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Advanced gastric and gastroesophageal junction cancers (GC/GEJCs) harbor diverse molecular signatures, highlighting the need for intricate evaluations to identify potential therapeutic targets. Although whole-transcriptome sequencing (WTS) has emerged as a useful tool for understanding these molecular intricacies, its clinical implications have yet to be fully elucidated. This study evaluated the correlation between immunohistochemistry (IHC) and WTS, compared their clinical significance, and identified potential therapeutic targets undetectable through IHC alone. We enrolled 140 patients with advanced GC/GEJC and assessed them using IHC for six pivotal biomarkers: claudin-18 (CLDN18), human epidermal growth factor receptor 2 (HER2), multiple receptor tyrosine kinases (RTKs), and programmed death ligand 1 (PD-L1). Concurrently, WTS was employed as part of the analyses in MONSTAR-SCREEN-2, a multicenter multiomics study. IHC analysis revealed 16.4% HER2, 39.3% CLDN18 (2+/3 + ≥75%), and 15.8% PD-L1 (combined positive score ≥ 10) positivity, among other molecular markers. Significant correlations were observed between IHC and WTS for all six pivotal biomarkers. Among nineteen HER2 IHC-positive patients treated with anti-HER2 therapeutics, ERBB2 status in WTS was significantly associated with progression-free survival (ERBB2-high vs. -low: median 9.0 vs. 5.6 months, log-rank p = 0.046). IHC-based molecular profiling revealed significantly high expression of CLDN18 in RTK-negative patients, with 78.4% positive for either CLDN18 or PD-L1. Additionally, WTS revealed elevated expression of pivotal biomarkers in patients displaying negative targetable biomarkers via IHC. Our findings highlighted the significant correlation between IHC and WTS, reinforcing the clinical utility of WTS. A subset with IHC-negative but WTS-positive status may benefit from specific biomarker-targeted therapies., (© 2024 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Background: Trifluridine/tipiracil plus VEGF inhibition with ramucirumab (RAM) for advanced gastric cancer (AGC) demonstrated clinical activity with an acceptable toxicity profile in previous phase II trial. However, little is known about its efficacy and safety in clinical practice in comparison with trifluridine/tipiracil monotherapy., Methods: We retrospectively investigated efficacy and safety of trifluridine/tipiracil plus RAM and trifluridine/tipiracil monotherapy as third or later line treatment for AGC patients., Results: Forty-one patients receiving trifluridine/tipiracil plus RAM and 60 patients receiving trifluridine/tipiracil monotherapy were analyzed. The objective response rate (ORR) and the disease control rate (DCR) were 13.5% and 64.9% in the trifluridine/tipiracil plus RAM group, and 3.8% and 42.3% in the trifluridine/tipiracil monotherapy group, respectively (ORR; P = 0.122, DCR; P = 0.052). The median progression-free survival (PFS) and the median overall survival (OS) were 3.0 months and 7.2 months in the trifluridine/tipiracil plus RAM group, and 1.8 months and 3.8 months in the trifluridine/tipiracil monotherapy group, respectively (HR for PFS = 0.66; P = 0.059, HR for OS = 0.50; P = 0.007). Multivariate analysis showed significantly longer PFS (HR = 0.52; P = 0.011) and OS (HR = 0.51; P = 0.031) in the trifluridine/tipiracil plus RAM group compared to the trifluridine/tipiracil monotherapy group. No unexpected adverse events were observed in both groups., Conclusions: Trifluridine/tipiracil plus RAM might show favorable anti-tumor activity with an acceptable toxicity profile in comparison with trifluridine/tipiracil monotherapy, suggesting one treatment option for AGC patients in salvage line. The combination needs further evaluation in ongoing randomized trials., (© 2023. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background: We conducted comprehensive clinical and molecular characterization of claudin 18.2 expression (CLDN18.2) in advanced gastric or gastroesophageal junction cancer (GC/GEJC)., Patients and Methods: Patients with advanced GC/GEJC who received systemic chemotherapy from October 2015 to December 2019 with available tumor specimens were analyzed. We evaluated clinicopathological features of CLDN18.2 expression with four molecular subtypes: mismatch repair deficient, Epstein-Barr virus-positive, human epidermal growth factor receptor 2-positive, and others. In addition, programmed death-ligand 1 (PD-L1) combined positive score (CPS), genomic alterations, and the expression of immune cell markers were assessed. Clinical outcomes of standard first- or second-line chemotherapy and subsequent anti-programmed cell death protein 1 (anti-PD-1) therapy were also investigated according to CLDN18.2 expression., Results: Among 408 patients, CLDN18.2-positive (moderate-to-strong expression in ≥75%) was identified in 98 patients (24.0%) with almost equal distribution in the four molecular subtypes or CPS subgroups. CLDN18.2-positive was associated with Borrmann type 4, KRAS amplification, low CD16, and high CD68 expression. Overall survival with first-line chemotherapy was not significantly different between CLDN18.2-positive and -negative groups [median 18.4 versus 20.1 months; hazard ratio 1.26 (95% confidence interval 0.89-1.78); P = 0.191] regardless of stratification by PD-L1 CPS ≥5. Progression-free survival and objective response rates of first- and second-line chemotherapy, and anti-PD-1 therapy also showed no significant differences according to CLDN18.2 