Patient description: The patient is a 45-year-old postmenopausal woman with cytologically confirmed breast cancer. A core biopsy revealed a 3 cm invasive ductal breast carcinoma in the left upper outer quadrant. The tumor is HER2-positive and ER/PR negative. Axillary sampling revealed 5 positive lymph nodes. CXR was remarkable for metastatic lesions. The patient is using multivitamins and iron supplements. She does not smoke or consume alcohol. She is not sexually active and has no children. She is a candidate for tumor resection and agrees to do so prior to chemotherapy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Metastatic Breast Cancer HER2 Positive Breast Carcinoma Women age ≥ 18 years Eastern Cooperative Oncology Group performance status 0-2 (Karnofsky >60%) Patients with metastatic breast cancer HER2 (human epidermal growth factor receptor 2)-positive breast cancer prospectively determined on the primary tumor by a local pathology laboratory and defined as: Immunohistochemistry (IHC) score of 3+ and/or positive by ISH (defined by In Situ Hybridization ratio of ≥ 2.0 for the number of HER2 gene copies to the number of chromosome 17 copies). Both IHC and ISH assays will be performed; however, only one positive result is required for eligibility Estrogen/progesterone receptor positive OR negative disease allowed Patients must have measurable disease per the Response Evaluation in Solid Tumors (RECIST) v1.1 Patients that have failed at least one anti-HER2 therapy in the metastatic setting Patients must have normal organ and marrow function as defined below absolute neutrophil count ≥1,500/mL platelets ≥100,000/mL  Metastatic breast cancer patients who are HER2 positive and have NOT progressed on at least one prior HER2-targeted therapies for metastatic disease Patients who have not recovered from CTCAE, v. 4.03 grade 2 or higher toxicities of prior therapy to the point that they would be appropriate for re-dosing will be ineligible for study treatment. Subjects receiving weekly therapy must have a washout period from prior chemotherapy of as least one week. Washout period for chemotherapy administered every 2, 3, or 4 weeks will be 2, 3, and 4 weeks respectively, provided subject has recovered from toxicities of prior therapy such that retreatment is appropriate Patients must be at least two weeks from prior RT Patients must have a one-week washout period from prior hormonal therapy (e.g. testosterone, estrogen, progestin, gonadotropin-releasing hormone antagonist) Patient has known active central nervous system (CNS) metastases and/or carcinomatous meningitis. Note: Patients with previously treated brain metastases may participate provided they are stable (without evidence of progression by imaging [using the identical imaging modality for each assessment, either MRI or CT scan] for at least 4 weeks prior to the first dose of study treatment and any neurologic symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and have not been using steroids for at least 7 days prior to study treatment. Carcinomatous meningitis precludes a patient from study participation regardless of clinical stability. No concurrent anti-cancer treatment of any type Patients with known germline BRCA 1 or BRCA 2 mutations Patient has undergone prior treatment with a known poly(ADP-ribose) polymerase (PARP) inhibitor Prior treatment of a total doxorubicin >360 mg/m2 (or equivalent) Patient has known active hepatitis B (eg, hepatitis B surface antigen [HBsAg] reactive) or hepatitis C (eg, hepatitis C virus ribonucleic acid [HCV RNA] [qualitative] is detected) Patient has a known history of human immunodeficiency virus (HIV) (HIV 1/2 antibodies)