CROI 2018 Abstract eBook

Abstract eBook

Poster Abstracts

eradication, and the factors responsible for distribution are largely unknown. This study investigated the influence of drug transporters, sex, and SHIV infection on ARV and active metabolite concentrations within lymph nodes of rhesus macaques. Methods: Twelve male (6 SHIV-, 6 SHIV+) and three female (2 SHIV-, 1 SHIV+) macaques were dosed to steady-state with six ARVs: emtricitabine (FTC, 16 mg/ kg), tenofovir (TFV, 30 mg/kg), efavirenz (EFV, 200 mg/day), raltegravir (RAL, 200 mg/day), maraviroc (MVC, 150 mg/day), and atazanavir (ATZ, 270 mg/kg). At necropsy, 24h post-dose, three lymph nodes per animal were snap frozen and stored at -80°C. ARV and active metabolite (emtricitabine triphosphate, FTCtp; tenofovir diphosphate, TFVdp) concentrations were measured by LC-MS/ MS (LLOQ: 0.002-0.01 ng/mL) and converted to ng/g of tissue using a density of 1.06 g/mL. Concentrations of eight (5 efflux, 3 uptake) drug transporters were measured using Quantitative Targeted Absolute Proteomics (QTAP, LLOQ: 0.1 pMol/mg protein). Median lymph node data for each animal was used for analyses. Data are presented as geometric mean (median range) and geometric mean ratio (GMR). Analyses were performed using Pearson Correlation, Kruskall-Wallis, and Mann-Whitney Rank Sum tests (p<0.05). Results: ARV concentrations are summarized in the table, and trended higher for 4/8 ARVs in SHIV- macaques (uninfected vs infected GMRs: 1.7-2.2), and 4/8 ARVs in females (female vs male GMR: 2.0--2.7). 5/8 transporters had low to no expression (>50% values below LLOQ). Concentrations of one efflux (BCRP) and two uptake (ENT1, OCT3) transporters were significantly greater than all others (p<0.001). ENT1 concentration was 8-fold higher than both BCRP and OCT3 (p<0.001). None of these three differed significantly by infection status (p=0.05) or sex (p>0.06). Transporter expression was not correlated with ARV or metabolite concentrations across sex or infection status. Conclusion: Modest differences in lymph node drug concentrations due to sex and infection status were noted. Low drug transporter levels, and lack of correlation between protein and drug concentrations, may indicate that lymph node ARV penetration occurs primarily by passive mechanisms. Future studies are warranted to further investigate sex differences in lymph nodes.

