Phase II study and biomarker analysis of cetuximab combined with modified FOLFOX6 in advanced gastric cancer

Immunotherapy for gastrointestinal malignancies

BACKGROUND

Gastrointestinal (GI) cancers are the most common human tumors encountered worldwide. The majority of GI cancers are unresectable at the time of diagnosis, and in the subset of patients undergoing resection, few are cured. There is only a modest improvement in survival with the addition of modalities such as chemotherapy and radiation therapy. Due to an increasing global cancer burden, it is imperative to integrate alternative strategies to improve outcomes. It is well known that cancers possess diverse strategies to evade immune detection and destruction. This has led to the incorporation of various immunotherapeutic strategies, which enable reprogramming of the immune system to allow effective recognition and killing of GI tumors.

METHODS

A review was conducted of the results of published clinical trials employing immunotherapy for esophageal, gastroesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers.

RESULTS

Monoclonal antibody therapy has come to the forefront in the past decade for the treatment of colorectal cancer. Immunotherapeutic successes in solid cancers such as melanoma and prostate cancer have led to the active investigation of immunotherapy for GI malignancies, with some promising results.

CONCLUSIONS

To date, monoclonal antibody therapy is the only immunotherapy approved by the US Food and Drug Administration for GI cancers. Initial trials validating new immunotherapeutic approaches, including vaccination-based and adoptive cell therapy strategies, for GI malignancies have demonstrated safety and the induction of antitumor immune responses. Therefore, immunotherapy is at the forefront of neoadjuvant as well as adjuvant therapies for the treatment and eradication of GI malignancies.

Pathology of gastric cancer and its precursor lesions

Gastric cancers are a histologically heterogenous group of neoplasms arising from unique epidemiologic and molecular backgrounds. There is accumulating evidence that the intestinal type of gastric adenocarcinoma develops through a multistep process beginning with chronic gastritis triggered primarily by Helicobacter pylori and progressing through atrophy, intestinal metaplasia, and dysplasia (intraepithelial neoplasia) to carcinoma. Loss of E-cadherin expression resulting from CDH1 gene alterations is the primary carcinogenetic event in hereditary diffuse gastric cancer. Proximal gastric adenocarcinomas likely result from either gastroesophageal reflux or H pylori gastritis. This article provides an update of the histologic, immunohistochemical, and molecular pathways of gastric cancer and its precursors.

Capecitabine and cisplatin with or without cetuximab for patients with previously untreated advanced gastric cancer (EXPAND): a randomised, open-label phase 3 trial

BACKGROUND

Patients with advanced gastric cancer have a poor prognosis and few efficacious treatment options. We aimed to assess the addition of cetuximab to capecitabine-cisplatin chemotherapy in patients with advanced gastric or gastro-oesophageal junction cancer.

METHODS

In our open-label, randomised phase 3 trial (EXPAND), we enrolled adults aged 18 years or older with histologically confirmed locally advanced unresectable (M0) or metastatic (M1) adenocarcinoma of the stomach or gastro-oesophageal junction. We enrolled patients at 164 sites (teaching hospitals and clinics) in 25 countries, and randomly assigned eligible participants (1:1) to receive first-line chemotherapy with or without cetuximab. Randomisation was done with a permuted block randomisation procedure (variable block size), stratified by disease stage (M0 vs M1), previous oesophagectomy or gastrectomy (yes vs no), and previous (neo)adjuvant (radio)chemotherapy (yes vs no). Treatment consisted of 3-week cycles of twice-daily capecitabine 1000 mg/m(2) (on days 1-14) and intravenous cisplatin 80 mg/m(2) (on day 1), with or without weekly cetuximab (400 mg/m(2) initial infusion on day 1 followed by 250 mg/m(2) per week thereafter). The primary endpoint was progression-free survival (PFS), assessed by a masked independent review committee in the intention-to-treat population. We assessed safety in all patients who received at least one dose of study drug. This study is registered at EudraCT, number 2007-004219-75.

FINDINGS

Between June 30, 2008, and Dec 15, 2010, we enrolled 904 patients. Median PFS for 455 patients allocated capecitabine-cisplatin plus cetuximab was 4.4 months (95% CI 4.2-5.5) compared with 5.6 months (5.1-5.7) for 449 patients who were allocated to receive capecitabine-cisplatin alone (hazard ratio 1.09, 95% CI 0.92-1.29; p=0.32). 369 (83%) of 446 patients in the chemotherapy plus cetuximab group and 337 (77%) of 436 patients in the chemotherapy group had grade 3-4 adverse events, including grade 3-4 diarrhoea, hypokalaemia, hypomagnesaemia, rash, and hand-foot syndrome. Grade 3-4 neutropenia was more common in controls than in patients who received cetuximab. Incidence of grade 3-4 skin reactions and acne-like rash was substantially higher in the cetuximab-containing regimen than in the control regimen. 239 (54%) of 446 in the cetuximab group and 194 (44%) of 436 in the control group had any grade of serious adverse event.

INTERPRETATION

Addition of cetuximab to capecitabine-cisplatin provided no additional benefit to chemotherapy alone in the first-line treatment of advanced gastric cancer in our trial.

FUNDING

Merck KGaA.

Cytotoxicity of cytokine-induced killer cells targeted by a bispecific antibody to gastric cancer cells

The aim of the present study was to investigate the cytotoxic activity of cytokine-induced killer (CIK) cells targeted by an epidermal growth factor receptor (EGFR)/CD3 bispecific antibody (BsAb) to the gastric cancer cell line SGC7901. A BsAb was constructed by chemically cross-linking a monoclonal antibody (McAb) against human CD3 with another McAb against human EGFR. An immunocytochemistry assay was performed to detect the expression of EGFR in SGC7901 cells. The cytotoxic activity of CIK cells targeted by the EGFR/CD3 BsAb was analyzed by the ⁵¹Cr release assay, Subsequently, a comparison of the cytotoxic activity between CIK cells targeted by EGFR/CD3 BsAb, CIK cells targeted by EGFR McAb or/and CD3 McAb and CIK cells was performed. The antineoplastic activity of the CIK cells directed using the EGFR/CD3 BsAb in vivo was analyzed by tumor growth and tumor reduction assays. The cell lysis rate of CIK cells targeted by the EGFR/CD3 BsAb was higher compared with those of CIK cells targeted by CD3 McAb only or by CD3 McAb and EGFR McAb. The lysis rates of the latter two groups were significantly higher than those of CIK cells targeted by EGFR McAb only and CIK cells (P<0.05). The mean tumor reduction using the administration of CIK cells directed by the EGFR/CD3 BsAb was higher than those of the other groups (P<0.05). The results indicate that the EGFR/CD3 BsAb is able to enhance the ability of CIK cells to bind to and kill gastric cancer cells in vitro and in vivo.

