A Study of Three Modified-Release Formulations of RO4917523 in Healthy Volunteers

Inclusion Criteria:

- Healthy male and female volunteers, 18 - 55 years of age inclusive Healthy status
will be defined by absence in evidence of any active or chronic disease following a
detailed medical and surgical history and a complete physical examination

- Body mass index (BMI) of 18 to 30 kg/m2, inclusive, and body weight of at least 50 kg

- Females of child-bearing potential must agree to use effective contraception as
defined by protocol

- Non-smoker for at least 90 days prior to dosing on Day 1

Exclusion Criteria:

- History or presence of a clinically significant psychiatric condition as defined by
protocol

- Participation in an clinical study with an investigational drug within 60 days or 5
times the half-life (whichever is longer) preceding first administration of study
drug. Participation in more than 3 other drug studies within 10 months preceding
first administration of study drug.

- Clinically significant disease or disorder

- Personal or family history of long QT syndrome or sudden death

- Any suspicion or history of alcohol and/or other substance abuse or dependence in the
last 6 months

- Subject likely to need concomitant medication during the study (including for dental
conditions), except for hormonal contraception or HRT

- Pregnant or lactating women, or women who intend to become pregnant during the course
of the study

- Positive for hepatitis B, hepatitis C or HIV infection

- Any confirmed significant allergic reactions against any drug, or multiple allergies