Early Virologic Response to Abacavir/Lamivudine and Tenofovir/Emtricitabine During ACTG A5202. Issue 6 (November 2013)

• Record Type: Journal Article
• Authors: Grant, Philip M.; Tierney, Camlin; Budhathoki, Chakra; Daar, Eric S.; Sax, Paul E.; Collier, Ann C.; Fischl, Margaret A.; Zolopa, Andrew R.; Balamane, Maya; Katzenstein, David
• Is Part Of: HIV clinical trials. Volume 14:Issue 6(2013)
• Page Start: 284
• Page End: 291
• Publication Date: 2013-11
• Subjects: anti-HIV agents -- drug therapy -- HIV infections -- treatment outcome -- virology; HIV Infections -- Chemotherapy -- Periodicals; AIDS (Disease) -- Chemotherapy -- Periodicals; HIV Infections -- Research -- Periodicals; AIDS (Disease) -- Research -- Periodicals; 616.979206105
• DOI: 10.1310/hct1406-284
• Languages: English
• ISSNs: 1528-4336

Abstract

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.