Molecular targeted therapy for advanced gastric cancer

Although medical treatment has been shown to improve quality of life and prolong survival, no significant progress has been made in the treatment of advanced gastric cancer (AGC) within the last two decades. Thus, the optimum standard first-line chemotherapy regimen for AGC remains debatable, and most responses to chemotherapy are partial and of short duration; the median survival is approximately 7 to 11 months, and survival at 2 years is exceptionally > 10%. Recently, remarkable progress in tumor biology has led to the development of new agents that target critical aspects of oncogenic pathways. For AGC, many molecular targeting agents have been evaluated in international randomized studies, and trastuzumab, an anti-HER-2 monoclonal antibody, has shown antitumor activity against HER-2-positive AGC. However, this benefit is limited to only ~20% of patients with AGC (patients with HER-2-positive AGC). Therefore, there remains a critical need for both the development of more effective agents and the identification of molecular predictive and prognostic markers to select those patients who will benefit most from specific chemotherapeutic regimens and targeted therapies.

Metastatic gastric cancer treatment: a little slow but worthy progress

Metastatic gastric cancer is incurable and remains one of the leading causes of cancer-related deaths around the world. Despite the significant progress in its systemic treatment, metastatic gastric cancer is still a major therapeutic challenge for oncologists. Newer chemotherapy regimens and the addition of molecularly targeted agents to chemotherapy seem to provide better clinical outcomes for patients with metastatic gastric cancer. The objective of this article is to review the current treatment approach for this formidable disease.

Molecular targeted agents for gastric cancer: a step forward towards personalized therapy

Gastric cancer (GC) represents a major cancer burden worldwide, and remains the second leading cause of cancer-related death. Due to its insidious nature, presentation is usually late and often carries a poor prognosis. Despite having improved treatment modalities over the last decade, for most patients only modest improvements have been seen in overall survival. Recent progress in understanding the molecular biology of GC and its signaling pathways, offers the hope of clinically significant promising advances for selected groups of patients. Patients with Her-2 overexpression or amplification have experienced benefit from the integration of monoclonal antibodies such as trastuzumab to the standard chemotherapy. Additionally, drugs targeting angiogenesis (bevacizumab, sorafenib, sunitinib) are under investigation and other targeted agents such as mTOR inhibitors, anti c-MET, polo-like kinase 1 inhibitors are in preclinical or early clinical development. Patient selection and the development of reliable biomarkers to accurately select patients most likely to benefit from these tailored therapies is now key. Future trials should focus on these advances to optimize the treatment for GC patients. This article will review recent progress and current status of targeted agents in GC.

Molecular targeted therapies in advanced gastric cancer: does tumor histology matter?

It is increasingly recognized that gastric cancer is a heterogeneous disease which may be divided into subgroups based on histological, anatomical, epidemiological and molecular classifications. Distinct molecular drivers and tumor biology, and thus different treatment targets and predictive biomarkers, may be implicated in each subtype. However, there is little evidence in the literature regarding the correlation among these different classifications, and particularly the molecular aberrations present in each subtype. In this review, we approach advanced gastric cancer (AGC) by presenting aberrant molecular pathways and their potential therapeutic targets in gastric cancer according to histological and anatomical classification, dividing gastric cancer into proximal nondiffuse, distal nondiffuse and diffuse disease. Several pathways are involved predominantly, although not exclusively, in different subtypes. This may help to explain the disappointing results of many published AGC trials in which study populations were heterogeneous regardless of clinicopathological characteristics of the primary tumor. Histological and anatomical classification may provide insights into tumor biology and facilitate selection of an enriched patient population for targeted agents in future studies and in the clinic. However, some molecular pathways implicated in gastric cancer have not been studied in correlation with histological or anatomical subtypes. Further studies are necessary to confirm the suggestion that such classification may predict tumor biology and facilitate selection of an enriched patient population for targeted agents in future studies and in the clinic.

Survival benefit of traditional Chinese herbal medicine (a herbal formula for invigorating spleen) for patients with advanced gastric cancer

BACKGROUND

Traditional Chinese herbal medicine (TCHM) is widely used for advanced gastric cancer (AGC) in China. In this study, the authors analyzed the prognostic factors of selected patients with AGC, and further studied the efficacy of TCHM (a herbal formula for invigorating spleen, formerly named Wei Chang' An) on AGC.

METHODS

Patients with uncured AGC were prospectively enrolled. All patients were enrolled to either the TCHM group or non-TCHM group. TCHM was administered orally to the patients in the TCHM group for 3 months or more. Cox regression analysis was performed to determine survival trends adjusted for clinical and demographic factors. Kaplan-Meier curves were used to assess the differences in survival time.

RESULTS

There were a total of 399 eligible patients with histologically confirmed adenocarcinoma of the stomach from 2001 to 2009. In the overall group, Cox regression analysis suggested that histological type (P = .016), radiotherapy (P = .000), cycle of chemotherapy (P = .000), and TCHM (P = .000) were independent prognostic factors. In a stratification analysis of stage for 213 patients who received 3 or more cycles of chemotherapy, there was a significant increase in median overall survival from 14.0 (non-TCHM group) to 20.0 (TCHM group) months (hazard ratio [HR] = 0.538, 95% confidence interval [CI] 0.385-0.750, P = .000). Among 186 patients who did not receive chemotherapy, but best supportive care, there was a significant increase in median overall survival from 7.0 (non-TCHM group) to 14.8 (TCHM group) months (HR = 0.443, 95% CI = 0.299-0.657, P = .000).

CONCLUSIONS

TCHM has an important potential value for improving the prognosis of patients with AGC.

Phase I study of matuzumab in combination with 5-fluorouracil, leucovorin and cisplatin (PLF) in patients with advanced gastric and esophagogastric adenocarcinomas

BACKGROUND

To evaluate the safety and tolerability of two different weekly doses of the fully humanized epidermal growth factor receptor (EGFR)-targeting monoclonal antibody matuzumab combined with high-dose 5-fluorouracil, leucovorin and cisplatin (PLF) in the first-line treatment of patients with EGFR-positive advanced gastric and esophagogastric adenocarcinomas.

METHODS

Patients were treated in two matuzumab dose groups with the first cohort of patients receiving 400 mg matuzumab in combination with PLF. Based on the safety observations the next cohort of patients received 800 mg matuzumab. The study was conducted in two parts, with phase A, designed to assess the safety and tolerability of the combination, and phase B designed to be a treatment continuation for those patients benefiting from treatment. Treatment cycles were 7 weeks each. Each patient received the dose of matuzumab they were assigned to at study entry for the duration of the study.

RESULTS

Fifteen EGFR-positive patients were enrolled into the two matuzumab dose groups; 400 mg dose n=7; 800 mg dose n=8. All patients experienced at least one adverse event (AE). No patient experienced any serious AE which was considered to be related to matuzumab. Two grade 3 AEs possibly related to matuzumab occurred in 2 different patients (13.3 %), both in the 800 mg dose group. No dose-limiting toxicity (DLT) was observed in the 400 mg group. The maximum tolerated dose of matuzumab was not reached. The best confirmed overall response rate was 26.7 %.

CONCLUSION

Matuzumab, in combination with PLF, demonstrated an acceptable safety profile with modest anti-tumor activity.

In vitro and in vivo antitumor activity of cetuximab in human gastric cancer cell lines in relation to epidermal growth factor receptor (EGFR) expression and mutational phenotype

BACKGROUND

Targeting the epidermal growth factor receptor (EGFR) pathway is an important approach for a variety of tumors. This study assessed the effect of cetuximab, an anti-EGFR monoclonal antibody, on three gastric cancer cell lines with different phenotypes in vitro and in a therapeutic orthotopic murine gastric cancer model.

