This study consists of Phase I and Phase II.~The objectives of Phase I are to determine the following in patients with non-small cell lung cancer (NSCLC) harboring EGFR activating mutations.~safety and tolerability of ASP8273.~the maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) of ASP8273 based on the dose limiting toxicity (DLT) profile.~pharmacokinetics (PK) of ASP8273.~antitumor activity of ASP8273.~The objectives of Phase II are to determine the following at the RP2D of ASP8273 in patients with NSCLC harboring EGFR mutation.~efficacy of ASP8273~safety of ASP8273~PK of ASP8273
Purpose of the study is to determine the following in patients with non-small cell lung cancer (NSCLC) harboring EGFR activating mutations.~the safety and tolerability of ASP8273.~the pharmacokinetics (PK) of ASP8273.~the antitumor activity of ASP8273.