A Study Evaluating Trastuzumab Emtansine Plus Pertuzumab Compared With Chemotherapy Plus Trastuzumab and Pertuzumab for Participants With Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancer

Exclusion Criteria

• •Stage IV (metastatic) breast cancer
• •Participants who have received prior anti-cancer therapy for breast cancer except those participants with a history of breast lobular carcinoma in situ (LCIS) that was surgically managed or ductal carcinoma in situ (DCIS) treated exclusively with mastectomy. In case of prior history of LCIS/DCIS, \>5 years must have passed from surgery until diagnosis of current breast cancer
• •Participants with multicentric (multiple tumors involving more than 1 quadrant) or bilateral breast cancer
• •Participants who have undergone incisional and/or excisional biopsy of primary tumor and/or axillary lymph nodes
• •Axillary lymph node dissection or positive sentinel lymph node prior to start of neoadjuvant therapy
• •History of concurrent or previously non-breast malignancies except for appropriately treated (1) non-melanoma skin cancer and (2) in situ carcinomas, including cervix, colon, and skin. A participant with previous invasive non-breast cancer is eligible provided he/she has been disease-free \>/= 5 years
• •Treatment with any investigational drug within 28 days prior to randomization
• •Current National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version (v) 4.0
• •Any significant concurrent medical or surgical conditions or findings that would jeopardize the participant's safety or ability to complete the study
• •Current pregnancy or breastfeeding