A new single-tablet, fixed-dose formulation consisting of elvitegravir, an HIV-1 
integrase strand transfer inhibitor (INSTI); cobicistat, a pharmacokinetic 
enhancer; emtricitabine, a nucleoside reverse transcriptase inhibitor; and 
tenofovir disoproxil fumarate (tenofovir DF), a nucleotide reverse transcriptase 
inhibitor (elvitegravir/cobicistat/emtricitabine/tenofovir DF 150 mg/150 mg/200 
mg/300 mg; Stribild®) is available in some countries for the once-daily 
treatment of HIV-1 infection in antiretroviral therapy-naïve adults. 
Elvitegravir/cobicistat/emtricitabine/tenofovir DF is the first INSTI-based 
single-tablet regimen available for the complete initial treatment of adults 
with HIV-1 infection. In two large, randomized, double-blind, phase III trials, 
once-daily treatment with elvitegravir/cobicistat/emtricitabine/tenofovir DF was 
effective in reducing plasma HIV-1 RNA levels to <50 copies/mL at the week 48 
assessment and showed virological efficacy noninferior to that of the 
efavirenz/emtricitabine/tenofovir DF single-tablet regimen or a once-daily 
regimen of atazanavir plus ritonavir (ritonavir-boosted atazanavir) plus the 
fixed-dose combination of emtricitabine/tenofovir DF. 
Elvitegravir/cobicistat/emtricitabine/tenofovir DF also showed durable efficacy 
in terms of achieving sustained suppression of HIV-1 RNA levels to <50 copies/mL 
for up to 144 weeks in both of the phase III trials. 
Elvitegravir/cobicistat/emtricitabine/tenofovir DF is an important addition to 
the group of simplified once-daily single-tablet regimens currently available 
for the effective treatment of HIV-1 infection in antiretroviral therapy-naïve 
patients and is among the preferred regimens recommended for use as initial 
treatment. It offers advantages over more complex multiple-tablet regimens that 
may impair treatment adherence, which is fundamental to the successful 
management of HIV-1 infection.