Trastuzumab and Pertuzumab in Treating Patients With Unresectable Locally Advanced or Metastatic Breast Cancer That Did Not Respond to Previous Trastuzumab

DISEASE CHARACTERISTICS:

* Histologically confirmed invasive breast cancer of 1 of the following stages:

  * Metastatic disease (stage IV)
  * Inoperable locally advanced disease

    * Disease progression after prior neoadjuvant chemotherapy required
* Disease progression on or after trastuzumab (Herceptin®) based-therapy

  * Received 1-3 prior trastuzumab-based regimens
* HER2/neu-positive tumor, defined as 3+ by fluorescent in situ hybridization
* Measurable disease, defined as at least 1 lesion that can be measured in at least one dimension
* No clinical signs or symptoms of brain and/or leptomeningeal metastases confirmed by CT scan or MRI

  * Brain and/or leptomeningeal metastases allowed if patient has stable lesions after standard treatment (surgery or radiotherapy), is asymptomatic on neurological exam, and is not receiving corticosteroid therapy to control symptoms
* Hormone receptor status:

  * Not specified

PATIENT CHARACTERISTICS:

* ECOG performance status 0-1
* Male or female
* Menopausal status not specified
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* Absolute neutrophil count ≥ 1,500/mm\^3
* Platelet count ≥ 75,000/mm\^3
* Creatinine ≤ 1.5 times upper limit of normal (ULN)
* Bilirubin ≤ 1.5 times ULN
* Alkaline phosphatase \< 5 times ULN
* AST and ALT ≤ 2.5 times ULN (5 times ULN if liver metastases are present)
* LVEF above lower limit of normal by echocardiogram or MRI
* No clinical signs or symptoms of heart failure
* No uncontrolled hypertension (i.e., blood pressure ≥ 180/100 mm Hg)
* No significant valvular disease (i.e., aortic or mitral regurgitation of 3 or 4+/4+ severity or stenosis of either valve)
* No history of uncontrolled cardiac arrhythmia
* No symptomatic or asymptomatic myocardial infarction
* No angina pectoris requiring medication
* No other documented significant cardiac event
* No poorly controlled diabetes mellitus (i.e., fasting blood sugar ≥ 200 mg/dL)
* No history of hypersensitivity reaction to trastuzumab
* No AIDS
* No nonmalignant condition requiring ≥ 20 mg of prednisone (or equivalent)
* No other malignancy within the past 5 years except carcinoma in situ of the cervix or nonmelanoma skin cancer
* No ongoing liver disease, including viral or other hepatitis, alcohol abuse, or cirrhosis
* No other serious medical illness
* No medical or psychiatric condition that would preclude study participation

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* Recovered from prior therapy
* More than 3 weeks since prior investigational anticancer agents
* More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin C), major surgery, or immunotherapy
* More than 4 weeks since prior radiotherapy except short-course palliative radiotherapy for bone pain
* More than 2 weeks since prior and no concurrent oral hormonal therapy
* More than 4 weeks since prior fulvestrant
* No prior doxorubicin hydrochloride or doxorubicin HCl liposome at a cumulative dose of \> 360 mg/m\^2
* No prior mitoxantrone hydrochloride at a cumulative dose of \> 120 mg/m\^2
* No prior epirubicin hydrochloride at a cumulative dose of \> 600 mg/m\^2
* No prior idarubicin at a cumulative dose of \> 90 mg/m\^2
* No concurrent radiation therapy, including for symptomatic bone metastases