METHODS

Three human gastric cancer cell lines (AGS, MKN-45, NCI-N87) were evaluated for cell surface EGFR expression, and K-ras and BRAF mutations. In vitro, the effects of cetuximab, carboplatin, irinotecan, and docetaxel were investigated. Orthotopic tumors derived from MKN-45 and NCI-N87 were established in nude mice. After 4 weeks, the animals received cetuximab (1 mg/kg, weekly i.p.) or carboplatin (20 mg/kg, weekly i.p.), or both agents. The volume of the primary tumor and local and systemic tumor spread were determined at autopsy at 14 weeks. Tumor sections were immunostained for EGFR, as well as stained for CD31 to analyze microvessel density.

RESULTS

Cell surface expression of EGFR was found only in AGS and NCI-N87 cells. AGS cells displayed a codon 12 K-ras mutation, and all three cell lines were BRAF wild-type. In vitro, cetuximab significantly reduced cell viability and proliferation only in EGFR-positive/K-ras wild-type NCI-N87 cells (-48%). In vivo, cetuximab in combination with carboplatin synergistically reduced tumor volume (-75%), dissemination (-63%), and vascularization (-47%) in NCI-N87 xenografts. Tumors derived from EGFR-negative MKN-45 cells were unaffected by cetuximab.

CONCLUSIONS

Cetuximab is effective in K-ras wild-type, EGFR-expressing gastric cancer cell lines and xenografts. In vivo, the combination of cetuximab with carboplatin displayed synergistic antitumor activity.

Erlotinib increases sensitivity of MKN45 cells to radiotherapy

AIM: To observe the effect of erlotinib combined with radiotherapy on cell cycle progression and apoptosis of human gastric carcinoma MKN45 cells to explore the mechanism by which erlotinib increases the sensitivity of MKN45 cells to radiotherapy.

METHODS: The effect of erlotinib and radiotherapy on MKN45 cells was examined by MTT assay and colony formation assay. The median inhibitory concentration (IC₅₀) and radiobiological parameters D₀ and Dq were calculated. Cell apoptosis and cell cycle progression were examined by flow cytometry. The expression of Bcl-2 and Bax proteins was detected by Western blot.

RESULTS: Both erlotinib and radiotherapy could inhibit MKN45 cell growth in a concentration- and dose-dependent manner (both P < 0.01). The inhibitory effect of erlotinib combined with radiotherapy on MKN45 cell growth was better than that of erlotinib or radiation alone. Combination treatment significantly decreased the percentages of cells in S phase cells and increased those in G₂/M and G₀/G₁ phases (71.87 ± 0.77 vs 60.72 ± 0.26, P < 0.01) and cell apoptosis. After treatment with erlotinib combined with radiotherapy, Bcl-2 protein expression decreased and Bax protein expression increased.

CONCLUSION: Erlotinib increases radiosensitivity of MKN45 cells by increasing the percentages of cells in G₂/M and G₀/G₁ phases and decreasing Bcl-2/Bax ratio to induce apoptosis.

Novel targeted agents for gastric cancer

Contemporary advancements have had little impact on the treatment of gastric cancer (GC), the world’s second highest cause of cancer death. Agents targeting human epidermal growth factor receptor mediated pathways have been a common topic of contemporary cancer research, including monoclonal antibodies (mAbs) and receptor tyrosine kinase inhibitors (TKIs). Trastuzumab is the first target agent evidencing improvements in overall survival in HER2-positive (human epidermal growth factor receptor 2) gastric cancer patients. Agents targeting vascular epithelial growth factor (VEGF), mammalian target of rapamycin (mTOR), and other biological pathways are also undergoing clinical trials, with some marginally positive results. Effective targeted therapy requires patient selection based on predictive molecular biomarkers. Most phase III clinical trials are carried out without patient selection; therefore, it is hard to achieve personalized treatment and to monitor patient outcome individually. The trend for future clinical trials requires patient selection methods based on current understanding of GC biology with the application of biomarkers.

Targeted therapy for esophagogastric cancers: a review

The incidence of esophagogastric cancers is increasing rapidly in the Western population. Despite better understanding of the biology and intense research in the treatment of these cancers, the long-term survival remains poor both in the locally advanced and metastatic settings. The addition of combined modality strategies has resulted in modest improvement in 5-year survival rates. A number of biologic agents targeting epidermal-derived growth factor receptor, vascular endothelial derived growth factor and its receptor, and mammalian target of rapamycin (mTOR) are being currently evaluated in Phase II and III clinical trials. Some of these, like trastuzumab, cetuximab, and bevacizumab, have shown promising results. This review provides a brief overview of the recent developments in biologic agents for the treatment of esophagogastric cancers.

Association of amphiregulin with the cetuximab sensitivity of gastric cancer cell lines

The therapeutic activity of the epidermal growth factor receptor (EGFR)-directed monoclonal antibody cetuximab in gastric cancer is currently being investigated in clinical studies. Reliable biomarkers for the identification of patients who are likely to benefit from this treatment are not available. In this study, we assessed the activity of cetuximab in five gastric cancer cell lines (AGS, AZ521, Hs746T, LMSU and MKN1). The viability of two of these cell lines, AZ521 and MKN1, was significantly reduced by cetuximab treatment. High expression and secretion levels of the EGFR-binding ligand, amphiregulin (AREG), were associated with cetuximab responsiveness. MET activation and mutations in Kirsten-Ras gene (KRAS) were associated with cetuximab resistance. By introducing a hierarchy between these markers, we established a model that facilitated the correct classification of all five gastric cancer cell lines as cetuximab responsive or non-responsive. The highest priority was allocated to activating KRAS mutations, followed by MET activation and finally by the levels of secreted AREG. In order to validate these results, we used three additional human gastric cancer cell lines (KATOIII, MKN28 and MKN45). In conclusion, we propose that our model allows the response of gastric cancer cell lines to cetuximab treatment to be predicted.

Relevance of MET activation and genetic alterations of KRAS and E-cadherin for cetuximab sensitivity of gastric cancer cell lines

PURPOSE

The therapeutic activity of the epidermal growth factor receptor (EGFR)-directed monoclonal antibody cetuximab in gastric cancer is currently being investigated. Reliable biomarkers for the identification of patients who are likely to benefit from the treatment are not available. The aim of the study was to examine the drug sensitivity of five gastric cancer cell lines towards cetuximab as a single agent and to establish predictive markers for chemosensitivity in this cell culture model. The effect of a combination of cetuximab with chemotherapy was compared between a sensitive and a nonsensitive cell line.

METHODS

EGFR expression, activation and localisation, the presence and subcellular localisation of the cell adhesion molecule E-cadherin as well as MET activation were examined by Western blot analysis, flow cytometry and immunofluorescence staining. Cells were treated with varying concentrations of cetuximab and cisplatin and 5-fluorouracil in tumour-relevant concentrations. The biological endpoint was cell viability, which was measured by XTT cell proliferation assay. Response to treatment was evaluated using statistical methods.

RESULTS

We assessed the activity of cetuximab in five gastric cancer cell lines (AGS, KATOIII, MKN1, MKN28 and MKN45). The viability of two cell lines, MKN1 and MKN28, was significantly reduced by cetuximab treatment. High EGFR expression and low levels of receptor activation were associated with cetuximab responsiveness. MET activation as well as mutations of KRAS and CDH1 (gene encoding E-cadherin) was associated with cetuximab resistance.

