Bevacizumab (BEV) continued beyond first progression in patients (pts) with metastatic colorectal cancer (mCRC) previously treated with BEV + chemotherapy (CT): Biomarker findings from ML18147.

452 Background: In ML18147, BEV + standard CT was continued as 2nd-line treatment for pts with mCRC progressing after 1st-line BEV + CT. ML18147 met its primary and secondary endpoints and had a comprehensive biomarker programme, including exploratory analyses of immunohistochemistry (IHC) and single nucleotide polymorphisms (SNPs). Methods: Tumour samples were analysed by IHC for VEGFA, VEGFR1, VEGFR2 and neuropilin-1; H-scores were generated. Tumor angiogenesis was determined by stereological analysis of CD31-stained microvessels; 183 SNPs of 30 mainly angiogenesis-related genes were genotyped. We assessed consistency of treatment effect point estimates, i.e. hazard ratios (HRs) on the same side of 1. Analyses were not adjusted for multiple testing or powered to detect statistically significant treatment by biomarker interactions. Results: IHC data were available for 213 pts (26% of ITT population) and SNP data for 274 pts (33% of ITT). There was no significant evidence of biomarker expression levels or...