This two-part, randomized, double-blind, placebo-controlled study will assess the safety, pharmacokinetics and pharmacodynamics of single and multiple ascending oral doses of RO5285119 in healthy volunteers. Anticipated time on study will be up to 9 weeks for each subject.

Inclusion Criteria:

• Healthy male adults, 18 to 45 years of age (Part 1) or healthy male or female adults, 18 to 65 years of age (Part 2)
• Body mass index (BMI) 18.0 to 30.0 kg/m2 inclusive
• Female subjects must be surgically sterile or postmenopausal
• Male subjects must use a barrier method of contraception for the duration of the study and for the three months after the last dosing

Exclusion Criteria:

• History or presence of any significant disease or disorder
• Positive for hepatitis B. hepatitis C or HIV infection
• History of drug or alcohol abuse or suspicion of regular consumption of drugs of abuse
• Participation in an investigational drug or device study within 3 months prior to first dosing
• Donation of blood within 3 months prior to first dosing
• Regular smoker (>5 cigarettes, >3 pipe-fulls, >3 cigars per day)
• History of hypersensitivity or allergic reactions
• Part 2: Contraindications for MRI scans