7503 Background: EGFR tyrosine kinase activating mutations are present in 10-26% of NSCLC tumors and are associated with increased response to gefitinib and erlotinib. However, little is known about how the efficacy and safety profile of erlotinib compares with CT in EGFR-mutant Caucasian p. We have performed a prospective, randomized phase III study comparing erlotinib with platinum-based CT in chemonaive advanced NSCLC p with EGFR mutations. Methods: From February 2007 to January 2011, we screened 1,227 p for EGFR mutations, and 174 patients were randomly assigned to receive erlotinib or platinum-based CT. The primary endpoint was progression-free survival (PFS). Secondary endpoints included response, overall survival and toxicity profiles. Results: 153 p (76 CT, 77 erlotinib) are evaluable for the interim analysis. p characteristics CT arm: 16 males; median age, 64; never smokers, 56; PS 0, 26; PS 1, 41; adenocarcinoma, 67. p characteristics erlotinib arm: 25 males; median age, 65; never smokers, 54; PS 0, 23; PS 1, 44; adenocarcinoma, 73. Preliminary results of the interim analysis are now available. Response rate was 10.5% to CT vs 54.5% to erlotinib (P<0.0001). PFS in the CT arm was 5.2 months (m) (95%CI, 4.4-5.8 m) compared to 9.4 m (95%CI, 7.9-12.3) in the erlotinib arm (HR, 0.42; P<0.0001). Median survival was 18.8 m in the CT arm and 22.9 m in the erlotinib arm (HR, 0.80; P=0.42). Most common toxicities were asthenia (68.9%), anemia (45.9%), nausea (40.5%) and neutropenia (36.5%) in the CT arm, and diarrhea (57.3%), asthenia (53.3%), and rash (49.3%) in the erlotinib arm. Final results of the interim analysis will be presented. Conclusions: The EURTAC study met its primary endpoint at the interim analysis. Erlotinib as first-line treatment for advanced NSCLC p with EGFR mutations improves PFS, with acceptable toxicity, compared to platinum-based chemotherapy.