ERBB2 and non-small cell lung carcinoma: The orally bioavailable reversible inhibitor, erlotinib, is FDA-approved for the treatment of NSCLC, and its closely related cousin, gefitinib, is approved for multiple solid tumors in countries outside the U.S. Afatinib is a second-generation, irreversible EGFR/ErbB2 inhibitor that has recently gained FDA approval for EGFR-mutant NSCLC along with a companion diagnostic test to determine the EGFR mutation status62,.63