A Study of ASP8273 in Subjects With Non-small Cell Lung Cancer (NSCLC) Harboring Epidermal Growth Factor Receptor (EGFR) Mutations

Study and subjects will be divided into two phases: a pharmacokinetic (PK) and a postpharmacokinetic phase. The pharmacokinetic phase will follow a randomized, 2 period, 2 sequence single dose crossover design. Each period will be 5 days in duration. Within the sequence, both an ASP8273 tablet and ASP8273 capsule will be administered under fasted condition. The postpharmacokinetic phase will consist of up to 1 cycle (28 days) of continuous once daily dosing in post PK phase with ASP8273 capsules. Dose modifications are allowed if necessary in post PK phase and they follow a step-wise dose reduction. Subject is able to re-escalate dose level if reaction is stable.