Sorafenib Plus S-1 in Advanced Solid Tumors

Primary Objective: 1. To define the recommended dose for phase II study of S-1 combined with sorafenib 2. To evaluate the dose-limiting toxicities of the combination therapy Secondary Objectives: 1. To characterize the pharmacokinetics (PK) of sorafenib and S-1 in the combination therapy 2. To investigate the impact of genetic polymorphisms of metabolic genes on the PK of sorafenib and S-1, respectively, as well as on the toxicity profile of the combination. 3. To determine the changes of biomarkers between pre- and post-treatments.