Molecular predictors of combination targeted therapies (cetuximab, bevacizumab) in irinotecan-refractory colorectal cancer (BOND-2 study).

BACKGROUND To test whether intratumoral gene expression levels and germline polymorphisms predict clinical outcome in metastatic colorectal cancer (mCRC) patients treated with cetuximab and bevacizumab plus irinotecan (CBI) vs. cetuximab and bevacizumab (CB)(BOND2). PATIENTS AND METHODS Genomic DNA was extracted for genotyping from 65 patients (31: CBI arm and 34: CB arm). Thirty five patients had tissue samples available for the gene expression assay (18: CBI arm and 17: CB arm). RESULTS High intratumoral gene expression levels of EGFR, VEGFR2 and NRP1 were associated with longer overall survival (OS) in patients receiving combined monoclonal antibodies with or without irinotecan. FCGR3A V158F, CyclinD1 A870G and EGFR R497K polymorphisms are associated with clinical outcome in patients received combined cetuximab and bevacizumab. CONCLUSIONS Intratumoral gene expression levels of EGFR, VEGFR2 and NRP as well as polymorphisms in FCGR3A, CyclinD1 and EGFR could predict clinical outcome in mCRC patients enrolled in BOND2, independent of KRAS mutation status.