Advanced lung cancer (non-small cell lung cancer) with a mutation in the EGFR (epidermal growth factor receptor) gene, which have disease progression after treatment with an EGFR inhibitor (erlotinib or gefitinib), and have progression of disease also after treatment with chemotherapy will be recruited. The trial has only one arm, of afatinib daily treatment. Blood and exhaled breath samples will be collected for investigations aiming to identify factors that predict response to afatinib.

Inclusion Criteria:

• Advanced NSCLC
• EGFR mutation or six months or longer benefit from EGFR TKIs
• Disease progression on chemotherapy, or inability to receive chemotherapy for medical reasons.
• Disease progression on EGFR TKI, or the presence of an EGFR mutation that does predicts for poor response to first generation EGFR TKIs.

Exclusion Criteria:

• Inability to take oral drugs