CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

352 Predictors of Viral Control After ART Interruption in SIV-Infected Rhesus Macaques Luca Micci 1 ; Emily Ryan 2 ; Steven E. Bosinger 2 ; Remi Fromentin 3 ; Rafick Sekaly 4 ; Nicolas Chomont 5 ; Jeffrey Lifson 6 ; Mirko Paiardini 2 1 Emory Univ, Atlanta, GA, USA; 2 Yerkes Natl Primate Rsr Cntr, Emory Univ, Atlanta, GA, USA; 3 Univ of Montreal, Montreal, QC, Canada; 4 Case Western Reserve Univ, Cleveland, OH, USA; 5 Univ de Montréal, Montreal, QC, Canada; 6 Frederick Natl Lab, Frederick, MD, USA Background: Antiretroviral therapy (ART) does not eradicate HIV and the virus rebounds upon ART interruption. Recently, a sustained control of HIV replication in the absence of ART has been achieved in a subset of subjects starting ART early after infection (post-treatment controllers; PTC). However, the virologic and immunologic determinants of post-ART control of HIV replication are still unclear, particularly in tissues. Understanding the mechanisms behind durably containing HIV replication may guide new strategies towards HIV remission. Here, we used the well-established model of SIV-infected rhesus macaques (RMs) to investigate the features associated with post-ART SIV control. Methods: We identified five SIV mac239 -infected RMs (B*08 - and B*17 - ) that, after seven months of ART initiated at two-months p.i., controlled viral rebound (<200 copies/mL) after structured treatment interruption (STI). Blood (PB), rectum (RB) and lymph node samples were longitudinally collected from these animals as well as from RMs that, under the same experimental conditions, experienced a robust SIV rebound after STI (NC). Total SIV-DNA and RNA was measured on purified PB CD4 T cells and mucosal tissues by qPCR; immunological parameters were determined by flow cytometry. Predictors associated with PTC status were evaluated by odds ratio analyses. Results: Before ART initiation, PTC had markedly reduced SIV-RNA levels in plasma and RB, lower SIV-DNA content in PB CD4 T cells and RB, reduced T-cell activation, and higher CD4 counts as compared to NC (P<0.01 for all measures). Levels of intestinal CD4 T cells were similar, but PTC had higher frequencies of Th17 and Th22 cells. On ART, PTC had significantly lower levels of residual plasma viremia (<3 copies/mL) and SIV-DNA content in PB CD4 T cells. The bulk and SIV-specific CD8 T cell compartment was comparable between the two groups, thus suggesting that PTC can achieve partial viral control without CD8 antiviral responses superior to those of NC. Remarkably, PB and RB SIV-RNA and DNA contents rapidly increased in NC after ART interruption, while remain stable or progressively decreased in PTC. Finally, partial control of SIV rebound in PTC resulted in higher CD4 levels and reduced inflammation in PB, RB and LN during the off-ART period. Conclusions: Lower pre-ART viremia, cell-associated SIV-DNA, and T cell activation with concomitant preservation of Th17 cell homeostasis are highly associated with prolonged viral control post ART interruption in SIV-infected RMs. 353 Antiretroviral Therapy in SIV Natural Hosts: Implications for AIDS Pathogenesis Francesca Calascibetta 1 ; Luca Micci 1 ; Diane Carnathan 1 ; Benton Lawson 1 ; Ann Chahroudi 2 ; Jeffrey Lifson 3 ; Mirko Paiardini 4 ; Guido Silvestri 4 1 Emory Univ, Atlanta, GA, USA; 2 Emory Univ Sch of Med, Atlanta, GA, USA; 3 Frederick Natl Lab, Frederick, MD, USA; 4 Yerkes Natl Primate Rsr Cntr, Emory Univ, Atlanta, GA, USA Background: The major obstacle to Human Immunodeficiency Virus (HIV) eradication is the presence of a small pool of long-lived latently infected cells that are not affected by antiretroviral therapy (ART), particularly, central memory (T CM ) and memory stem (T SCM ) CD4+ T cells. We recently showed that in sooty mangabeys (SMs) these subsets are relatively resistant to SIV infection when compared with rhesus macaques (RMs), while effector memory CD4+ T cells were infected at similar levels between the two species. Based on these data, we hypothesized that SMs may experience a significant decay of the viral reservoir during ART and, possibly, a slower rebound of viremia upon treatment interruption. Methods: Twelve experimental chronically SIV-infected SMs with viral load of 10 3 -10 5 vRNA copies/ml were treated with antiretroviral therapy (ART) regimen consisting of PMPA (20 mg/kg), FTC (30 mg/kg), Raltegravir (300 mg/day) and Darunavir (800 mg/day). The cohort