A Study of ASP2215 in Combination With Erlotinib in Subjects With Epidermal Growth Factor Receptor (EGFR) Activating Mutation-Positive (EGFRm+) Advanced Non-Small-Cell Lung Cancer (NSCLC) Who Have Acquired Resistance to an EGFR Tyrosine Kinase Inhibitor (TKI)

IInclusion Criteria:

* Participant had histologically or cytologically confirmed metastatic or locally advanced, unresectable non-small-cell lung cancer (NSCLC).
* Participant had a documented exon 19 deletion or exon 21 L858R EGFR activating mutation.
* Participant had received prior treatment with any EGFR tyrosine kinase inhibitor
* Participant had Eastern Cooperative Oncology Group (ECOG) performance status of less than or equal to 2 at screening.
* Participant had adequate organ function.
* Female participant must either:

  * Be of nonchildbearing potential:
  * Or, if of childbearing potential,

    1. Agree not to try to become pregnant during the study and for 45 days after the final study drug administration
    2. And had a negative serum pregnancy test at screening
    3. And, if heterosexually active, agreed to consistently use 2 forms of highly effective birth control
* Male participant and their female spouse/partners who were of childbearing potential must be using highly effective contraception consisting of 2 forms of birth control
* Phase 1b Participants only:

  * Participant was not expected to show a therapeutic response to existing available treatment.
  * Intervening anticancer treatment subsequent to the EGFR TKI was allowed (but not required).
* Additional inclusion criteria for phase 2 Participants only:

  * Participant had a NSCLC tissue sample obtained after participant developed resistance to EGFR TKI therapy that was available for central testing.
  * Participant's baseline tumor specimen (obtained after participant developed resistance to EGFR TKI therapy) is T790M negative.
  * Participant received an EGFR TKI for at least 6 months and progressed on this therapy within the past 28 days.
  * Participant had not had any intervening anticancer treatment subsequent to the EGFR TKI with the exception of radiotherapy which was allowed if it occurred at least 14 days prior to the first dose of study drug.
  * Participant had at least 1 measureable lesion (not including any lesion that was irradiated) based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

Exclusion Criteria:

* Participant had an ongoing toxicity greater than or equal to grade 3 (NCI CTCAE version 4.03) attributable to prior NSCLC treatment at the time of screening.
* Participant received any agent with antitumor activity (other than an EGFR inhibitor, including a T790M inhibitor) including chemotherapy, radiotherapy, immunotherapy, within 14 days prior to the first dose of study drug (palliative radiotherapy is allowed).
* Participant received ASP2215 previously.
* Participant received blood transfusions or hematopoietic growth factor therapy within 14 days prior to the first dose of study drug.
* Participant had a major surgical procedure (other than study-related biopsy) within 14 days prior to the first dose of study drug, or a major surgical procedure was planned to occur during the study.
* Participant had active hepatitis B or C or other active hepatic disorder.
* Participant t was known to have human immunodeficiency virus (HIV) infection.
* Participant had symptomatic central nervous system (CNS) metastasis. Participants with asymptomatic, untreated CNS metastases were allowed. Participants with previously treated and currently asymptomatic CNS metastases were eligible provided they met the following:

  * Any whole brain radiotherapy (WBRT) was completed at least 2 weeks prior to the first dose of study drug.
  * Any stereotactic radiosurgery (SRS) was completed at least 1 week prior to the first dose of study drug.
  * Participant did not require steroids or did not require escalating doses of steroids for at least 2 weeks prior to the first dose of study drug.
* Participant had evidence of active infection requiring systemic therapy within 14 days prior to the first dose of study drug.
* Participant had uncontrolled hypertension.
* Participant had severe or uncontrolled systemic diseases or active bleeding diatheses.
* Participant had history of drug-induced interstitial lung disease or any evidence of active interstitial lung disease.
* Participant had ongoing cardiac arrhythmia (including atrial fibrillation) that was grade ≥ 2.
* Participant currently had Class 3 or 4 New York Heart Association congestive heart failure.
* Participant had history of severe/unstable angina, myocardial infarction or cerebrovascular accident within 6 months prior to the first dose of study drug.
* Participant had history of gastrointestinal ulcer within 28 days prior to the first dose of study drug.
* Participant had a history of gastrointestinal bleeding within 90 days prior to the first dose of study drug.
* Participant had concurrent corneal disorder or any ophthalmologic condition which makes the participant unsuitable for study participation .
* Participant had any condition which made the participant unsuitable for study participation.
* Participant had hypokalemia or hypomagnesemia at screening.
* Participant had QTcF interval \> 450 ms on 12-lead ECG at screening.
* Participant was known to have long QT syndrome.
* Participant was taking medication known to prolong the QT interval.