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HIV Clin Trials. 2013 Nov-Dec;14(6):284-91. doi: 10.1310/hct1406-284.

Early virologic response to abacavir/lamivudine and tenofovir/emtricitabine during ACTG A5202.

Author information

1
Division of Infectious Diseases, Stanford University, Palo Alto, California.
2
Center for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts.
3
Division of HIV Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California.
4
Division of Infectious Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
5
Division of Infectious Diseases, University of Washington, Seattle, Washington.
6
Division of Infectious Diseases, University of Miami, Miami, Florida.

Abstract

BACKGROUND:

ACTG A5202 randomized treatment-naïve individuals to tenofovir-emtricitabine (TDF/FTC) or abacavir-lamivudine (ABC/3TC) combined with efavirenz (EFV) or atazanavir/ritonavir (ATV/r). Individuals in the high screening viral load (VL) stratum (≥100,000 copies/mL) had increased rates of virologic failure with ABC/3TC.

OBJECTIVE:

To compare regimen-specific early virologic response.

METHODS:

Using Wilcoxon rank-sum tests, we compared regimen-specific VL changes from entry to week 4 in A5202 subjects (N = 1,813) and from entry to week 1, 2, and 4 in substudy subjects (n = 179). We evaluated associations between week 4 VL change and time to virologic failure with Cox proportional hazards models.

RESULTS:

TDF/FTC and ABC/3TC produced similar week 4 VL declines in the entire study population and in the high VL stratum. EFV produced greater VL declines from baseline at week 4 than ATV/r (median -2.1 vs -1.9 log10 copies/mL; P < .001). In the substudy of subjects with week 1, 2, and 4 VL data, there was no difference in VL decline in individuals randomized to TDF/FTC versus ABC/3TC, but EFV resulted in greater VL decline from entry at each of these timepoints than ATV/r. Smaller week 4 VL decline was associated with increased risk of virologic failure.

CONCLUSIONS:

Within all treatment arms, a less robust week 4 virologic response was associated with higher risk for subsequent virologic failure. However, between-regimen differences in week 4 VL declines did not parallel the previously reported differences in longer term virologic efficacy in A5202, suggesting that between-regimen differences in responses were not due to intrinsic differences in antiviral activity.

KEYWORDS:

HIV infections; anti-HIV agents; drug therapy; treatment outcome; virology

PMID:
24334181
PMCID:
PMC4060613
DOI:
10.1310/hct1406-284
[Indexed for MEDLINE]
Free PMC Article

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