Mitoxantrone plus vinorelbine in pretreated patients with metastatic breast cancer

Vinorelbine and mitoxantrone have both been demonstrated to have significant antitumor activity in patients with breast cancer. The aim of this study was to evaluate the efficacy and safety of the combination as second or third line treatment in patients with metastatic breast cancer (MBC). Fifty-one previously treated patients with MBC were enrolled from October 2001 to May 2004 and 48 were eligible for evaluation. Median age was 59 years (range 33-82) and ECOG performance status was <= 2. Distant sites of metastasis were as follows: liver 64%, bone 49%, lung 36%, lymph nodes 6%, skin 4%, brain 2% and other sites 6%. All patients received vinorelbine 20 mu g/m(2), D1+8 and mitoxantrone 10 mu g/m(2) D8 every 21 days for 6 cycles. All eligible patients were analyzed for toxicity and response. Two patients (4%) achieved complete response and 12 (25.5%) partial response. The objective overall response rate was 29.5% (95% confidence interval [CI] 17 - 45), 9 (19%) patients had stable disease, 17 (36%) had progressive disease and 7 (15%) were non-evaluable. After a median follow up of 18 months, overall survival was 13 months (range 0.8 - 38+) and median time to disease progression was 5 months (range I 32). A total of 280 cycles was delivered. The relative dose intensities of mitoxantrone and vinorelbine were 79% and 77%, respectively. Toxicities (grade III-IV) were as follows: leukopenia 18 (38%), neutropenia 21 (45%), thrombocytopenia 1 (2%), anemia 4 (8.5%), alopecia 2 (4%) and constipation 1 (2%). Febrile neutropenia was recorded in one patient. There were no treatment related deaths. The combination of mitoxantrone and vinorelbine is an effective regimen with manageable toxicity in pretreated patients with advanced breast cancer.