3704 Background: FOLFOX-4 recently emerged as standard chemotherapy for mCRC. Over the last 4 years we have been reporting encouraging results with FFG and thus began a randomized trial of FFG v. FOLFOX (2005 ASCO/GI poster). Bevacizumab was added to both arms since. Methods: Fifty four out of 190 planned pts are evaluable now. Interim analysis will be after enrollment of 90 pts. Median age is 64, PS 0–1 and 50% of pts have at least 3 metastatic tumors. RECIST criteria is used for the evaluation of response. Bevacizumab 5mg/kg.b.w. is given IV q. 2 weeks. FFG as described before is given weekly x 6 q. 8 weeks: Folinic Acid 100mg/m2 IV/60min., 5-FU 450mg/m2 IVP and Gemcitabine 900mg/m2 IV/90min. FOLFOX-4 is given according to standard criteria. All pts in main institution have blood and/or tumor tissue analysis for circulating tumor cells (CTC), microarrays and pharmacogenomics. Twenty ml of blood are drawn into sodium heparinized tube. A novel cell adhesion matrix (CAM) is used to detect the presence of viable CTC and a population of CAM reactive leucocytes. Results: The overall response rate is 30% (1CR, 7PR) and 26% (1CR, 6PR) for FFG and FOLFOX respectively. The clinical benefit, CR+PR+SD, is seen in 60% of FFG and 52% of FOLFOX pts. It is too early to assess TTP and OS. Seventeen pts in FFG and 13 in FOLFOX developed grade 3–4 neutropenia, 3 and 2 respectively had grade 3 thrombocytopenia. Five pts in FOLFOX group were hospitalized (PE, TIA and stroke) with 2 deaths being analyzed. There were 2 hospital admissions for FFG pts unrelated to treatment. Two of 3 pts in FFG group showed 3–4 fold increase CAM reactive white cells and 10 fold decrease in viable CTC. Of these 3, one is CR and 2 are responding to treatment. Conclusions: These preliminary results, are encouraging for FFG in regards to less incidence of severe complications and ease of administration. Cell separation based on preferential adhesion of tumor cells to CAM coated surface seems to be rapid/ reliable method of assessing treatment response. Supported in part by grant from NIH R42 CA108247 and Eli Lilly Co Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Eli Lilly Eli Lilly Eli Lilly Eli Lilly