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