GSK1349572 Drug Interaction Study With Atazanavir/Ritonavir and Atazanavir

GSK1349572 is an integrase inhibitor that will be evaluated for the treatment of HIV infection. As GSK1349572 progresses into clinical trials in HIV-infected patients where combination antiretroviral therapy is the standard of care, it is likely that it will be dosed with protease inhibitors (PIs) including atazanavir/ritonavir (ATV/RTV) and atazanavir alone. Ritonavir is a substrate of CYP3A and inhibitor of CYP3A and Pgp and atazanavir is an inhibitor of UGT1A1. Ritonavir is also a known inducer of CYP and UGT enzymes. As GSK1349572 likely undergoes metabolism by CYP and UGT enzymes and is a Pgp substrate, a drug interaction study between GSK1349572 and ATV is warranted. GSK1349572 is not an inhibitor or inducer of CYP3A and is not expected to have impact on pharmacokinetics (PK) of atazanavir and ritonavir. Accordingly, the primary objective of this study is to compare steady-state plasma PK, safety and tolerability of GSK1349572 30 mg every 24h (q24h) with and without ATV/RTV 300/100 mg q24h or ATV 400mg q24h. Approximately 24 subjects will receive GSK1349572 30mg q24h for 5 days (Treatment A). Subjects will then be administered GSK1349572 30mg q24h in combination with either ATV/RTV 300/100 mg q24h (Treatment B, n=12) or ATV 400 mg q24h (Treatment C, n=12) for 14 days. There will be no washout between treatments. Safety evaluations and serial PK samples will be collected during each treatment period. A follow-up visit will occur 7-14 days after the last dose of study drug. This study will be conducted at one center in the US, with healthy adult male and female subjects.