This Phase 1, open-label, randomized, 4-period crossover study is designed to determine the relative bioavailability of GDC-0941 administered as a single dose of the market image formulation at 3 different hardnesses (hardness 1, 2, and 3) and as a single dose of the Phase 2 formulation to healthy male and female volunteers. Participants will be randomly assigned to 4 possible treatment sequences, each comprising 4 periods (1 per formulation), and GDC-0941 will be administered based on the assigned sequence. The study is expected to last 8 weeks.

Inclusion Criteria:

• Male and female participants between 18 and 55 years of age, inclusive,
• Body mass index (BMI) between 18.5 to 32 kg/m2, inclusive,
• Healthy, as determined by no clinically significant findings from medical history, ECG, and vital signs, and who are able to swallow and tolerate a tethered Heidelberg pH Capsule and have gastric pH measurements taken

Exclusion Criteria:

• Any medical condition or history of such condition that may, in the opinion of the investigator, contraindicate participation in this study