Gefitinib (INN, /ɡɛˈfɪtɨnɪb/, trade name Iressa, marketed by AstraZeneca and Teva), is a drug used for certain breast, lung and other cancers. Gefitinib is an EGFR inhibitor, like erlotinib, which interrupts signaling through the epidermal growth factor receptor (EGFR) in target cells. Therefore, it is only effective in cancers with mutated and overactive EGFR.
Read more about Gefitinib: Mechanism of Action, Clinical Uses, Studies, Adverse Effects