Key

Inclusion Criteria:

1. Histologically or cytologically proven diagnosis of adenocarcinoma of the breast with
evidence of either locally recurrent disease not amenable to resection or radiation
therapy with curative intent, or metastatic disease, both progressing after at least
6 months of hormonal therapy for ER+ breast cancer

2. ER-positive, HER2-negative

3. At least 2 months must have elapsed from the use of tamoxifen

4. At least 6 months must have elapsed from the use of fulvestrant

5. At least 2 weeks must have elapsed from the use of any other anti-cancer hormonal
therapy

6. At least 4 weeks must have elapsed from the use of any chemotherapy

7. Females, 18 years of age or older

8. Postmenopausal status

9. Eastern Cooperative Oncology Group (ECOG) Performance status ≤ 2

Key Exclusion Criteria:

1. Untreated or symptomatic CNS metastases.

2. Endometrial disorders

3. More than 1 prior chemotherapy in the advanced/metastatic setting (prior adjuvant
chemotherapy is allowed so long as it occurred ≥ 12 months prior to enrollment)

4. Current treatment with any systemic anti-cancer therapies for advanced disease or any
systemic experimental treatment on another clinical trial