This single-center, randomized, investigator/subject-blind, adaptive multiple ascending-dose, placebo-controlled study will evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of RO5545965 in healthy volunteers. Subjects will be randomized to receive either RO5545965 or matching placebo daily for 12 days.

Inclusion Criteria:

• Adult male and female volunteers, 18 - 64 years of age, inclusive Healthy status is defined by absence of evidence of any active or chronic disease following detailed medical and surgical history and a complete physical examination
• Body mass index (BMI) 18 to 30 kg/m2 inclusive
• Female subject must be post-menopausal or surgically sterile
• Male subjects with female partners of child-bearing potential must use two methods of contraception, one of which must be a barrier method, for the duration of the study and for at least 30 days after the last dose of study drug

Exclusion Criteria:

• History of any clinically significant disease or disorder
• Concomitant disease or condition that could interfere with, or the treatment of which might interfere with, the conduct of the study, or that would, in the opinion of the investigator, pose an unacceptable risk to the subject in this study
• Clinically significant abnormalities in laboratory test results
• Suspicion of regular consumption of drug of abuse
• Positive for hepatitis B, hepatitis C or HIV infection
• Participation in an investigational drug or device study within 90 days prior to screening
• Regular smoker (>5 cigarettes, >1 pipeful or >1 cigar per day)
• History of clinically significant hypersensitivity or allergic drug reactions