated in about one-third of human cancers. One of the malignancies that is mostly affected by this axis is gastric cancer (GC), one of the most fatal cancers worldwide. In the present review, we aimed to illustrate the significance of the PI3K/Akt/mTOR axis in the pathogenesis of GC and also provided a wide perspective about the application of the inhibitors of this axis in the therapeutic strategies of this malignancy.

Multikinase inhibitor-induced liver injury in patients with cancer: A review for clinicians

BACKGROUND

Multikinase inhibitors (MKI) are targeted molecular agents that have revolutionized cancer management. However, there is a paucity of data concerning MKI-related liver injury risk and clinical guidelines for the management of liver toxicity in patients receiving MKI for cancer are scarce.

DESIGN

We conducted a PubMed search of articles in English published from January 2000 to December 2018 related to hepatotoxicity of the 29 FDA-approved MKIs at doses used in clinical practice. The search terms were the international non-proprietary name of each agent cross-referenced with «hepatotoxicity», «hepatitis», «hepatic adverse event», or «liver failure», and «phase II clinical trial», «phase III clinical trial», or «case report».

RESULTS

Following this search, 140 relevant studies and 99 case reports were considered. Although asymptomatic elevation of aminotransferase levels has been frequently observed in MKI clinical trials, clinically significant hepatotoxicity is a rare event. In most cases, the interval between treatment initiation and the onset of liver injury is between one week and two months. Liver toxicity is often hepatocellular and less frequently mixed. Life-threatening MKI-induced hepatic injury has been described, involving fulminant liver failure or death. Starting from existing data, a description of MKI-related liver events, grading of hepatotoxicity risk, and recommendations for management are also given for various MKI molecules.

CONCLUSION

All MKIs can potentially cause liver injury, which is sometimes irreversible. As there is still no strategy available to prevent MKI-related hepatotoxicity, early detection remains crucial. The surveillance of liver function during treatment may help in the early detection of hepatotoxicity. Furthermore, the exclusion of potential causes of hepatic injury is essential to avoid unnecessary MKI withdrawal.

ALDH1A3-mTOR axis as a therapeutic target for anticancer drug-tolerant persister cells in gastric cancer

Tumors consist of heterogeneous cell populations that contain cancer cell subpopulations with anticancer drug-resistant properties called "persister" cells. While this early-phase drug tolerance is known to be related to the stem cell-like characteristic of persister cells, how the stem cell-related pathways contribute to drug resistance has remained elusive. Here, we conducted a single-cell analysis based on the stem cell lineage-related and gastric cell lineage-related gene expression in patient-derived gastric cancer cell models. The analyses revealed that 5-fluorouracil (5-FU) induces a dynamic change in the cell heterogeneity. In particular, cells highly expressing stem cell-related genes were enriched in the residual cancer cells after 5-FU treatment. Subsequent functional screening identified aldehyde dehydrogenase 1A3 (ALDH1A3) as a specific marker and potential therapeutic target of persister cells. ALDH1A3 was selectively overexpressed among the ALDH isozymes after treatment with 5-FU or SN38, a DNA topoisomerase I inhibitor. Attenuation of ALDH1A3 expression by RNA interference significantly suppressed cell proliferation, reduced the number of persister cells after anticancer drug treatment and interfered with tumor growth in a mouse xenograft model. Mechanistically, ALDH1A3 depletion affected gene expression of the mammalian target of rapamycin (mTOR) cell survival pathway, which coincided with a decrease in the activating phosphorylation of S6 kinase. Temsirolimus, an mTOR inhibitor, reduced the number of 5FU-tolerant persister cells. High ALDH1A3 expression correlated with worse prognosis of gastric cancer patients. These observations indicate that the ALDH1A3-mTOR axis could be a novel therapeutic target to eradicate drug-tolerant gastric cancer cells.

