Therapeutic Cancer Vaccine (AST-301, pNGVL3-hICD) in Patients With Breast Cancer

Key Inclusion Criteria: * Has a residual invasive cancer in the breast(non-pCR) after neoadjuvant treatment * Has stage I, II, or III disease prior to surgery per American Joint Committee on Cancer (AJCC) * HER 2 1+ by IHC or HER2 2+by IHC without gene amplification by ISH, as defined by American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines. * Hormone receptor (ER and PR) negative by ASCO/CAP guidelines * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Demonstrates adequate organ function. Key Exclusion Criteria: * Has a history of hypersensitivity or other contraindications to rhGM-CSF * Has a history of invasive malignancy ≤5 years prior to first administration of investigational drug except for adequately treated non-melanoma skin cancer or carcinoma in situ. * Is on immune suppression therapy or has a history of immune suppression therapy ≤4 weeks prior to the first administration of investigational drugs * Has a history of autoimmune disease or inflammatory disease * Has active infection including tuberculosis, hepatitis B, hepatitis C or human immunodeficiency virus (HIV) infection * Is pregnant or breastfeeding or expecting to conceive children