CONCLUSION

These data indicate that our examinations may be clinically relevant, and the candidate markers should therefore be tested in clinical studies.

Current status of targeted therapies in advanced gastric cancer

INTRODUCTION

In metastatic gastric cancer, chemotherapy is the standard treatment because it prolongs survival when compared to best supportive care alone. However, even after the use of more effective regimens, the overall survival remains disappointing, justifying the need for new treatment options.

AREAS COVERED

Areas covered in this review include the most common molecular pathways, which have provided novel targets in gastric cancer therapy. These therapeutic strategies include EGFR inhibitors, anti-angiogenic agents, cell cycle inhibitors and apoptosis promoters.

EXPERT OPINION

Several mAbs and kinase inhibitors, especially those targeting EGFR and VEGF/VEGFR, have already demonstrated promising activity in gastric cancer. The Phase III ToGA trial reported an increase in overall survival for patients with human EGF receptor (HER)2-positive gastric cancer treated with chemotherapy and trastuzumab compared to chemotherapy alone. This means that accurate HER2 testing in gastric cancer is necessary. Final data of ongoing trials with novel agents will be critical to further progress with this cancer.

Targeted therapies in the treatment of gastric cancer

Gastric cancer (GC) constitutes a major cause of cancer deaths worldwide. Recent improvements in both surgical techniques and adjuvant and neoadjuvant radiotherapy and chemotherapy approaches have increased the survival of patients with loco-regional disease. However most patients with GC have advanced disease either at diagnosis or at follow up. Despite recent advances in the treatment of advanced disease, these patients still have poor outcomes. An emerging understanding of the molecular pathways that characterize cell growth, cell cycle, apoptosis, angiogenesis and invasion has provided novel targets in cancer therapy. In this review we describe the current status of targeted therapies in the treatment of GC. These therapeutic strategies include epidermal growth factor receptor inhibitors, antiangiogenic agents, cell cycle inhibitors, apoptosis, promoters and matrix metalloproteinases inhibitors.

Targeted therapy in the management of advanced gastric cancer: are we making progress in the era of personalized medicine?

BACKGROUND

Gastric cancer is one of the leading causes of cancer death. With greater understanding of the molecular basis of carcinogenesis, targeted agents have led to a modest improvement in the outcome of advanced gastric cancer (AGC) patients.

METHODS AND RESULTS

We conducted an overview of the published evidence regarding the use of targeted therapy in AGC patients. Thus far, the human epidermal growth factor receptor (HER) pathway, angiogenic pathway, and phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin pathway have emerged as potential avenues for targeted therapy in AGC patients. The promising efficacy results of the Trastuzumab for Gastric Cancer trial led to the approved use of trastuzumab-based therapy as first-line treatment for patients with HER-2+ AGC. On the other hand, the Avastin® in Gastric Cancer trial evaluating bevacizumab in combination with chemotherapy did not meet its primary endpoint of a longer overall survival duration despite a significantly higher response rate and longer progression-free survival time in patients in the bevacizumab arm. Phase III data are awaited for other targeted agents, including cetuximab, panitumumab, lapatinib, and everolimus.

CONCLUSION

Recent progress in targeted therapy development for AGC has been modest. Further improvement in the outcome of AGC patients will depend on the identification of biomarkers in different patient populations to facilitate the understanding of gastric carcinogenesis, combining different targeted agents with chemotherapy, and unraveling new molecular targets for therapeutic intervention.

NF-κB and targeted therapy of gastric cancer: recent research progress

Gastric cancer is a main cause of cancer death worldwide. Despite the knowledge that Helicobacter pylori constitutes the main cause of gastric cancer, the mechanisms for gastric carcinogenesis are still elucidated. Cancer development and progression depend on the balance between cell survival and death signals. Common cell survival signaling pathways are activated by carcinogens as well as by inflammatory cytokines, which contribute substantially to tumorigenesis. Nuclear factor-kappaB (NF-κB) is a major cell survival signal. Recent studies with cell culture systems and animal models have certified the links between NF-κB and gastric carcinogenesis and resistance to chemotherapy. Inhibition of NF-κB activation can enhance the sensitivity of cancer cells to chemotherapeutic drugs. In this review, we summarize recent progress in understanding the role of the NF-κB pathway in gastric cancer development as well as in modulating NF-κB for gastric cancer prevention and therapy.

Phase II study of biweekly cetuximab in combination with irinotecan as second-line treatment in patients with platinum-resistant gastro-oesophageal cancer

BACKGROUND

The purpose of this phase II trial was to evaluate the efficacy and safety of cetuximab and irinotecan as second-line treatment in patients with gastro-oesophageal adenocarcinoma.

PATIENTS AND METHODS

Patients with failure to first-line platinum-based chemotherapy received cetuximab 500 mg/m(2) and irinotecan 180 mg/m(2) every second week until disease progression. Toxicity was evaluated according to The Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) v. 3.0. Antitumour activity was assessed according to Response Evaluation Criteria in Solid Tumours (RECIST) v. 1.0.

RESULTS

Sixty-three patients were enrolled, median age was 60 years, median performance status was 1 (0-1), 35 patients had two or more organs involved. The median number of courses was 5 (range 1-25). Response rate was 11% (6 partial response (PR)) and 37% had stable disease. Median progression free survival was 2.8 months and overall survival (OS) was 6.1 months. Grade 3-4 toxicity included: diarrhoea (6%), fatigue (5%), vomiting (5%) and neutropenia (16%). Two patients developed febrile neutropenia. Forty-six patients (73%) had developed grade 1-2 skin rash. Patients developing skin rash had a prolonged survival with an OS at 7.1 months.

CONCLUSIONS

The combination of cetuximab and irinotecan is active as second-line therapy in patients with gastro-oesophageal cancer. Cetuximab induced skin rash was associated with prolonged survival.

Targeted therapies and predictive markers in epithelial malignancies of the gastrointestinal tract

CONTEXT

In recent years, there has been a tremendous amount of interest in the development of targeted therapies for the treatment of human cancers. Increased understanding of the specific molecular pathways and driver mutations critical to cancer cell growth have allowed the development of these advanced therapeutics. Among these, inhibitors of the epidermal growth factor receptor and HER2/neu pathways now play a major role in the management of gastrointestinal cancers in addition to other solid malignancies. In colorectal and gastric cancers, the use of epidermal growth factor receptor inhibitors and HER2/neu inhibitors has increased the available treatment options for patients with advanced disease.

OBJECTIVE

To focus on the current targeted therapies and predictors of response in malignancies of the gastrointestinal tract.

DATA SOURCES

Medical literature searchable on PubMed (US National Library of Medicine) as well as older studies revealed by the literature review were used as the source of data.

CONCLUSION

Gene testing of critical elements of the pathways targeted by these agents (such as KRAS mutational analysis in colorectal tumors and HER2/neu testing in gastric cancers) allows the ability to predict which patients will respond to these treatments. As the molecular profiling of tumors and our understanding of cancer genomics and epigenetic alterations continues to grow, it is expected that these personalized targeted therapies will form one of the mainstays of gastrointestinal cancer treatment.

Adenocarcinoma of the GEJ: gastric or oesophageal cancer?

