Vinorelbine + mitomycin C as second-line treatment of metastatic breast cancer: A two-stage phase 2 study

Second-line treatment of patients with metastatic breast cancer resistant to anthracyclines is an important clinical issue. The aim of the present two-stage phase II study was to evaluate activity and toxicity of vinorelbine + mitomycin C (VM) in such patients. Fifty-five patients were entered and received vinorelbine 30 mg/m² on days 1 and 8 + mitomycin C 10 mg/m² on day 1, every 4 weeks, up to 9 cycles. Two complete and 23 partial responses were observed for an overall response rate of 45.4% (95% CI 32.0-59.4). Median survival was 13 months and probability of surviving after a 1-year follow-up was 58%. Toxicity was never life-threatening, but G-CSF was used in 45% of cycles to contrast neutropenia that was the most frequent side effect. These results are consistent with previous studies and strongly support VM being considered among the optimal polychemotherapy regimens for second-line treatment of metastatic breast cancer in clinical practice; for clinical research aims, VM should be used as control arm for randomized trials evaluating the activity of new drugs against breast cancer.