status., Conclusions: CLDN18.2 expression in advanced GC/GEJC was associated with some clinical and molecular features but had no impact on treatment outcomes with chemotherapy or checkpoint inhibition. CLDN18.2-positive also had no impact on overall survival. This information could be useful to interpret the results from currently ongoing clinical trials of CLDN18.2-targeted therapies for advanced GC/GEJC and to consider a treatment strategy for CLDN18.2-positive GC/GEJC., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This phase I study was designed to: (1) determine the maximum tolerated dose (MTD) and recommended dose (RD) of the fibroblast growth factor receptor (FGFR) inhibitor futibatinib in Japanese patients with advanced solid tumors, and (2) examine the antitumor activity of the RD in patients with gastric cancer (GC) or other advanced solid tumors who have FGFR or FGF/FGFR abnormalities, respectively. In the dose-escalation phase, patients were assigned to 21-day cycles of oral futibatinib 8-160 mg three times a week (TIW) or 16 or 20 mg once daily (QD). In the expansion phase, patients received oral futibatinib 56, 80, or 120 mg TIW, or 16 or 20 mg QD. Eighty-three patients received futibatinib TIW (n = 40) or QD (n = 43). No dose-limiting toxicities were observed according to the final study protocol definition, and the MTD was not reached. The most common adverse events with both regimens were hyperphosphatemia (TIW, 82.5%; QD, 100.0%) and decreased appetite (TIW, 40.0%; QD, 58.1%). Hyperphosphatemia was asymptomatic, not leading to futibatinib discontinuation. The overall response rate (ORR) was 11.5% in patients with FGF/FGFR abnormalities. Notably, in GC patients harboring FGFR2 copy number (CN) ≥10, the ORR was 36.4% versus 0 in patients with CN <10. Therefore, futibatinib had a generally predictable and manageable safety profile in patients with advanced solid tumors. Antitumor activity was seen in patients with FGF/FGFR abnormalities, particularly those with GC and high FGFR2 CNs. Thus, futibatinib 20 mg QD was chosen as the RD for phase II studies., (© 2022 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Background: Although several randomized trials (RCTs) showed survival benefits of immune checkpoint inhibitor (ICI) plus first-line chemotherapy for advanced gastric or gastroesophageal cancer (AGC), these trials could enroll patients who fulfilled the strict eligibility criteria or waited for certain screening period for central assessment of PD-L1 status., Methods: We retrospectively compared characteristics and clinical outcomes of the patients with AGC who received first-line chemotherapy in control arm of RCTs with ICIs (control group) or clinical practice (practice group) at our institution from February 2016 to April 2019., Results: The control group had a better baseline Eastern Cooperative Oncology Group performance status (PS0, 81.2% vs. 51.4%, p < 0.001) and a longer interval from first visit to first-line chemotherapy initiation (19 days vs. 9 days, p < 0.001) than the practice group. Median overall survival (OS) was 20.3 months in control group and 15.7 months in practice group, with a trend of longer OS in control group than that in practice group (hazard ratio, 0.71; p = 0.062). More patients in control group were treated with subsequent chemotherapy including ICIs., Conclusion: Patients with AGC in RCTs of ICIs had a better PS or a higher chance to receive subsequent chemotherapy, resulting in a better prognosis than those treated in clinical practice. This information should be considered when interpreting RCT results and applying new treatments into clinical practice., (© 2022. The Author(s) under exclusive licence to Japan Society of Clinical Oncology.)

Purpose: We previously reported preliminary activity of regorafenib plus nivolumab (REGONIVO) or lenvatinib plus pembrolizumab (LENPEM) in advanced gastric cancer (AGC). Meanwhile, several studies demonstrated liver metastases are less responsive to immunotherapy., Patients and Methods: Combined efficacy outcomes with a longer follow-up in a phase Ib trial of REGONIVO and a phase II trial of LENPEM were examined in AGC with or without liver metastases (REGONIVO plus LENPEM cohort). We also investigated the efficacy of anti-PD-1 monotherapies (anti-PD-1 monotherapy cohort). A comparison of the immune microenvironment between gastric primary tumors and liver metastases was also conducted by multiplex IHC., Results: In the REGONIVO plus LENPEM cohort, with a median follow-up of 14.0 months, objective response rate (ORR), median progression-free survival (mPFS), and median overall survival (mOS) were 46%, 7.8 months, and 15.6 months in patients with liver metastases, while 69%, 6.9 months, and 15.5 months in those without. In the anti-PD-1 monotherapy cohort, with a median follow-up of 27.6 months, ORR, mPFS, and mOS were 9%, 1.4 months, and 6.4 months in patients with liver metastases, while 22%, 2.3 months, and 9.0 months in those without. Multiplex IHC revealed liver metastases were associated with an abundance of immune-suppressive cells, such as tumor-associated macrophages and regulatory T cells, with fewer CD8+ T cells compared with gastric primary tumors., Conclusions: Anti-PD-1 antibodies plus regorafenib or lenvatinib for AGC showed promising antitumor activity with a longer follow-up, irrespective of liver metastases status, despite a more immune-suppressive tumor microenvironment in liver metastases., (©2022 The Authors; Published by the American Association for Cancer Research.)

