Capillary density has no value as an early biomarker of bevacizumab efficacy in metastatic colorectal cancers: a prospective clinical trial

BACKGROUND: Bevacizumab is a recombinant humanized monoclonal immunoglobulin G1 antibody targeting VEGF-A. It is currently used with chemotherapy as the first- or second-line therapy in metastatic colorectal cancer. Previous studies have showed that anti-angiogenic agents decrease capillary density. We evaluated the link between decreased capillary density and the response to bevacizumab-based chemotherapy. RESULTS: Overall, 43 patients with metastatic colorectal cancer treated with first-line bevacizumab-based chemotherapy were enrolled. At Day 90, progressive disease was observed in 12 patients (27.9%). All patients presented decreased capillary density. ROC analysis at different time points and capillary density variation showed a poor diagnostic performance regarding response at Day 90. MATERIALS AND METHODS: From 2013 to 2015, patients with metastatic colorectal cancer treated in our French cancer care center and eligible for bevacizumab with chemotherapy were enrolled in a prospective single-center study. Capillary density was assessed using capillaroscopy at Day 1, Day 15 and Day 30. Response to bevacizumab was assessed at Day90 according to CHUN criteria. CONCLUSIONS: Capillary density measured using capillaroscopy is not a good predictor of the early response to bevacizumab-based chemotherapy. (NCT01810744).