Safety and Efficacy of E/C/F/TDF Versus RTV-Boosted ATV Plus FTC/TDF in HIV-1 Infected, Antiretroviral Treatment-Naive Women

Key Inclusion Criteria: * Female (at birth), age ≥ 18 years * Ability to understand and sign a written informed consent form * Plasma HIV-1 RNA levels ≥ 500 copies/mL * No prior use of any approved or investigational antiretroviral drug for any length of time * Screening genotype report must show sensitivity to emtricitabine (FTC), tenofovir disoproxil fumarate (TDF) and atazanavir (ATV) boosted with ritonavir (RTV) * Normal ECG * Adequate renal function: Estimated glomerular filtration rate ≥ 70 mL/min according to the Cockcroft Gault formula * Hepatic transaminases ≤ 5 x upper limit of normal (ULN) * Total bilirubin ≤ 1.5 mg/dL * Adequate hematologic function * Serum amylase ≤ 5 x ULN * Women of childbearing potential must agree to utilize protocol recommended contraception methods or be non-heterosexually active, or practice sexual abstinence from screening throughout the duration of the study period and for 30 days following the last dose of study drug * Women who utilize hormonal contraceptive as one of their birth control methods must have used the same method for at least three months prior to study dosing. Key Exclusion Criteria: * A new AIDS defining condition diagnosed within the 30 days * Females receiving drug treatment for Hepatitis C, or females who are anticipated to receive treatment for Hepatitis C during the course of the study * Females experiencing decompensated cirrhosis * Females who are breastfeeding * Positive serum pregnancy test (female of childbearing potential) * Have an implanted defibrillator or pacemaker * Have an ECG pulse rate interval ≥ 220 msec * Current alcohol or substance use which may potentially interfere with the female's study compliance * History of malignancy within the past 5 years or ongoing malignancy other than cutaneous Kaposi's sarcoma (KS), basal cell carcinoma, or resected, non-invasive cutaneous squamous carcinoma * Active, serious infections requiring parenteral antibiotic or antifungal therapy within 30 days prior to baseline * Participation in any other clinical trial without prior approval * Any other clinical condition or prior therapy that would make the female unsuitable for the study or unable to comply with the dosing requirements * Females receiving ongoing therapy with any disallowed medications, including drugs not to be used with elvitegravir, cobicistat, FTC, TDF, ATV, RTV; or females with any known allergies to the excipients of Stribild® tablets, Truvada® tablets, atazanavir capsules or ritonavir tablets Note: Other protocol defined Inclusion/Exclusion criteria may apply.