Background: Immune checkpoint inhibitors may enhance the efficacy of radiotherapy (RT) in cancer treatment but the effect remains unknown in metastatic gastric cancer (mGC). This study aimed to compare the tumor shrinkage by palliative RT for mGC patients with or without previous exposure to anti-PD-1 therapy., Methods: Data of 36 mGC patients who had received palliative RT from April 2013 to May 2019 were analyzed. Primary tumor responses were evaluated through a volumetric measurement-based method using computed tomography (CT) and endoscopic responses were evaluated in patients who underwent endoscopy before and after RT. Tumor microenvironment (TME) immune status was investigated by analyzing tumor-infiltrating lymphocytes by flow cytometry., Results: Among 36 patients, 18 had previous exposure to anti-PD-1 before RT showing no significant differences in baseline characteristics with the other 18 patients without exposure to anti-PD-1 treatment. Tumor responses were observed in 28% (5/18) and none (0/18) in the anti-PD-1-exposed vs. naïve group, respectively (P = 0.045). Five out of eight patients in the anti-PD-1-exposed group, who underwent endoscopy after RT showed partial response, but none in the anti-PD-1-naïve patients showed response (P = 0.026). Increase in the CD8 + T cell/effector regulatory T cell ratio in TILs after anti-PD-1 therapy was noted in three responders to RT, but not in the other three non-responders., Conclusions: Prior exposure to anti-PD-1 therapy increases tumor response to RT. Immune profiling suggests that anti-PD-1 therapy may enhance the efficacy of RT by immunoactivation in the TME.

Background: Pembrolizumab, an anti-PD-1 antibody, results in tumour response in around 15% of patients with advanced gastric cancer who have a PD-L1 combined positive score of at least 1. Lenvatinib, a multikinase inhibitor of VEGF receptors and other receptor tyrosine kinases, substantially decreased tumour-associated macrophages and increased infiltration of CD8 T cells, resulting in enhanced anti-tumour activity of PD-1 inhibitors in an in-vivo model. We aimed to assess the combination of lenvatinib plus pembrolizumab in patients with advanced gastric cancer in a phase 2 study., Methods: This study was an open-label, single-arm, phase 2 trial undertaken at the National Cancer Center Hospital East (Chiba, Japan). Eligible patients were aged 20 years or older and had metastatic or recurrent adenocarcinoma of the stomach or gastro-oesophageal junction, an Eastern Cooperative Oncology Group performance status of 0 or 1, and measurable disease according to the Response Evaluation Criteria in Solid Tumors (RECIST version 1.1), irrespective of the number of previous lines of treatment. Patients received 20 mg oral lenvatinib daily plus 200 mg intravenous pembrolizumab every 3 weeks until disease progression, development of intolerable toxicity, or withdrawal of consent. The primary endpoint was objective response rate according to RECIST, analysed in all patients who were eligible and received protocol treatment at least once. The safety analysis included all those who received protocol treatment at least once, regardless of eligibility. This study is registered at ClinicalTrials.gov, NCT03609359, and enrolment is complete., Findings: Between Oct 15, 2018, and March 25, 2019, 29 patients were enrolled in the first-line or second-line settings. At data cutoff (March 20, 2020), the median follow-up was 12·6 months (IQR 10·5-14·3). 20 (69%, 95% CI 49-85) of 29 patients had an objective response. The most common grade 3 treatment-related adverse events were hypertension (in 11 [38%] patients), proteinuria (five [17%]), and platelet count decrease (two [7%]). No grade 4 treatment-related adverse events, serious treatment-related adverse events, or treatment-related deaths occurred., Interpretation: Lenvatinib plus pembrolizumab showed promising anti-tumour activity with an acceptable safety profile in patients with advanced gastric cancer. On the basis of these results, a confirmatory trial will be planned in the future., Funding: Merck Sharp & Dohme., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: We evaluated the association between molecular subtypes of advanced gastric cancer (AGC) and the efficacy of standard chemotherapy or immune checkpoint inhibitors., Experimental Design: Patients with AGC who received systemic chemotherapy from October 2015 to July 2018 with available molecular features were analyzed. We investigated the efficacy of standard first- (fluoropyrimidine + platinum ± trastuzumab) and second-line (taxanes ± ramucirumab) chemotherapy, and subsequent anti-PD-1 therapy in patients with four molecular subtypes: MMR-D (mismatch repair deficient), EBV + , HER2 + , and all negative., Results: 410 patients were analyzed: MMR-D 5.9%, EBV + 4.1%, HER2 + 13.7%, and all negative 76.3%. In 285 patients who received standard first-line chemotherapy, the median progression-free survival (PFS) times were 4.2, 6.0, 7.5, and 7.6 months and the objective response rates (ORR) were 31%, 62%, 60%, and 49% in MMR-D, EBV + , HER2 + , and all-negative subtypes, respectively. Multivariate analysis showed shorter PFS in MMR-D versus all-negative patients [HR, 1.97; 95% CIs, 1.09-3.53; P = 0.022]. In second-line setting, there were no significant differences in efficacy. In 110 patients who received anti-PD-1 therapy, median PFS times were 13.0, 3.7, 1.6, and 1.9 months and the ORRs were 58%, 33%, 7%, and 13%, respectively. Twelve patients with MMR-D received subsequent anti-PD-1 therapy and showed longer PFS compared with that in 10 (83%) patients who received earlier-line chemotherapy., Conclusions: MMR-D might result in shorter PFS with first-line chemotherapy for AGC. Subsequent anti-PD-1 therapy achieved higher ORR and longer PFS than prior chemotherapy in most patients with MMR-D, supporting the earlier use of immune checkpoint inhibitors., (©2020 American Association for Cancer Research.)

