Trastuzumab Emtansine in Treating Patients With HER2-Positive Metastatic or Locally Advanced Breast Cancer That Cannot Be Removed by Surgery

Inclusion Criteria:

Signed study-specific informed consent form
Histologically or cytologically documented breast cancer
Metastatic or unresectable locally advanced/recurrent breast cancer
HER2-positive disease documented as in situ hybridization (ISH)-positive and/or 3+ by immunohistochemistry (IHC) on previously collected tumor tissue
Absolute neutrophil count (ANC) > 1500 cells/mm^3
Platelet count > 100,000/mm^3
Hemoglobin > 9.0 g/dL (patients are allowed to receive transfused red blood cells [RBC] to achieve this level)
Total bilirubin =< 1.5 × upper limit of normal (ULN), except in patients with previously documented Gilbert's syndrome, in which case the direct bilirubin should be less than or equal to the ULN
Serum glutamic oxaloacetic transaminase (SGOT) (aspartate aminotransferase [AST]) and serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) =< 2.5 × ULN
Alkaline phosphatase =< 2.5 × ULN (patients with hepatic and/or bone metastases: alkaline phosphatase =< 5 × ULN)
Serum creatinine < 1.5 × ULN
International normalized ratio (INR) < 1.5 × ULN
Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2
Left ventricular ejection fraction (LVEF) >= 50% by either echocardiogram (ECHO) or multigated acquisition scan (MUGA)
Negative results of serum pregnancy test for premenopausal women of reproductive capacity and for women < 12 months after entering menopause
For women of childbearing potential and men with partners of childbearing potential, agreement by the patient and/or partner to use a highly effective, non-hormonal form of contraception or two effective forms of non-hormonal contraception; female patients of childbearing potential must agree to use two effective forms of non-hormonal contraception; effective methods of contraception include: intrauterine device (IUD); female condom; male condom; diaphragm with spermicide; cervical cap; or a sterile sexual partner; male patients with partners of childbearing potential must use barrier contraception; in addition, male patients should also have their partners use another method of contraception from the time of informed consent through the duration of study activity
Willingness and ability to comply with scheduled visits, treatment plans, laboratory tests, and other study procedures, including thrombokinetic studies and platelet function studies

Exclusion Criteria:

CANCER-RELATED CRITERIA

Known platelet disorder, such as von Willebrand's disease or baseline platelet count of < 100,000/mm^3
Chemotherapy =< 21 days before first study treatment
Trastuzumab =< 21 days before first study treatment
Lapatinib =< 14 days before first study treatment
Investigational therapy or any other therapy =< 28 days before first study treatment
Any prior ado-trastuzumab emtansine

Previous radiotherapy for the treatment of unresectable, locally advanced/recurrent or metastatic breast cancer is not allowed if:

The last fraction of radiotherapy has been administered within 14 days of first on-study thormbokinetic study
The patient has not recovered from any resulting acute toxicity (to grade =< 1) prior to first on-study thormbokinetic study
Brain metastases that are untreated or symptomatic, or require any radiation, surgery, or steroid therapy to control symptoms from brain metastases within 14 days of first on-study thrombokinetic study; for patients with newly diagnosed brain metastases or unequivocal progression of brain metastases on screening scans, localized treatment (i.e., surgery, radiosurgery, and/or whole brain radiotherapy) is required before study enrollment; subjects with known brain metastases must have clinically controlled neurologic symptoms, defined as surgical excision and/or radiation therapy followed by 14 days of stable neurologic function prior to the first thrombokinetic procedure; patients with small brain metastases not symptomatic and deemed requiring treatment by managing clinicians or study investigators may be permitted to enroll on study
History of intolerance (including grade 3 or 4 infusion reaction) or hypersensitivity to trastuzumab or murine proteins
Current peripheral neuropathy of grade >= 3 per the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v. 4.0
Current use of any platelet functioning inhibitors (including aspirin) within 14 days of first on-study thrombokinetic study

CARDIOPULMONARY FUNCTION CRITERIA

Current unstable ventricular arrhythmia requiring treatment
History of symptomatic congestive heart failure (CHF) (New York Heart Association [NYHA] classes II-IV)
History of myocardial infarction or unstable angina within 6 months of enrollment
History of a decrease in LVEF to < 40% or symptomatic CHF with previous trastuzumab treatment
Severe dyspnea at rest due to complications of advanced malignancy or requiring current continuous oxygen therapy

GENERAL CRITERIA

Current severe, uncontrolled non-cancer systemic disease (e.g., clinically significant cardiovascular, pulmonary, or metabolic disease) resulting in a life expectancy of < 6 months
Major surgical procedure or significant traumatic injury within 28 days before enrollment or anticipation of the need for major surgery during the course of study treatment
Current pregnancy or lactation
Current known active infection with human immunodeficiency virus (HIV), hepatitis B, and/or hepatitis C virus; for patients who are known carriers of hepatitis B virus (HBV), active hepatitis B infection must be ruled out based on negative serologic testing and/or determination of HBV deoxyribonucleic acid (DNA) viral load per local guidelines
Assessed by the investigator to be unable or unwilling to comply with the requirements of the protocol