Single Arm Pilot Trial of Adaptive Therapy (AT) With Capecitabine for the Treatment of Metastatic Estrogen Receptor Positive, Hormone Refractory Breast Cancer
This phase II trial evaluates the effect of capecitabine on tumor response using imaging and tumor markers to adjust dose (adaptive therapy) in patients with estrogen receptor (ER) positive, HER2 negative breast cancer that has spread from where it first started to other areas in the body (metastatic). Capecitabine is in a class of medications called antimetabolites. It is taken up by tumor cells and breaks down into fluorouracil, a substance that kills tumor cells. Adaptive therapy with capecitabine based on tumor burden response may slow or stop the growth of tumor cells in patients with metastatic ER positive, HER2 negative breast cancer.
• Age ≥ 18 years
• Histological confirmation of estrogen-receptor positive (ER+), HER2-negative overexpression or amplification negative as per American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines, metastatic breast cancer
• Measurable disease. Bone only disease allowed if associated with soft tissue component that is measurable by Response Evaluation Criteria is Solid Tumors (RECIST) 1.1 criteria
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1 or 2
• Hemoglobin ≥ 9.0 g/dL (obtained ≤ 14 days prior to registration), no transfusions allowed ≤ 14 days prior to registration
• Absolute neutrophil count (ANC) ≥ 1500/mm\^3 (obtained ≤ 14 days prior to registration)
• Platelet count ≥ 100,000/mm\^3 (obtained ≤ 14 days prior to registration)
• Total bilirubin ≤ 1.5 x upper limit of normal (ULN) (obtained ≤ 14 days prior to registration)
• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3 x ULN (≤ 5 x ULN for patients with liver involvement) (obtained ≤ 14 days prior to registration)
• Prothrombin time (PT)/international normalized ratio (INR)/activated partial thromboplastin time (aPTT) ≤ 1.5 x ULN OR if patient is receiving anticoagulant therapy and INR or aPTT is within target range of therapy (obtained ≤ 14 days prior to registration)
• Calculated creatinine clearance ≥ 45 ml/min using the Cockcroft-Gault formula (obtained ≤ 14 days prior to registration)
• Negative serum or urine pregnancy test done ≤ 7 days prior to registration, for persons of childbearing potential only. NOTE: If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required
• Provide written informed consent
• Ability to complete questionnaire(s) by themselves or with assistance
• Willingness to provide mandatory blood specimens for correlative research
• Ability to undergo re-staging CT scans as required by the protocol
• Willing to return to enrolling institution at the specified frequency for follow-up (during the active monitoring phase of the study)