Additional information about the study can be found at www.clinicaltrials.gov.About Tenofovir Alafenamide Fumarate Tenofovir alafenamide fumarate (TAF) is a nucleotide reverse transcriptase inhibitor and a novel prodrug of tenofovir, the active agent in Viread ® (tenofovir disoproxil fumarate). Phase 1b dose-ranging studies identified a dose of TAF that is ten times lower than Viread and provides greater antiviral efficacy. The smaller milligram size of TAF may enable the development of new fixed-dose combinations and single tablet regimens for HIV therapy that are not feasible with Viread. About Elvitegravir As an integrase inhibitor, elvitegravir interferes with HIV replication by blocking the ability of the virus to integrate into the genetic material of human cells. Elvitegravir was licensed by Gilead from Japan Tobacco Inc. (JT) in March 2005. Under the terms of Gilead’s agreement with JT, Gilead has exclusive rights to develop and commercialize elvitegravir in all countries of the world, excluding Japan, where JT retains rights. Gilead submitted a New Drug Application (NDA) to FDA for elvitegravir on June 27, 2012, and the agency has set a target action date under the Prescription Drug User Fee Act (PDUFA) of April 27, 2013. About Cobicistat Cobicistat is Gilead’s proprietary potent mechanism-based inhibitor of cytochrome P450 3A (CYP3A), an enzyme that metabolizes drugs in the body. Unlike ritonavir, cobicistat acts only as a pharmacoenhancing or “boosting” agent and has no antiviral activity. Gilead submitted an NDA to FDA for cobicistat on June 28, 2012, and a PDUFA date of April 28, 2013 has been set. TAF, elvitegravir and cobicistat are investigational products and their safety and efficacy have not yet been established. Important Safety Information about Stribild Stribild contains four Gilead compounds in a complete once-daily, single tablet regimen: elvitegravir 150 mg; cobicistat 150 mg; emtricitabine 200 mg; and tenofovir disoproxil fumarate 300 mg. Stribild is indicated as a complete regimen for the treatment of HIV-1 infection in adults who are antiretroviral treatment-naïve. Stribild does not cure HIV-1 infection.