A Randomized Phase III Trial of Adjuvant Therapy Comparing Chemotherapy Alone (Six Cycles of Docetaxel Plus Cyclophosphamide or Four Cycles of Doxorubicin Plus Cyclophosphamide Followed by Weekly Paclitaxel) to Chemotherapy Plus Trastuzumab in Women With Node- Positive or High-Risk Node-Negative HER2-Low Invasive Breast Cancer

Inclusion Criteria:

- The tumor must be unilateral invasive adenocarcinoma of the breast on histologic
examination

- All of the following staging criteria (according to the 7th edition of the American
Joint Committee on Cancer [AJCC] Cancer Staging Manual) must be met:

- By pathologic evaluation, primary tumor must be pT1-3

- By pathologic evaluation, ipsilateral nodes must be pN0, pN1 (pN1mi, pN1a,
pN1b,pN1c), pN2a, pN2b, pN3a, or pN3b

- If pN0, one of the following criteria must be met:

- pT2 and estrogen receptor (ER) negative and progesterone receptor
(PgR) negative

- pT2 and ER positive (PgR status may be positive or negative) and
either grade 3histology or Oncotype DX Recurrence Score of >= 25; or

- pT3 regardless of hormone receptor status, histologic grade, and
Oncotype DX Recurrence Score

- No T4 tumors including inflammatory breast cancer

- No definitive clinical or radiologic evidence of metastatic disease

- NOTE: Chest imaging (mandatory for all patients) and other imaging (if required)
must have been performed within 90 days prior to randomization

- No synchronous or previous contralateral invasive breast cancer (patients with
synchronous and/or previous contralateral DCIS or lobular carcinoma in situ [LCIS]
are eligible)

- No previous ipsilateral invasive breast cancer or ipsilateral DCIS (patients with
synchronous or previous ipsilateral LCIS are eligible)

- HER2 status of the primary tumor must be evaluated prior to randomization; all
testing performed must indicate that the tumor is HER2-low as defined below

- IHC must be performed and the IHC staining results must indicate a score of 1+
(in situ hybridization [ISH] testing is not required) or 2+ (ISH must also be
performed and must indicate that the tumor is HER2-low as described below)

- If ISH testing is performed, test results must be as follows and IHC must be 1+
or 2+: The ratio of HER2 to CEP17 must be < 2.0 or, if a ratio was not
performed, the HER2 gene copy number must be < 4 per nucleus

- Note: If the IHC staining intensity is reported as a range, e.g., 0 to 1+ or 1+
to 2+, the higher intensity score in the range should be used to determine
eligibility

- No primary tumor with any of the following HER2 testing results:

- IHC staining intensity:

- 0 on all evaluations of specimens

- 3+ on evaluation of any specimen

- ISH with a ratio of HER2 to CEP17 >= 2.0 on evaluation of any specimen

- ISH result indicating HER2 gene copy number >= 4 per nucleus on evaluation of
any specimen

- The patient must have undergone either a total mastectomy or breast-conserving
surgery (lumpectomy) (patients who have had a nipple-sparing mastectomy are eligible)

- For patients who undergo lumpectomy, the margins of the resected specimen must
be histologically free of invasive tumor and DCIS as determined by the local
pathologist; if pathologic examination demonstrates tumor at the line of
resection, additional operative procedures may be performed to obtain clear
margins; if tumor is still present at the resected margin after re-excision(s),
the patient must undergo total mastectomy to be eligible (patients with margins
positive for LCIS are eligible without additional resection)

- For patients who undergo mastectomy, margins must be free of gross residual
tumor(patients with microscopic positive margins are eligible as long as
post-mastectomy RT of the chest wall will be administered)

- The interval between the last surgery for breast cancer (treatment or staging)
and randomization must be no more than 84 days

- The patient must have completed one of the procedures for evaluation of pathologic
nodal status listed below:

- Sentinel lymphadenectomy alone:

- If pathologic nodal staging based on sentinel lymphadenectomy is pN0 or
pN1b

- If pathologic nodal staging based on sentinel lymphadenectomy is pN1mi or
pN1a, the primary tumor must be T1 or T2 by pathologic evaluation and the
nodal involvement must be limited to 1 or 2 positive nodes

- Sentinel lymphadenectomy followed by removal of additional non-sentinel lymph
nodes if the sentinel node (SN) is positive

- Axillary lymphadenectomy with or without SN isolation procedures

- The patient must have ER analysis performed on the primary tumor prior to
randomization; if ER analysis is negative, then PgR analysis must also be performed
(either the core biopsy or surgical resection specimen can be used for ER/PgR
testing); patients with a primary tumor that is hormone receptor-positive or
receptor-negative are eligible

- Pre- or postmenopausal

- Eastern Cooperation Oncology Group (ECOG) performance status of 0 or 1

- Absolute neutrophil count (ANC) must be >= 1,200/mm^3

- Platelet count must be >= 100,000/mm^3

- Hemoglobin must be >= 10 g/dL

- Total bilirubin must be =< upper limit of normal (ULN) for the lab unless the patient
has a bilirubin elevation > ULN to 1.5 x ULN due to Gilbert disease or similar
syndrome involving slow conjugation of bilirubin

- Alkaline phosphatase must be =< 2.5 x ULN for the lab

- Aspartate aminotransferase (AST) must be =< 1.5 x ULN for the lab (if alanine
aminotransferase [ALT] is performed instead of AST [per institution's standard
practice], the ALT value must be =< 1.5 x ULN; if both were performed, the AST must
be =< 1.5 x ULN)

