In an open-label randomised clinical study (GS-01-934), antiretroviral-naïve HIV-1 infected patients received either a once daily regimen of emtricitabine, tenofovir disoproxil fumarate and efavirenz (n=255) or a fixed combination of lamivudine and zidovudine (Combivir) administered twice daily and efavirenz once daily (n=254).