Background: The efficacy and safety of chemotherapy (CTx) after anti-PD-1 therapy in patients with advanced gastric cancer (AGC) remains unclear., Methods: Medical records of consecutive patients with AGC treated with both CTx (taxanes plus ramucirumab, taxanes monotherapy or irinotecan) and anti-PD-1 therapy from June 2015 to April 2019 were retrospectively analysed. Patients were divided into two groups based on prior exposure to anti-PD-1 therapy: anti-PD-1-exposed and anti-PD-1-naïve groups. CTx-related outcomes were compared between two groups in the overall population and each CTx population., Results: In total, 233 patients (67 anti-PD-1-exposed, 166 anti-PD-1-naïve) were included. In the overall population, the objective response rate (ORR) to CTX was 44.6% in the anti-PD-1-exposed group and 19.6% in the anti-PD-1-naïve group (p=0.001); the median progression-free survivals (PFS) were 3.7 months and 3.3 months (HR=0.82, p=0.20), respectively. Among patients receiving taxanes plus ramucirumab (n=149), ORR (60.6% vs 20.0%, p<0.001) and median PFS (4.8 vs 3.4 months, p=0.004, HR=0.56) were significantly better in the anti-PD-1-exposed group (n=39) compared with the anti-PD-1-naïve group (n=110). These differences were not observed in patients receiving taxane monotherapy (n=34) or irinotecan (n=50). CTx after anti-PD-1 therapy showed no severe or unexpected adverse events., Conclusions: Prior anti-PD-1 therapy might increase tumour response to taxanes plus ramucirumab without unexpected adverse events, which warrants further investigations in a large cohort., Competing Interests: Competing interests: AK reports research funding from Ono, Sumitomo Dainippon and Taiho. TE, MO, SM and KS have nothing to disclose. YN reports research funding from Ono pharmaceutical and Taiho Pharmaceutical. DK reports receiving honoraria from Takeda, Chugai, Lilly, Merck Serono, Taiho and Sysmex. YK reports a consulting or advisory role for Takeda; personal fees from Bayer, Lilly, Taiho, MSD and Sanofi; and research funding from Astra Zeneca, Daiichi-Sankyo, Incyte, Taiho, Ono, Boehringer Ingelheim, Chugai, Amgen, Genmab and Takeda. HT reports grants and personal fees from Takeda, personal fees from Taiho, personal fees from Chugai, grants from Sysmex, grants from Daiichi-Sankyo. TK reports personal fees from MSD; and research funding from Astellas, Bristol-Myers Squibb, MSD, Oncolys BioPharma, Ono, Shionogi. TD reports a consulting or advisory role for AbbVie, Amgen, Bayer, Boehringer Ingelheim, Daiichi-Sankyo, MSD, Novartis, Sumitomo Dainippon, Rakuten Medical, Taiho and Takeda; honoraria from AbbVie, Astellas, Bristol-Myers Squibb, Oncolys Biopharma, Ono and Taiho; and research funding from AbbVie, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi-Sankyo, Eisai, Kyowa Hakko Kirin, Lilly, Merck Serono, MSD, Novartis, Pfizer, Quintiles, Sumitomo Group and Taiho. TY reports a consulting or advisory role for Chugai, Lilly, Merck Serono and Sanofi; honoraria from Chugai, Takeda, Eli Lily, Merck Biopharma; and research funding from Chugai, GlaxoSmithKline, MSD, Nippon Boehringer Ingelheim, Novartis, Sanofi, Ono, Daiichi-Sankyo, Parexel and Sumitomo Dainippon. KS reports paid consulting or advisory roles for Astellas, Lilly, Bristol-Myers Squibb, Takeda, Pfizer, Ono and MSD; honoraria from Novartis, AbbVie and Yakult; and research funding from Astellas, Lilly, Ono, Sumitomo Dainippon, Daiichi-Sankyo, Taiho, Chugai, MSD and Medi Science., (© Author (s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. Published by BMJ on behalf of the European Society for Medical Oncology.)

