New developments and standard of care in the management of advanced gastric cancer.

Advanced gastric adenocarcinoma is a common disease with a poor prognosis whose treatment has for decades been based on cytotoxic chemotherapy, including platinum salts in first-line, and taxane or irinotecan in second or later line. Recent years have seen the emergence of new drugs that have improved patient survival, such as trastuzumab in first-line for HER2-positive tumors, ramucirumab alone or in combination with paclitaxel in second-line, and trifluridine-tipiracil beyond the second-line treatment. More recently, two monoclonal antibodies have demonstrated their efficacy in combination with oxaliplatin-based first-line chemotherapy, nivolumab (anti-PD1) for PD-L1 CPS ≥5 tumors, and zolbetuximab for tumors overexpressing Claudin 18.2. In addition, regorafenib has been also showed effective in phase 3 trial for heavily pretreated patients. Based on phase 2 studies, trastuzumab-deruxtecan was approved in 2022 by the EMA for HER2-positive pretreated patients. This agent is currently evaluated in phase 3 study (DESTINY-Gastric04 trial), as are several other anti-HER2 (zanidatamab, margetuximab, tucatinib), immune checkpoint inhibitors, or targeted therapies (anti-FGFR2b).

Targeting HGF/c-Met Axis Decreases Circulating Regulatory T Cells Accumulation in Gastric Cancer Patients.

Elucidating mechanisms involved in tumor-induced immunosuppression is of great interest since it could help to improve cancer immunotherapy efficacy. Here we show that Hepatocyte Growth Factor (HGF), a pro-tumoral and proangiogenic factor, and its receptor c-Met are involved in regulatory T cells (Treg) accumulation in the peripheral blood of gastric cancer (GC) patients. We observed that c-Met is expressed on circulating monocytes from GC patients. The elevated expression on monocytes is associated with clinical parameters linked to an aggressive disease phenotype and correlates with a worse prognosis. Monocyte-derived dendritic cells from GC patients differentiated in the presence of HGF adopt a regulatory phenotype with a lower expression of co-stimulatory molecules, impaired maturation capacities, and an increased ability to produce interleukin-10 and to induce Treg differentiation in vitro. In the MEGA-ACCORD20-PRODIGE17 trial, GC patients received an anti-HGF antibody treatment (rilotumumab), which had been described to have an anti-angiogenic activity by decreasing proliferation of endothelial cells and tube formation. Rilotumumab decreased circulating Treg in GC patients. Thus, we identified that HGF indirectly triggers Treg accumulation via c-Met-expressing monocytes in the peripheral blood of GC patients. Our study provides arguments for potential alternative use of HGF/c-Met targeted therapies based on their immunomodulatory properties which could lead to the development of new therapeutic associations in cancer patients, for example with immune checkpoint inhibitors.

Direct and Indirect Modulation of T Cells by VEGF-A Counteracted by Anti-Angiogenic Treatment.

Vascular endothelial growth factor A is known to play a central role in tumor angiogenesis. Several studies showed that VEGF-A is also an immunosuppressive factor. In tumor-bearing hosts, VEGF-A can modulate immune cells (DC, MDSC, TAM) to induce the accumulation of regulatory T-cells while simultaneously inhibiting T-cell functions. Furthermore, VEGFR-2 expression on activated T-cells and FoxP3high regulatory T-cells also allow a direct effect of VEGF-A. Anti-angiogenic agents targeting VEGF-A/VEGFR contribute to limit tumor-induced immunosuppression. Based on interesting preclinical studies, many clinical trials have been conducted to investigate the efficacy of anti-VEGF-A/VEGFR treatments combined with immune checkpoint blockade leading to the approvement of these associations in different tumor locations. In this review, we focus on the impact of VEGF-A on immune cells especially regulatory and effector T-cells and different therapeutic strategies to restore an antitumor immunity.

Human Epidermal Growth Factor Receptor 2 (HER2) in Advanced Gastric Cancer: Current Knowledge and Future Perspectives.

The discovery of human epidermal growth factor receptor 2 (HER2) overexpression in 15-20% of gastric adenocarcinomas has been a key advance in the global care of this disease. Validated by the ToGA trial in the first-line setting of advanced HER2-positive (+) gastric cancer (GC), trastuzumab, an anti-HER2 monoclonal antibody (mAb), was the first therapeutic agent to significantly improve the prognosis of these patients. Since these results, many attempts have been made to improve the clinical outcomes of patients with HER2+ GC. However, all the other HER2-targeting molecules have failed to show a survival benefit in large phase III studies. The value of continuing trastuzumab after disease progression has been suggested by several retrospective studies. However, recent results of a randomized phase II trial showed no benefit from this strategy. On the other hand, novel therapeutic methods, such as immunotherapy, are emerging as new tools in the strategy of care of advanced GC, even if their benefit in the specific HER2+ population remains undetermined. Furthermore, substantial progress has been made in the understanding of the mechanisms leading to resistance to anti-HER2 therapies, and in the screening methods to detect them, thus opening new perspectives. The aim of this review was firstly to summarize the existing data on the specific strategy of care of HER2+ advanced GC, and secondly, to describe current knowledge regarding the potential mechanisms of resistance to HER2-targeting therapies. Lastly, we report the prospects for overcoming these potential obstacles, from future therapeutic strategies to new detection methods.

