Statement: Patients must have LVEF < 50% to be eligible for the primary trial.
Primary_evidence: Inclusion Criteria:   Female or male patient diagnosed with stage I-IV breast cancer   HER2 positive breast cancer, defined by immunohistochemical staining for HER2 protein of 3+ intensity and/or amplification of the HER2 gene on fluorescence in situ hybridization (FISH)  2.0 on breast specimen or biopsy of a metastatic site   LVEF < 50% and  40% documented in echocardiogram done within the last 30 days   HER2 therapy naïve or currently receiving non-lapatinib HER2 targeted therapy   Patient receiving or planning to receive trastuzumab, trastuzumab with pertuzumab or ado-trastuzumab emtansine, for at least 3 months, alone or in combination with other systemic treatment or radiation   Age  18 years   Patient is willing and able to comply with protocol required assessments and procedures Exclusion Criteria:   Previous hospitalization due to documented heart failure in the last 12 months   Current signs or symptoms of heart failure or ischemia   History of arrhythmia requiring pharmacological or electrical treatment   Concomitant use of anthracyclines or use of anthracyclines in the last 50 days   Pregnant or lactating patients. Patients of childbearing potential must implement contraceptive measures during study treatment and for 7 months after last dose of treatment drug and must have negative urine or serum pregnancy test within 7 days prior to registration.   History of significant neurologic or psychiatric disorders including psychotic disorders or dementia that would prohibit the understanding and giving of informed consent.
Secondary_evidence: Inclusion Criteria:   Histologically or cytologically confirmed, HER2-negative adenocarcinoma of the breast, with measurable or non-measurable locally recurrent or metastatic disease. Locally recurrent disease must not be amenable to resection with curative intent.   ECOG performance status of 0 or 1   For women of childbearing potential, use of an acceptable and effective method of non-hormonal contraception   For patients who have received recent radiotherapy, recovery prior to randomization from any significant acute toxicity, and radiation treatments have to be completed more than 3 weeks from randomization Exclusion Criteria:   Disease-Specific Exclusions:   HER2-positive status   Prior chemotherapy for locally recurrent or metastatic disease   Prior hormonal therapy < 2 weeks prior to randomization   Prior adjuvant or neo-adjuvant chemotherapy is allowed, provided its conclusion has been for at least 12 months prior to randomization   Investigational therapy within 28 days of randomization   General Medical Exclusions:   Life expectancy of < 12 weeks   Inadequate organ function   Uncontrolled serious medical or psychiatric illness   Active infection requiring intravenous (IV) antibiotics at screening   Pregnancy or lactation   History of other malignancies within 5 years prior to screening, except for tumors with a negligible risk for metastasis or death