AIM: To discuss treatment with eribulin in clinical practice outside a clinical trial.METHODS: Archives of patients treated for metastatic breast cancer were reviewed and 21 patients treated with the new chemotherapeutic eribulin mesylate, a synthetic analog of a natural marine product, were identified. Information on patients’ characteristics and treatment outcomes was extracted. Treatment with eribulin mesylate was initiated at the recommended dose of 1.4 mg/m2 on days 1 and 8 of a 21-day cycle in 17 patients and at a decreased dose of 1.1 mg/m2 on days 1 and 8 of a 21-day cycle in 4 patients due to comorbidities and frailty. Efficacy of the drug was evaluated using the revised Response Evaluation Criteria in Solid Tumors criteria. Progression-Free Survival and overall survival(OS) were calculated using the Kaplan-Meier method starting from the date of eribulin therapy initiation to the date of disease progression documentation or death, respectively.RESULTS: The median age of patients at the time of eribulin mesylate treatment was 53 years(range 34-75). Sixteen patients had estrogen receptor(ER) and/or partial response(PR) positive disease and 5 had ER/PR negative disease(all triple negative). Eight patients had received 2 or 3 previous lines of chemotherapyfor metastatic disease and 13 patients had received 4 or more lines of treatment. The median number of cycles of eribulin received was 3(range 1-16 years). All patients, except one, discontinued treatment due to progressive disease and one patient due to adverse effects. Six patients had a dose reduction due to side effects. All patients had progressed at the time of the report with a median time to progression of 3 mo(range 1 to 14 mo). Fifteen patients had died with a median OS of 7 mo(range 1-18 mo). Six patients were alive with a median follow-up of 13.5 mo(range 7 to 19 mo).CONCLUSION: This series of patients confirms the activity of eribulin in a heavily pre-treated metastatic breast cancer population consistent with phase Ⅱ and Ⅲ trials. AIM: To discuss treatment with eribulin in clinical practice outside a clinical trial. METHODS: Archives of patients treated for metastatic breast cancer were reviewed and 21 patients treated with the new chemotherapeutic eribulin mesylate, a synthetic analog of a natural marine product, were identified. Information on patients’ characteristics and treatment outcomes were extracted. Treatment with eribulin mesylate was initiated at the recommended dose of 1.4 mg / m2 on days 1 and 8 of a 21-day cycle in 17 patients and at a decreased dose of 1.1 mg / m2 on days 1 and 8 of a 21-day cycle in 4 patients due to comorbidities and frailty. Efficacy of the drug was evaluated using the revised Response Evaluation Criteria in Solid Tumors criteria. Progression-Free Survival and overall survival (OS) were calculated using the Kaplan-Meier method starting from the date of eribulin therapy initiation to the date of disease progression documentation or death, respectively .RESULTS: The median age of patien ts at the time of eribulin mesylate treatment was 53 years (range 34-75). Sixteen patients had estrogen receptor (ER) and / or partial response (PR) positive disease and 5 had ER / PR negative disease (all triple negative). Eight patients had 2 or 3 previous lines of chemotherapy for metastatic disease and 13 patients had received 4 or more lines of treatment. The median number of cycles of eribulin received was 3 (range 1-16 years). All patients, except one, discontinued Six patients had a dose reduction due to side effects. All patients had progressed at the time of the report with a median time to progression of 3 mo (range 1 to 14 months) . Fifteen patients had died with a median OS of 7 mo (range 1-18 mo). Six patients were alive with a median follow-up of 13.5 mo (range 7 to 19 mo) .CONCLUSION: This series of patient confirms the activity of eribulin in a heavily pre-treated metastatic breast cancer population consistent with phase Ⅱ and Ⅲ trials