Many non-small cell lung cancers (NSCLC) contain a mutant form of a protein called epidermal growth factor receptor (EGFR) and are treated with drugs that target this protein. Erlotinib or afatinib are the typical first treatments, but the average response is only a year.
ASP8273 is a drug designed to block mutated EGFR permanently. Laboratory studies have shown that ASP8273 prevented the growth of tumor cells that expressed mutated EGFR and was effective after erlotinib or afatinib had stopped working.
The purpose of this study is to find the highest dose of ASP8273 that can be given safely in patients with NSCLC that expresses mutant EGFR and has grown despite prior therapy that targeted this protein. ASP8273 is taken orally (by mouth).