e14517 Background: Inspired by the promising results seen in patients (pts) with chemo-resistant metastatic colorectal cancer we evaluated a biweekly schedule of cetuximab (cet) and irinotecan (iri) - (Cetiri) (Pfeiffer et al. Ann Oncol 2008) in platinum resistant GEC. Methods: We treated and evaluated 111 consecutive pts with histological verified GEC adenocarcinoma and documented failure to first-line platinum-based treatment. Pts received cet 500 mg/m2 and iri 180 mg/m2 day 1 every 2nd week until progression or unacceptable toxicity. Toxicity was evaluated according to NCI-CTCAE v. 3.0. Response rate (RR) was evaluated according to RECIST v. 1.0 every 8th week. Clinical parameters and blood samples at baseline were analyzed in order to find prognostic and predictive values for prolonged overall survival (OS). Results: Pts were included from December 2007 to August 2010. Median age was 63 years (range 33-81). Performance status (PS) was 0-1 in 95 % of the pts. Thirty-six (46%) pts had more than two organs involved. Median number of courses were 5 (1-46). RR was 13% (13 PR) and 48 % had stable disease for at least 2 months. Median PFS and OS were 3.3 months (CI 2-4) and 5.6 months (CI: 5-7) respectively. Seventy six (68%) pts had treatment induced skin toxicity, rash. In a univariate analysis PS 0-1, normal baseline haematology and skin rash was associated with significantly increased survival. These parameters retained significance in a multivariate analysis. One patient had a curative intended resection after 28 courses and had an overall survival at 29.5 months. Two pts are still alive. Conclusions: Biweekly Cetiri is a convenient and well-tolerated second-line (SL) regimen in pts with GEC adenocarcinoma. Good PS, normal baseline haematology and development of skin rash indicate increased survival. Based on our findings biweekly Cetiri can be recommended as SL treatment to GEC pts in a good PS. Further studies into the role of rash are warranted.