The data generated from this single dose escalation component of the study (safety, tolerability, and where applicable, PK profile, and, if available, PD data) will enable decisions regarding progression from one to dose the next higher dose later within Cohorts 1 and 2. This data will also be reviewed in decisions regarding study progression to repeat dosing in Cohorts 3 and 4, and the most suitable doses of GSK1325756 that should be selected for these repeat dose cohorts.