Background: Hyperprogressive disease (HPD) during treatment with anti-programmed death-1/programmed death-ligand 1 monoclonal antibodies has anecdotally been reported in some types of cancers, but is not well-characterized in patients with advanced gastric cancer (AGC)., Methods: Total 62 AGC patients treated with nivolumab in a single institution from September 2017 to April 2018 were enrolled in this study. Tumor responses were assessed according to Response Evaluation Criteria in Solid Tumors version 1.1, and HPD was defined as ≥ two fold increase in tumor growth rate. Clinicopathological and molecular characteristics associated with HPD were also investigated., Results: Thirteen of 62 patients (21%) developed HPD after nivolumab treatment. Overall survival (OS) and progression-free survival (PFS) were significantly shorter in patients with HPD than in patients without HPD (median OS: 2.3 months vs. not reached, P < 0.001; median PFS: 0.7 months vs. 2.4 months, P < 0.001). Liver metastases (77% vs. 41%), Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 1 or 2 (77% vs. 29%), and a large sum of target lesion diameters at baseline (median 104.2 mm vs. 44.9 mm) were significantly associated with HPD. Absolute neutrophil count (ANC) and C-reactive protein (CRP) level significantly increased in the first 4 weeks in only patients with HPD., Conclusions: HPD was observed in AGC patients treated with nivolumab and correlated with some clinicopathological characteristics. Elevations in ANC and CRP levels upon treatment might indicate HPD.

Background: Clinicopathological and molecular features of responders to nivolumab for advanced gastric cancer (AGC) are not well understood., Methods: Patients (pts) with AGC who were treated with nivolumab after two or more chemotherapy regimens in a single institution from September 2017 to May 2018 were enrolled in this study. PD-L1 expression in tumor cells (TC) and mismatch repair (MMR) were analyzed by immunohistochemistry. Epstein-Barr virus (EBV) was detected by in situ hybridization. Cancer genome alterations were evaluated by a next-generation sequencing-based panel. High tumor mutation burden (TMB) was defined as more than 10 mutations/megabase., Results: A total of 80 pts were analyzed in this study. Tumor response was evaluated in 72 pts with measurable lesions and 14 pts (19%) had an objective response. Overall response rate (ORR) was significantly higher in pts with ECOGPS 0 in those with PS 1 or 2, MMR-deficient (MMR-D) in those with MMR-proficient (MMR-P), PD-L1+ in TC in those with PD-L1- in TC and PIK3CA mutation in those with PIK3CA wild-type. ORR was 31% in pts with at least one of the following factors; MMR-D, high TMB, EBV+ and PD-L1+ in TC vs. 0% in those without these factors. Progression-free survival was significantly longer in pts with PS 0 than in those with PS 1 or 2, MMR-D than in those with MMR-P, and PD-L1+ in TC than in those with PD-L1- in TC., Conclusions: Some features were associated with favorable response to nivolumab for AGC. Combining these features might be useful to predict efficacy.

Background: Recently, the U.S. Food and Drug Administration approved pembrolizumab for patients (pts) with PD-L1-positive metastatic gastric cancer (MGC) based on 22C3 immunohistochemistry (IHC) assay. However, little is known about detailed clinicopathological features of 22C3 PD-L1 expression in MGC., Patients and Methods: Pts with histologically confirmed MGC were eligible for this prospective observational study. PD-L1 expression (22C3) on tumor cell (TC) or immune cell (IC) and mismatch repair (MMR) were analyzed by IHC. Epstein-Barr virus (EBV) was detected by in situ hybridization. The expressions of tyrosine kinase receptors (RTKs) and cancer genome alterations were evaluated by IHC or next-generation sequencing., Results: A total of 225 pts were analyzed in this study. PD-L1 expression on TC, PD-L1 on IC, MMR-deficient (D-MMR), and EBV positivity were identified in 8.4, 65.3, 6.2, and 6.2% cases, respectively. PD-L1 expression in TC was more frequently observed in pts with D-MMR (P < 0.001), PIK3CA mutation (P = 0.020), and KRAS mutation (P = 0.002), and PD-L1 on IC was associated with EBV positivity (P = 0.034), and lymph-node metastasis (P < 0.001). PD-L1 expression on either IC or TC was less frequently observed in pts with peritoneal metastasis and Borrmann Type 4. A significant association was not observed between PD-L1 expression and RTKs expression or presence of other gene alterations. PD-L1 expression on either TC or IC was not prognostic factor., Conclusions: 22C3 PD-L1 expression in MGC was associated with distinct clinicopathological features, but was not a prognostic factor.

