Tenofovir Disoproxil Fumarate/Emtricitabine/Efavirenz Versus Combivir/Efavirenz in Antiretroviral-Naive HIV-1 Infected Subjects

A Phase 3, Randomized, Multicenter Study of the Treatment of Antiretroviral-Naive HIV-1 Infected Subjects Comparing Tenofovir Disoproxil Fumarate and Emtricitabine in Combination With Efavirenz vs Combivir (Lamivudine/Zidovudine) and Efavirenz

The purpose of Study GS-01-934 was to assess the efficacy and safety of two simplified antiretroviral treatment (ART) regimens in ART-naive, human immunodeficiency virus, type 1 (HIV-1) infected participants. The primary objective of the study was to assess noninferiority of emtricitabine (FTC) and tenofovir disoproxil fumarate (tenofovir DF; TDF) in combination with efavirenz (EFV) relative to Combivir (CBV) in combination with EFV in the treatment of HIV-1 infected ART-naive participants, determined by the achievement and maintenance of confirmed HIV-1 ribonucleic acid (RNA) < 400 copies/mL (c/mL) through Week 48, as defined by the United States (US) Food and Drug Administration (FDA) time-to-loss-of-virologic-response (TLOVR) algorithm.

This study was originally planned as a 48-week, Phase 3, randomized, open-label, multicenter study comparing EFV+FTC+TDF (administered as the individual component drugs) versus CBV (lamivudine/zidovudine) + EFV to assess the efficacy and safety of both treatments in ART-Naive, HIV-1 infected participants. The regimen of CBV (administered twice daily) + EFV (administered once daily) served as the active control treatment and was compared with the regimen of EFV+FTC+TDF; each component drug in the EFV+FTC+TDF regimen was administered once daily.

Week 48 to Week 96:

The study was extended and continued to evaluate the efficacy and safety of the two regimens up to a total treatment duration of 96 weeks. The regimen of EFV+FTC+TDF continued to be dosed as the component drugs (EFV + FTC + TDF), once daily, without regard to meals. The regimen of CBV+EFV was dosed as 2 pills (CBV, twice daily in the morning without regard to meals) + EFV (once daily, without regard to meals).

Week 96 to Week 144:

A further study extension changed the 3-pill EFV+FTC+TDF regimen to a 2-pill regimen of EFV + Truvada ([TVD]: a fixed-dose combination pill containing FTC/TDF), once daily without regard to meals, and continued to evaluate the efficacy and safety of the two regimens for a further 48 weeks up to a total study treatment duration of 144 weeks. The regimen of CBV+EFV continued to be dosed as 2 pills (CBV, twice daily in the morning without regard to meals) + EFV (once daily, without regard to meals).

Week 144 to end of study (Week 240):

A final study extension provided all study participants from both treatment regimens the option to switch their respective treatments to the 1-pill regimen of for a further 96 weeks up to a total study duration of 240 weeks (5 years) to further assess the efficacy and safety of ART regimen simplification. At sites in France, the study was extended by a further 48 weeks (Year 6) or until ATR became commercially available (whichever happened first); once ATR became commercially available in France participants were not required to complete the full 288 weeks of the study.

Inclusion Criteria: Participants must have met all inclusion criteria within 28 days prior to randomization unless specified otherwise including:

• Plasma HIV-1 RNA levels greater than 10,000 c/mL using Roche Amplicor HIV-1 Monitor Test Version 1.5 Standard
• Adequate renal function: Calculated creatinine clearance greater than or equal to 50 mL/min according to the Cockcroft-Gault Formula.
• Hepatic transaminases (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) 3 x upper limit of normal (ULN).
• Total bilirubin less than or equal to 1.5 mg/dL.
• Adequate hematologic function (absolute neutrophil count greater than or equal to 1,000/mm^3; platelets greater than or equal to 50,000/mm^3; hemoglobin greater than or equal to 8.0 g/dL).
• Serum amylase less than or equal to 1.5 x ULN.
• Serum phosphorus greater than or equal to 2.2 mg/dL.
• Willingness to use effective contraception by both males and females while on study treatment and for 30 days following study drug completion.
• Life expectancy greater than or equal to 1 year
• The ability to understand and sign written informed consent form obtained prior to initiation of study procedures.

Exclusion Criteria: Participants were not eligible for entry to the study if any of the following were met:

• Prior treatment with any non-nucleoside reverse transcriptase inhibitor (NNRTI), nucleoside reverse transcriptase inhibitor (NRTI), or protease inhibitor (PI).
• A new AIDS-defining condition diagnosed (exception CD4 criteria) within 30 days of baseline.
• Receiving ongoing therapy with any of the following: nephrotoxic agents, probenecid, systemic chemotherapeutic agents, systemic corticosteroids, interleukin-2, drugs that interact with efavirenz. Administration of any of the above medications must be discontinued at least 30 days prior to baseline visit and for duration of study.
• Pregnant or lactating participants.
• Malignancy other than cutaneous Kaposi's sarcoma (KS) or basal cell carcinoma. Participants with biopsy-confirmed KS were eligible but must not have received any systemic therapy for KS within 30 days of baseline and not anticipated starting systemic therapy during the study.
• Prior history of renal or bone disease.
• Any other clinical condition prior to therapy that would make the participant unsuitable for the study or unable to comply with the dosing requirements in the opinion of the investigator.