On April 16, 2010, the U. S. Food and Drug Administration (FDA) approved erlotinib tablets (Tarceva®; OSI Pharmaceuticals, Inc., Melville, NY) for maintenance treatment of patients with stage IIIB/IV non-small cell lung cancer (NSCLC) whose disease had not progressed after four cycles of platinum-based first-line chemotherapy. In total, 889 patients received either erlotinib (150 mg) or placebo once daily. Progression-free survival (PFS), in all patients and in patients with epidermal growth factor receptor (EGFR)(+) tumors by immunohistochemistry (IHC), was the primary efficacy endpoint. Overall survival (OS) was a secondary sponsor endpoint but was the primary regulatory endpoint. Median PFS times were 2.8 months and 2.6 months in the erlotinib and placebo arms, respectively (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.62-0.82; p < .001). Median OS times were 12.0 months and 11.0 months, favoring erlotinib (HR, 0.81; 95% CI, 0.70-0.95). The PFS and OS HRs in patients with EGFR(+) tumors by IHC were 0.69 (95% CI, 0.58-0.82) and 0.77 (95% CI, 0.64-0.93), respectively. The PFS and OS HRs in patients with EGFR(-) tumors by IHC were 0.77 (95% CI, 0.51-1.14) and 0.91 (95% CI, 0.59-1.38), respectively. Following disease progression, 57% of placebo-treated patients received additional chemotherapy, compared with 47% of erlotinib-treated patients. Fourteen percent of placebo-treated patients received erlotinib or gefitinib, 31% received docetaxel, and 14% received pemetrexed. In total, 59% of placebo-treated patients who received treatment received FDA approved second-line NSCLC drugs. The most common adverse reactions in patients receiving erlotinib were rash and diarrhea.