Afatinib is a quinazoline compound having a 3-chloro-4-fluoroanilino group at the 4-position, a 4-dimethylamino-trans-but-2-enamido group at the 6-position, and an (S)-tetrahydrofuran-3-yloxy group at the 7-position. Used (as its dimaleate salt) for the first-line treatment of patients with metastatic non-small cell lung cancer. It has a role as a tyrosine kinase inhibitor and an antineoplastic agent. It is a member of quinazolines, a member of furans, an organofluorine compound, an enamide, an aromatic ether, a tertiary amino compound, a member of monochlorobenzenes and a secondary carboxamide.