Inclusion Criteria:

• Histologically confirmed diagnosis of unresectable Stage IIIB or Stage IV relapsed or recurrent NSCLC.

• Subjects must have:

  1. documented (radiological or clinical) progressive disease (PD) following a prior response (including stable disease) to monotherapy with erlotinib or gefitinib that was administered for at least 12 weeks prior to progression OR
  2. a documented T790M EGFR mutation
• Measurable disease defined according to RECIST
• ECOG performance status of 0 or 1.
• Sexually active subjects must use an accepted method of contraception during the course of the study.
• Female subjects of childbearing potential must have a negative pregnancy test at enrollment.

Exclusion Criteria:

• Received radiation to ≥25% of his or her bone marrow within 30 days of XL647 treatment.
• Received erlotinib or gefitinib, or other anticancer therapy within 14 days of the first dose of study drug.
• Received an investigational drug (excluding erlotinib or gefitinib) within 30 days of the first dose of study drug.
• Receiving anticoagulation therapy with warfarin.
• Not recovered to Grade ≤1 from adverse events (AEs) due to antineoplastic agents, investigational drugs, or other medications that were administered prior to study enrollment.
• Corrected QT interval (QTc) of >0.45 seconds.
• Progressive, symptomatic, or hemorrhagic brain or leptomeningeal metastases.
• Requires steroid or anticonvulsant therapy for the treatment of brain metastases.