Mitoxantrone, fluorouracil, and high-dose leucovorin: an effective, well-tolerated regimen for metastatic breast cancer.

Between September 1988 and August 1990, we treated 35 women with metastatic breast cancer with a novel regimen containing mitoxantrone, fluorouracil (5-FU), and high-dose leucovorin. This regimen was designed to take full advantage of the favorable toxicity profiles of these agents while maintaining a high level of activity. All patients had received previous chemotherapy (adjuvant only, 15 patients; at least one metastatic regimen, 20 patients). Seven patients had received previous doxorubicin, but none within 6 months of study entry. Of 31 assessable patients, 20 (65%) had objective responses (two complete, 18 partial), with a median response duration of 6 months (range, 3 to 16+ months). Four patients with bone metastases (abnormal bone scan only) and pain were not considered assessable by strict response criteria; two of these patients had sustained symptomatic relief for 6 and 8 months, respectively. Myelosuppression was the most frequent toxicity but was mild in most patients; only four hospitalizations for fever and neutropenia were required (2% of courses). No severe thrombocytopenia occurred and no RBC transfusions were required. Alopecia, mucositis, and nausea/vomiting were uncommon and were not severe in any patient. The combination of mitoxantrone, 5-FU, and high-dose leucovorin is well tolerated and active as a first- or second-line treatment for metastatic breast cancer. Comparison with other standard regimens for breast cancer is indicated.