Subject with Cystic Fibrosis have increased clearance of many drugs. Based on pre-clinical
data SB656933 was found to have low clearance and high bio-availability. This study will
characterize the PK profile of a single dose of SB656933 in patients with Cystic Fibrosis.
There will be two groups of subjects. The first group of subjects will receive a single dose
of 50mg SB-656933. The second group of subjects will receive a single dose of up to 300 mg
SB-656933. Subjects will first be screened for eligibility related to cystic fibrosis
history. Safety evaluations will be undertaken and plasma samples for pharmacokinetic
analysis will be collected. Additional blood samples will be taken for the pharmacodynamic
endpoints CD11b and GAFS. Subjects are not required to stay overnight after their 12 hour PK
sample collection on Day 1, although they may do so if they wish. On Day 2 and 3, they will
return for collection of additional safety measurements, and further plasma and blood samples
will be taken for 24 and 48 h pharmacokinetics and 24h CD11b/GAFS measurements, respectively.
A follow up visit (Visit 3) will be made 4-7 days after the treatment period. Subjects will
be enrolled in the study for approximately 3to 7 weeks (from screening to follow-up).