(TFV-DP) in foreskin and urethra lymphocytes were measured in 5 macaques 24h after a single oral dose of TDF (22mg/kg). Results: Both urethral and foreskin had an increased frequency of CD4 T cell populations expressing CCR5 (p=0.01 and p=0.009) and HLA-DR (p=0.0005 and p=0.001) compared to PBMC. Consistent with typical immune restricted tissue sites, effector memory T cells were the main CD4 T cell subtype in both urethral and foreskin tissues (p=0.01 and p=0.005). Urethral tissues contained a greater frequency of both CDC and PDC within leukocyte populations compared to blood or foreskin (p<0.05 for all comparisons). The frequency of local CD4 T cells expressing HLA-DR and CX3CR1 was also higher in urethral tissues compared to foreskin (p=0.007 and p=0.05, respectively). In contrast, foreskin tissues contained a greater frequency of T cells within the leukocyte population (p=0.03) and a higher CD4/CD8 T cell ratio (p=0.006). Expression of α4β7 on CD4 T cells and frequency of monocytes and NK cells was similar in both tissue compartments. The median TFV-DP concentrations were similar in foreskin (221 fmols/106 cells; range = 1-1,249) and urethral (161 fmols/106 cells; range = 19-756). Conclusion: We defined differences in immune cell composition in urethral and foreskin tissues based on both CDC and PDC abundance and CD4 T cell expression of HIV susceptibility markers HLA-DR and CX3CR1. High concentrations of TFV-DP in both urethral and foreskin tissues are reassuring, and support findings of protective efficacy seen with oral TDF regimens for PrEP in men. 478 SEMINAL TENOFOVIR CONCENTRATIONS, VIRAL SUPPRESSION AND SEMEN QUALITY WITH TAF VS TDF Arkaitz Imaz 1 , Jordi Niubo 1 , Mackenzie L. Cottrell 2 , Emilia Perez 3 , Angela Kashuba 2 , Juan M. Tiraboschi 1 , Sandra Morenilla 1 , Benito Garcia 1 , Daniel Podzamczer 1 1 Bellvitge University Hospital, Barcelona, Spain, 2 University of North Carolina Chapel Hill, Chapel Hill, NC, USA, 3 L’Hospitalet Clinical Laboratory, Barcelona, Spain Background: Antiretroviral drugs penetration into the male genital tract (MGT) has been evaluated in the context of suppressing HIV replication and in the prevention of sexual transmission. The efficacy of tenofovir alafenamide (TAF) in the MGT has not yet been described. Additionally, seminal drug concentrations may influence semen quality. There is no information about this for TAF. Methods: This prospective study enrolled 14 HIV-1 infected men on stable ART with TDF/FTC/EVG/COBI and HIV RNA <40c/mL. ART was switched to TAF/ FTC/EVG/COBI. At baseline, and 12 weeks post-switch, RNA in seminal plasma (SP) and blood plasma (BP), tenofovir (TFV) in SP & BP, and TFVdp in peripheral blood mononuclear cells (PBMC) and seminal mononuclear cells (SMC) at the end of the dosing interval (C24h) were measured. Validated LC-MS/MS were used to quantify drug concentrations. HIV-1 RNA was determined by real-time PCR. Semen analyses were also performed at baseline and 12 weeks post-switch and semen quality was assessed according to WHO 2010 guidelines. Data are presented as median (range). Statistical analysis was performed by the nonparametric Wilcoxon signed-rank test. Results: Patient characteristics at baseline were: age 42 (34-58) years; time on ART 10.5 (1-20) years; time on TDF/FTC/EVG/COBI 18 (7-53) months; time with HIV-1 RNA <40 copies/mL 82 (15-197) months; CD4 count 632 (309-1742) cells/ μL. All patients had HIV-1 RNA <40 copies/mL in both BP and SP at baseline and 12 weeks after switching to TAF. Median TFV and TFVdp C24 in BP and SP are shown in the Table. With TAF, TFV C24 in SP was 11.9-fold higher than TFV C24 in BP. This concentration was significantly lower than TFV C24 in SP with TDF dosing but 9.6-fold higher than the IC50 (11.5 ng/mL). In contrast, median TFVdp in SMC achieved with TAF was 6% of TFVdp in PBMC. Although the TFVdp SMC:PBMC ratio was significantly lower with TAF in comparison to TDF, TFVdp C24 achieved in SMC with TAF and TDF were comparable. Median TFVdp C24 in SMC was below the TFVdp EC50 (36.7 fmol/million CD4 cells) for both TAF and TDF. No significant differences were observed in sperm concentration, motility, vitality and morphology between TAF and TDF. Conclusion: Seminal extracellular and intracellular TFV distribution differs between TAF and TDF. Nevertheless, both formulations plus FTC/EVG/COBI maintained HIV-1 RNA suppression in semen. Differences in MGT distribution between TAF and TDF are not associated with differences in semen quality.

Poster Abstracts

477 HIV TARGET CELL DISTRIBUTION AND TFV PENETRATION IN FORESKIN AND URETHRA Alison S. Kohlmeier , Kenji Nishiura, Natalia Makarova, Jessica Radzio-Basu, Gerardo Garcia-Lerma, Charles Dobard CDC, Atlanta, GA, USA Background: Female to male HIV transmission represents an important route of HIV infection and yet the immune cell composition of foreskin and urethral tissues and how antiretroviral drugs penetrate into these two anatomical compartments has been largely understudied. We performed a comprehensive immune characterization of HIV target cells in foreskin and urethral tissues from macaques, and investigated the relative penetration of tenofovir following a single oral dose of tenofovir disoproxil fumarate (TDF). Methods: Foreskin and urethral tissue were harvested from 7 rhesus macaques at necropsy and processed into cell suspensions using enzymatic digestion. CD4 and CD8 T cells, B cells, NK cells, monocytes, conventional dendritic cells (CDC), plasmacytoid dendritic cells (PDC), and HIV susceptibility markers CCR5, α4β7, HLA-DR, and CX3CR1 were measured by flow cytometry. TFV diphosphate

CROI 2018 171