Efficacy of doxifluridine combined with weekly paclitaxel therapy in the treatment of advanced or recurrent breast cancer: results of the JMTO BC01 phase II trial.

We conducted a phase II study to determine the availability and safety of combination chemotherapy with weekly paclitaxel and doxifluridine (a capecitabine metabolite) in the treatment of advanced or recurrent breast cancer. Patients were treated with a combination chemotherapy regimen: doxifluridine was orally administered at 800 mg/day for 14 days, followed by a 7-day washout period. Paclitaxel was given intravenously on days 1 and 8 at 80 mg/m2 for 1 h, followed by a 1-week washout period. This 3-week cycle of therapy was repeated as long as possible (at least eight cycles) until the progression of the tumor and drug-related adverse effects were no longer observed. From May 2003 to December 2005, 26 patients were enrolled in the study. The overall response rate was 53.8% (95% confidence interval, 33.4-73.4%). The clinical benefit rate, including long-term no change, was 65.4% (95% confidence interval, 44.3-82.8%). Time to progression and survival time were 297 and 1182 days, respectively, for the 26 enrolled patients. No severe toxicities were observed. Grade 3/4 leucopenia in three patients, neutropenia in five patients, increased serum creatinine in three patients, hypercalemia in one patient, hypocalcemia in one patient, nausea/vomiting in two patients, and diarrhea in one patient. The good response rate and long time to progression and overall survival time of this doxifluridine combined with weekly paclitaxel therapy indicate its potential as a first-line or second-line treatment for advanced or recurrent breast cancer patients.