Trastuzumab, Cyclophosphamide, and Vaccine Therapy in Treating Patients With High-Risk or Metastatic Breast Cancer

DISEASE CHARACTERISTICS:

* Histologically confirmed adenocarcinoma of the breast, meeting one of the following criteria:

  * Metastatic disease
  * High-risk disease, defined as early-stage disease with pathologic involvement of locoregional lymph nodes

    * Patients who are/will be receiving standard adjuvant trastuzumab \[Herceptin®\] for high-risk disease will participate in this study during the single-agent trastuzumab portion of their therapy
* No clinical or radiographical evidence of active disease
* Not eligible for therapy of known curative potential for metastatic breast cancer
* HER2/neu-overexpressing disease, defined as HER2/neu positive by IHC 3+ staining or by FISH+ amplification
* Stable CNS disease allowed provided it has been adequately treated and is not under active treatment
* Hormone receptor status not specified

PATIENT CHARACTERISTICS:

* Menopausal status not specified
* ECOG performance status 0-1
* ANC \> 1,000/mm\^3
* Platelet count \> 100,000/mm\^3
* Serum creatinine \< 2.0 mg/dL
* Serum bilirubin ≤ 2.0 mg/dL (unless elevation is due to known Gilbert's syndrome)
* AST/ALT ≤ 2 times upper limit of normal (ULN)
* Alkaline phosphatase ≤ 5 times ULN
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* Cardiac ejection fraction normal by MUGA OR ≥ 45% by ECHO
* No other malignancies within the past 5 years, except for carcinoma in situ of the cervix, superficial nonmelanoma skin cancer, or superficial bladder cancer
* No prior or currently active autoimmune disease\* requiring management with systemic immunosuppression, including any of the following:

  * Inflammatory bowel disease
  * Systemic vasculitis
  * Scleroderma
  * Psoriasis
  * Multiple sclerosis
  * Hemolytic anemia or immune-mediated thrombocytopenia
  * Rheumatoid arthritis
  * Systemic lupus erythematosus
  * Sjögren syndrome
  * Sarcoidosis
  * Other rheumatologic disease
* No symptomatic intrinsic lung disease or extensive tumor involvement of the lungs resulting in dyspnea at rest
* HIV-negative
* No evidence of active acute or chronic infection
* No uncontrolled medical problems
* No active major medical or psychosocial problems that could be complicated by study participation
* No corn allergy
* No known severe hypersensitivity to trastuzumab (except for mild to moderate infusion reactions that are easily managed and do not recur) NOTE: \*Asthma or chronic obstructive pulmonary disease that does not require daily systemic corticosteroids allowed

PRIOR CONCURRENT THERAPY:

* Any number of prior chemotherapy regimens for metastatic breast cancer allowed
* Prior or concurrent trastuzumab in the adjuvant or metastatic setting allowed
* More than 28 days since prior and no concurrent systemic oral steroids

  * Topical, ocular, or nasal steroids allowed
* More than 28 days since prior and no concurrent chemotherapy, radiotherapy, or biologic therapy (except trastuzumab)
* More than 28 days since prior and no concurrent participation in another investigational clinical trial involving a new drug
* Concurrent endocrine therapy or bisphosphonates allowed