Vaccine to Prevent Recurrence in Patients With HER-2 Positive Breast Cancer

Inclusion Criteria: * Clinical stage I-III HER2 positive breast cancer treated with neoadjuvant chemotherapy including HER-2 directed treatment for at least 12 weeks. * Residual invasive carcinoma in the breast or axillary nodes in the final pathology from resected tumor following neoadjuvant chemotherapy. * Completed last cycle of cytotoxic chemotherapy (excluding ado-trastuzumab emtansine \[T-DM1\]) or radiation \> 30 days with resolution of all acute toxic effects of prior therapy to grade ≤ 2 (except alopecia) * Currently on HER-2 targeted therapy (eg; trastuzumab +/- pertuzumab or T-DM1) per standard of care or has completed HER-2 targeted therapy less than 6 months ago * Age ≥ 18 years. * Eastern Cooperative Group (ECOG) performance status 0 or 1. * Must have normal organ and marrow function as defined below: * Absolute neutrophil count (ANC) ≥ 1,000/ μL * Platelets ≥ 75,000/ μL * Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN), except patients with Gilbert's syndrome in whom total bilirubin must be \<3.0 mg/dL * AST/ALT ≤ 3 x institutional upper limit of normal (ULN) * Creatinine ≤ 1.5 x institutional upper limit of normal (ULN) * Hemoglobin A1C \<6.5% * Left ventricular ejection fraction (LVEF) above institutional lower limit of normal (by echocardiogram or MUGA scan within 90 days of registration). * Females of child-bearing potential must agree to use dual methods of contraception and have a negative serum pregnancy test at screening, and males must use an effective barrier method of contraception if sexually active with a female of child-bearing potential. For both male and female participants, effective methods of contraception must be used throughout the study and for three months following the last dose. * Ability to understand and willingness to sign a written informed consent document prior to initiation of any screening or study-specific procedures. Exclusion Criteria: * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, congenital prolonged QT syndrome, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. * Uncontrolled autoimmune disease requiring active systemic treatment. * Known hypersensitivity reaction to the Granulocyte-macrophage colony stimulating factor (GM-CSF) adjuvant; any known contraindication to GM-CSF. * Pregnant or breast feeding. * Known HIV-positive. * Known current or a history of hepatitis B or C virus, including chronic and dormant states, unless disease has been treated and confirmed cleared. * Major surgery within 4 weeks of initiation of study drug. * Current extended use of immunosuppressive agents or systemic corticosteroids. Topical, ocular, intra-articular, intranasal, inhalational corticosteroids (with minimal systemic absorption) are allowed. A brief course of corticosteroids for prophylaxis (eg., for contrast dye allergy) or for treatment of non-autoimmune conditions (eg., delayed-type hypersensitivity reaction caused by a contact allergen) is permitted. * Potential participant is currently on active treatment in any other clinical protocol or investigational trial that involves administration of experimental therapy and/or therapeutic devices, or investigational drug.