5-fluorouracil + cyclophosphamide + epidoxorubicin + levofolinic acid

The drug combination "5-fluorouracil + cyclophosphamide + epidoxorubicin + levofolinic acid" is a chemotherapy regimen studied in a phase I-II clinical trial for the treatment of metastatic breast cancer. Patients received cyclophosphamide 600 mg/m² on day 1, levofolinic acid 100 mg/m² plus 5-fluorouracil 375 mg/m² on days 1-3, and epidoxorubicin in three refracted doses on days 1-3 with granulocyte colony stimulating factor (G-CSF) rescue for 10 days. The maximum tolerated dose (MTD) of epidoxorubicin was determined to be 35 mg/m²/day, as higher doses (40 mg/m²/day) led to dose-limiting toxicities including prolonged grade 4 leukopenia, severe proctitis, and grade 3 diarrhea. At the recommended dose, the regimen showed a high overall response rate of 78% (22% complete response and 56% partial response) in patients with metastatic breast cancer, with objective responses observed at various tumor sites including bone and viscera, which are typically less responsive to chemotherapy. However, despite the high response rate, the duration of tumor regression and patient survival were not particularly impressive. Due to this, the study authors concluded that routine use of this aggressive regimen for palliation of advanced breast cancer is not recommended, though the results might be useful for planning neoadjuvant or adjuvant trials with curative intent.