Inclusion Criteria:

• Stage IIIB or Stage IIIC breast cancer who are within 1 year of diagnosis and initiating treatment with chemotherapy and trastuzumab; and are in complete remission
• Stage IV breast cancer in first complete remission and defined as NED (no evidence of disease) or with stable bone only disease who are within 6 months of initiating maintenance trastuzumab
• NED status should be documented by chest/abdominal CT, PET or PET/CT within the last 90 days
• Bone only disease documented as stable or healed by PET, PET/CT, or MRI within the last 90 days; stable bone-only disease must be documented with bone scan performed within the last 6 months
• HER2 overexpression by IHC of 2+ or 3+, in the primary tumor or metastasis or documented gene amplification by FISH analysis; if overexpression is 2+ by IHC, then patients must have HER2 gene amplification documented by FISH
• Eligible subjects must have been treated to NED or stable bone only disease status with trastuzumab and/or chemotherapy and be off cytotoxic chemotherapy or immunosuppressive agents (e.g. systemic steroids) for at least 30 days prior to enrollment (concurrent hormonal therapy allowed; concurrent bisphosphonate therapy allowed)
• Patients on trastuzumab should continue trastuzumab monotherapy per standard of care (the dosing and schedule of trastuzumab should follow standard guidelines as described below: trastuzumab 2mg/kg IV weekly or trastuzumab 6mg/kg IV every 3 weeks)
• Subjects must have an ECOG Performance Status Score =< 1
• Non-menopausal female subjects must agree to contraception for the remainder of their childbearing years
• Male subjects must use an acceptable form of contraception throughout the course of the study
• Hematocrit >= 30,000
• Platelet count >= 100,000
• WBC >= 3000/mcl
• Stable creatinine =< 2.0 mg/dl or a creatinine clearance greater than 60 ml/min
• Serum bilirubin < 1.5 mg/dl
• SGOT < 2x ULN
• Laboratory tests should be performed within 60 days of enrollment
• Subjects must have recovered from major infections and/or surgical procedures and, in the opinion of the investigator, not have any significant active concurrent medical illnesses precluding protocol treatment
• Patients on trastuzumab monotherapy must have adequate cardiac function as demonstrated by normal ejection fraction (EF) on MUGA scan or echocardiogram performed within last 6 months

Exclusion Criteria:

• Subjects cannot be simultaneously enrolled in other treatment studies
• Patients cannot be receiving any other concurrent immunomodulators besides trastuzumab
• Any contraindication to receiving GM-CSF based vaccine products
• Cardiac disease, specifically restrictive cardiomyopathy, unstable angina within the last 6 months prior to enrollment, New York Heart Association functional class III-IV heart failure on active treatment with normalized LVEF on therapy, and symptomatic pericardial effusion
• Active autoimmune disease
• Subjects can not have active immunodeficiency disorder, e.g. HIV
• Cannot be pregnant or breast feeding