Understanding Mechanisms of Acquired Resistance to BIBW2992

Inclusion Criteria: * Participants must have histologically or cytologically confirmed stage IIIB, IV or recurrent non-small cell lung cancer * A somatic mutation in epidermal growth factor receptor (EGFR) must be present as documented by a CLIA-certified laboratory * There must be radiographic measurable or evaluable disease * Participants must be willing, at the time of signing consent, to agree to a future biopsy of their tumor tissue at the time of disease progression, provided such a biopsy is safe and feasible at that time. * Performance status must be 0, 1 or 2 on the Eastern Cooperative Oncology Group scale * 18 years of age or older * Normal organ and marrow function as outlined in the protocol * Women of child-bearing potential and men must agree to use adequate contraception prior to study entry and for the duration of study participation Exclusion Criteria: * Prior EGFR tyrosine kinase inhibitor therapy (including gefitinib, erlotinib, or any experimental EGFR TKI agents) * Known brain metastases, unless they have undergone definitive therapy and are neurologically stable at the time of study entry * Standard chemotherapy or radiation less than 2 weeks of starting BIBW 2992, or experimental systemic cancer therapy less then 4 weeks of starting BIBW 2992. Note that prior palliative radiation to bony disease, CNS disease, or a limited thoracic area is allowed if there is measurable or progressive disease outside the field of radiation. * Another malignancy within the last 3 years (except for non-melanoma skin cancer or a non-invasive/in situ cancer) * Known pre-existing and clinically active interstitial lung disease * Significant gastrointestinal disorders with diarrhea as a major symptom * History of clinically relevant cardiovascular abnormalities such as uncontrolled hypertension, congestive heart failure NYHA classification of 3, unstable angina or poorly controlled arrhythmia, or myocardial infarction within 6 months * Cardiac left ventricular function with resting ejection fraction \<50% * Any other concomitant serious illness or organ system dysfunction which in the opinion of the investigator would either compromise patient safety or interfere with the evaluation of the safety of the study drug * Pregnancy or breast feeding * History of allergic reactions attributed to compounds of similar chemical or biologic composition of BIBW 2992 * Life expectancy of \< 12 weeks