Gemcitabine and oxaliplatin (GEMOX) alone or with cetuximab in first-line treatment of advanced biliary cancers (ABC): Exploratory analyses according to tumor KRAS/BRAF mutations and EGFR expression in a randomized phase II trial (BINGO).

4127 Background: Gemcitabine-platinum regimens are the standard of care for ABC. Whether GEMOX- cetuximabmay be beneficial in ABC patients (pts) was tested in BINGO, an international, open-label, randomized phase II study (ASCO 2012). With a 4-month progression-free survival (PFS) rate of 63% [CI: 52-74], the primary endpoint was met (target, ≥60%; GEMOX, 54% [43-65]). However, median PFS (6.1 vs. 5.5 months) and overall survival (OS) (11.0 vs. 12.4 months) were similar in both arms. Available data on KRAS/BRAF mutation ratesin ABC pts are sparse. Methods: Planned exploratory endpoints included tumor KRAS/BRAF mutational status ( high-resolution meltingand DNA sequencing) and EGFR expression score (immunohistochemistry [IHC]), and their impact on patient outcome according to treatment arm. Results: Tumor samples were collected for 91 (61%) consenting pts among the 150 randomized pts, and were suitable for DNA analysis and IHC in 75 (50%) and 77(51%) pts, respectively. Tumor KRASand BRAF mutations (MT) w...