A Study of PI3-Kinase Inhibitor GDC-0941 in Combination With Paclitaxel, With and Without Bevacizumab or Trastuzumab, and With Letrozole, in Participants With Locally Recurrent or Metastatic Breast Cancer

Inclusion Criteria:

- Confirmed adenocarcinoma of the breast with locally recurrent or metastatic disease

- Adequate organ and bone marrow function as assessed by laboratory tests

- Evaluable disease or disease measurable per RECIST

- Agreement to use an effective form of contraception for the duration of the study

Exclusion Criteria:

- History of malabsorption syndrome or other condition that would interfere with
enteral absorption

- Any condition requiring full-dose anticoagulants, such as warfarin, heparin, or
thrombolytic agents

- Prior anti-cancer therapy (e.g., chemotherapy, biologic therapy, radiotherapy, or
hormonal therapy) within 4 weeks or 5 half-lives (whichever is shorter) of the first
dose of study treatment

- Uncontrolled current illness

- Active small or large intestine inflammation (such as Crohn's disease or ulcerative
colitis)

- Clinically significant history of liver disease, including cirrhosis, current alcohol
abuse, or current known active infection with human immunodeficiency virus (HIV),
hepatitis B virus, or hepatitis C virus

- Known HIV infection

- New York Heart Association (NYHA) Class II or greater congestive heart failure

- Active ventricular arrhythmia requiring medication

- Pregnancy, lactation, or breastfeeding

- Known significant hypersensitivity to study drugs or excipients

- History of arterial thromboembolic disease within 6 months of first study treatment

- No more than two prior chemotherapy regimens for metastatic disease