e15013 Background: To date, few studies have investigated the use of cetuximab in combination with oxaliplatin and capecitabine in the first-line treatment of mCRC. We therefore conducted an uncontrolled, open-label, multicenter study to evaluate the efficacy and safety of this combination in this setting. Methods: Patients (pts) received intravenous (iv) oxaliplatin 130 mg/m2 (3h day 1) plus capecitabine 1,000 mg/m2 twice daily (days 1–14) every 3 weeks (XELOX) and cetuximab 400 mg/m2 iv week 1 then 250 mg/m2 weekly over 8 cycles. Treatment was continued until disease progression (PD), unacceptable toxicity or completion of therapy. Pts were followed until death. The primary endpoint was overall response rate (ORR). A sample size of 45 pts was necessary to obtain a 95% confidence interval (CI) for ORR with a maximum width of 15% assuming an ORR of 50–80%. Results: From Sept 2005-Jan 2007, 49 pts were enrolled (ITT population): 67% male, mean age 60 (range: 44–75) years, 56.3% ECOG PS 0. Of 42 pts evaluable for ORR, 4 (9.5%) achieved a complete response, 31 (73.8%) a partial response, 6 (14.3%) had stable disease and 1 (2.4%) had PD. The ORR was 83.3% (95% CI: 72.0–94.6%). Median time to progression was 9 months (95% CI: 7.1–10.9 months). Of the 49 pts evaluable for safety, 27 (55.1%) had at least one grade 3/4 toxicity, 42 (85.7%) had acne-like rash (8 pts [16.3%] grade 3). Most common grade 3/4 toxicities included diarrhea (n=9;18.4%) and changes in potassium (n=6;12.2%). 24 (3.4%) AEs led to dose reductions (12 unrelated, 10 unlikely and 2 definitely related to cetuximab), 56 (7.8%) led to a dose delay (12 unrelated, 28 unlikely, 8 possibly, 6 probably, 2 definitely related to cetuximab) and 2 (0.3%) led to infusion rate reduction (not treatment related). 27 (55.1%) pts discontinued therapy: 10 (20.4%) due to AEs, 7 (14.3%) PD, 10 (20.4%) other reasons. 33 (67.3%) pts died: 30 (61.2%) due to PD, 2 (4.1%) intercurrent event/disease, 1 (2.0%) acute pancreatitis. The results according with the HGFR evaluation by IHC will be presented. Conclusions: In this first-line mCRC study, 83.3% of pts treated with cetuximab, oxaliplatin and capecitabine achieved an overall response. This combination appears to be a highly active and well-tolerated regimen. No significant financial relationships to disclose.