Xenogeneic HER2/Neu DNA Immunization for Patients With Metastatic and High Risk Breast Cancer: A Phase I Study to Assess Safety and Immunogenicity

Breast cancer patients with AJCC Stage III or metastatic (AJCC Stage IV) disease that over-express HER2 will potentially be eligible for this trial. Patients may have measurable disease, evaluable disease or be without evidence of disease. They may be receiving hormonal therapy and they may have already received trastuzumab (Herceptin) or be receiving trastuzumab during this study. Inclusion Criteria: Patients must have ALL of the features listed below: * AJCC Stage IV breast cancer (histologically confirmed) with no evidence of disease or stable disease. Patients may be either off therapy or on hormone therapy and/or trastuzumab. OR AJCC Stage III breast cancer \< or = to 36 months post completion of adjuvant therapy. * Pathology slides must be reviewed by the Department of Pathology at MSKCC. * HER2 over-expression by FISH or by staining 3+ on immunohistochemistry in either the primary or metastatic tumor. * Karnofsky performance status \> or = to 80%. * Patients must have recovered from the toxicity of any prior therapy, and not received major surgery, radiation therapy, or chemotherapy for at least 4 weeks prior to entry into the trial. (Ongoing hormonal therapy and/or trastuzumab administration is permitted.) * Age \> 18 years Exclusion Criteria: * Pregnancy (Women of child bearing potential must not be pregnant and have a normal pregnancy test within 2 weeks of starting treatment.) Woman who may yet bear children and sexually active men must be using appropriate …