A Phase II study of paclitaxel by 24-hour infusion and ifosfamide in anthracycline-resistant metastatic breast carcinoma

BACKGROUND. A Phase II study was performed to investigate the efficacy and tolerability of paclitaxel and ifosfamide chemotherapy for the treatment of anthracycline-resistant metastatic breast carcinoma (MBC). METHODS. Recurrent or progressed MBC within 12 months after anthracycline-based chemotherapy was defined as anthracycline-resistant. A 24-hour infusion of paclitaxel (175 mg/m²) on Day 1 and subsequent infusions of ifosfamide (1.8 g/m²/day) with mesna (360 mg/m²/day) on Days 2-4, were performed every 3 weeks. Twenty-one patients were eligible for toxicity analysis. Response rate and survival duration were evaluated in 21 patients. Frontline chemotherapy was the FAC (5-fluorouracil, doxorubicin, cyclophosphamide) regimen in all patients. RESULTS. Objective response was found in 9 patients (42.9%), including complete response in 3 (13.4%). Median response duration and median survival duration were 10 months (range, 2-24+) and 19+ months (range, 2-32+), respectively. Sixteen (76%) experienced Grade 3/4 leukopenia controllable with granulocyte macrophage colony-stimulating factor. Other significant toxicities were peripheral neuropathy (n = 3), mucositis (n = 2), and liver dysfunction (n = 1). However, there was no chemotherapy-related death. CONCLUSIONS. Paclitaxel by 24-hour infusion combined with ifosfamide is efficacious in the treatment of anthracycline-resistant MBC with tolerable toxicity. Further trials verifying the result of the authors' study are warranted.