Adding an Immunotherapy Drug, MEDI4736 (Durvalumab), to the Usual Chemotherapy Treatment (Paclitaxel, Cyclophosphamide, and Doxorubicin) for Stage II-III Breast Cancer

Defined as a continuous measure of the extent of residual cancer after neoadjuvant chemotherapy that combines the largest diameter of the cancer in the breast, the tumor cell cellularity of the cancer, and the largest diameter and number of involved axillary lymph nodes into a single RCB score. RCB will be analyzed by comparing RCB 2-3 to RCB 0-1.

Analyses will be performed using log-rank testing, Cox regression, and Kaplan-Meier estimation.

Analyses will be performed using log-rank testing, Cox regression, and Kaplan-Meier estimation. Will also be conducted at alpha = 0.05 (2-sided).

Defined as the absence of residual invasive cancer on hematoxylin and eosin evaluation of the complete resected breast and specimen and all sampled regional lymph nodes following completion of neoadjuvant systemic therapy (ypT0/Tis ypN0). At the completion of all treatment and surgery for all enrolled participants, there will be a comparison of pCR rates between the treatment arms. pCR rates will be compared by a test of two proportions followed by logistic regression to estimate the odds ratio after adjustment for the stratification factors.