Oral stomatitis and mTOR inhibitors: A review of current evidence in 20,915 patients

BACKGROUND

Traditional treatment of malignancies with chemotherapeutic agents is often affected by the damage inflicted on non-cancerous cells. Toxicities of the oral cavity, such as mucositis and stomatitis, are some of the most significant and unavoidable toxicities associated with anti-cancer therapies. For such reason, in the last decades, newer targeted agents have been developed aiming to decrease the rates of side effects on healthy cells. Unfortunately, targeted anti-cancer therapies also showed significant rate of toxicity on healthy tissues. mTOR inhibitors showed some adverse events, such as hyperglycemia, hyperlipidemia, hypophosphatemia, hematologic toxicities, and mucocutaneous eruption, but the most important are still stomatitis and skin rash, often reported as dose-limiting side effects.

PATIENTS AND METHODS

A search of the literature was performed by authors on the PubMed online database using the following key words: "sirolimus" OR "everolimus" OR "temsirolimus" OR "deforolimus" OR "ridaforolimus" combined with the Boolean operator AND with the terms: "stomatitis" OR "mucositis" OR "oral pain." Titles and abstracts of 382 potentially relevant studies were screened; of these, 114 studies were excluded because they did not report the inclusion criteria. In the second round, 268 studies were read full-text, but only 135 reported the inclusion criteria and were included for data extraction. Of the included studies, 95 referred to everolimus use, 16 to ridaforolimus, and 26 to temsirolimus (two studies referred to both everolimus and temsirolimus).

RESULTS

The incidence rate of stomatitis according to the agent used was 25.07% (3,959/15,787) for everolimus, 27.02% (724/2,679) for temsirolimus, and 54.76% (598/1,092) for ridaforolimus. All the three agents analyzed showed high rates of low-grade stomatitis (G1-G2), while the onset of severe stomatitis (G3-G4) was rare.

CONCLUSIONS

Analysis of the reports with patients treated with everolimus, temsirolimus, and ridaforolimus showed a clear prevalence of stomatitis grade 1 or 2. These data differ from that of patients treated with conventional chemotherapy in which mucositis is predominantly of grade 3 or 4.

Attenuation of everolimus-induced cytotoxicity by a protective autophagic pathway involving ERK activation in renal cell carcinoma cells

Aim

The mammalian target of rapamycin (mTOR) pathway is a critical target for cancer treatment and the mTOR inhibitor everolimus (RAD001) has been approved for treatment of renal cell carcinoma (RCC). However, the limited efficacy of RAD001 has led to the development of drug resistance. Autophagy is closely related to cell survival and death, which may be activated under RAD001 stimulation. The aim of the present study was to identify the underlying mechanisms of RAD001 resistance in RCC cells through cytoprotective autophagy involving activation of the extracellular signal-regulated kinase (ERK) pathway.

Methods and results:

RAD001 strongly induced autophagy of RCC cells in a dose- and time-dependent manner, as confirmed by Western blot analysis. Importantly, suppression of autophagy by the pharmacological inhibitor chloroquine effectively enhanced RAD001-induced apoptotic cytotoxicity, as demonstrated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Western blot analysis, indicating a cytoprotective role for RAD001-induced autophagy. In addition, as was shown by the MTT assay, flow cytometry, and Western blot analysis, RAD001 robustly activated ERK, but not c-Jun N-terminal kinase and p38. Activation of ERK was inhibited by the pharmacological inhibitor selumetinib (AZD6244), which effectively promoted RAD001-induced cell death. Moreover, employing AZD6244 markedly attenuated RAD001-induced autophagy and enhanced RAD001-induced apoptosis, which play a central role in RAD001-induced cell death. Furthermore, RAD001-induced autophagy is regulated by ERK-mediated phosphorylation of Beclin-1 and B-cell lymphoma 2, as confirmed by Western blot analysis.

Conclusion

These results suggest that RAD001-induced autophagy involves activation of the ERK, which may impair cytotoxicity of RAD001 in RCC cells. Thus, inhibition of the activation of ERK pathway-mediated autophagy may be useful to overcome chemoresistance to RAD001.

