Apatinib Versus Bevacizumab in Second-line Therapy for Colorectal Cancer(ABST-C)

Bevacizumab, as an antibody of vascular endothelial generated factor (VEGF), combined with the fluorouracil-based chemotherapy regimens for metastatic colorectal cancer, has become the classical first-line treatment. However, vast majority of patients eventually will suffer progression disease. The second-line treatment includes replacing chemotherapy regimens whistle continuing bevacizumab or other anti-VEGF antibodies, such as Aflibercept and Ramucirumab. Apatinib is a small molecule tyrosine kinase inhibitor (TKI), which can highly selectively bind to and strongly block VEGF receptor 2 (VEGFR - 2), also potently suppress the activities of Ret, c-kit and c-src, resulting in reduced cell migration, proliferation, and tumor microvascular density mediated by VEGF .There are already robust data showing that antibodies aimed at blocking VEGF signaling pathways combined with chemotherapy to treat advanced colorectal cancer is superior as compared to chemotherapy alone. Thus, we hypothesize that the effect of using the second-line chemotherapy regimens combined with apatinib may be superior to those combined with bevacizumab. In this study,the patients who have progressed following or on first-line oxaliplatin and 5-FU combined with bevacizumab are randomised into two arms. Patients in the experimental arm receive second-line FOLFIRI combined with apatinib and those in the control arm receive second-line FOLFIRI combined with bevacizumab. To compare the efficacy and safety of the two arms, progression-free survival(PFS) is the primary end point.If apatinib is superior to bevacizumab in the second-line setting,it is one possible option of anti-angiogenic therapy in combination with second-line FOLFIRI for treatment of advanced colorectal cancer.