Study Comparing Concomitant Docetaxel + Gemcitabine to Sequential Therapy of Docetaxel Followed by Gemcitabine

Inclusion Criteria: * Patients with histologic or cytologic diagnosis of breast cancer with evidence of unresectable, locally recurrent, or metastatic disease. * Females, 18 to 75 years of age * pre-treated with ONE anthracyclines containing chemotherapy either in neoadjuvant/adjuvant or 1st line metastatic setting will be enrolled into the study * Patients with clinically measurable lesions will be enrolled in this study. Measurability is determined according to RECIST criteria * Performance status of 70 or higher on the Karnofsky Performance Scale * Adequate bone marrow reserve * Adequate liver function * Adequate renal function * Informed consent form patient or guardian * Childbearing potential either terminated by surgery, radiation, or menopause, use of an approved contraceptive method Exclusion Criteria: * Active infection (at the discretion of the investigator). * Known or suspected brain metastases requiring steroid or radiation treatment. * Pregnancy (recent negative urine pregnancy test for pre-menopausal patients mandatory) * Breast-feeding * Serious concomitant systemic disorders incompatible with the study (at the discretion of the investigator). * Second primary malignancy (except in situ carcinoma of the cervix or adequately treated basal cell carcinoma of the skin). * Bone metastases, pleural effusion, or ascites as the only site of disease. * Bone marrow transplantation or autologous stern cell infusion following high-dose chemotherapy for adjuvant or metastatic disease.