15025 Background: We report here results of phase II study for a combination therapy with paclitaxel/doxifluridine to treat advanced/recurrent gastric cancer showing resistance to S-1. S-1 is an oral fluoropyrimidine drug that combines tegafur, CDHP, and oxonic acid (Oxo), which has been most frequently used in Japan. Methods: Subject registration was started to employ 35 patients with advanced/recurrent gastric cancer, who were selected among those with measurable lesions fitting to RECIST, and with resistant to S-1 treatment (PS, 0–2; and patient’s ages ranged from over 20 to under 75 years). We employed dosages that Hyodo et. al. used in phase I study and recommended as a standard regimen including paclitaxel, 80 mg/m2, i.v. on days 1 and 8; and doxifluridine, 600 mg/m2, p.o. on days 1–14.. These were repeated every 3 weeks. Primary endpoint of present phase II study was: RR; and secondary endpoints were OS, PFS, and onset rate of adverse events. Results: From September, 2003 to March, 2005, 35 patients were registered: including 28 men; 7 women; median age of 66 years (range, 49–75 years); and PS levels were, zero with 21 and one with 14 patients. In 33 eligible patients, except 2, clinical usefulness was evaluated resulting in response rate of 18.2% (PR, 6; SD, 15; PD, 10; and NE, 2 patients). OS was 321 days, and PFS was 119 days. Severe adverse events were found in 3 patients to discontinue the present treatment though; other adverse events were relatively mild without no death due to the present therapy. Conclusions: Patients in the present study with advanced/recurrent gastric cancer were those resistant to S-1 treatment. Response rate was 18.2% increasing to 63.6% when SD was added. OS resulted in relatively long period of 321 days, while OS from initial time starting S-1 treatment was 619 days. This suggests that the present treatment is useful as the sequential therapy. Adverse events were controllable suggesting a high reliability of the present therapy. In conclusion, the present therapy with paclitaxel/doxifluridine could be a treatment of choice as an useful second line chemotherapy for patients undergone S-1 treatment. No significant financial relationships to disclose.