Adjuvant Capecitabine in Treating Patients with Stage I-II Triple-Negative Breast Cancer and Residual Disease

Inclusion Criteria

• Anatomic stage I - III triple-negative breast cancer at diagnosis
• Estrogen receptor (ER) and progesterone receptor (PR) status =< 10%
• Residual disease following at least 4 cycles of neoadjuvant chemotherapy. Patients who received other investigational immunotherapy or targeted therapy during the neoadjuvant phase of treatment are eligible
• >= 18 years of age
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
• All clinically significant toxic effects of prior cancer therapy resolved to grade =< 1 by the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0 (NCI CTCAE, v 5.0), except alopecia and G2 neuropathy
• No evidence of metastatic disease
• A minimum 4-week wash out from previous chemotherapy treatment is required (this does not apply for patients receiving low dose capecitabine with radiation); patients receiving adjuvant pembrolizumab are eligible
• Has completed adjuvant radiation if planned. Patients who received low dose capecitabine concurrent with radiation as a radiosensitizer are eligible
• Absolute neutrophil count (ANC) >= 1,500 cells/uL (>= 1,500/mm^3)
• Platelets >= 100,000 cells/uL (>= 100,000/mm^3)
• Bilirubin =< 1.5 times the specific institutional upper limit of normal (ULN). Exception: If Gilbert’s syndrome; then =< 5 times ULN
• Aspartate transaminase (AST) and alanine transaminase (ALT) each =< 2.5 x ULN
• Serum creatinine =< 1.5 x ULN; or calculated creatinine clearance > 50 mL/min using the Cockcroft Gault formula
• Planned for 6 months or 8 cycles of adjuvant capecitabine (this can be given as monotherapy or concurrent with adjuvant pembrolizumab)
• Women of childbearing potential (WOCBP) must have a negative pregnancy test
• WOCBP must agree to use effective contraception during the study and for 3 months after the last dose
• Male participants and their female partners of child bearing potential must be willing to use an appropriate method of contraception during the study and for 3 months after the last dose
• Capable of giving signed informed consent, which includes compliance with requirements and restrictions listed in the informed consent form (ICF) and in the protocol
• Patients must enroll within 8 weeks of completion of definitive surgery or adjuvant radiotherapy if indicated

Exclusion Criteria

• Metastatic or locally recurrent breast cancer
• Has not had definitive surgical resection
• Pregnant or breastfeeding
• Has not completed definitive adjuvant radiation if planned
• Known human immunodeficiency virus (HIV) positivity or active hepatitis B or C
• Investigational agents within 4 weeks of study initiation
• Inability to swallow oral medications