This randomized, double-blind, placebo-controlled study will evaluate the safety, tolerability, pharmacokinetics of RO6870868 in healthy volunteers. Subjects will be randomized to receive single ascending doses of either RO6870868 or placebo, with or without food.

Inclusion Criteria:

• Healthy male and female subjects, 18 to 65 years of age, inclusive. Healthy status is defined by absence of evidence of any active or chronic disease following a detailed medical and surgical history and a complete physical examination
• Women of non-childbearing potential including women who have undergone hysterectomy or bilateral oophorectomy and postmenopausal females
• Male subjects must be willing to use effective contraception as defined by protocol for the duration of the study and for one month after the last dose of study medication
• Body Mass Index (BMI) at screening of 18 to 32 kg/m2, inclusive
• Non-smokers, or use of < 10 cigarettes (or equivalent nicotine-containing product) per day
• No medical or social conditions that would potentially interfere with the subjects ability to comply with the study visit schedule or the study assessments

Exclusion Criteria:

• Pregnant (positive pregnancy test) or lactating women, and male partners of women who are pregnant or lactating
• History of drug or alcohol abuse within the last year
• History of immunologically mediated disease
• History or symptoms of any significant disease including (but not limited to) neurological, cardiovascular, endocrine, respiratory, gastrointestinal, hepatic, or renal disorder
• Personal or family history of congenital long QT syndrome or sudden death
• Evidence of an active or suspected cancer or a history of malignancy where in the investigator's opinion, there is a risk of recurrence. History of having received any systemic anti-neoplastic (including radiation) or immunomodulatory treatment (including systemic oral or inhaled corticosteroids) \