To Excavate Biomarkers Predictive of the Response for Capecitabine plus RAD001 through Nanostring-Based Multigene Assay in Advanced Gastric Cancer Patients

Comprehensive characterization of individual patients' tumour is important to realize personalized medicine. Here, we investigate to identify subsets that benefit from capecitabine plus RAD001 in advanced gastric cancer (GC) patients by comprehensive high-throughput genomic analysis (nCounter assay). Archival tumour tissue blocks, if possible, were collected at phase II trial of capecitabine plus RAD001 in 47 refractory GC patients (at clinicaltrials.gov NCT#01099527). A total of 42 formalin-fixed, paraffin-embedded (FFPE) tumour samples were available for nanostring based-multigene Assay. An nCounter assay of 519 kinase panels has been used. We performed correlation analyses between expression levels of kinase genes and response for capecitabine plus RAD001. Among 42 patients with An nCounter assay of 519 kinase panels, 4 patients achieved confirmed partial response and 15 patients revealed stable disease, resulting in an overall response rate (ORR) of 9.5%. No difference in ORR was observed in terms of gender, performance status, primary tumour site, gastric resection, histologic subtype, Lauren classification, No. of metastatic site and No. of chemotherapy. In subgroups with response for capecitabine plus RAD001, there is significant overexpression of 6 genes among 519 kinase gene such as EPHA2 (P = 0.0025), PIM1 (P = 0.0031), KSR1 (P = 0.0033), and EIF2AK4 (P = 0.0046) that are related to the activation of mTOR signalling. This study is first report that investigated to identify biomarkers predictive of the response for RAD001 containing treatment in refractory GC patients, by comprehensive high-throughput genomic analysis (nCounter assay).

Targeted Therapies for Advanced Oesophagogastric Cancer: Recent Progress and Future Directions

The genomic landscape of oesophagogastric (OG) cancer is highly complex. The recent elucidation of some of the pathways involved has suggested a number of novel targets for therapy. This therapy is urgently required as with conventional chemotherapy regimens patients with advanced OG cancer still have a median overall survival of under a year. This review outlines the rationale for the current treatment of OG cancer with chemotherapy and describes both previously conducted and ongoing clinical trials of novel agents in this area. The targets and associated treatments discussed include HER-2, EGFR, VEGF, c-Met, FGFR-2, PI3K, mTOR andIGF-1. To date only two targeted treatments, trastuzumab and ramucirumab, have become part of the treatment paradigm for OG cancer, partly due to difficulties in defining predictive biomarkers in this disease. However, there are a number of promising drugs in the pipeline and this article seeks to describe these and other potential novel approaches including targeting DNA repair deficiencies and the immune system.

Evolving treatments for advanced gastric cancer: appraisal of the survival trend

Introduction and areas covered: We analysed the results of the main clinical studies looking at patients with advanced gastric or esophagogastric junction cancer, in order to differentiate between what is already clinical evidence and what is a promise for the cure of such patients. Thus, achievements from key studies, which had been purposely directed at chemotherapy, molecular target therapies and immunotherapy in both first and second-line setting were analysed. Metronomic chemotherapy, which consists of the administration of continuative low-dose anticancer drugs, was considered also. Expert commentary: It was found that patients included in experimental arms of randomized trials compared with controls have often benefited from a statistically significant extension of overall survival. However, further studies are awaited to bring new drugs into clinical practice and to validate candidate biomarkers predictive of response.

The Inositide Signaling Pathway As a Target for Treating Gastric Cancer and Colorectal Cancer

Gastric cancer and colorectal cancer are the leading cause of cancer mortality and have a dismal prognosis. The introduction of biological agents to treat these cancers has resulted in improved outcomes, and combination chemotherapy with targeted agents and conventional chemotherapeutic agents is regarded as standard therapy. Additional newly clarified mechanisms of oncogenesis and resistance to targeted agents require the development of new biologic agents. Aberrant activation of the inositide signaling pathway by a loss of function PTEN mutation or gain of function mutation/amplification of PIK3CA is an oncogenic mechanism in gastric cancer and colorectal cancer. Clinical trials with biologic agents that target the inositide signaling pathway are being performed to further improve treatment outcomes of patients with advanced gastric cancer and metastatic colorectal cancer (CRC). In this review we summarize the inositide signaling pathway, the targeted agents that inhibit abnormal activation of this signaling pathway and the clinical trials currently being performed in patients with advanced or metastatic gastric cancer and metastatic CRC using these targeted agents.

