Cyclophosphamide, methotrexate, and chronic oral tegafur modulated by folinic acid in the treatment of patients with advanced breast carcinoma

Abstract

Chronic oral tegafur (a 5-fluorouracil prodrug) modulated by folinic acid has antitumor activity in patients with metastatic breast carcinoma resistant to 5-fluorouracil or doxorubicin-based regimens. In this study, bolus 5-fluorouracil was substituted with chronic oral tegafur and folinic acid in a cyclophosphamide, methotrexate, and 5-fluorouracil-based regimen to study the activity of this novel regimen in patients with advanced breast carcinoma. This study was comprised of patients with advanced breast carcinoma and measurable or evaluable disease. Patients with prior chemotherapy were eligible. The regimen was comprised of cyclophosphamide, 600 mg/m2, and methotrexate, 40 mg/m2, both given intravenously on Day 1, and tegafur, 750 mg/m2, with folinic acid, 45 mg/day, both given orally in 3 daily fractions on Days 2-14, every 3 weeks. Forty-seven patients were included, 44 of whom were fully assessable. Three patients (7%) achieved a complete remission and 17 (38.6%) achieved a partial remission, for an objective response rate of 45.5% (95% confidence interval, 29-59%). The median duration of response was 11 months. In previously untreated patients the response rate was 54.5%. In patients previously treated with anthracycline or 5-fluorouracil-based regimens the response rates were 41% and 39%, respectively. Sixteen patients (36.4%) had disease stabilization. The median overall time to progression was 10 months. Toxicities usually were mild and were comprised of leukocytopenia, mucositis, emesis, and diarrhea. Chronic oral tegafur and folinic acid combined with intravenous cyclophosphamide and methotrexate at the dose and schedule used in the current study has significant antitumor activity both as first-line chemotherapy as well as in other patients with advanced breast carcinoma who had prior chemotherapy. This regimen is well tolerated, with gastrointestinal toxicity being the most frequent and dose-limiting toxicity.