Role of plasma angiogenesis factors in the efficacy of first‐line chemotherapy combined with biologics in RAS wild‐type metastatic colorectal cancer: Results from the GI‐SCREEN CRC‐Ukit study

BACKGROUND: Several biomarkers have been established for metastatic colorectal cancer (mCRC). We investigated whether plasma angiogenesis factors could predict the efficacy of biologics combined with chemotherapy in first‐line (1L) treatment in patients with RAS wild‐type mCRC and the dynamics of plasma angiogenesis factors at progression during 1L treatment. METHODS: In this multicenter prospective observational study, serial plasma samples were prospectively collected at pretreatment and progression stages; 17 plasma angiogenesis factors were analyzed using the multiplex assay with Luminex® technology. Interactions between the pretreatment measurements and treatment groups on progression‐free survival (PFS) and overall survival (OS) in patients with RAS wild‐type were assessed using the propensity‐score weighted Cox proportional hazards model. RESULTS: From February 2018 to September 2020, 202 patients were enrolled in the 1L cohort; 133 patients had RAS wild‐type (chemotherapy plus bevacizumab [BEV group, n = 33] and plus anti‐epidermal growth factor receptor monoclonal antibodies [aEGFR group, n = 100]). A trend of strong interaction on PFS was observed for interleukin‐8 (IL‐8) (p = 0.0752) and soluble vascular cell adhesion molecule‐1 (sVCAM‐1) (p = 0.0156). Regarding OS, IL‐8 (p = 0.0283), soluble vascular endothelial growth factor‐receptor‐1 (sVEGFR‐1) (p = 0.0777) and sVCAM‐1 (p = 0.0011) tended to differentiate the treatment effect. In 112 patients, plasma samples were evaluable for dynamic analysis (57 and 55 from the BEV and aEGFR groups, respectively). In the BEV group, six factors significantly increased during progression, whereas two decreased. In the aEGFR group, three factors significantly increased, and six decreased. CONCLUSION: Pretreatment plasma IL‐8 and sVCAM‐1 levels could be predictive biomarkers to distinguish BEV and anti‐EGFR mAbs when combined with chemotherapy in the 1L treatment of RAS wild‐type mCRC. Several plasma angiogenesis factors showed significant change at progression in 1L chemotherapy plus biologics for RAS wild‐type mCRC, which are potential biomarkers for selecting an optimal angiogenesis inhibitor in second‐line treatment.