Background: Fibroblast growth factor receptor (FGFR2) has been proposed as a target in gastric cancer. However, appropriate methods to select patients for anti-FGFR2 therapies have not yet been established., Methods: We used in situ techniques to investigate FGFR2 mRNA expression and gene amplification in a large cohort of 1036 Japanese gastric cancer patients. FGFR2 mRNA expression was determined by RNAscope. FGFR2 gene amplification was determined by dual-color in situ hybridization (DISH)., Results: We successfully analyzed 578 and 718 samples by DISH and RNAscope, respectively; 2% (12/578) showed strong FGFR2 gene amplification (FGFR2:CEN10 >10); moderate FGFR2 gene amplification (FGFR2:CEN10 <10; ≥2) was detected in 8% (47/578); and high FGFR2 mRNA expression of score 4 (>10 dots/cell and >10% of positive cells with dot clusters under a 20× objective) was seen in 4% (29/718). For 468 samples, both mRNA and DISH data were available. FGFR2 mRNA expression levels were associated with gene amplification; FGFR2 mRNA levels were highest in the highly amplified samples (n = 12). All highly amplified samples showed very strong FGFR2 mRNA expression (dense clusters of the signal visible under a 1× objective). Patients with very strong FGFR2 mRNA expression showed more homogeneous FGFR2 mRNA expression compared to patients with lower FGFGR2 mRNA expression. Gastric cancer patients with tumors that had an FGFR2 mRNA expression score of 4 had shorter RFS compared with score 0-3 patients., Conclusion: RNAscope and DISH are suitable methods to evaluate FGFR2 status in gastric cancer. Formalin-fixed paraffin-embedded (FFPE) tissue slides allowed evaluation of the intratumor heterogeneity of these FGFR2 biomarkers.

Background: Ramucirumab has recently proved to be effective for advanced or recurrent gastric cancer (AGC). Ascites and peritoneal metastasis are among the most common complications of AGC. However, there are few data on the safety and efficacy of paclitaxel plus ramucirumab in patients with AGC with ascites. The purpose of this retrospective study was to evaluate the safety and efficacy of paclitaxel plus ramucirumab in patients with AGC with ascites., Methods: We retrospectively evaluated the safety and efficacy of paclitaxel plus ramucirumab in patients with AGC with ascites in comparison with patients without ascites in a single institution from June 2015 to May 2016. The median progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method, and differences evaluated using the Log-lank test. The differences in baseline characteristics and response rates of each ascites group were calculated for homogeneity by chi-square tests and for trends by Fisher's exact test., Results: Eighty-three patients were analyzed in this study. Ascites was detected in 40 patients, 26 patients (31%) had small to moderate ascites and 14 (17%) had massive ascites. The proportion of patients who started with a reduced dose of paclitaxel was higher for patients with massive ascites than others. The frequencies of any grade 3 or 4 hematological toxicity were 51% in patients without ascites, 77% in patients with small to moderate ascites, and 71% in patients with massive ascites. The frequencies of common ramucirumab-related adverse events were also not significantly different among ascites groups, however one patient had a tumor hemorrhage, and one patient had a gastrointestinal perforation. PFS and OS were shorter in patients with massive ascites than in patients with small or moderate ascites or patients without ascites., Conclusions: The use of paclitaxel and ramucirumab in patients with AGC with large amounts of ascites was tolerable with adequate dose modification. However, we should pay attention to the risks of ramucirumab-related toxicity in patients with bleeding tumors or intestinal stenosis.

Background: Antibody-drug conjugates have emerged as a powerful strategy in cancer therapy and combine the ability of monoclonal antibodies to specifically target tumour cells with the highly potent killing activity of drugs with payloads too toxic for systemic administration. Trastuzumab deruxtecan (also known as DS-8201) is an antibody-drug conjugate comprised of a humanised antibody against HER2, a novel enzyme-cleavable linker, and a topoisomerase I inhibitor payload. We assessed its safety and tolerability in patients with advanced breast and gastric or gastro-oesophageal tumours., Methods: This was an open-label, dose-escalation phase 1 trial done at two study sites in Japan. Eligible patients were at least 20 years old with breast or gastric or gastro-oesophageal carcinomas refractory to standard therapy regardless of HER2 status. Participants received initial intravenous doses of trastuzumab deruxtecan from 0·8 to 8·0 mg/kg and dose-limiting toxicities were assessed over a 21-day cycle; thereafter, dose reductions were implemented as needed and patients were treated once every 3 weeks until they had unacceptable toxic effects or their disease progressed. Primary endpoints included identification of safety and the maximum tolerated dose or recommended phase 2 dosing and were analysed in all participants who received at least one dose of study drug. The dose-escalation study is the first part of a two-part study with the second