Multi-center phase II study for combination therapy with paclitaxel/doxifluridine to treat advanced/recurrent gastric cancer showing resistance to S-1 (OGSG 0302)

Background: A pre-clinical study demonstrated that paclitaxel induced thymidine phosphorylase in the tumor tissues. The combination of paclitaxel and doxifluridine is expected to exert extra anti-tumor effects. We evaluated the efficacy of this combination in patients with unresectable or recurrent gastric cancer who had been previously treated with S-1. Methods: Registration was started to enroll 35 patients with advanced/recurrent gastric cancer, who were selected among those with measurable lesions fitting to response evaluation criteria in solid tumors, and with resistant to S-1 treatment. This regimen is consisted of paclitaxel, 80 mg/m(2), iv on days 1 and 8; and doxifluridine, 600 mg/m(2), po on days 1-14. The treatment was repeated every three weeks. Primary endpoint was response rate (RR); and secondary endpoints were overall survival (OS), progression free survival (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 performance status (PS) levels were, zero with 21 and one with 14 patients. In 33 eligible patients, except two, clinical usefulness was evaluated resulting in RR of 18.2% (partial response, 6; stable disease, 15; progressive disease, 10; and not evaluable, 2 patients). Median survival time was 321 days and median PFS was 119 days. Severe adverse events were found in three patients to discontinue the present treatment. Conclusions: The combination of paclitaxel and doxifluridine might be a treatment of choice as a second line chemotherapy for patient undergone S-1 treatment.