A drug used to treat certain types of non-small cell lung cancer. It is also used together with gemcitabine to treat pancreatic cancer and is being studied in the treatment of other types of cancer. OSI-774 is a type of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. Also called erlotinib, erlotinib hydrochloride, CP-358,774, and Tarceva.