Efficacy of a docetaxel-5FU-oxaliplatin regimen (TEFOX) in first-line treatment of advanced gastric signet ring cell carcinoma: an AGEO multicentre study.

BACKGROUND: Triplet chemotherapy, with docetaxel-5FU-oxaliplatin (TEFOX), has yielded promising results in patients with advanced and operable gastric adenocarcinoma. This may prove useful in treating signet ring cell carcinoma (SRCC), which is known to be chemoresistant and has a poor prognosis. We therefore evaluated TEFOX in patients with untreated advanced SRCC. METHODS: Patients with metastatic or locally advanced non-resectable SRCC were treated with TEFOX. Chemotherapy was administered every 14 days, with combined docetaxel (50 mg/m2) and oxaliplatin (85 mg/m2) followed by 5FU (2400 mg/m2). RESULTS: Among 65 patients enrolled, including 17 with linitis plastica, ORR and DCR were 66.1% and 87.6%, respectively. Median PFS and OS were 9.7 months (95% CI [6.9-11.4]) and 14.3 months (95% CI [11.6-21.6]) respectively. Twenty-six patients (40%) initially considered as unresectable had secondary resection (n = 24) or radiotherapy (n = 2) with curative intent, with median PFS and OS of 12.4 and 26.2 months, respectively. CONCLUSIONS: TEFOX appears to be effective as first-line treatment in advanced gastric SRCC and has an acceptable safety profile. It allowed a curative intent approach in 40% of patients. Considering the low chemosensitivity of SRCC reported with other chemotherapy regimens and pending for randomised studies, TEFOX might be an option in advanced gastric SRCC.

Trastuzumab in Combination with FOLFIRI in Patients with Advanced HER2-Positive Gastro-Esophageal Adenocarcinoma: A Retrospective Multicenter AGEO Study.

BACKGROUND: Trastuzumab with fluoropyrimidine and cisplatin is the standard first-line treatment in patients with HER2-positive advanced gastro-esophageal adenocarcinoma. However, there are no safety and efficacy data of trastuzumab with FOLFIRI. OBJECTIVE: To evaluate safety and efficacy of FOLFIRI plus trastuzumab in patients with HER2-positive advanced gastro-esophageal adenocarcinoma. PATIENTS AND METHODS: This retrospective multicenter study included all consecutive patients with HER2-positive advanced gastro-esophageal adenocarcinoma treated with FOLFIRI plus trastuzumab between 2012 and 2015. RESULTS: A total of 33 patients (median age, 60.3; performance status 0-1, 78.8%) with HER2-positive advanced gastro-esophageal adenocarcinoma treated with FOLFIRI plus trastuzumab in first (n = 3), second (n = 20) or third (n = 10) line of chemotherapy were included. There was one case of a severe non-hematological adverse event corresponding to a left ventricular systolic dysfunction. The most common hematological grade 3 or 4 adverse events were neutropenia (12.9%) and thrombocytopenia (6.4%). There was no febrile neutropenia. For patients treated with FOLFIRI plus trastuzumab in second-line chemotherapy, the median overall survival was 9.5 months. CONCLUSIONS: This is the first western population-based study of FOLFIRI plus trastuzumab reporting a satisfactory safety profile and a potential efficacy in advanced HER2-positive gastric cancer.

Trastuzumab beyond progression in patients with HER2-positive advanced gastric adenocarcinoma: a multicenter AGEO study.

INTRODUCTION: Trastuzumab in combination with platinum-based chemotherapy is the standard first-line regimen in HER2-positive advanced gastric cancer. However, there are very few data concerning efficacy of continuing trastuzumab beyond first-line progression. METHODS: This retrospective multicenter study included all consecutive patients with HER2-positive advanced gastric or gastro-esophageal junction (GEJ) adenocarcinoma who received a second-line of chemotherapy with or without trastuzumab after progression on platinum-based chemotherapy plus trastuzumab. Progression-free survival (PFS) and overall survival (OS) were estimated from the start of second-line chemotherapy using the Kaplan-Meier method and compared using log-rank test. The prognostic variables with P values ≤ 0.05 in univariate analysis were eligible for the Cox multivariable regression model. RESULTS: From May 2010 to December 2015, 104 patients were included (median age, 60.8 years; male, 78.8%; ECOG performance status [PS] 0-1, 71.2%). The continuation (n=39) versus discontinuation (n=65) of trastuzumab beyond progression was significantly associated with an improvement of median PFS (4.4 versus 2.3 months; P=0.002) and OS (12.6 versus 6.1 months; P=0.001. In the multivariate analysis including the ECOG PS, number of metastatic sites and measurable disease, the continuation of trastuzumab beyond progression remained significantly associated with longer PFS (HR, 0.56; 95% CI, 0.35-0.89; P=0.01) and OS (HR, 0.47; 95% CI, 0.28-0.79; P=0.004). CONCLUSION: This study suggests that continuation of trastuzumab beyond progression has clinical benefit in patients with HER2-positive advanced gastric cancer. These results deserve a prospective randomized validation.