According to WHO (2010) adenocarcinomas of the esophagogastric junction (GEJ) are defined as tumors that cross the most proximal extent of the gastric folds regardless of where the bulk of the tumor lies. In addition, these neoplasms are now classified as esophageal cancers by UICC (2010). Recent studies, however, revealed two types of carcinogenesis in the distal oesophagus and at the GEJ, one of intestinal type (about 80 %) and the other of gastric type (about 20 %). These are characterized by marked differences in morphology, tumor stage at diagnosis, and prognosis. Furthermore, both cancer types show different targetable biomarker expression profiles such as Her2 in the intestinal and EGFR in the non-intestinal pathway indicating new therapy options. Due to the fact that carcinomas of the intestinal pathway were typically associated with Barrett's mucosa which was not the case in the non-intestinal-type tumors, this challenges the paradigm "no goblets no Barrett's". Moreover, even the cancer risk of intestinal-type metaplasia has seriously been questioned by a Danish population-based study where Barrett's mucosa turned out to be only a weak indicator of esophageal and GEJ cancer (1 case in 860 patients years). Thus, two biologically different types of cancer arise at the GEJ-esophageal and gastric type that open distinctive targeted treatment options and also question our current concept about the diagnostics of potential precursor lesions as well as the associated screening and surveillance strategy.

Biomarker analysis of cetuximab plus oxaliplatin/leucovorin/5-fluorouracil in first-line metastatic gastric and oesophago-gastric junction cancer: results from a phase II trial of the Arbeitsgemeinschaft Internistische Onkologie (AIO)

Background

The activity of the epidermal growth factor receptor (EGFR)-directed monoclonal antibody cetuximab combined with oxaliplatin/leucovorin/5-fluorouracil (FUFOX) was assessed in first-line metastatic gastric and oesophago-gastric junction (OGJ) cancer in a prospective phase II study showing a promising objective tumour response rate of 65% and a low mutation frequency of KRAS (3%). The aim of the correlative tumour tissue studies was to investigate the relationship between EGFR gene copy numbers, activation of the EGFR pathway, expression and mutation of E-cadherin, V600E BRAF mutation and clinical outcome of patients with gastric and OGJ cancer treated with cetuximab combined with FUFOX.

Methods

Patients included in this correlative study (n = 39) were a subset of patients from the clinical phase II study. The association between EGFR gene copy number, activation of the EGFR pathway, abundance and mutation of E-cadherin which plays an important role in these disorders, BRAF mutation and clinical outcome of patients was studied. EGFR gene copy number was assessed by FISH. Expression of the phosphorylated forms of EGFR and its downstream effectors Akt and MAPK, in addition to E-cadherin was analysed by immunohistochemistry. The frequency of mutant V600E BRAF was evaluated by allele-specific PCR and the mutation profile of the E-cadherin gene CDH1 was examined by DHPLC followed by direct sequence analysis. Correlations with overall survival (OS), time to progression (TTP) and overall response rate (ORR) were assessed.

Results

Our study showed a significant association between increased EGFR gene copy number (≥ 4.0) and OS in gastric and OGJ cancer, indicating the possibility that patients may be selected for treatment on a genetic basis. Furthermore, a significant correlation was shown between activated EGFR and shorter TTP and ORR, but not between activated EGFR and OS. No V600E BRAF mutations were identified. On the other hand, an interesting trend between high E-cadherin expression levels and better OS was observed and two CDH1 exon 9 missense mutations (A408V and D402H) were detected.

Conclusion

Our finding that increased EGFR gene copy numbers, activated EGFR and the E-cadherin status are potentially interesting biomarkers needs to be confirmed in larger randomized clinical trials.

Trial registration

Multicentre clinical study with the European Clinical Trials Database number 2004-004024-12.

Antitumor effect of cetuximab in combination with S-1 in EGFR-amplified gastric cancer cells

Overexpression of human epidermal growth factor receptor (EGFR) has been detected in gastric cancer (GC) and is associated with poor outcomes. Combination treatment regimens with EGFR-targeting agents and cytotoxic agents are considered to be a potential therapeutic option for EGFR-overexpressing GC. Herein, we have investigated the effects of combination treatment with the oral fluoropyrimidine S-1 and the EGFR-targeting agent cetuximab in GC cells with or without EGFR overexpression. EGFR expression was determined by FACS and quantitative PCR in GC cells. Experimental 5-fluorouracil (5FU) was used instead of S-1 for in vitro experiments. The efficacy of 5FU or cetuximab monotherapy or combination 5FU/cetuximab therapy was examined in vitro and in vivo. Clinical specimens were examined for EGFR by immunohistochemistry (IHC). EGFR expression score was defined as strong membrane and cytoplasmic staining in at least 50–75% of cells. The combination of 5FU and cetuximab synergistically inhibited cell proliferation and exhibited an enhanced proapoptotic effect in GC cells with EGFR overexpression. Cetuximab also induced down-regulation of phosphorylation of EGFR and AKT, leading to diminished signaling. The antitumor effect of the combination of S-1 and cetuximab in vivo was also greater than that of either drug alone. Our preclinical findings thus indicate that the combination of S-1 and EGFR-targeting therapy is a promising treatment option for GC with EGFR overexpression.

Phase II study of sunitinib as second-line treatment for advanced gastric cancer

PURPOSE

This phase II, open-label, multicenter study assessed the oral, multitargeted, tyrosine kinase inhibitor sunitinib in patients with advanced gastric or gastroesophageal junction adenocarcinoma who had received prior chemotherapy.

EXPERIMENTAL DESIGN

Patients received sunitinib 50 mg/day on Schedule 4/2 (4 weeks on treatment, followed by 2 weeks off treatment). The primary endpoint was objective response rate; secondary endpoints included clinical benefit rate, duration of response, progression-free survival (PFS), overall survival (OS), pharmacokinetics, pharmacodynamics, safety and tolerability, and quality of life.

RESULTS

Of 78 patients enrolled, most had gastric adenocarcinoma (93.6%) and metastatic disease (93.6%). All were evaluable for safety and efficacy. Two patients (2.6%) had partial responses and 25 patients (32.1%) had a best response of stable disease for ≥6 weeks. Median PFS was 2.3 months (95% confidence interval [CI], 1.6-2.6 months) and median OS was 6.8 months (95% CI, 4.4-9.6 months). Grade ≥ 3 thrombocytopenia and neutropenia were reported in 34.6% and 29.4% of patients, respectively, and the most common non-hematologic adverse events were fatigue, anorexia, nausea, diarrhea, and stomatitis. Pharmacokinetics of sunitinib and its active metabolite were consistent with previous reports. There were no marked associations between baseline soluble protein levels, or changes from baseline, and measures of clinical outcome.

CONCLUSIONS

The progression-delaying effect and manageable toxicity observed with sunitinib in this study suggest that although single-agent sunitinib has insufficient clinical value as second-line treatment for advanced gastric cancer, its role in combination with chemotherapy merits further study.

