A Randomized, Controlled Trial of Raltegravir Intensification in Antiretroviral-treated, HIV-infected Patients with a Suboptimal CD4+ T Cell Response

Hiroyu Hatano (.) 2 3 Timothy L. Hayes 1 2 Viktor Dahl 0 2 Elizabeth Sinclair 2 3 Tzong-Hae Lee 2 5 Rebecca Hoh 2 3 Harry Lampiris 2 3 4 Peter W. Hunt 2 3 Sarah Palmer 0 2 Joseph M. McCune 2 3 Jeffrey N. Martin 2 3 Michael P. Busch 2 3 5 Barbara L. Shacklett 1 2 Steven G. Deeks 2 3 0 Karolinska Institutet and Swedish Institute for Infectious Disease Control , Solna, Sweden 1 University of California , Davis 2 Received 15 June 2010; accepted 15 September 2010. Potential conflicts of interest: H.H. and S.G.D. have received research support from Merck. All other authors report no potential conflicts. Both raltegravir and placebo pills were provided by Merck and reagents were provided by Gen-Probe at no cost to this study. Presented in part: 17th Conference on Retroviruses and Opportunistic Infections , San Francisco , February 2010. Abstract 101LB. Hospital , Bldg 80, Ward 84, 995 Potrero Ave, San Francisco, CA 94110 3 University of California , San Francisco 4 San Francisco VA Medical Center , California 5 Blood Systems Research Institute , San Francisco Background. Some human immunodeficiency virus (HIV)-infected individuals are not able to achieve a normal CD41 T cell count despite prolonged, treatment-mediated viral suppression. We conducted an intensification study to assess whether residual viral replication contributes to replenishment of the latent reservoir and whether mucosal HIV-specific T cell responses limit the reservoir size. Methods. Thirty treated subjects with CD41 T cell counts of ,350 cells/mm3 despite viral suppression for >1 year were randomized to add raltegravir (400 mg twice daily) or matching placebo for 24 weeks. The primary end points were the proportion of subjects with undetectable plasma viremia (determined using an ultrasensitive assay with a lower limit of detection of ,.3 copy/mL) and a change in the percentage of CD381HLA-DR1CD81 T cells in peripheral blood mononuclear cells (PBMCs). Results. The proportion of subjects with undetectable plasma viremia did not differ between the 2 groups (P 5 .42). Raltegravir intensification did not have a significant effect on immune activation or HIV-specific responses in PBMCs or gut-associated lymphoid tissue. Conclusions. Low-level viremia is not likely to be a significant cause of suboptimal CD41 T cell gains during HIV treatment. Clinical Trials Registration. NCT00631449. - infection [1]. However, a significant proportion of individuals are unable to achieve a normal CD41 T cell count despite prolonged viral suppression with effective HAART. In one study, 25% of patients who started HAART at a CD41 T cell count of ,200 cells/mm3 were unable to achieve a CD41 T cell count of .500 cells/ mm3 even after more than 710 years of HAART [2]. Moreover, having a suboptimal CD41 T cell response has been associated with significant clinical consequences, including increased AIDS-related and nonAIDS-related morbidity and mortality [36]. The mechanisms of suboptimal immune recovery are not completely understood. Persistent T cell activation may be causally related to the inability to reconstitute normal CD41 T cell counts, perhaps owing to its effect on lymphoid tissue architecture [711]. Moreover, ongoing low-level viral replication may be the proximal cause of persistent activation during HAART [1215]. Several studies have attempted to address this issue [1518], although none have focused on the host responses to HIV in both blood and gut-associated lymphoid tissue (GALT). We conducted a randomized, double-blinded, placebocontrolled study of raltegravir intensification to assess whether ongoing viral replication contributes to immune activation and suboptimal immune recovery during HAART. Our secondary objective was to explore the host determinants of viral persistence in both blood and GALT. Subjects Thirty HIV-infected, HAART-treated subjects with CD41 T cell counts of ,350 cells/mm3 for >1 year despite viral suppression (,40 to 75 copies/mL) for >1 year were enrolled in this randomized, placebo-controlled study. In 15 subjects raltegravir (400 mg twice daily) was added to their current suppressive HAART regimens for 24 weeks, and in 15 subjects matching placebo was added for 24 weeks; subjects were randomized to treatment in a double-blinded fashion. Twenty-one of 30 subjects also consented to undergo 3 serial colorectal biopsies. All subjects provided written informed consent. This study was approved by the University of California San Francisco (UCSF) Committee on Human Research. Subjects were seen every 4 weeks. Plasma and peripheral blood mononuclear cells (PBMCs) were stored, and detailed interviews were conducted at most visits. Adherence to study drug was measured at every study visit by self-report and by pill count. An independent data monitoring committee including 3 individuals from the scientific community met 12, 24, 48, and 60 weeks after the enrollment of the first subject and 60 weeks after the enrollment of the last subject. No significant adverse events occurred during the study. The 2 primary end points were (1) the proportion of subjects with undetectable plasma RNA (,.3 copy/ mL assay [19]) at week 12 and (2) a change in the percentage of CD381HLA-DR1CD81 T cells in PBMCs, given that immune activation levels have been shown to be a strong and independent predictor of HIV disease progression [7, 8, 20]. The sample size was based on data from prior studies [12, 21]. To achieve 80% statistical power to detect a 35% difference in proportion of subjects with undetectable plasma viremia, 14 subjects would be needed in each group (assuming a type I error of 5%) [22]. Similarly, to achieve 80% statistical power to detect a 5.5% difference in activated CD81 T cells, 13 subjects would be needed in each group (assuming a type I error of 5%). Our prior work has indicated that a 5.5% difference in activated CD81 T cells is clinically meaningful; among treated patients with virologic suppression for a median of 2 years, we observed that for every 5% increase in the percentage of activated CD81 T cells, there was a mean of 35 fewer CD41 T cells/mm3 gained [7]. We therefore enrolled 15 subjects in each group to account for potential losses to follow-up and early treatment discontinuations. Virologic Measurements Plasma RNA was measured at baseline and week 12 with an ultrasensitive assay, with a lower limit of detection of ,.3 copy/mL (median, 6.5 mL of plasma) [19]. Cell-associated RNA and proviral DNA was measured from PBMCs at baseline and weeks 4 and 24. The transcription-mediated amplification assay (Aptima; Gen-Probe) was used to measure cell-associated RNA. This assay is a nucleic acid-amplification test that has been approved by the Food and Drug Administration for the early detection of HIV infection in plasma (in the screening of blood donors) and has also been validated for clinical diagnostic use [23]. A modified approach of published methods for PBMC extraction and transcripti (...truncated)