dose-expansion part ongoing and enrolling patients as of July 8, 2017, in Japan and the USA. This trial is registered at ClinicalTrials.gov, number NCT02564900., Findings: Between Aug 28, 2015, and Aug 26, 2016, 24 patients were enrolled and received trastuzumab deruxtecan (n=3 for each of 0·8, 1·6, 3·2, and 8·0 mg/kg doses; n=6 for each of 5·4 and 6·4 mg/kg). Up to the study cutoff date of Feb 1, 2017, no dose-limiting toxic effects, substantial cardiovascular toxic effects, or deaths occurred. One patient was removed from the activity analysis because they had insufficient target lesions for analysis. The most common grade 3 adverse events were decreased lymphocyte (n=3) and decreased neutrophil count (n=2); and grade 4 anaemia was reported by one patient. Three serious adverse events-febrile neutropenia, intestinal perforation, and cholangitis-were reported by one patient each. Overall, in 23 evaluable patients, including six patients with low HER2-expressing tumours, ten patients achieved an objective response (43%, 95% CI 23·2-65·5). Disease control was achieved in 21 (91%; 95% CI 72·0-98·9) of 23 patients. Median follow-up time was 6·7 months (IQR 4·4-10·2), with nine (90%) of ten responses seen at doses of 5·4 mg/kg or greater., Interpretation: The maximum tolerated dose of trastuzumab deruxtecan was not reached. In this small, heavily pretreated study population, trastuzumab deruxtecan showed antitumour activity, even in low HER2-expressing tumours. Based on safety and activity, the most likely recommended phase 2 dosing is 5·4 or 6·4 mg/kg., Funding: Daiichi Sankyo Co, Ltd., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Antibodies against programmed death 1 (PD-1) and its ligand programmed death ligand 1 (PD-L1) have recently demonstrated promising results in gastric cancer (GC). PD-L1 expression, the presence of tumor-infiltrating lymphocytes (TILs), and mismatch repair (MMR) deficiency have been proposed as predictive biomarkers for anti-PD-1/PD-L1 antibodies. The aim of this study was to investigate the clinical relevance of PD-L1 expression with TIL, MMR, and Epstein-Barr virus (EBV) status in GC., Methods: We performed a tissue microarray analysis in 487 advanced GC patients who underwent gastrectomy. PD-L1 expression on tumor cells (TCs) and tumor-infiltrating immune cells (TIICs), the densities of TILs, and MMR status were evaluated by immunohistochemistry. EBV was detected by in situ hybridization., Results: PD-L1 expression on TCs and TIICs, MMR deficiency, and EBV positivity were identified in 22.8, 61.4, 5.1, and 5.1 % cases respectively. PD-L1 expression was more frequently observed in the elderly (TCs P = 0.002), in males (TCs P = 0.029; TIICs P = 0.043), in patients with poorly differentiated adenocarcinoma with solid-type histological features (TCs P < 0.001; TIICs P < 0.001), in patients with MMR deficiency (TCs P < 0.001; TIICs P < 0.001), and in patients with EBV positivity (TCs P = 0.001; TIICs P = 0.050). Strong association was observed between PD-L1 expression and high densities of CD3-positive, CD8-positive, or forkhead box P3 positive TILs (TCs P < 0.001; TIICs P < 0.001). Neither PD-L1 expression on TCs nor that on TIICs was an independent prognostic factor in multivariate analysis., Conclusions: In GC, PD-L1 expression was associated with distinct clinicopathological features, including high densities of TILs, MMR deficiency, and EBV positivity, but was not a prognostic factor.

Background: This study was conducted to investigate whether human epidermal growth factor receptor 2 (HER2) status, epidermal growth factor receptor (EGFR) status, and c-MET status are independent prognostic factors for advanced gastric cancer patients who received standard chemotherapy., Method: Unresectable or recurrent gastric or gastroesophageal junction cancer patients with histologically confirmed adenocarcinoma treated with S-1 plus cisplatin as first-line chemotherapy were eligible. Formalin-fixed paraffin-embedded tumor samples were examined for HER2, EGFR, and c-MET status using immunohistochemistry (IHC). Additionally, gene amplification was examined using fluorescent in situ hybridization (FISH) for HER2. Positivity was defined as an IHC score of 3+ or an IHC score of 2+/FISH positive for HER2, and an IHC score of 2+ or 3+ for both EGFR and c-MET., Results: Of the 293 patients from nine institutions, 43 (15%) were HER2 positive, 79 (27%) were EGFR positive, and 120 (41%) were c-MET positive. Ten patients (3%) showed positive co-expression of HER2, EGFR, and c-MET. After a median follow-up time of 58.4 months with 280 deaths, there was no significant difference in overall survival (OS) in terms of HER2 and EGFR status. However, there was a significant difference in OS between c-MET-positive and c-MET-negative patients [median, 11.9 months vs 14.2 months; hazard ratio, 1.31 (95% confidence interval, 1.03-1.67); log-rank P = 0.024]. Multivariate analysis also showed that c-MET positivity was still a prognostic factor for OS [hazard ratio, 1.30 (95% confidence interval, 1.02-1.67); P = 0.037]., Conclusions: The study suggested that c-MET-positive status had poor prognostic value. These data could be used as the basis for future clinical trials for targeting agents for advanced gastric cancer patients.