Evolving standards of care in advanced gastric cancer

Despite its decreasing incidence in western countries, the care of gastric cancer remains a concern, as many patients are diagnosed with advanced disease. Whereas localized gastric cancer has benefited from advances in surgical management and perioperative chemotherapy, patients with unresectable or metastatic disease have a poor prognosis. However, advances in chemotherapy have still arisen, with the onset of more convenient and active schedules of treatment, but no significant breakthrough has been achieved in terms of survival. Recent trials in advanced gastric cancer have been focusing on targeted therapies. This article aims to focus on the current state of the art in terms of chemotherapy for advanced gastric cancer, as well as to describe and explain the rationale and hopes for newer therapies that are currently under investigation.

Molecular targeted agents for gastric and gastroesophageal junction cancer

Despite recent improvements in surgical techniques and chemotherapy, advanced cancers of the stomach and gastroesophageal junction (GEJ) continue to have poor clinical outcomes. However, molecules intimately related to cancer cell proliferation, invasion, and metastasis have been studied as candidates for molecular targeted agents. Target molecules, such as the epidermal growth factor receptor, vascular endothelial growth factor receptor, and P13k/Akt/mTor pathway, as well as the insulin-like growth factor receptor, c-Met pathways, fibroblast growth factor receptor, and other pathways are considered to be promising candidates for molecular targeted therapy for gastric and GEJ cancer. In this review we focus on the recent developments in targeting relevant pathways in these types of cancer.

Phase II trial of modified FOLFOX6 and erlotinib in patients with metastatic or advanced adenocarcinoma of the oesophagus and gastro-oesophageal junction

BACKGROUND

There is increased recognition that cancers of the upper GI tract comprise distinct epidemiological and molecular entities. Erlotinib has shown activity in patients with adenocarcinoma of the oesophagus/gastro-oesophageal junction (GEJ), but not in distal gastric cancer. mFOLFOX6 is one of several active regimens used to treat adenocarcinoma of the Eso/GEJ. This study evaluates the efficacy and safety of mFOLFOX6 and erlotinib in patients with metastatic or advanced Eso/GEJ cancers.

METHODS

Patients with previously untreated advanced or metastatic Eso/GEJ adenocarcinoma are treated with oxaliplatin 85 mg m(-2), 5-FU 400 mg m(-2), LV 400 mg m(-2) on day 1, 5-FU 2400 mg m(-2) over 48 h and erlotinib 150 mg PO daily. Treatment was repeated every 14 days. The primary objective was response rate (RR), secondary objectives include toxicity, progression-free survival (PFS), overall survival (OS) and to correlate clinical outcome with expression patterns and molecular alterations in the epidermal growth factor receptor-dependent pathways.

RESULTS

A total of 33 patients were treated and evaluable: there were two complete responses, 15 partial responses for an objective RR of 51.5% (95% CI, 34.5-68.6%). Median PFS was 5.5 months (95% CI, 3.1-7.5 months) and median OS was 11.0 months (95% CI, 8.0-17.4 months). The most common grade 3-4 toxicities were: diarrhoea (24%), nausea/vomiting (11%), skin rash (8%) and peripheral neuropathy (8%). The frequency of alterations was KRAS mutations (8%), EGFR mutations (0%) and HER2 amplification (19%).

CONCLUSION

In patients with Eso/GEJ adenocarcinoma, mFOLFOX6 and erlotinib is active, has an acceptable toxicity profile and FOLFOX ± erlotinib could be considered for further development.

Biweekly cetuximab and irinotecan as second-line therapy in patients with gastro-esophageal cancer previously treated with platinum

BACKGROUND

Until recently there has been no proven second-line therapy for patients with advanced gastro-esophageal cancer (GEC). Since 2004, Denmark has had a national health program where non-proven therapy can be offered to patients with advanced cancer, after approval by an expert panel appointed by the National Board of Health. This program has accelerated the introduction and implementation of new therapies in Denmark. Inspired by therapy in metastatic colorectal cancer, a combination of cetuximab and irinotecan (Cetiri) was chosen for second-line therapy in GEC patients. We report our experience with Cetiri as second-line therapy in patients with GEC.

METHODS

All patients had histologically confirmed GEC and all patients had progressive disease during or after first-line platinum-containing chemotherapy. The patients received cetuximab 500 mg/m(2) on day 1 and irinotecan 180 mg/m(2) on day 1 every 2nd week until progression or unacceptable toxicity. Toxicity was prospectively evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 3.0.

RESULTS

From December 2007 to February 2009, 50 consecutive patients received Cetiri as second-line therapy. Median performance status (PS) was 1. The median number of courses was seven. Seven patients (14%) had a partial response. Median progression-free survival (PFS) was 3.3 months and overall survival (OS) was 5.5 months; two patients are still alive without progressive disease. Major toxicities were: diarrhea (8%), fatigue (10%), neutropenia (16%), and febrile neutropenia (2%).

CONCLUSION

Cetiri every two weeks is a convenient and well-tolerated second-line regimen in GEC patients. A promising effect was seen in patients with PS 0-1 and in patients who developed a rash.

TS and ERCC-1 mRNA expressions and clinical outcome in patients with metastatic colon cancer in CONFIRM-1 and -2 clinical trials

To validate established cutoff levels of thymidylate synthase (TS) and excision repair cross-complementing (ERCC-1) intratumoral mRNA expressions in tumor samples from metastatic colorectal cancer (mCRC) patients treated with PTK787/ZK222584 (PTK/ZK). From 122 samples of patients with mCRC enrolled in CONFIRM-1 (Colorectal Oral Novel Therapy for the Inhibition of Angiogenesis and Retarding of Metastases) or CONFIRM-2, mRNA was isolated of microdissected formalin-fixed paraffin-embedded samples and quantitated using TaqMan-based technology. Existing TS and ERCC-1 cutoff levels were tested for their prognostic value in first-line and second-line therapy. TS expression was associated with overall survival (OS) in first-line, but not second-line therapy. ERCC-1 was associated with OS in patients treated with first-line and second-line FOLFOX4. In first-line FOLFOX4, combination of high TS and/or high ERCC-1 was associated with shorter OS. A correlation was observed between ERCC-1 expression and benefit from PTK/ZK+FOLFOX4 treatment. TS and ERCC-1 expression is associated with clinical outcome in mCRC. Baseline TS and ERCC-1 levels may allow the selection of patients who benefit from FOLFOX4 chemotherapy.

Anti-HER agents in gastric cancer: from bench to bedside

Despite some advances in the past few years, the search for effective treatment modalities for advanced gastric and gastro-esophageal junction cancer is far from over. Available data clearly demonstrate that the development of new drugs will have little, if any, chance of success if it is not guided by in-depth knowledge of disease biology. However, using biologic agents to target key molecular pathways, such as those regulated by human epidermal growth factor receptor (HER) family members, may be effective. Indeed, the positive results achieved by the anti-HER2 agent trastuzumab in a phase III trial in HER2-positive patients support this approach. Many new anti-HER molecules are now under evaluation for the treatment of gastric and gastro-esophageal junction cancer, but so far attempts to identify reliable predictive factors from phase I and II trials have produced inconclusive results. In addition, large phase III trials are still being conducted in molecularly unselected populations. Refining patient selection is essential to maximize the benefit of targeted agents, to avoid significant toxicities and for the development of alternative therapeutic approaches in patients who have nonresponsive disease.

