The Role of Bexarotene in Inducing Susceptibility to Chemotherapy in Metastatic TNBC

Metastatic Triple-Negative Taxane-Resistant Breast Cancer: Investigating the Role of Bexarotene in Inducing Susceptibility to Chemotherapy by Differentiating Cancer Cells From a Mesenchymal-Like to an Epithelial-Like Phenotype

Triple-negative breast cancer (TNBC) is biologically aggressive and has limited systemic treatment options, often compounded by treatment resistance.

Cell state transitions, e.g. epithelial-to-mesenchymal transition (EMT) govern cancer cell behaviour.

The investigators hypothesize that by inducing change in cell state change, TNBC cells that have manifested taxane-resistance will be more sensitized to subsequent chemotherapy.

Inclusion Criteria:

• Patients with histologically or cytologically proven metastatic TNBC
• Patients whose TNBC has progressed after prior taxane therapy in the (neo)adjuvant or metastatic setting, and have not received Capecitabine or 5-fluorouracil
• Females aged 21 years and older
• ECOG performance status 0 or 1
• Life expectancy greater than three months
• Patients have normal organ and marrow function
• Site(s) of disease amenable to serial bedside biopsies before, during and after study treatment

Exclusion Criteria:

• Previous palliative radiotherapy to potentially biopsy-able lesion
• Active symptomatic central nervous system (CNS) metastases
• Spinal cord compression not definitively treated with surgery and/or radiation
• Uncontrolled pleural effusion, pericardial effusion, ascites requiring recurrent drainage procedures