A phase 2/3 multicenter, open-label, multicohort, two-part study evaluating the pharmacokinetics (PK), safety, and antiviral activity of Elvitegravir (EVG) administered with a background regimen (BR) containing a Ritonavir-boosted protease inhibitor (PI/r) in HIV-1 infected, antiretroviral treatment-experienced pediatric subjects

This is an open-label, multicenter, multicohort, two-part study to confirm the dose and evaluate the safety and tolerability of ritonavir-boosted elvitegravir (EVG/r) in HIV-1 infected, treatment-experienced subjects aged 4 weeks to less than 18 years of age. The dose of EVG will be determined by intensive pharmacokinetic sampling at Day 10. The safety and antiviral activity of EVG will also be evaluated.