A Multicentre Phase I-II Study to Investigate the Combination of Bendamustine With Weekly Paclitaxel as First or Second Line Therapy in Patients With Metastatic Breast Cancer

Inclusion Criteria: * Written informed consent must be obtained and documented according to the local regulatory requirements prior to beginning specific protocol procedures; * Pathological confirmed primary carcinoma of the breast. * Locally advanced or metastatic disease * Up to one previous palliative chemotherapy that did not contain docetaxel or paclitaxel. Previous adjuvant treatment with taxanes is allowed when the last application of the taxane was given at least 1 year before entering the trial. * Patients must have either measurable or non-measurable lesions according to the WHO criteria * At least 4 weeks since radiotherapy, with full recovery. The measurable disease must be completely outside the radiated field or there must be pathological proof of progressive disease. * Complete radiological and clinical tumor assessment within 4 weeks prior to registration performed as clinically indicated * Karnofsky-Index ≥ 60 % * Age ≥ 18 years * Absolute neutrophil count ≥ 1,500 cells/µl, platelets ≥ 100,000/µl, and hemoglobin ≥ 9 g/dl * Bilirubin within normal limits; evaluation of transaminases and alkaline phosphatase ≤ 5x upper normal limit * Serum creatinine ≤ 2.0 mg/dl * Normal left ventricular ejection fraction (LVEF) by echocardiogramme * Patients of childbearing potential, pregnancy test must be negative * If fertile effective contraception must be used throughout the study Exclusion Criteria: * Known or suspected hypersensitivity reaction to the investigational compounds or incorporated substances; * Concurrent immunotherapy or hormonal treatment for cancer (Bisphosphonates may be continued) * Symptomatic parenchymal brain metastases not responding to treatment * Life expectancy less than 3 months * Other serious illness or medical condition that may interfere with the understanding and giving of informed consent and the conduct of the study * Concurrent treatment with other experimental drugs or any other anti-cancer therapy within the last 28 days; * History of congestive heart failure or other significant uncontrolled cardiac disease * Pregnant or nursing women