Early Virologic Response to Abacavir/Lamivudine and Tenofovir/Emtricitabine During ACTG A5202 HIV CLINICAL TRIALS Grant, P. M., Tierney, C., Budhathoki, C., Daar, E. S., Sax, P. E., Collier, A. C., Fischl, M. A., Zolopa, A. R., Balamane, M., Katzenstein, D. 2013; 14 (6): 284-291


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.To compare regimen-specific early virologic response.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.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.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.

View details for DOI 10.1310/hct1408-284

View details for Web of Science ID 000328443500003

View details for PubMedID 24334181