New drug cocktail aims to wipe out breast cancer before surgery

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patients must have HER2-positive Stage II or III histologically confirmed invasive carcinoma of the breast. A minimum tumor size of 2 cm determined by physical exam or imaging is required. * HER-2 positive, confirmed by central testing (Clarient labs): IHC 3+ and/or FISH positive based on one of the three following criteria: * Single-probe average HER2 copy number≥6.0 signals/cell OR * Dual-probe HER2/CEP17 \<2.0 with an average HER2 copy number ≥6.0 signals/cell OR * Dual-probe HER2/CEP17 ratio ≥2.0 * ER/PR determination is required. * Bilateral breast cancers are allowed if both cancers are HER2-positive. * Patients with multifocal or multicentric disease are eligible as long as one area meets eligibility criteria. * Breast imaging should include the ipsilateral axilla. For subjects with a clinically negative axilla, a sentinel lymph node biopsy will be performed either before or after preoperative therapy at the discretion of the subject's physicians. For subjects with a clinically positive axilla, a needle aspiration, core biopsy or SLN procedure will be performed to determine the presence of metastatic disease in the lymph nodes. * Men and women (with any menopausal status) ≥ 18 years of age * ECOG performance status 0 or 1 * Required laboratory values: * ANC ≥1500/mm3 * Hemoglobin ≥ 9 g/dl * Platelets ≥100,000/mm3 * Serum creatinine \< 1.5 X ULN (institutional) * Total bilirubin ≤ 1.0 X ULN (institutional) For patients with Gilbert syndrome, the direct bilirubin should be within the institutional normal range. * AST and ALT ≤ 1.5x ULN (institutional) * Alkaline phosphatase ≤1.5x ULN (institutional) * Documentation of hepatitis B virus (HBV) and hepatitis C virus (HCV) serologies is required: this includes hepatitis B surface antigen (HBsAg) and/or total hepatitis B core antibody (HBcAb) in addition to HCV antibody testing. * Only for patients who test positive for hep B/C virus: PTT/INR \< ULN (institutional) * Left ventricular ejection fraction (LVEF) ≥ 55% * Premenopausal women must have a negative serum pregnancy test, including women who have had a tubal ligation and for women less than 12 months after the onset of menopause. * Women of childbearing potential and men with partners of childbearing potential must be willing to use one highly effective form of non-hormonal contraception or two effective forms of non-hormonal contraception by the patient and/or partner and continue its use for the duration of the study treatment and for 7 months after the last dose of study treatment. * Potent CYP3A4 inhibitors, such as ketoconazole and erythromycin, should be avoided during the study treatment period with T-DM1. * Excessive alcohol intake should be avoided (occasional use is permitted). * Patients with a history of ipsilateral DCIS are eligible. * Patients undergoing breast conservation therapy (i.e. lumpectomy) must not have any contraindications to radiation therapy. * Willing and able to sign informed consent. * Willing to provide tissue for research purposes. Exclusion Criteria: * Pregnant or nursing women due to the teratogenic potential of the study drugs. * Active, unresolved infection. * Receipt of intravenous antibiotics for infection within 7 days prior to enrollment. * Patients with active liver disease, for example, due to hepatitis B virus, hepatitis C virus, autoimmune hepatic disorder, or sclerosing cholangitis. * Uncontrolled hypertension (systolic \>180 mm Hg and/or diastolic \>100 mm Hg) or clinically significant (i.e. active) cardiovascular disease: cerebrovascular accident/stroke or myocardial infarction within 6 months prior to first study medication, unstable angina, congestive heart failure (CHF) of New York Heart Association (NYHA) Grade II or higher, or serious cardiac arrhythmia requiring medication. * Significant symptoms (Grade ≥2) peripheral neuropathy. * Other concurrent serious diseases that may interfere with planned treatment, including severe pulmonary conditions/illness, uncontrolled infections, uncontrolled diabetes. * Any prior treatment for the current breast cancer, including chemotherapy, hormonal therapy, radiation or experimental therapy.