This is a Phase I, single-center, three-arm, randomized, double-blind, active- and placebo-controlled study to investigate the effect of GDC-0449 on the QT/QTc interval in healthy female subjects of non-childbearing potential.

Inclusion Criteria:

• Female, over 45 years of age
• In good health, as determined by the absence of clinically significant findings from the screening visit
• Body mass index between 18 and 32 kg/m^2 inclusive, with a body weight > 45 kg
• Of non-childbearing potential

Exclusion Criteria:

• History of any clinically significant gastrointestinal, renal, hepatic, broncho-pulmonary, neurological, psychiatric, cardiac, vascular, endocrinological, hematological, or allergic disease; metabolic disorder; cancer; or cirrhosis
• Allergy to moxifloxacin or any quinolone antibiotics or any confirmed significant allergic reactions against any drug, or multiple allergies in the judgment of the investigator
• Personal or family history of congenital long QT syndrome or family history of sudden death
• Participation in an investigational drug or device study with an investigational drug within the last 3 months or six times the elimination half-life, whichever is longer, prior to Day 1 of the study