- Alkaline phosphatase and AST may not both be > the ULN

- Patients with AST or alkaline phosphatase > ULN are eligible for inclusion in the
study if liver imaging (CT, MRI, PET-CT, or PET scan) performed within 90 days prior
to randomization does not demonstrate metastatic disease and the above requirements
are met

- Patients with alkaline phosphatase that is > ULN but =< 2.5 x ULN or unexplained bone
pain are eligible for inclusion in the study if a bone scan, positron emission
tomography (PET)-computed tomography (CT) scan, or PET scan performed within 90 days
prior to randomization does not demonstrate metastatic disease

- The most recent post operative serum creatinine performed within 6 weeks prior to
randomization must be =< ULN for the lab

- Not pregnant or nursing

- Negative pregnancy test

- Left ventricular ejection fraction (LVEF) assessment must be performed within 90 days
prior to randomization; LVEF assessment performed by 2-dimensional (D) echo
cardiogram is preferred, however, multi-gated acquisition (MUGA) scan maybe
substituted based on institutional preferences

- For patients who will receive the TC chemotherapy regimen, the LVEF must be >=
50% regardless of the cardiac-imaging facility's lower limit of normal

- For patients who will receive the AC→WP chemotherapy regimen, the LVEF must be
>= 55% regardless of the cardiac-imaging facility's lower limit of normal

- NOTE: Since the pre-entry LVEF serves as the baseline for comparing subsequent
LVEF assessments, it is critical that this baseline study be an accurate
assessment. If the baseline LVEF is > 70%, the investigator is encouraged to
have the accuracy of the initial LVEF result confirmed and repeat the test if
the accuracy is uncertain

- No history of non-breast malignancies (except for in situ cancers treated only by
local excision and basal cell and squamous cell carcinomas of the skin) within 5
years prior to randomization

- No cardiac disease (history of and/or active disease) that would preclude the use of
the drugs included in the treatment regimens, including, but not limited to:

- Active cardiac disease:

- Angina pectoris that requires the current use of anti-anginal medication

- Ventricular arrhythmias except for benign premature ventricular
contractions

- Supraventricular and nodal arrhythmias requiring a pacemaker or not
controlled with medication

- Conduction abnormality requiring a pacemaker

- Valvular disease with documented compromise in cardiac function

- Symptomatic pericarditis

- History of cardiac disease:

- Myocardial infarction documented by elevated cardiac enzymes or persistent
regional wall abnormalities on assessment of left ventricle (LV) function

- History of documented congestive heart failure (CHF)

- Documented cardiomyopathy

- No hypertension defined according to the following ineligibility criteria:

- For patients who will receive TC (regardless of the patient's age): uncontrolled
hypertension defined as sustained systolic blood pressure (BP) > 150 mm Hg or
diastolic BP > 90 mm Hg (patients with initial BP elevations are eligible if
initiation or adjustment of BP medication lowers pressure to meet entry
criteria)

- For patients < 50 years old who will receive AC→WP: uncontrolled hypertension
defined as sustained systolic BP > 150 mm Hg or diastolic BP > 90 mm Hg
(patients with initial BP elevations are eligible if initiation or adjustment of
BP medication lowers pressure to meet entry criteria)

- For patients >= 50 years old who will receive AC→WP: uncontrolled hypertension
defined as sustained systolic BP > 150 mm Hg or diastolic BP > 90 mm Hg OR
controlled hypertension (systolic BP =< 150 mm Hg and diastolic BP =< 90 mmHg),
if anti-hypertensive medication(s) are needed

- NOTE: Patients who are not eligible based on the AC→WP regimen BP criteria but
who meet the TC regimen BP criteria are eligible for B-47 if the intended
chemotherapy regimen is changed to TC

- No active hepatitis B or hepatitis C with abnormal liver function tests

- No intrinsic lung disease resulting in dyspnea

- No poorly controlled diabetes mellitus

- No active infection or chronic infection requiring chronic suppressive antibiotics

- No nervous system disorder (paresthesia, peripheral motor neuropathy, or peripheral
sensory neuropathy) >= grade 2, per the Common Terminology Criteria for Adverse
Events (CTCAE) v4.0

- No conditions that would prohibit administration of corticosteroids

- No known hypersensitivity to any of the study drugs or excipients, e.g., polysorbate
80 and Cremophor EL

- No other non-malignant systemic disease that would preclude the patient from
receiving study treatment or would prevent required follow-up

- No psychiatric or addictive disorders or other conditions that, in the opinion of the
investigator, would preclude the patient from meeting the study requirements

- Concurrent participation in NSABP-B-39 allowed

- No previous therapy with anthracyclines, taxanes, or trastuzumab for any malignancy

- No chemotherapy or HER2-targeted therapy administered for the currently diagnosed
breast cancer prior to randomization

- No whole-breast radiation therapy (RT) prior to randomization or partial-breast RT
that cannot be completed on or before the date of randomization

- No use of any investigational product within 30 days prior to randomization

- No continued endocrine therapy such as raloxifene or tamoxifen (or other SERM) or an
aromatase inhibitor (patients are eligible if these medications are discontinued
prior to randomization)

- No continued use of sex hormonal therapy, e.g., birth control pills, ovarian hormone
replacement therapy (patients are eligible if these medications are discontinued
prior to randomization)

- No chronic daily treatment with corticosteroids with a dose of >= 10 mg/day
methylprednisol one equivalent (excluding inhaled steroids)

- No other concurrent chemotherapy

- No other concurrent targeted therapy for malignancy

- No partial-breast irradiation following randomization