88 Background: Over 1 million individuals worldwide annually are diagnosed with GECa. The majority of patients(pts) present with inoperable locally advanced or metastatic disease(dx). Even with resectable dx 5 year survival is low at ~40% with current best treatment (tx). Following initial platinum based therapy there is no established standard 2nd line tx. Besides HER2-directed therapy there has been little progress with targeted biologic agents. ICORG, the all-Ireland Cooperative Oncology Research Group investigated the utility of the tyrosine kinase inhibitor sorafenib in a multicentre trial. Methods: A prospective Phase II, nonrandomised, open label, one arm study of single agent sorafenib in the tx of platinum pre-treated relapsed GECa was conducted. Primary objective was dx control rate (DCR) post 4 months of tx. Secondary endpoints were OS, PFS, TTP, ORR, tolerability/toxicity and biomarkers of tx response/resistance. The protocol allowed for an interim analysis to be performed if clinically indicated. A sample size of 54 pts was identified using the single stage Fleming design approach to test whether the proportion responding, P, is ≤ 0.35 or ≥ 0.50. Pts received Sorafenib 400mg bid p.o. continuously q28days until dx progression or intolerable toxicity. Response by RECIST was evaluated by CT q8weeks. For pts with sufficient tumour samples translational studies were done. Results: An interim review performed in Nov 2012 (35 months post study opening) indicated that 33/41 evaluable pts recruited to date had progressed before completing 4 months of tx. Therefore, the number of evaluable pts with dx control could not reach the pre-specified figure of 22, & the hypothesis P >= 0.50 was rejected. Fifteen pts had just 1 cycle of tx, 5 of whom completed ≤ 2 weeks. A further 14 pts had 2 cycles. Median survival time to progression was 56 days (95% CI 53 – 59 days).Median OS was 120 days (95% CI 91 – 149 days). Safety data analyses and translational studies are ongoing and will be available for presentation at the meeting. Conclusions: Sorafenib as monotherapy is inactive in platinum pretreated pts with relapsed GECa. A significant unmet clinical need for novel effective therapies remains. Clinical trial information: 2008-005062-31.