Time to progression (TTP) is defined as the interval between the date of randomization and the earliest date of progression of disease (PD) or death due to breast cancer. The investigator assessed PD based on radiological PD (imaging data) and clinical symptomatic progress (Response Evaluation Criteria in Solid Tumors [RECIST] Criteria: target lesion (TL), at least a 20% increase in the sum of largest diameter (LD) of TLs or the appearance of one or more new lesions; non-TL (NTL), the appearance of one or more new lesions and/or unequivocal progression of existing NTLs). TTP was assessed in participants who died due to breast cancer or progressed, as assessed by the investigator, as well as in those who were censored and completed follow-up and those who were censored but are still being followed. For censored participants (those without a documented date of disease progression/death due to breast cancer), the date of the last radiographic assessment was used.