Weekly paclitaxel and 5-fluorouracil in pretreated patients with metastatic breast cancer: A phase I study

Background: Recent studies have shown a good activity/tolerability for weekly paclitaxel and 5-fluorouracil in protracted continuous infusion (p.c.i.) in metastatic breast cancer patients pretreated with anthracyclines. Materials and Methods: To define the MTD of weekly paclitaxel (days 1-8-15-22, every 4 weeks with a starting dose of 75 mg/m 2 and subsequent dose escalation: 90 mg/m 2 and 105 mg/m 2) in combination with a fixed dose of 5-fluorouracil in p.c.i. (250 mg/m 2/day for 3 weeks + 1 week of rest). Results: Eleven patients were enrolled; on Step III two patients experienced DLT (1 G 3 mucositis and 1 febrile neutropenia). G 3-4 toxicities were: G 3 mucositis (2 out of 11), G 3-4 neutropenia (1 out of 11). Conclusion: The recommended schedule for phase II studies is: paclitaxel 90 mg/m 2/w + 5-fluorouracil 250 mg/m 2 in p.c.i. for 21 days. This is the first phase I trial with the combination of weekly paclitaxel and 5-fluorouracil p.c.i. in advanced breast cancer patients.