Person:

Zheng, Summer

Background: Most HIV-1-infected patients on effective antiretroviral therapy (ART) with plasma HIV-1 RNA levels below the detection limits of commercial assays have residual viremia measurable by more sensitive methods. We assessed whether adding raltegravir lowered the level of residual viremia in such patients. Methods and Findings: Patients receiving ART who had plasma HIV-1 RNA levels below 50 copies/mL but detectable viremia by single copy assay (SCA) were randomized to add either raltegravir or placebo to their ART regimen for 12 weeks; patients then crossed-over to the other therapy for an additional 12weeks while continuing pre-study ART. The primary endpoint was the plasma HIV-1 RNA by SCA averaged between weeks 10 and 12 (10/12) compared between treatment groups. Fifty-three patients were enrolled. The median screening HIV-1 RNA was 1.7 copies/mL. The HIV-1 RNA level at weeks 10/12 did not differ significantly between the raltegravir-intensified (n = 25) and the placebo (n= 24) groups (median 1.2 versus 1.7 copies/mL, p = 0.55, Wilcoxon rank sum test), nor did the change in HIV-1 RNA level from baseline to week 10/12 (median 20.2 and 20.1 copies/mL, p = 0.71, Wilcoxon rank sum test). There was also no significant change in HIV-1 RNA level from weeks 10/12 to weeks 22/24 after patients crossed-over. There was a greater CD4 cell count increase from baseline to week 12 in the raltegravir-intensified group compared with the placebo group (+42 versus244 cells/mm3, p= 0.082, Wilcoxon rank sum test), which reversed after the cross-over. This CD4 cell count change was not associated with an effect of raltegravir intensification on markers of CD4 or CD8 cell activation in blood. Conclusion: In this randomized, double-blind cross-over study, 12 weeks of raltegravir intensification did not demonstrably reduce low-level plasma viremia in patients on currently recommended ART. This finding suggests that residual viremia does not arise from ongoing cycles of HIV-1 replication and infection of new cells. New therapeutic strategies to eliminate reservoirs that produce residual viremia will be required to eradicate HIV-1 infection.

Background. Intensification of antiretroviral therapy with raltegravir does not affect levels of residual human immunodeficiency virus (HIV)-1 viremia, but it has led to increased levels of episomal HIV-1 DNA in some patients, suggesting antiviral activity against otherwise unresponsive components of the viral reservoir. Effects of raltegravir on host cells remain less well understood. Methods. We used comprehensive and unbiased microarray-based transcriptional profiling to analyze gene expression changes in CD8+ T cells from participants in a randomized clinical trial (AIDS Clinical Trials Group [ACTG] A5244) comparing raltegravir-intensified to nonintensified antiretroviral therapy. Results. Although raltegravir intensification failed to induce statistically significant changes in HIV-1 DNA or residual plasma viremia, we observed significant increases in the expression intensity of 121 host gene transcripts. In functional annotations of these transcripts, we found that they were mainly involved in glucose and carbohydrate metabolism, immune regulation, control of cell proliferation, and tumor suppression. Two of the raltegravir-responsive gene transcripts were statistically correlated with levels of residual HIV-1 RNA, but none of the remaining 119 transcripts were associated with immunologic or virologic characteristics of the study patients. Conclusions. Together, these findings demonstrate that raltegravir intensification can induce previously unrecognized, statistically significant gene expression changes in host CD8+ T lymphocytes.