A multicenter phase II trial of single-agent cetuximab in advanced esophageal and gastric adenocarcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) is overexpressed in a significant proportion of esophageal and gastric carcinomas. Although previous studies have examined tyrosine kinase inhibitors of EGFR, there remains limited data regarding the role of EGFR-directed monoclonal antibody therapy in these malignancies. We carried out a multi-institutional phase II study of cetuximab, a monoclonal antibody against EGFR, in patients with unresectable or metastatic esophageal or gastric adenocarcinoma.

PATIENTS AND METHODS

Thirty-five patients with previously treated metastatic esophageal or gastric adenocarcinoma were treated with weekly cetuximab, at an initial dose of 400 mg/m(2) followed by weekly infusions at 250 mg/m(2). Patients were followed for toxicity, treatment response, and survival.

RESULTS

Treatment with cetuximab was well tolerated; no patients were taken off study due to drug-related adverse events. One (3%) partial treatment response was noted. Two (6%) patients had stable disease after 2 months of treatment. Median progression-free survival and overall survival were 1.6 and 3.1 months, respectively.

CONCLUSION

Although well tolerated, cetuximab administered as a single agent had minimal clinical activity in patients with metastatic esophageal and gastric adenocarcinoma. Ongoing studies of EGFR inhibitors in combination with other agents may define a role for these agents in the treatment of esophageal and gastric cancer.

Clinical significance of miR-146a in gastric cancer cases

PURPOSE

The profiles of microRNAs change significantly in gastric cancer. MiR-146a is reported to be a tumor suppressor in pancreatic cancer, breast cancer, and prostate cancer. We investigated the clinical significance of miR-146a in gastric cancer, in particular focusing on hypothetical miR-146a target genes, such as epidermal growth factor receptor (EGFR) and interleukin-1 receptor-associated kinase (IRAK1).

EXPERIMENTAL DESIGN

We examined miR-146a levels in 90 gastric cancer samples by q-real-time (qRT)-PCR and analyzed the association between miR-146a levels and clinicopathologic factors and prognosis. The regulation of EGFR and IRAK1 by miR-146a was examined with miR-146a-transfected gastric cancer cells. Moreover, we analyzed the association between miR-146a levels and the G/C single nucleotide polymorphism (SNP) within pre-miR-146a seed sequences in 76 gastric cancer samples, using direct sequencing of genomic DNA.

RESULTS

In 90 clinical samples of gastric cancer, miR-146a levels in cancer tissues were significantly lower than those in the corresponding noncancerous tissue (P < 0.001). Lower levels of miR-146a were associated with lymph node metastasis and venous invasion (P < 0.05). Moreover, a lower level of miR-146a was an independent prognostic factor for overall survival (P = 0.003). Ectopic expression of miR-146a inhibited migration and invasion and downregulated EGFR and IRAK1 expression in gastric cancer cells. In addition, G/C SNP within the pre-miR-146a seed sequence significantly reduced miR-146a levels in the GG genotype compared with the CC genotype.

CONCLUSIONS

MiR-146a contains an SNP, which is associated with mature miR-146a expression. MiR-146a targeting of EGFR and IRAK1 is an independent prognostic factor in gastric cancer cases.

An open-label, multicentre biomarker-oriented AIO phase II trial of sunitinib for patients with chemo-refractory advanced gastric cancer

BACKGROUND

Sunitinib monotherapy in pretreated patients with advanced gastric cancer (AGC) was investigated. Preplanned analyses of tumour biomarkers on treatment outcome were performed.

PATIENTS AND METHODS

Patients received sunitinib 50mg/day for 4 weeks with 2 weeks rest until disease progression or unacceptable toxicity. The primary end-point was objective response rate (ORR). Secondary end-points included progression-free survival (PFS), overall survival (OS) and safety.

RESULTS

Fifty-two patients were enrolled and treated (safety population, SP). In the intention to treat population (n=51); the ORR was 3.9%, median PFS was 1.28 months [95% CI, 1.18-1.90], median OS was 5.81 months [95% CI, 3.48-12.32], the estimated one-year survival rate was 23.7% [95%CI: 12.8-36.5]. In subgroup analyses, tumour VEGF-C expression compared with no expression was associated with significantly shorter median PFS (1.23 versus 2.86 months, logrank p=0.0119) but there was no difference in tumour control rate (p=0.142). In the SP, serious adverse events occurred in 26 patients, leading to 13 deaths, all sunitinib unrelated. Thirty-eight patients died from progressive disease, nine died <60 days after treatment start.

CONCLUSION

Sunitinib monotherapy was associated with limited tumour response and good/moderate tolerability in this setting.

Molecularly targeted therapy for gastric cancer: current status and future prospects

Gastric cancer remains the second leading cause of cancer death worldwide. Currently, chemotherapy is the mainstay of treatment for patients with metastatic gastric cancer. Although new chemotherapeutic regimens improved the survival of patients with advanced gastric cancer, the median survival in all randomized trials remains unsatisfactory. Novel treatment options are urgently needed to improve the outcome of patients with advanced gastric cancer. Understanding the molecular pathways that characterize cell growth, apoptosis, angiogenesis and invasion has enabled us to use new approaches to treat this disease in clinical situations. The aim of this review is to summarize the most recent publications on targeted therapies for advanced gastric cancer.

Targeted therapies for metastatic esophagogastric cancer

The prognosis and long-term survival for patients with metastatic esophagogastric cancer (EGC) is poor. Historically, the mainstay of treatment has been combination chemotherapy. More recently, a number of targeted therapies have been developed and are being studied with the goal of improving response rate and survival in patients with metastatic EGC. To date, the only targeted therapy which has been clinically approved is trastuzumab which targets the HER2/Neu oncogene. However, only a small group of patients with EGCs are HER2 amplified, and there are other important targets/pathways which play a role in the development of these cancers that are currently being studied. With the identification of these other clinically relevant pathways, it is anticipated that several other therapies will be approved in the future.

New trends in epidermal growth factor receptor-directed monoclonal antibodies

The epidermal growth factor receptor (EGFR) has been the focus of much attention in the age of targeted cancer therapeutics. In addition to its role in signal transduction under physiological conditions, it has been of interest because it is highly expressed in many tumor types and influences growth and survival in malignant states. Advances in the understanding of the EGFR and in genetic engineering have led to the development of monoclonal antibodies targeting the extracellular domain of the membrane-bound receptor. Cetuximab and panitumumab are the two most advanced such compounds. Thus far, cetuximab has achieved regulatory approval in metastatic colorectal cancer, and locally advanced and metastatic squamous cell cancer of the head and neck; panitumumab has been approved for metastatic colorectal cancer. This review will focus on the EGFR signaling network, monoclonal antibodies against EGFR and the pertinent clinical trials in this field of oncology using such agents.

