Two cases in which eribulin mesylate was effective for taxane-resistant advanced breast cancer

We experienced 2 cases in which eribulin mesylate was effective for taxane-resistant advanced breast cancer. Case 1: A 65-year-old woman was diagnosed with advanced breast cancer (T4cN2aM0, stage MB) and treated with chemotherapy (nab-paclitaxel). Bone metastasis was observed; then, she sequentially received epirubicin and cyclophosphamide, nab-paclitaxel, and bevacizumab and paclitaxel. However, lung metastases appeared, and we changed the regimen to eribulin mesylate. We administered 11 courses of eribulin mesylate before bone marrow metastasis appeared. Eribulin mesylate was effective for more than 1 year. Case 2: A 77-year-old woman was diagnosed with advanced breast cancer (T4bN3cM1, stage IV), and liver and pleural metastasis were observed during an examination at the first visit. Four courses of nab-paclitaxel were administered, but because of the increase in pleural effusion, we changed the regimen to eribulin mesylate. Thirteen courses of eribulin mesylate were administered before the disease progressed. The progression-free survival was 9.53 months. Through the 2 cases in which eribulin mesylate was effective for taxane-resistant advanced breast cancer, the effect of eribulin mesylate compared to taxane was clinically inferred.