of SMs was divided in four-treatment interruption groups, each of three animals, receiving ART for to 2, 6, 9 and 12 months. Virological and immunological parameters were monitored prior to, during and after ART administration. Results: All animals receiving ART experienced a rapid and significant decline of the plasma viral load with eleven out of twelve SMs showing viremia suppression below the limit of detection (60 copies/ml). Analysis of total circulating CD4 + T cells showed minor changes in terms of frequency and absolute number. Interestingly, the depletion of intestinal memory CD4+ T cells, which is associated with SIV infection of SMs, was reverted when viral replication was controlled by ART and higher levels of intestinal CD4+ T cells were maintained even after therapy interruption. Moreover, ART was associated with decreased frequency of CD8+ HLADR+ T cells in blood and mucosal tissues. While ART induced variable decrease in the level of cell-associated SIV-DNA in blood, therapy interruption resulted in viral rebounds in all treated SMs. Conclusions: This is the first study in which a potent and prolonged four-drug ART regimen was administered to SIV-infected SMs. The treatment was safe and effective in suppressing viral replication, with ART inducing a remarkable level of immunologic reconstitution in the gut. However, ART interruption resulted in rapid viral rebound in all animals, thus indicating that the virus reservoir persists for at least a year despite low levels of infection in CD4+ T CM and T SCM . 354 Bryostatin-1 for Latent-Virus Reactivation: A Phase I, Double-Blind Clinical Trial Carolina Gutiérrez 1 ; Nadia Madrid-Elena 1 ; Sergio Serrano-Villar 1 ; María Jesús Pérez-Elias 2 ; María E. Martín 1 ; Coral Barbas 3 ; Javier Ruperez 3 ; Eduardo Muñoz 4 ;Trevor Castor 5 ; Santiago Moreno 2 1 Ramón y Cajal Hosp, IRYCIS, Madrid, Spain; 2 Hosp Universitario Ramón y Cajal, Madrid, Spain; 3 CEMBIO, San Pablo CEU Univ, Madrid, Spain, Madrid, Spain; 4 Córdoba Univ, Córdoba, Spain; 5 Aphios Corporation, Boston, MA, USA Background: The protein kinase C (PKC) agonist bryostatin-1 has been found to be highly potent in inducing latent viral expression through NF-kB signaling. It may also have synergistic effects when combined with other latency reversing agents (LRA). However, no clinical trials with the drug have been performed in HIV-infected patients. Methods: In this pilot, double blind phase I clinical trial (NCT 02269605), we included aviremic HIV-1 infected patients on suppressive antiretroviral therapy (ART) to evaluate the effect of two different single doses of bryostatin-1 (10 µg/m 2 or 20 µg/m 2 ) compared with placebo. The primary outcomes were safety and the change from baseline in the cell associated unspliced (CA-US) HIV-1 RNA. Secondary endpoints were PKC activation, plasma HIV-1 RNA, and markers of early immune activation. Bryostatin-1 plasma levels were assessed at baseline, and at 15 min, 30 min, 60 min, and at 2, 4, 8 12, and 24 hours post-infusion. Results: Twelve patients were included, four in each Study Group. Bryostatin-1 was well tolerated in all the patients regardless the dose of the drug they received. No abnormalities were detected in blood cell counts or blood chemistry. No detectable increases of intracellular HIV-1 mRNA was induced by the single dose infused, without differences between the bryostatin-1 and placebo groups (p=0.44). Using a transcription mediated amplification (TMA) assay, the proportion of positive and negative HIV-1 RNA plasma samples were similar in the three groups, without correlation with the CA-US HIV-1 RNA levels (p=0.676) (Figure 1). We also failed to detect any effect on PKC activity

Poster Abstracts

with any of the two doses of bryostatin-1 (p=0.23), as well as in biomarkers activation (CD25 and CD69). After the single dose of bryostatin-1, plasma levels were undetectable in all the patients that received 10 µg/m 2 , and below 50 pg/mL in those receiving 20 µg/m 2 (Figure 2). Conclusions: In this first clinical trial in HIV-infected patients, bryostatin-1 was safe at the doses administered. However, the drug did not show any effect on PKC activity or on the transcription of latent HIV, probably due to the low plasma levels. Given the safety profile of the drug, clinical trials with multiple doses of bryostatin-1 or with a combination of bryostatin-1 and other drugs shown to be synergistic in ex vivo studies are warranted.

135

CROI 2016