Cetuximab enhances the activities of irinotecan on gastric cancer cell lines through downregulating the EGFR pathway upregulated by irinotecan

PURPOSE : Treatment effects of advanced gastric cancer (AGC) are unsatisfactory, and novel therapeutic approaches are much needed. The epidermal growth factor receptor (EGFR) monoclonal antibody cetuximab inhibits the growth of several human cancer cells but has been tested rarely for the treatment of GC. The synergy between cetuximab and irinotecan has been reported in colorectal cancer, but the mechanisms are still not fully clarified. Consequently, we hypothesized cetuximab/irinotecan combination should enhance the antitumor activity of irinotecan in GC cells. METHODS : The in vitro antiproliferative, pro-apoptotic, cell cycle arrest effects and induction of senescence were examined in SGC-7901 and MKN-45 GC cell lines. The effects of cetuximab or irinotecan as single agents or the combination on the expression of p53, p16, and EGFR signaling pathways were also studied. RESULTS : The study revealed that cetuximab alone did not show any antiproliferative, pro-apoptotic, cell cycle arrest or cellular senescence effect on GC cells but when combined with irinotecan synergistically inhibits GC cell proliferation and induces apoptosis and G2/M phase arrest. Irinotecan increases phosphorylation of EGFR, MAPK, and AKT and decreases the expression of P27(Kip1), which could be all abrogated by its combination with cetuximab. The combination could also inhibit the expression of Cyclin D1 and phosphorylated mTOR while had no impact on p53, p16, PTEN, and HIF-1alpha. CONCLUSIONS : Cetuximab enhances the activities of irinotecan on GC cells via the downregulation of the EGFR pathway upregulated by irinotecan. Combination therapy with cetuximab and irinotecan, a novel therapeutic approach, warrants further study in GC.

Oncogenic mutations in gastric cancer with microsatellite instability

AIM

Mitogen-activated protein kinase (MAPK) cascade and phosphatidylinositol 3-kinase (PI3K) survival pathways are frequently activated in the progression of gastrointestinal malignancies. In this study, we aimed to determine the frequency of gene mutations in members of these pathways--Epithelial Growth Factor Receptor (EGFR), KRAS, BRAF, PIK3CA and MLK3 in a series of 63 gastric carcinomas with high levels of microsatellite instability (MSI).

METHODS

Gene mutation analysis was performed by PCR amplification followed by direct sequencing. In selected tumour cases, EGFR expression was evaluated by immunohistochemistry. Association studies between molecular data and clinicopathologic characteristics were performed.

RESULTS

Mutations in EGFR (3'-untranslated region [UTR] polyA repeat), KRAS, PIK3CA and MLK3 genes occurred in 30 (47.6%), 11 (17.5%), 9 (14.3%) and 2 (3.2%) of the MSI gastric cancer (GC) cases, respectively. No BRAF or EGFR hotspot mutations were identified. Overall, mutations in at least one of these genes were found in 55.6% (35/63) of gastric carcinomas. From those mutant cases 40.0% (14/35) of them had concomitant gene mutations, always involving EGFR polyA deletions. Interestingly, we observed significant associations between oncogenic mutations and female gender (p = 0.046) old age of diagnosis (p = 0.001) and intestinal subtype (p = 0.043).

CONCLUSION

Our results show that MSI gastric carcinoma frequently shows activation of EGFR-MAPK and PI3K pathways. Within all alterations found, deletions of the A13 repeats of EGFR were common, suggesting this molecular event as an important biomarker for stratification of GC patients for treatment with EGFR inhibitors.

Cetuximab with irinotecan, folinic acid and 5-fluorouracil as first-line treatment in advanced gastroesophageal cancer: a prospective multi-center biomarker-oriented phase II study

BACKGROUND

Cetuximab plus irinotecan/folinic acid/5-fluorouracil (5-FU) (IF) was evaluated as first-line treatment of patients with advanced gastric cancer and gastroesophageal junction tumors. Preplanned analyses of the influence of tumor biomarkers on treatment outcome were carried out.

PATIENTS AND METHODS

Patients received weekly cetuximab (400 mg/m(2) on day 1, subsequently 250 mg/m(2)) plus irinotecan (80 mg/m(2)) and a 24-hour continuous infusion of folinic acid (200 mg/m(2)) and 5-FU (1500 mg/m(2)) on days 1, 8, 15, 22, 29 and 36 of a 50-day cycle, until progressive disease (PD).

RESULTS

The most common grade 3/4 toxic effects in 49 patients were diarrhea (15%) and skin toxic effects (14%). In 48 assessable patients, the overall response rate was 46% and disease control rate was 79%. Median progression-free survival (PFS) and overall survival (OS) was 9.0 months [95% confidence interval (CI) 7.1-15.6] and 16.5 months (95% CI 11.7-30.1), respectively. Tumor response was more common than nonresponse in epidermal growth factor receptor-expressing tumors (P = 0.041). Tumor PTEN expression was associated with longer PFS (P = 0.035) and OS (P = 0.0127) than no PTEN expression.

CONCLUSION

Cetuximab plus IF was well tolerated and efficacy data were encouraging. This treatment combination and the role of selected biomarkers are under investigation in the ongoing phase III EXPAND trial.

Phase II selection design trial of concurrent chemotherapy and cetuximab versus chemotherapy followed by cetuximab in advanced-stage non-small-cell lung cancer: Southwest Oncology Group study S0342

PURPOSE

Randomized clinical trials failed to show a survival benefit for epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors plus concurrent chemotherapy in patients with metastatic non-small-cell lung cancer (NSCLC), with preclinical data suggesting potential negative interactions. In contrast, pilot trials of the EGFR-targeted antibody, cetuximab, plus chemotherapy suggested enhanced antitumor activity. This randomized phase II trial was designed to select a cetuximab plus chemotherapy regimen for phase III evaluation.

PATIENTS AND METHODS

Treatment-naive patients with advanced-stage NSCLC were randomly assigned to receive paclitaxel (225 mg/m(2)) and carboplatin (area under the curve, 6) every 3 weeks plus concurrent cetuximab (400 mg/m(2) loading dose followed by 250 mg/m(2) weekly) for four cycles followed by maintenance cetuximab or sequential paclitaxel-carboplatin for four cycles followed by cetuximab.

RESULTS

Of 242 patients enrolled, 224 were eligible and assessable for response (106 and 118 patients in the concurrent and sequential arms, respectively). With a median follow-up time of 32 months, the median overall survival was 10.9 months (95% CI, 9.2 to 13.0 months) for patients receiving concurrent therapy and 10.7 months (95% CI, 8.5 to 12.8 months) for patients receiving sequential therapy (P = .57); 1-year survival rates were 45% (95% CI, 36% to 54%) and 44% (95% CI, 35% to 53%), respectively. Response rates and progression-free survival times were similar in both arms, as was grade 3 rash, whereas sensory neuropathy was higher in the concurrent arm (15% v 5% in the sequential arm; P = .036).

CONCLUSION

Although both regimens met the efficacy criterion for continued evaluation, the concurrent regimen of paclitaxel/carboplatin plus cetuximab was chosen.

New insights into the mechanisms of gastric cancer multidrug resistance and future perspectives

Gastric cancer is still the second leading cause of cancer death worldwide. Chemotherapy is one of the major treatment options for advanced gastric cancer. The efficacy of chemotherapy for gastric cancer is poor due to insensitivity and the development of multidrug resistance (MDR). Gastric cancer MDR involves a large number of molecules and complex mechanisms. Classical drug-resistant molecules, such as P-glycoprotein/ABCB1 and MRP1/ABCC1, have been found to play important roles in mediating MDR in some gastric cancers. In recent years, new molecules and mechanisms have been found to be associated with the development of gastric cancer MDR and might provide new targets for tackling gastric cancer MDR. Combined use of molecularly targeted therapy with chemotherapy may offer improved outcomes for gastric cancer patients and might provide new threads of hope for gastric cancer treatment.