Single-Center, Open-label Study Investigating the Excretion Balance, Pharmacokinetics and Metabolism of a Single Oral Dose of [14C]-radio-labeled RO4602522 in Healthy Male Volunteers

RO4602522 is a new investigational compound that may eventually be used for the
treatment of Alzheimer*s disease. RO4602522 is an inhibitor of MAO-B. MAO-B has
been chosen as a target for drug development in Alzheimer*s disease because
there is evidence to suggest that it is involved in the etiology of the
disease. In patients with Alzeimer*s disease, brain MAO-B activity is increased
compared with age-matched controls.
RO4602522 is not registered as a drug but has been given to humans before.

Primary:
* To explore the routes and rates of elimination of [14C]-labeled RO4602522.
* To investigate the pharmacokinetics of total drug related material, RO4602522
and its metabolites as appropriate.
Secondary:
* To investigate metabolic profiles of RO4602522 in plasma and excreta and
characterize any major metabolites.

This is an open-label study, with 6 healthy male volunteers. The volunteers
will receive [14C]-labeled RO4602522 as a capsule for oral administration.

A single dose of 60 mg radio labeled study medication in the form of an oral
capsule.
In this study radio labeled RO4602522 will be used. The amount of radioactivity
in this dose will be 2.81 MBq (MBq = megaBecquerel, this is a unit to express
the amount of radioactivity in the study drug). The average environmental
background radiation burden in The Netherlands is approximately 2 mSv per year
(mSv = miliSievert, this is the unit which indicates the burden on the human
body; thus the effect on the human body of the amount of radioactivity
administered). The additional radiation burden in this study due to the
administration of 2.81 MBq 14C-labeled RO4602522 is calculated to be 0.5 mSv.
This is approximately 25 % of the average annual radiation burden.

During the study, several assessments are performed that can be more or less
inconvenient:

Blood draw, indwelling canula
During this study less then 500 ml of blood will be drawn. It is anticipated
that on Day -1 an indwelling canula will be inserted for most of the blood
sampling on Day 1 and 2. On the other days during this study, blood will be
drawn by direct puncture of the vein.

Collection of urine and feces
Urine and feces will be collected until the day of discharge (thus until Day 8
- 12). In addition, when the radioactivity level is above the pre-defined
levels, collection of urine and feces may have to be continued at home.

Heart trace (ECG*s)
ECG*s will be made on Day 1 and day of discharge.