Biomarker Study of Immune-mediated Mechanism of Action of Neoadjuvant Trastuzumab in HER2+ Breast Cancer Patients

Inclusion Criteria:

* Previously untreated, infiltrating primary breast cancer with locally advanced, inflammatory, or early stage tumor (either greater than 2 cm in diameter or node positive) with no evidence of metastatic disease.
* HER2 positivity (either immunohistochemistry 3+ or fluorescent in situ hybridization amplification).
* Age 18 or older.
* Eastern Cooperative Oncology Group performance status of 0 to 1.
* Availability of tumor tissue for biologic and molecular examination before starting primary treatment.
* Left ventricular ejection fraction within the institutional range of normal.
* Normal organ and marrow function.
* Adequate contraception methods for women of childbearing potential.
* Prior diagnosis of cancer is allowed as long as patient is free of disease and has been off treatment for the prior malignancy for a minimal interval of 3 years.
* Written informed consent.

Exclusion Criteria:

* Either stage I or IV breast cancer.
* Prior trastuzumab or pertuzumab.
* Any prior chemotherapy.
* Treatment with any other investigational agent, or participation in another clinical trial within 28 days prior to enrolment.
* Undergone major surgery (e.g., intrathoracic, intra-abdominal or intra-pelvic) 4 weeks prior to starting study drug or who have not recovered from side effects of such surgery.
* Breast radiotherapy prior to starting study.
* Known hypersensitivity to the investigational drugs or any of their excipients.
* Evidence of any disease, neurological or metabolic dysfunction, physical examination finding or laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of an GOIRC-01-2016 ImmunHER Protocol Version 1.0, 11 April 2016 Page 6 of 140 investigational drug, or puts the patient at high risk for treatment-related complications.
* Moderate/severe hepatic impairment (Child- Pugh B/C).
* Uncontrolled inter-current illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
* Concurrent malignancy or malignancy within 3 years prior to study enrollment, with the exception of adequately treated basal cell carcinoma, squamous cell carcinoma or other non-melanomatous skin cancer, or insitu carcinoma of the uterine cervix.
* Pregnancy or breastfeeding (breast feeding should be discontinued to be enrolled in the study).
* Women of childbearing potential that refusal to adopt adequate contraceptive measures.
* Unwilling or unable to comply with the protocol. -