Combination Study of a New Taxane and Capecitabine in Patients With Metastatic Breast Cancer

Inclusion Criteria: * Histologically or cytologically proven diagnosis of breast adenocarcinoma that is now metastatic or locally recurrent and inoperable with curative intent. * Prior treatment with a standard regimen of anthracycline and taxane. * Female patients at least 18 years old. * Eastern Cooperative Oncology Group (ECOG) performance status (PS): 0-2 * Adequate organ and bone marrow function * Measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) criteria (For the part I component, patients with non-measurable disease are accepted.) * Resolution of all clinically significant toxic effects * Completion of all prior therapy ≥ 3 weeks prior to registration. Patients on bisphosphonate therapy may continue such therapy. * Patients must be either post-menopausal, surgically sterile, or using effective contraception. * Willing and able to comply with study procedures and sign informed consent Exclusion Criteria: * History of any second malignancy within the last 5 years (except adequately treated basal cell or squamous cell skin cancer, or in situ carcinoma of the cervix uteri). * Patients receiving more than one adjuvant regimen or more than one metastatic regimen * Known brain or leptomeningeal disease. * Concurrent treatment on another clinical trial or with any other cancer therapy including chemotherapy, biological therapy, hormonal therapy, radiotherapy, chemoembolization therapy, cryotherapy, targeted non-cytotoxic therapies, or patients planning to receive these treatments during the study. * Prior treatment with capecitabine, XRP9881, or any investigational chemotherapy. * History of hypersensitivity to taxanes, Polysorbate-80, or to compounds with similar chemical structures. Patients with known intolerance to fluoropyrimidines or patients with known dihydropyrimidine dehydrogenase (DPD) deficiency. * Concurrent treatment with potent inhibitors of cytochrome P450 3A4, or patients planning to receive these treatments. For patients who were receiving treatment with such agents, a one-week washout period is required prior to registration. * Peripheral neuropathy grade ≥ 2. * Any of the following within the 6 months prior to registration: myocardial infarction, severe/unstable angina, coronary/peripheral artery bypass graft surgery, clinically symptomatic and uncontrolled cardiovascular disease, or clinically significant cardiac arrhythmias (grade 3-4). * History of inflammatory bowel disease or chronic diarrhea. * Lack of physical integrity of the upper gastrointestinal tract, malabsorption syndrome, or inability to take oral medication. * Other severe acute or chronic medical or psychiatric condition, or significant laboratory abnormality requiring further investigation or that may cause undue risk for the patient's safety. * Known human immunodeficiency virus (HIV) infection requiring treatment or acquired immunodeficiency-syndrome (AIDS)-related illness. * Patients who are pregnant or breastfeeding.