TRIGGER is the acronym for an open-label, single-arm, phase II multi-center study of erlotinib (Tarceva) treatment in patients with locally advanced or metastatic (stages IIIB-IV) NSCLC who have not received previous chemotherapy for their disease and who present activating mutations in EGFR. The primary objective of the TRIGGER study is to evaluate the efficacy of erlotinib (Tarceva; 150 mg) on 12-month progression-free survival (PFS). The gene discussed is EGFR; the disease is non-small cell lung carcinoma.