Autophagy inhibition enhances RAD001-induced cytotoxicity in human bladder cancer cells

Background

Mammalian target of rapamycin (mTOR), involved in PI3K/AKT/mTOR pathway, is known to play a central role in regulating the growth of cancer cells. The PI3K/AKT/mTOR pathway enhances tumor survival and proliferation through suppressing autophagy, which sustains energy homeostasis by collecting and recycling cellular components under stress conditions. Conversely, inhibitors of the mTOR pathway such as RAD001 induce autophagy, leading to promotion of tumor survival and limited antitumor efficacy. We thus hypothesized that the use of autophagy inhibitor in combination with mTOR inhibition improves the cytotoxicity of mTOR inhibitors in bladder cancer.

Materials and methods

The cytotoxicity of RT4, 5637, HT1376, and T24 human bladder cancer cells treated with RAD001 alone or combined with autophagy inhibitors (3-methyladenine (3-MA), bafilomycin A1 (Baf A1), chloroquine, or hydroxychloroquine) was assessed using the WST-8 cell viability kit. The autophagy status in cells was analyzed by the detection of microtubule-associated light chain 3 form II (LC3-II), using immunofluorescent staining and Western blot. Acidic vesicular organelle (AVO) formation in treated cells was determined by acridine orange vital staining. Inhibition of mTOR pathway by RAD001 was monitored by using a homemade quantitative polymerase chain reaction gene array, while phospho-mTOR was detected using Western blot. Induced apoptosis was determined by measurement of caspase 3/7 activity and DNA fragmentation in cells after treatment.

Results

Advanced bladder cancer cells (5637, HT1376, and T24) were more resistant to RAD001 than RT4. Autophagy flux detected by the expression of LC3-II showed RAD001-induced autophagy. AVO formation was detected in cells treated with RAD001 and was inhibited by the addition of 3-MA or Baf A1. Cotreatment of RAD001 with autophagy inhibitors further reduced cell viability and induced apoptosis in bladder cancer cells.

Conclusion

Our results indicate that simultaneous inhibition of the mTOR and autophagy pathway significantly enhances apoptosis, and it is suggested to be a new therapeutic paradigm for the treatment of bladder cancer.

NanoString expression profiling identifies candidate biomarkers of RAD001 response in metastatic gastric cancer

Background

Gene expression profiling has contributed greatly to cancer research. However, expression-driven biomarker discovery in metastatic gastric cancer (mGC) remains unclear. A gene expression profile predicting RAD001 response in refractory GC was explored in this study.

Methods

Total RNA isolated from 54 tumour specimens from patients with mGC, prior to RAD001 treatment, was analysed via the NanoString nCounter gene expression assay. This assay targeted 477 genes representing 10 different GC-related oncogenic signalling and molecular subtype-specific expression signatures. Gene expression profiles were correlated with patient clinicopathological variables.

Results

NanoString data confirmed similar gene expression profiles previously identified by microarray analysis. Signature I with 3 GC subtypes (mesenchymal, metabolic and proliferative) showed approximately 90% concordance where the mesenchymal and proliferative subtypes were significantly associated with signet ring cell carcinoma and the WHO classified tubular adenocarcinoma GC, respectively (p=0.042). Single-gene-level correlations with patient clinicopathological variables showed strong associations between FHL1 expression (mesenchymal subtype) and signet ring cell carcinoma, and NEK2, OIP5, PRC1, TPX2 expression (proliferative subtype) with tubular adenocarcinoma (adjusted p<0.05). Increased BRCA2 (p=0.040) and MMP9 (p=0.045) expression was significantly associated with RAD001 good response and longer progression-free survival outcome (BRCA2, p=0.012, HR 0.370 95% CI (0.171 to 0.800); MMP9, p=0.010, HR 0.359 95% CI (0.166 to 0.779)). In contrast, increased BTC (p=0.035) expression was significantly associated with RAD001 poor response and poor progression-free survival (p=0.031, HR 2.336 95% CI (1.079 to 5.059) by univariate Cox regression analysis.

Conclusions

Microarray results are highly reproducible with NanoString nCounter gene expression profiling. Additionally, BRCA2 and MMP9 expression are potential predictive biomarkers for good response in RAD001-treated mGC.

