The aims of this study are to evaluate the safety and tolerability of single intravenous (IV) doses of GW856553 in healthy adult subjects and to investigate the relationship between PK and PD markers within the first few hours following administration of study drug to support progression of this formulation into a patient population.~Subjects in Cohort 1 (n=4) will receive a single 1mg IV dose (given as a 15 minute infusion) of GW856553. Safety, tolerability and PK exposures will be reviewed, and in an optional cohort (Cohort 2) (n=4), the dose may be adjusted upward or downward based on data from Cohort 1. Based on the results from Cohort 1 (and Cohort 2 if required), Cohort 3 (n=12) will be dosed appropriately to receive a single IV 15 minute infusion of GW856553.~After a one week washout, Cohort 3 subjects will receive a single oral dose of 15mg GW856553. Access to both IV and oral PK in the same individuals will permit calculation of absolute bioavailability for the oral dose. Subjects will be resident in the research unit from the morning prior to dosing until after the last PK blood sample is collected at 24 hours after the dose of study drug (excluding any washout period).
The purpose of this study is to evaluate the safety of an IV infusion of GW856553 in healthy volunteers.