Background: In a previous dose-finding trial, in previously treated patients with metastatic breast cancer (MBC), we showed that the combination of Mitoxantrone (M) and Paclitaxel (P) may be an interesting (response rate: 69%) and well-tolerated regimen. On the basis of these results, our group started a new trial in chemotherapy-naive patients with MBC.
Patients and method: Forty-six women entered in this trial, and all patients were evaluated for response and toxicity. Schedule of treatment was P 175 mg/m2 over 3 hr day 1 and M 12 mg/m2 day 1, every 3 weeks. Patients were reevaluated every 3 months and chemotherapy was continued unless tumor progression or unacceptable toxicity occurred.
Result: The intent-to-treat objective response was 61% (95% confidence interval: 49%-78%). Five patients (11%) obtained complete response and 23 (50%) partial response with a median time to failure of 14 months. The median survival was 22 months (range 1-39). The principal toxicity was hematological: 38 (82%) patients had grade 3 to 4 leukopenia; only 2 patients had grade 4 anemia and one grade 4 thrombocytopenia. Nonhematological toxicity (grade 3-4) was mild and cardiotoxicity was infrequent.
Conclusion: This trial suggests the combination of M and P is an active palliative regimen for patients with MBC. Toxicity was moderate. The infrequent development of cardiotoxicity suggests this combination may not share the problems reported with P plus doxorubicin combinations.