Monotherapy With Eribulin In Her2 Negative Metastatic Breast Cancer as a First Line Treatment

Inclusion Criteria: * Histologically confirmed metastatic breast cancer HER2 negative, stage IIIb/IV * Previous history of early disease (stage I-IIIb), surgically resected and treated with standard chemotherapy for at least 12 weeks at which included a taxane or ixabepilone * Patients must have progressed in the 36 months after treatment with taxanes or ixabepilone. * Age ≥ 18 years * Given written informed consent * Index of Eastern Cooperative Oncology Group (ECOG) of 0 or 1 * Patients must have recovered from toxicities related with previous treatment (CTC ≥ 1) * Measurable or evaluable disease (RECIST 1.1) * Adequate bone marrow function * Adequate hepatic function * Adequate renal function * Life expectancy ≥ 3 months Exclusion Criteria: * Breast cancer patients initially diagnosed with local disease advanced or metastatic disease. * Patients who have previously received cytotoxic therapy Hormone therapy permitted if the patients have interrupted it at least two weeks before the start of the study treatment. * Major surgery or significant traumatic injury during the 4 weeks prior to study treatment or patients who may require major surgery during the assay. * Brain metastases or leptomeningeal uncontrolled. * Serious medical condition and / or not properly controlled (unstable angina, lung function severe impaired, uncontrolled diabetes, active serious infection,liver disease, HIV seropositivity, active bleeding diathesis) * Other malignancies in the last three years, except: cervical carcinoma in situ, basal cell carcinoma or squamous cell skin carcinoma,that have been properly treated * Patients who are pregnant or breastfeeding, or adults with reproductive capacity wich are not using effective contraception. * Patients receiving chronic treatment with systemic corticosteroids or other immunosuppressive drugs (except corticosteroids with a daily dose equivalent to prednisone ≤ 20mg on a stable dose regimen one minimum of 4 weeks prior to study entry. Topical and inhaled corticosteroids are allowed * Active alcoholism or drugs addiction documented. * Prior history of noncompliance with medical regimens * Patients who do not want or can not comply with the study protocol