 This is a Phase 1, open-label, randomized, 2-sequence, cross-over, pharmacokinetic PK study evaluating the effect of the DPD inhibitory action of CDHP as an S-1 component compared with FT alone on the PK of 5-FU in patients with advanced solid tumors. The study will be conducted in 2 parts Cross-Over Pharmacokinetic Phase and S-1 Extension Phase. 