CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

(Css) in different compartments in the body. The purpose of this study was to describe the steady-state PK of TFV-DP and FTC-TP in genital, rectal, and blood compartments in HIV- positive and negative males and females. Methods: HIV-positive and negative adults were enrolled in an intensive PK study of daily TDF/FTC for 30 days. Peripheral blood mononuclear cells (PBMC) were obtained at first dose, days 3, 7, 20, and 30. Rectal biopsies and genital sampling were performed once each per participant, at staggered visits. Females underwent a cervical brush collection and males provided one semen sample. Cervical cells, seminal leukocytes, and rectal mononuclear cells were isolated, counted, assessed for viability, and lysed. First order PK was used to determine average steady-state values (Css) in each compartment for TFV-DP and FTC-TP. Comparisons were made between the genders and according to HIV status using unpaired t-tests, only for PBMC data given limits on sample sizes. Results: Thirteen females (10 HIV negative) and 24 males (11 HIV negative) were included. Available samples from female participants included 13 cervical, 10 rectal, and 253 PBMC, and those frommales included 18 seminal, 20 rectal, and 414 PBMC. Steady-state was reached in all compartments for both TFV-DP and FTC-TP within 30 days. Css values are shown in the table. TFV-DP and FTC-TP Css in PBMC did not differ significantly by gender or HIV-status, although females trended toward higher concentrations of TFV-DP in PBMC (p=0.08). Females also appeared to have higher TFV-DP in rectal cells. Genital cell concentrations at steady-state were ~10-fold greater in females compared with males for both TFV-DP and FTC-TP.

Css of TFV-DP and FTC-TP in PBMC, genital, and rectal compartments in males and females (mean or point estimate, 95% confidence interval) Conclusions: These findings illustrate differential drug penetration at steady-state in genital, rectal and blood compartments, which is relevant for prevention of HIV acquisition and suppression of HIV replication within potential reservoirs of the body. Females trended to have higher concentrations in these compartments relative to males. This information provides concentration ranges to help inform dose-response relationships for the prevention and treatment of HIV infection. 526 Effects of Tenofovir/Emtricitabine on Endogenous Deoxyribonucleotide Pools In Vivo Xinhui Chen 1 ; Kevin McAllister 1 ; Jia-Hua Zheng 1 ; Jose R. Castillo-Mancilla 1 ; Amie Meditz 2 ; Brandon Klein 1 ; Sharon M. Seifert 1 ; Lane Bushman 1 ; Peter L. Anderson 1 1 University of Colorado Anschutz Medical Campus, Aurora, CO, US; 2 Beacon Center of Infectious Diseases, Boulder, CO, US Background: The potential effects of nucleoside analogs on endogenous deoxyribonucleotides (dNTP) in vivo have not been fully elucidated. The goal of this study was to characterize and quantify the effects of tenofovir-disoproxil fumarate (TDF)/emtricitabine (FTC) therapy on endogenous dNTP pools in HIV-negative and HIV-positive adults. Methods: Participants were enrolled in a pharmacokinetic study of daily TDF/FTC therapy. Peripheral blood mononuclear cells (PBMC) were collected at baseline (pre-drug), and days 1, 3, 7, 20, and 30 during dosing. HIV-negative adults had visits on days 5, 15, and 30 of drug washout, while HIV-positive adults continued therapy through day 60. The 8 hours post dose samples were used from all on-drug study visits. PBMC were isolated, counted, lysed, and endogenous dNTP including dCTP, dGTP, TTP, and dATP were quantified with validated LC-MS/MS methodology. Comparisons were made with paired t-tests. Results: 276 PBMC samples were analyzed from 40 participants (21 HIV-negative and 19 HIV-positive); 13 female and 27 male, average age 33 years. 34 subjects completed all study visits, two HIV negative and four HIV-positive subjects stopped early. dNTP were generally (not statistically) higher at baseline in HIV-negative vs HIV-positive participants, with median values of 834 vs 780 (dCTP), 303 vs 244 (dGTP), 475 vs 386 (TTP), and 153 vs 152 (dATP) fmol/10 6 cells. Compared with baseline values, HIV-negative subjects had a reduction of 26% for dCTP (p=0.003), 30% for dGTP (p=0.001), 53% for TTP (p<0.001), and 21% for dATP (p=0.06) by day 3; while corresponding values for HIV-positive subjects were 17% for dCTP (p=0.20), 12% for dGTP (p=0.36), 34% for TTP (p=0.01), and an increase of 9% for dATP (p=0.99). dNTP generally remained below baseline until drug discontinuation. After 5 days of washout in HIV-negative participants, dNTP had essentially returned to baseline values with differences of -6% for dCTP (p=0.33), -14% for dGTP (p=0.16), -1% for TTP (p=0.87), and -11% for dATP (p=0.07). Conclusions: Endogenous dNTP pools in PBMCs decreased during TDF/FTC therapy, with greater reductions among HIV-negative subjects. These dNTP changes may indicate direct perturbation (eg drug interference with dNTP regulation pathways) and/or indirect perturbation (eg drug-induced reduction of immune activation, in turn reducing dNTP). The effects of lower dNTP on cellular function and antiviral effect should be evaluated in future studies. 527 Higher Cell Accumulation and Antiviral Activity of Lopinavir/Ritonavir Nanoparticles Philip Martin 1 ;Tom O. McDonald 2 ; Marco Giardiello 2 ; Steven P. Rannard 2 ; Andrew Owen 1 1 University of Liverpool, Liverpool, United Kingdom; 2 University of Liverpool, Liverpool, United Kingdom Background: Using an emulsion-templated freeze-drying technique we have synthesised combination lopinavir/ritonavir (LPV/RTV) solid drug nanoparticles (SDNs) with 70% weight drug loading in the dry state and compared their antiretroviral activity and cellular accumulation in primary immune cells. Methods: MT4 cells (NIBSC, UK) and primary immune cells (CD4+ T lymphocytes, CD56+ natural killer cells, CD14+monocytes and monocyte-derived macrophages (MDM)) (Lonza, UK) from 4 donors, were incubated with either combination aqueous solutions or combination solid drug nanoparticle (SDN) suspensions at 10 m M lopinavir (LPV; 0.1 m Ci H 3 ) and ritonavir (RTV) at 1:4, 1:8 or 1:40 ratio, for 60 minutes. Aliquots of media (extracellular) and lysed cells (intracellular) were sampled and a cellular accumulation ratio determined. Antiviral activity by combination SDNs and aqueous solutions were assessed against HIVIII B infected MT4 cells at the same ratios. Data analysis was conducted using GraphPad Prism 3.0 and StatsDirect software. Results: Cellular accumulation of LPV/RTV SDNs was higher than the equivalent aqueous solution in MT4 (1:4, 1.8-fold, p < 0.0001; 1:8, 1.7-fold, p < 0.0001 and 1:40; 2.0-fold p < 0.0001), CD4+ (1:4; 1.6-fold; p < 0.0001, 1:8; 1.7-fold p < 0.0001 and 1:40; 2.0-fold p < 0.0001), CD14+ (1:4; 1.1-fold; p = 0.03, 1:8; 1.2-fold p = 0.0002, 1:40; 1.5-fold; p = 0.0001), CD56+ (1:4; 1.4-fold; p < 0.0001, 1:8; 1.5-fold p < 0.0001, 1:40; 1.5-fold p < 0.0001) and MDM (1:4; 2.2-fold; p < 0.0001, 1:8; 2.3-fold p < 0.0001 and 1:40; 2.7-fold p < 0.0001).

Poster Abstracts

344

CROI 2015