Abstract The receptor tyrosine kinase c-Met and its ligand hepatocyte growth factor (HGF) play important roles in cell growth, migration, and survival. Dysregulation of the c-Met/HGF signaling pathway has been found in many human malignancies. LY2801653 was identified and developed as a novel, potent, and orally active small molecule inhibitor of human c-Met. It demonstrated dose dependent inhibition of c-Met phosphorylation in xenograft tumors with a long lasting PD effect. In the current study, the anti-tumor activity of LY2801653 was evaluated in a panel of human patient derived xenograft models. LY2801653 displayed potent anti-tumor efficacy in a number of non small cell lung, renal, pancreatic, and breast tumor models. Examination of c-Met expression in these tumors by immunohistochemistry (IHC) revealed a good correlation between response and c-Met expression in the tumor tissue. Interestingly, the two non small cell lung adenocarcinoma models LXFA526 and LXFA1647 that were resistant to EGFR inhibitors Cetuximab and Erlotinib, displayed high sensitivity towards LY2801653. High level of genomic amplification of c-Met locus was found in these models, consistent with the hypothesis that c-Met activation represents one of the resistant mechanisms to EGFR inhibition. LY2801653 treatment led to increase in functional vessel areas, and decrease in tumor hypoxia. Enhanced anti-tumor efficacy was achieved when Erlotinib was combined with LY2801653. In summary, these results demonstrated the promising therapeutic potential of LY2801653 in mono and combination therapy of cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3611.