A Phase Ib/II Study Evaluating the Combination of Weekly Docetaxel and Cisplatin Together with Capecitabine and Bevacizumab in Patients with Advanced Esophago-Gastric Cancer

Recent Trends and Advancements in the Diagnosis and Management of Gastric Cancer

Gastric cancer is an enigmatic malignancy that has recently been shown to be increasing in incidence globally. There has been recent progress in emerging technologies for the diagnosis and treatment of the disease. Improvements in non-invasive diagnostic techniques with serological tests and biomarkers have led to decreased use of invasive procedures such as endoscopy. A multidisciplinary approach is used to treat gastric cancer, with recent significant advancements in systemic therapies used in combination with cytotoxic chemotherapies. New therapeutic targets have been identified and clinical trials are taking place to assess their efficacy and safety. In this review, we provide an overview of the current and emerging treatment strategies and diagnostic techniques for gastric cancer.

Anti-angiogenic therapies for gastric cancer

Tumor angiogenesis plays an important role in cancer cell proliferation and metastasis. In gastric cancer, among the numerous clinical trials investigating various anti-angiogenic therapies, such as antivascular endothelial growth factor (VEGF) or anti-VEGF receptor (VEGFR)-2 monoclonal antibodies, VEGF-Trap and VEGFR tyrosine kinase inhibitors, the anti-VEGFR-2 antibody ramucirumab was shown to prolong overall survival not only as a single agent but also in combination with paclitaxel as a second-line chemotherapy. Additionally, apatinib, a selective VEGFR-2 tyrosine kinase inhibitor, prolonged survival as a third-line or later treatment option in patients with advanced gastric cancer. Preliminary results of studies investigating ramucirumab plus immune checkpoint inhibitors in gastric cancer were encouraging, and further investigations are ongoing. In China, apatinib in combination with cytotoxic agents is being investigated for systemic chemotherapy or maintenance therapy as an earlier treatment option. The clinical activity in gastric cancer of the multikinase inhibitor regorafenib was suggested in a randomized phase II study. A global phase III trial comparing regorafenib with placebo is currently ongoing. Further studies of anti-angiogenic therapy combined with not only chemotherapy but also immune checkpoint inhibitors are also being pursued, providing hope for improved survival in patients with gastric cancer.

A systematic review and meta-analysis on the effect of angiogenesis blockade for the treatment of gastric cancer

Introduction

To date, anti-vascular endothelial growth factor (VEGF) monoclonal antibody (mAb, bevacizumab), anti-VEGF receptor mAb (ramucirumab) and selective vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (sunitinib, sorafenib and apatinib) have been tested in the clinical trials.

Materials and methods

In the current study, results of 32 clinical trials (24 Phase I or II, 8 Phase III) were systematically reviewed and meta-analysis was performed in 8 Phase III trial results.

Results

It was found that median overall survival (OS) time and progression-free survival (PFS) time were significantly longer in the patients treated with antiangiogenic reagents compared to that in the patients with placebo when all of 8 Phase III clinical trials were analyzed together (OS: odds ratio = 0.805, 95% CI: 0.719–0.901, P < 0.001; PFS: odds ratio = 0.719, 95% CI: 0.533–969, P = 0.030).

Conclusion

Meta-analysis on bevacizumab (4 out 8 Phase III trials) indicated that neither OS nor PFS was significantly different between the groups treated with bevacizumab or placebo with or without combination of other chemotherapeutic reagents (OS: odds ratio = 0.909, 95% CI: 0.780–1.059, P = 0.221; PFS: odds ratio = 0.985, 95% CI: 0.865–1.122, P = 0.826). By contrast, meta-analysis on ramucirumab (3 out of 8 Phase III trials) revealed that ramucirumab was significantly favored in the treatment of gastric cancer with significant different OS between the two groups (odds ratio = 0.720, 95% CI: 0.604–0.858, P < 0.001). In addition, patients treated with VEGF or VEGFR blockers had higher morbidity of hypertension and neutropenia, but lower risk of side effects of vomiting and anemia. These findings suggest that addition of antiangiogenesis reagents, especially anti-VEGFR-mAb, to the first- or second-line chemotherapy could prolong patient’s OS and PFS time in the advanced or metastatic gastric cancer.

Regorafenib inhibited gastric cancer cells growth and invasion via CXCR4 activated Wnt pathway

AIM

Regorafenib is an oral small-molecule multi kinase inhibitor. Recently, several clinical trials have revealed that regorafenib has an anti-tumor activity in gastric cancer. However, only part of patients benefit from regorafenib, and the mechanisms of regorafenib's anti-tumor effect need further demonstrating. In this study, we would assess the potential anti-tumor effects and the underlying mechanisms of regorafenib in gastric cancer cells, and explore novel biomarkers for patients selecting of regorafenib.

METHODS

The anti-tumor effects of regorafenib on gastric cancer cells were analyzed via cell proliferation and invasion. The underlying mechanisms were demonstrated using molecular biology techniques.

RESULTS

We found that regorafenib inhibited cell proliferation and invasion at the concentration of 20μmol/L and in a dose dependent manner. The anti-tumor effects of regorafenib related to the decreased expression of CXCR4, and elevated expression and activation of CXCR4 could reverse the inhibition effect of regorafenib on gastric cancer cells. Further studies revealed that regorafenib reduced the transcriptional activity of Wnt/β-Catenin pathway and led to decreased expression of Wnt pathway target genes, while overexpression and activation of CXCR4 could attenuate the inhibition effect of regorafenib on Wnt/β-Catenin pathway.

CONCLUSIONS

Our findings demonstrated that regorafenib effectively inhibited cell proliferation and invasion of gastric cancer cells via decreasing the expression of CXCR4 and further reducing the transcriptional activity of Wnt/β-Catenin pathway.