Background: In advanced gastric cancer (AGC), most clinical trials are designed on the basis of protein expression or gene amplification of specific genes. Recently, next-generation sequencing (NGS) allowed us to comprehensively profile the tumor gene status. This study aimed to elucidate the profiling between gene alterations and protein expression in AGC to aid in future clinical trials on AGC., Patients and Methods: Formalin-fixed, paraffin-embedded tumor samples from 121 stage III/IV gastric cancer patients were examined for protein expression of tyrosine kinase receptors (RTKs; ERBB2, EGFR, c-MET, and FGFR2) using immunohistochemistry (IHC). Furthermore, 409 cancer-related genes were sequenced to detect mutations and copy number variations using NGS., Results: Most ERBB2 overexpression (IHC 3+) cases (80.0%) had ERBB2 amplification and did not have other RTK amplification or oncogene mutations. However, one-fourth of MET overexpression cases (25.0%) had ERBB2 alterations. EGFR and FGFR2 overexpression cases had ERBB2 alterations or other gene alterations such as KRAS or PIK3CA. On the other hand, most of the four RTK amplification cases (88.2%) were mutually exclusive with each amplification. However, RTK amplification did not simply correlate with protein overexpression, whereas cases with RTK high-level amplification had protein overexpression and rarely showed other co-existing gene alterations., Conclusion: AGC involves a complicated arrangement of protein expression and gene alterations. Comprehensive analyses of NGS and IHC will be necessary to design the optimal therapy for treating the appropriate population of patients in future clinical trials., (© The Author 2015. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The cancer stroma, including cancer-associated fibroblasts (CAFs), is known to contribute to cancer cell progression and metastasis, suggesting that functional proteins expressed specifically in CAFs might be candidate molecular targets for cancer treatment. The purpose of the present study was to explore the possibility of using TEM1 (tumor endothelial marker 1), which is known to be expressed in several types of mesenchymal cells, as a molecular target by examining the impact of TEM1 expression on clinicopathological factors in gastric cancer patients. A total of 945 consecutive patients with gastric cancer who underwent surgery at the National Cancer Center Hospital East between January 2003 and July 2007 were examined using a tissue microarray approach. TEM1 expression in CAFs or vessel-associated cells was determined using immunohistochemical staining. Three items (CAF-TEM1-positivity, CAF-TEM1-intensity, and vessel-TEM1-intensity) were then examined to determine the correlations between the TEM1 expression status and the recurrence-free survival (RFS), overall survival (OS), cancer-related survival (COS), and other clinicopathological factors. Significant correlations between CAF-TEM1-positivity or CAF-TEM1-intensity and RFS, OS, or COS were observed (P < 0.001, Kaplan-Meier curves); however, no significant correlation between vessel-TEM1-intensity and RFS, OS, or COS was observed. A univariate analysis showed that CAF-TEM1-positivity and CAF-TEM1-intensity were each correlated with a scirrhous subtype, tumor depth, nodal status, distant metastasis, serosal invasion, lymphatic or venous vessel infiltrations, and pTMN stage. This study suggests that the inhibition of TEM1 expression specifically in the CAFs of gastric carcinoma might represent a new strategy for the treatment of gastric cancer., (© 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: Although patients with advanced gastric cancer (AGC) have a poor prognosis when conventional therapies fail, they are often candidates for phase I trials. However, there is no detailed report on clinical outcomes of patients with AGC treated in phase I trials., Methods: We retrospectively reviewed the medical records of 66 consecutive patients with AGC enrolled in phase I trials between March 2008 and July 2014 at our institution in Japan., Results: Median age was 66 years (range, 28-78 years) and median number of previous lines of conventional chemotherapy was 3 (range, 1-6). Five (8.6 %) and seven (12 %) patients showed objective response and stable disease >3 months, respectively. Although the time to treatment failure (TTF) of the best phase I treatment was shorter than that of the last line of conventional chemotherapy (median 1.5 vs. 2.3 months; P = 0.002), TTF of the best phase I treatment was longer than that of the last line of treatment in 21 patients (32 %). Severe adverse events and grade 3 or higher toxicities were reported in eight (12 %) and 13 patients (20 %), respectively. No treatment-related death was observed. Median survival time from the start of phase I treatment was 7.5 months, and four deaths (6 %) within 30 days after last administration were observed., Conclusion: Phase I trials of patients with AGC was acceptably feasible with some efficacy signal. Our results suggest that phase I trials might be one treatment option for patients with AGC when conventional therapies fail.

Unlabelled: The incidence of gastrointestinal bleeding, thromboembolic events and gastrointestinal perforation during chemotherapy with metastatic or unresectable gastric cancer has been unknown. To clarify the incidence of these events, we reviewed the clinical records of our hospital., Patients and Methods: We investigated metastatic or unresectable gastric cancer patients who received chemotherapy during January 2002 to December 2006. Grade≥3 (CTCAE v3.0) adverse events from the first day of chemotherapy to 1 month after the last day of chemotherapy were investigated., Results: A total of 292 patients received chemotherapy. Patient characteristics were as follows: median age 63.5 years (range, 28 to 87); performance status 0/1/2/3: 129/129/31/3; male: female, 206:86, histopathological type intestinal/diffuse/unclassified-adenocarcinoma/others: 91/139/58/4. We found the incidence of Grade≥3 gastrointestinal bleeding in 7 patients (2.4%), thromboembolic events in 5 patients (1.7%) and gastrointestinal perforation in 3 patients (1.0%). Thromboembolic events in patients under 55 years of age were associated with a higher incidence (p=0. 0046)., Conclusion: The incidence was not so high as expected. We should be aware of the frequency of these toxicities in the treatment of gastric cancer.