7019 Background: Modest benefits from concurrent chemoradiotherapy (CRT) in patients with locally advanced NSCLC warrant more effective treatment regimen. Cetuximab, a monoclonal antibody against the epidermal growth factor receptor has shown activity in NSCLC. Feasibility data and toxicity have been published previously. We report treatment outcome of a multicenter phase II study of the combination of high dose accelerated RT and daily dose cisplatin with or without weekly cetuximab. Methods: Patients with locally advanced NSCLC received accelerated RT (66 Gy in 24 fractions) and concurrent daily cisplatin (6 mg/m2) with (Arm A) or without (Arm B) additional weekly cetuximab (400 mg/m2 loading dose one week prior to the RT start followed by weekly 250 mg/m2). The Objective Local Response Control (OLRC) was determined at 6 and 24 weeks after treatment using response evaluation criteria in solid tumours criteria. Results: Between Feb 2009 and May 2011, 102 patients were included. Median follow-up was 13 months. Patients and tumor characteristics are shows in the Table. Stage distribution was: II (8%), IIIa (51%), and IIIb (40%). The CRT was well tolerated. The OLRC at 24 weeks was 79% in Arm A and 80% in Arm B. The one-year progression free survival and overall survival were 58% (45%-76%) and 76% (64%-91%) for Arm A and 49% (35%-68%) and 72% (58%-89%) for Arm B respectively. Conclusions: The addition of cetuximab to low dose cisplation CRT does not improve OLRC in an unselected patient cohort but data on longterm disease control and survival are to be awaited. [Table: see text]