A Study of GDC-0927 in Postmenopausal Women With Locally Advanced or Metastatic Estrogen Receptor Positive Breast Cancer

Inclusion Criteria:

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
ER-positive tumor, HER2-negative breast cancer
No prior treatment with GDC-0810 (allowed only during dose expansion stage)
No more than 2 prior chemotherapies in the advanced or metastatic setting
At least 2 months must have elapsed from the use of tamoxifen
At least 6 months must have elapsed from the use of fulvestrant
At least 2 weeks must have elapsed from the use of any other endocrine therapy
At least 3 weeks must have elapsed from the use of any chemotherapy
Females, 18 years of age or older
Postmenopausal status as defined by the protocol
Eastern Cooperative Oncology Group (ECOG) Performance status less than or equal to ( Adequate organ function

Exclusion Criteria:

Untreated or symptomatic brain metastases
Current treatment with any systemic anti-cancer therapies for advanced disease or any systemic experimental treatment on another clinical trial
Any of the following within 12 months prior to enrollment: myocardial infarction, severe/unstable angina, ongoing cardiac dysrhythmias of Grade greater than or equal to (>/=) 2, atrial fibrillation of any grade, coronary/peripheral artery bypass graft, symptomatic congestive heart failure, or cerebrovascular accident including transient ischemic attack
Active inflammatory bowel disease or chronic diarrhea, short bowel syndrome, or upper gastrointestinal surgery including gastric resection
Known Human Immunodeficiency Virus (HIV) infection
Major surgery within 4 weeks prior to enrollment
Radiation therapy within 2 weeks prior to enrollment