Inclusion Criteria:

- Postmenopausal women

- Breast cancer that is locally advanced or metastatic

- HER2 negative disease, and a known positive hormone receptor status (common breast
cancer classification tests)

- A tumor sample must be shipped to a central lab for identification of biomarkers
(PI3K activation status) before randomization

- Prior treatment with AIs

- Evidence of progression to the combination of mTORi and endocrine therapy given as
the last therapy prior to study entry

- Adequate bone marrow and organ function

Exclusion Criteria:

- More than 1 prior chemotherapy given for locally advanced or metastatic disease

- Previous treatment with PI3K inhibitors, AKT inhibitors or fulvestrant

- Symptomatic CNS metastases

- Concurrent malignancy or malignancy within 3 years prior to start of study treatment

- Certain drugs or radiation within 2-4 weeks of enrollment

- Increasing or chronic treatment (> 5 days) with corticosteroids or another
immunosuppressive agent

- Active heart (cardiac) disease or a history of cardiac dysfunction as defined in the
protocol

- HyperSsensitivity to fulvestrant treatment excipients

- Certain scores on an anxiety and depression mood questionnaire given at screening

- Other protocol defined criteria may apply