Background: Dovitinib (TKI258) is an investigational multi-targeting tyrosine kinase inhibitor with potent inhibitory activity against several class III,IV,V RTKs relevant in cancer, including VEGF receptors-1,2,3, bFGF receptors-1,2,3, PDGFR and c-KIT. The addition of bevacizumab to chemotherapy is presently employed in management of colorectal cancer but did not improve survival in gastric cancer (AVAGAST). FGF pathway activation has been related to aggressive gastric and colorectal cancer, resistance to anti-VEGF therapy may be mediated in part by FGF upregulation. FGFR2 amplification is reported in subsets of gastric cancer (Hara et al. Lab Invest (1998) 78(9):1143-53). FGFR2 is required for cell proliferation and survival in FGFR2 amplified gastric cancer cell lines (Kunli et al. Cancer Rsch (2008) 68; 2340), which are sensitive to FGFR2 inhibitors, including Dovitinib. Methods: This trial is a single arm open label phase I trial in patients with treatment naïve advanced gastric or colorectal cancer. We will employ the standard “3+3” phase I dose escalation design to determine the recommended phase II dose of dovitinib in combination with standard doses of capecitabine (1000mg/m2 bid d1-d14 q21) and oxaliplatin (130mg/m2 q21). 4 dose levels of dovitinib (5 days on, 2 days off: 200mg, 300mg,400mg,500mg) and a dose level minus 1 have been defined. In a dose expansion cohort, 12 patients with advanced gastric or gastroesophageal adenocarcinoma will be treated with dovitinib, capecitabine and oxaliplatin at the recommended phase II dose (RP2D). Our secondary objectives are to describe the toxic effects and pharmacokinetics of dovitinib when administered in combination with capecitabine/oxaliplatin and identify any activity of the TKI258/XELOX treatment combination in gastric and colorectal cancer. Exploratory pharmacodynamic investigations as well as molecular studies to deeply characterize patient tumors will be performed.