Capecitabine in Treating Patients with Metastatic Breast Cancer or Advanced/Metastatic Gastrointestinal Cancers

Inclusion Criteria

• Ability of participant OR legally authorized representative (LAR) to understand this study, and the willingness to sign a written informed consent
• Females with metastatic breast cancer who are eligible for capecitabine monotherapy; for HER2 positive breast cancer, concurrent trastuzumab is allowed OR
• Both males and females with advanced/metastatic GI cancers eligible for capecitabine monotherapy, including metastatic colorectal cancer, metastatic gastric and esophageal cancers, and unresectable or metastatic pancreatic cancer and cholangiocarcinoma, including gall bladder carcinoma, concurrent trastuzumab is allowed for HER2 positive gastric/esophageal cancer
• No limit to the number of prior chemotherapy or endocrine therapy regimens received; use of a previous fluoropyrimidine-containing regimen in advanced/metastatic setting is permitted as long as the subject discontinued the regimen for reasons other than progression
• Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) criteria 1.1
• Women of childbearing potential must have a negative serum pregnancy test 48 hours prior to initiating treatment
• There is no restriction on the use of fluoropyrimidine-containing regimen in the neoadjuvant or adjuvant setting
• Metastatic colorectal cancers, patients starting maintenance capecitabine after a course of oxaliplatin or irinotecan based chemotherapy are eligible
• Measurable or non-measurable disease per RECIST criteria 1.1
• Must have completed prior chemotherapy or radiation therapy at least 2 weeks prior to registration
• Pathologic confirmation of respective malignancies; biopsy of metastatic disease is preferred but not mandatory
• Performance status: Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2
• May have previously treated brain central nervous system (CNS) metastasis with radiation completed at least 2 weeks prior to registration. Prior radiation to places other than CNS disease must be completed at least 14 days prior to registration. Any number of prior radiation therapy regimens is allowed provided all toxicity of prior therapy is resolved to grade 1 or less
• Life expectancy of < 3 months
• Absolute neutrophil count >= 1,000/uL
• Hemoglobin >= 9 g/L
• Platelets >= 50,000/uL
• Total bilirubin =< 2 X institutional upper limit of normal (IULN)
• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) =< 5 X IULNl
• Creatinine clearance > 50 ml/min
• Women of child-bearing potential and men with partners of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and for 30 days following completion of therapy; should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately; a woman of child-bearing potential is any female (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: * Has not undergone a hysterectomy or bilateral oophorectomy; OR * Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months)

Exclusion Criteria

• Has used capecitabine in a past regimen for metastatic disease
• Is currently using, or planning to use another investigational agent
• Has known dihydropyrimidine dehydrogenase (DPD) deficiency
• Has symptomatic brain or CNS metastases
• Has leptomeningeal disease
• Is not pregnant or nursing
• No barriers to taking oral medications, for example uncontrolled nausea, vomiting, diarrhea at baseline, lack of physical integrity of the upper gastrointestinal tract, or malabsorption syndrome
• No recent (=< 3 months) of partial or complete bowel obstruction unless surgically corrected