This open-label, sequential, ascending, multi-dose, Phase 1 study will enroll up to 72 subjects with previously treated advanced solid tumor. Subjects at each dose level will receive KW-2450 orally, once daily for 28 days followed by a 1-week observation period. After completing the 1 week observation period, all subjects will receive KW-2450 on a continuous daily schedule. All doses of KW-2450 will be administered to subjects under overnight fasting conditions.