Targeted therapies in gastric cancer and future perspectives

Advanced gastric cancer (AGC) is associated with a high mortality rate and, despite multiple new chemotherapy options, the survival rates of patients with AGC remains poor. After the discovery of targeted therapies, research has focused on the new treatment options for AGC. In the last two decades, many targeted molecules were developed against AGC. Currently, two targeted therapy molecules have been approved for patients with AGC. In 2010, trastuzumab was the first molecule shown to improve survival in patients with HER2-positive AGC as part of a first-line combination regimen. In 2014, ramucirumab was the second targeted molecule to improve survival rates and was suggested as treatment for patients with AGC who had progressed after first-line platinum plus fluoropyrimidine with or without anthracycline chemotherapy. Ramucirumab was the first targeted therapy acting as a single agent in patients with advanced gastroesophageal cancers. Although these two molecules were introduced into clinical use, many other promising molecules have been tested in phase I-II trials. It is obvious that in the near future many different targeted therapies will be in use for treatment of AGC. In this review, the current status of targeted therapies in the treatment of AGC and gastroesophageal junction tumors, including HER (2-3) inhibitors, epidermal growth factor receptor inhibitors, tyrosine kinase inhibitors, antiangiogenic agents, c-MET inhibitors, mammalian target of rapamycin inhibitors, agents against other molecular pathways fibroblast growth factor, Claudins, insulin-like growth factor, heat shock proteins, and immunotherapy, will be discussed.

Gastric cancer: The times they are a-changin'

Gastric cancer is the third leading cause of cancer death worldwide. Even though during these last decades gastric cancer incidence decreased in Western countries, it remains endemic and with a high incidence in Eastern countries. The survival in advanced and metastatic stage of gastric cancer is still very poor. Recently the Cancer Genoma Atlas Research Network identified four subtypes with different molecular profiles to classify gastric cancer in order to offer the optimal targeted therapies for pre-selected patients. Indeed, the key point is still the selection of patients for the right treatment, on basis of molecular tumor characterization. Since chemotherapy reached a plateau of efficacy for gastric cancer, the combination between cytotoxic therapy and biological agents gets a better prognosis and decreases chemotherapeutic toxicity. Currently, Trastuzumab in combination with platinum and fluorouracil is the only approved targeted therapy in the first line for c-erbB2 positive patients, whereas Ramucirumab is the only approved targeted agent for patients with metastatic gastric cancer. New perspectives for an effective treatment derived from the immunotherapeutic strategies. Here, we report an overview on gastric cancer treatments, with particular attention to recent advances in targeted therapies and in immunotherapeutic approach.

Current and Future Therapies for Advanced Gastric Cancer

The treatment of patients with advanced gastric cancer remains a challenging area of oncology. Extensive trials of differing chemotherapy regimens have yielded no international consensus on the optimal combination, and overall survival with chemotherapy alone remains poor. Recently an improved understanding of the molecular drivers of the disease has opened up promising new avenues of treatment through the use of biological targeted agents. The anti-HER2 monoclonal antibody trastuzumab was the first targeted agent to significantly prolong survival in the first-line treatment of a molecularly-selected subgroup of patients. More recently the anti-vascular endothelial growth factor receptor 2 monoclonal antibody ramucirumab has demonstrated a modest survival benefit in previously treated patients as both a monotherapy and in combination with chemotherapy. Immunotherapy and the use of checkpoint inhibitors are a further exciting area of development with promising preliminary results for the activity of the anti-Programmed Death 1 Receptor antibody pembrolizumab and ongoing trials of a number of immune-modulating agents. Continuing research to identify novel targets and therapies aims to make further incremental gains in survival. In this review we outline the evidence base supporting current chemotherapy regimens and describe the latest advances in the development and use of molecularly targeted and immune-modulating agents.

Phase II trial of everolimus in patients with refractory metastatic adenocarcinoma of the esophagus, gastroesophageal junction and stomach: possible role for predictive biomarkers

PURPOSE

Our study was designed to evaluate the efficacy and safety of everolimus in patients with pre-treated metastatic gastric and esophagus cancers in a US-based population focusing on biomarker correlation.

METHODS

Patients with advanced upper GI adenocarcinomas who progressed after 1-2 prior regimens received everolimus 10 mg PO daily. The primary endpoint was disease control rate (DCR). Secondary endpoints included progression-free survival (PFS), toxicity, overall survival (OS) and biomarker correlatives of the mTOR pathway. Target accrual was 50 patients based on one-sided type I error of 10 % and power of 90 %.

