This is a Phase I, single center, two-part, randomized, open label, cross-over study. Part 1 of this study will evaluate the PK, safety, and tolerability of GSK525762 when administered alone and when co-administered following repeat dosing of itraconazole, a known strong inhibitor of Cytochrome P450 3A4 (CYP3A4) and a Para-glycoprotein (Pgp) inhibitor. Part 1 will consist of 2 Cohorts with preliminary PK and safety data obtained from Cohort 1 informing Cohort 2. Part 2 (one Cohort) of the study will evaluate the PK, safety, and tolerability of GSK525762 when administered alone and when co-administered following repeat dosing of rifampicin, a known potent inducer of CYP3A4. In vitro inhibition data indicate CYP3A4 may be the major route of clearance for GSK525762 and co-administration of drug therapies which modulate CYP3A4 (i.e.CYP3A4 inhibitors and inducers) is likely to alter the exposure of GSK525762 (i.e. increase or decrease exposure, respectively). The data generated from this current study to justify exclusion criteria on concomitant medications which affect CYP3A4 or Pgp and also inform potential dose modification in case of co-administration with medication affecting CYP3A4 activity. All subjects will undergo a screening visit within 28 days of the first dose of study drug followed by one treatment period and a follow-up visit 7-10 days after the last dose of GSK525762. Subjects in Part 1 will participate in the study for up to 45 days and subjects in Part 2 will participate for up to 56 days.