This is a Phase 2 and open-label (subject will know the treatment he or she is receiving) study. The subject will receive either Erlotinib alone or Erlotinib + CS-7017 in this study.

The study will determine what effect adding CS-7017 to Erlotinib has on safety and length of survival in subjects with advanced non-small cell lung cancer who failed the first treatment.

Inclusion Criteria:

• Histologically or cytologically confirmed stage IIIB or IV NSCLC.
• Recurrent disease (either no response to treatment or subsequent relapse after an objective response) that has progressed after first line therapy.
• Measurable disease according to Response Evaluation Criteria In Solid Tumors (RECIST) Version 1.1 criteria.
• ≥ 18 years of age.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2.
• Adequate organ and bone marrow function.
• Resolution of any toxic effects of prior therapy (except alopecia) to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), Version 4.0 grade ≤ 1.
• Agreement to use effective contraception while on treatment and for at least 3 months after end of treatment.

Exclusion Criteria:

• Treatment with anticancer therapy within 3 weeks before study treatment.
• Therapeutic or palliative radiation therapy within 2 weeks or major surgery within 4 weeks before study treatment (except for radiotherapy for brain metastases).
• Administration of other thiazolidinediones (TZDs) within 4 weeks before study treatment.
• Current need for concomitant use of other TZDs during the study.
• Uncontrolled infection requiring IV antibiotics, antivirals, or antifungals, known human immunodeficiency virus (HIV) infection, or active hepatitis B or C infection at time of screening.
• History of any of the following conditions within 6 months before initiating study treatment: diabetes mellitus requiring treatment with insulin or TZD agents; myocardial infarction with significant impairment of cardiac function; severe/unstable angina pectoris; coronary/peripheral artery bypass graft; New York Heart Association (NYHA) class III or IV congestive heart failure; malabsorption syndrome, chronic diarrhea (lasting > 4 weeks), inflammatory bowel disease, or partial bowel obstruction.
• Pericardial or pleural effusion (eg, requiring drainage) or pericardial involvement with the tumor. Participants with minimal pleural effusion may be eligible upon request by Investigator and approval by Sponsor.
• Pregnant or breast feeding.
• Prior treatment with epidermal growth factor receptor (EGFR) inhibitors.

De-identified individual participant data (IPD) and applicable supporting clinical trial documents may be available upon request at https://vivli.org/. In cases where clinical trial data and supporting documents are provided pursuant to our company policies and procedures, Daiichi Sankyo will continue to protect the privacy of our clinical trial participants. Details on data sharing criteria and the procedure for requesting access can be found at this web address: https://vivli.org/ourmember/daiichi-sankyo/

Studies for which the medicine and indication have received European Union (EU) and United States (US), and/or Japan (JP) marketing approval on or after 01 January 2014 or by the US or EU or JP Health Authorities when regulatory submissions in all regions are not planned and after the primary study results have been accepted for publication.

Formal request from qualified scientific and medical researchers on IPD and clinical study documents from clinical trials supporting products submitted and licensed in the United States, the European Union and/or Japan from 01 January 2014 and beyond for the purpose of conducting legitimate research. This must be consistent with the principle of safeguarding study participants' privacy and consistent with provision of informed consent.