RESULTS

Forty-five patients were evaluable, 21 gastric, 11 esophagus and 13 from the GEJ. The median age was 64 (range 38-73); all patients had an ECOG of 0 or 1; and 18 patients (40 %) had only 1 prior regimen. The most common grade 3-4 adverse events included fatigue (24 %) and thrombocytopenia (22 %). We observed 1 partial response with 39 % of evaluable patients having stable disease. Median OS was 3.4 months (95 % CI 2.7-5.6 months), and PFS was 1.8 months (95 % CI 1.7-2.2 months). There was a strong correlation between ≥2 + IHC staining for p-S6 in tumor samples with better PFS (p < 0.0001) and DCR (p = 0.0001).

CONCLUSIONS

Our clinical outcomes were inferior to the Asian studies, which may be explained by disease heterogeneity. However, there was a similar strong correlation between clinical benefit and tumor high pS6. Testing this biomarker in patient samples from the randomized phase III Granite trial may lead to a positive predictive marker.

Phase II study of capecitabine and the oral mTOR inhibitor everolimus in patients with advanced pancreatic cancer

Purpose

The combination of an mTOR inhibitor with 5-fluorouracil-based anticancer therapy is attractive because of preclinical evidence of synergy between these drugs. According to our phase I study, the combination of capecitabine and everolimus is safe and feasible, with potential activity in pancreatic cancer patients.

Methods

Patients with advanced adenocarcinoma of the pancreas were enrolled. Eligible patients had a WHO performance status 0–2 and adequate hepatic and renal functions. The treatment regimen consisted of capecitabine 1000 mg/m² BID day 1–14 and everolimus 10 mg daily (5 mg BID) in a continuous 21-day schedule. Tumor assessment was performed with CT-scan every three cycles. Primary endpoint was response rate (RR) according to RECIST 1.0. Secondary endpoints were progression-free survival, overall survival and 1-year survival rate.

Results

In total, 31 patients were enrolled. Median (range) treatment duration with everolimus was 76 days (1–431). Principal grade 3/4 toxicities were hyperglycemia (45 %), hand-foot syndrome (16 %), diarrhea (6 %) and mucositis (3 %). Prominent grade 1/2 toxicities were anemia (81 %), rash (65 %), mucositis (58 %) and fatigue (55 %). RR was 6 %. Ten patients (32 %) had stable disease resulting in a disease control rate of 38 %. Median overall survival was 8.9 months (95 % CI 4.6–13.1). Progression-free survival was 3.6 months (95 % CI 1.9–5.3).

Conclusions

The oral regimen with the combination of capecitabine and everolimus is a moderately active treatment for patients with advanced pancreatic cancer, with an acceptable toxicity profile at the applied dose level.

Successful control of heavily pretreated metastatic gastric cancer with the mTOR inhibitor everolimus (RAD001) in a patient with PIK3CA mutation and pS6 overexpression

Background

Everolimus (RAD001) is an orally administered mTOR inhibitor that is well known for its antitumor efficacy and that has been approved for the treatment of several solid tumors, including renal cell carcinoma. In gastric cancer (GC), despite previous preclinical and phase I/II studies suggesting the promising efficacy of everolimus in previously treated AGC, more recent trials revealed that only certain subsets of patients might benefit from treatment with everolimus.

Case presentation

A 26-year-old man with metastatic gastric cancer with multiple liver lesions was treated with everolimus after failure of 1st-line and 2nd-line chemotherapy. A durable partial response was achieved for over 2 years. After progression from initial everolimus treatment, sequential cytotoxic chemotherapies were tried but failed rapidly. Everolimus was re-tried as salvage chemotherapy (re-treatment), and the patient achieved stable disease for 1 year until his death. Subsequent mutational analysis and immunohistochemical (IHC) staining with the tumor tissues just before re-treatment with everolimus revealed a PIK3CA hotspot mutation and pS6 overexpression in the primary tumor. After two cycles of everolimus re-treatment, the overexpression of pS6 became nearly absent in follow-up IHC staining.

