This single-center, randomized, placebo-controlled, double-blind study will assess the safety, pharmacokinetics and pharmacodynamics of RO6836191 in healthy male volunteers in two parts. Part 1 will assess the safety of oral single ascending doses of RO6836191 compared to placebo in fasted volunteers. In Part 2, participants will be given two single oral doses of RO6836191 or placebo under low or normal-salt diet conditions. A subset of these participants will subsequently receive a single IV dose of RO6836191 for further analysis.

Inclusion Criteria:

• Healthy male volunteers, aged 18 to 45 years old.
• No active or chronic disease following a detailed medical and surgical history and complete physical examination.
• A BMI between 18 to 30 kg/m2 inclusive.
• Use of a highly effective form of birth control for the duration of the study and until 90 days after the last dose.

Exclusion Criteria:

• Any clinically relevant current or history of conditions or illnesses.
• Clinically significant symptoms of infection within 5 days of the first dosing day or a history of recurrent infections.
• Any suspicion or history of alcohol abuse and/or consumption of other drugs of abuse.
• Smokers unable or unwilling to restrict to 5 cigarettes daily during the study and to not smoke during the stay at the clinic.
• Any cardiac abnormalities.
• Blood donation over 450 mL within three months prior to screening.
• Participation in an investigational drug or device study within 3 months prior to dosing.
• Corticosteroid use within 3 months prior to dosing.