The importance of sequence in rescheduling bevacizumab and chemotherapy administration in the first-line treatment of metastatic colorectal carcinoma (mCRC).

617 Background: One of the proposed mechanisms of action for bevacizumab is by reducing the interstitial fluid pressure (IFP) allowing an increased penetration and uptake of chemotherapy agents in tumors. Clinical and laboratory data suggest that the decrease of IFP occurs after a few days of bevacizumab administration and intratumoral delivery of chemotherapy increase when bevacizumab precedes chemotherapy. We hypothesized that altering the schedule of BEV/FOLFOX regimen would improve the efficacy of the regimen and increase objective response rate. Methods: Patients (pts) with mCRC or locally advanced colorectal cancer, with ECOG PS 0-2 were eligible. The treatment schedule was Bevacizumab 5mg/Kg on day 1, standard FOLFOX-4 regimen on days 8-9 at cycles repeated every 14 days. Prior 5-FU/oxaliplatin adjuvant treatment was allowed. The pts were treated for 6 months or until reaching a plateau of response. Standard RECIST v1.1 response evaluation criteria were used. Primary endpoint of the study was the p...