Conclusions

Everolimus monotherapy was satisfactory in a patient with refractory metastatic GC harboring PIK3CA and pS6 aberrations. These molecular alterations might be potential biomarkers that can predict the treatment response of everolimus, particularly in the terms of durable disease control. This case suggests and emphasizes that close evaluation of biomarkers in tumor tissue may be essential for identifying highly favorable groups among various subpopulations with AGC.

Targeting specific molecular pathways holds promise for advanced gallbladder cancer therapy

Gallbladder cancer is the most common and aggressive malignancy of the biliary tract. The complete surgical resection is the only potentially curative approach in early stage; however, most cases are diagnosed in advanced stages and the response to traditional chemotherapy and radiotherapy is extremely limited, with modest impact in overall survival. The recent progress in understanding the molecular alterations of gallbladder cancer has shown great promise for the development of more effective treatment strategies. This has mainly resulted from the identification of molecular alterations in relevant intracellular signaling pathways-Hedgehog, PI3K/AKT/mTOR, Notch, ErbB, MAPK and angiogenesis-which are potential tailored targets for gallbladder cancer patients. This review discusses the recent remarkable progress in understanding the molecular alterations that represent novel prognosis molecular markers and therapeutic targets for gallbladder cancer, which will provide opportunities for research and for developing innovative strategies that may enhance the benefit of conventional chemotherapy, or eventually modify the fatal natural history of this orphan disease.

Integrated analysis of cancer-related pathways affected by genetic and epigenetic alterations in gastric cancer

BACKGROUND

The profiles of genetic and epigenetic alterations in cancer-related pathways are considered to be useful for selection of patients likely to respond to specific drugs, including molecular-targeted and epigenetic drugs. In this study, we aimed to characterize such profiles in gastric cancers (GCs).

METHODS

Genetic alterations of 55 cancer-related genes were analyzed by a benchtop next-generation sequencer. DNA methylation statuses were analyzed by a bead array with 485,512 probes.

RESULTS

The WNT pathway was activated by mutations of CTNNB1 in 2 GCs and potentially by aberrant methylation of its negative regulators, such as DKK3, NKD1, and SFRP1, in 49 GCs. The AKT/mTOR pathway was activated by mutations of PIK3CA and PTPN11 in 4 GCs. The MAPK pathway was activated by mutations and gene amplifications of ERBB2, FLT3, and KRAS in 11 GCs. Cell-cycle regulation was affected by aberrant methylation of CDKN2A and CHFR in 13 GCs. Mismatch repair was affected by a mutation of MLH1 in 1 GC and by aberrant methylation of MLH1 in 2 GCs. The p53 pathway was inactivated by mutations of TP53 in 19 GCs and potentially by aberrant methylation of its downstream genes in 38 GCs. Cell adhesion was affected by mutations of CDH1 in 2 GCs.

CONCLUSIONS

Genes involved in cancer-related pathways were more frequently affected by epigenetic alterations than by genetic alterations. The profiles of genetic and epigenetic alterations are expected to be useful for selection of the patients who are likely to benefit from specific drugs.

The challenge of targeted therapies for gastric cancer patients: the beginning of a long journey

INTRODUCTION

Despite significant improvements in systemic chemotherapy over the last two decades, the prognosis of patients with advanced disease remains dismal. Collaborative, high-quality research and advances in high-throughput technologies have contributed to elucidate molecular pathways underpinning disease progression and have stimulated many clinical studies testing target therapies in the advanced disease setting. Although progress has been made thanks to trastuzumab in HER2 positive tumours, antiangiogenic drugs have produced conflicting results and EGFR-inhibitors have failed to show major improvements.

AREAS COVERED

While commenting on the results of many key Phase III randomized trials, the Authors discuss the most promising classes of novel targeted agents and present the current challenges toward a customized treatment.

EXPERT OPINION

Palliative chemotherapy became the worldwide standard of care for patients with advanced gastric cancers, producing significant life prolongation and improvement of life quality. Nevertheless, long-term outcomes of those patients remain poor. Because of the encouraging advancement in novel targeted therapies, such a disappointing scenario is now evolving. While results serve as a springboard for future research, more comprehensive efforts are needed to clarify the biological mechanisms underpinning cancer progression and help clinicians to develop new effective treatments.