Capecitabine/Cyclophosphamide

Low dose metronomic chemotherapy (LDMC) in patients with metastatic breast cancer (MBC) is used as a palliative regiment with the aim to prolong and improve quality of life. The effect of LDMC is not fully elucidated. The aim is to evaluate the effect of LDMC with Capecitabine and Cyclophosphamide (CX) and to discover new potential predictive markers and potential markers for monitoring treatment effect.

Primary Objectives:
To assess the safety for each cohort of patients on a fixed-dose combination pill of capecitabine and cyclophosphamide administered at flat dose and with metronomic schedule (defined as continuous daily treatment without interruption) in patients with metastatic breast cancer.
To assess the pharmacokinetics (PKs) and bioavailability of the fixed-dose combination pill of capecitabine and cyclophosphamide administered at different doses/regimens by metronomic schedule in patients with metastatic breast cancer.
Secondary Objectives:
To assess antitumor activity of the fixed-dose combination pill of capecitabine and cyclophosphamide administered at different doses/regimens by metronomic schedule in patients with metastatic breast cancer given at 3 different doses and schedules (regimen 1=standard dose twice daily [BID], regimen 2=full dose once daily [OD], regimen 3=low dose [OD])
Disease Control Rate (DCR)
Overall Response Rate (ORR)
Time to Progression (TTP) using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria (version 1.1).
To evaluate the compliance under treatment.
To describe evolution of toxicities.
To assess safety all along patient's treatment.