A Study of Pertuzumab in Combination With Trastuzumab Plus an Aromatase Inhibitor in Participants With Metastatic Human Epidermal Growth Factor Receptor 2 (HER2)-Positive and Hormone Receptor-Positive Advanced Breast Cancer

Inclusion Criteria:

Participants with HER2-positive and hormone receptor-positive advanced metastatic or locally advanced breast cancer
Post-menopausal status over 1 year
HER2-positive as assessed by local laboratory on primary or metastatic tumor
Hormone-receptor positive defined as estrogen receptor-positive and/or progesterone receptor-positive
At least one measurable lesion and/or non-measurable disease evaluable according to Response Evaluation Criteria In Solid Tumors Version 1.1

Exclusion Criteria:

Previous systemic non-hormonal anticancer therapy in the metastatic or locally advanced breast cancer setting
Previous treatment with anti-HER2 agents for breast cancer, except trastuzumab and/or lapatinib in the neoadjuvant or adjuvant setting
Disease progression while receiving adjuvant trastuzumab and/or lapatinib treatment
History of persistent Grade 2 or higher hematological toxicity according to National Cancer Institute-Common Toxicity Criteria Version 4.0
Disease-free interval from completion of adjuvant/neo-adjuvant systemic non-hormonal treatment to recurrence of within 6 months
Other malignancies within the last 5 years, except for carcinoma in situ of the cervix or basal cell carcinoma
Clinical or radiographic evidence of central nervous system metastases or significant cardiovascular disease