CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

HIV PDR trends in Honduras 2013-2014. PDR trends by date of enrolment were estimated using a moving average approach, with 3-month windows, moving by 2-month intervals. TDR prevalence and 95% confidence intervals (CI) are shown. The number of individuals enrolled for each estimation is shown: dark gray, individuals coming from Tegucigalpa; light gray, individuals coming from other parts of the country. PDR, pre-antiretroviral treatment drug resistance; NRTI, nucleoside reverse transcriptase inhibitors; NNRTI, non-nucleoside reverse transcriptase inhibitors; PI, protease inhibitors. Conclusions: The global PDR prevalence in Honduras remains at the intermediate level, after 10 years of widespread availability of ART with PDR mutation frequency being highly influenced by ADR mutation frequency. Decreasing trends were observed for NNRTI PDR, which will have to be confirmed by periodic HIVDR surveillance. 608 High Prevalence of Genotypic Resistance to Integrase inhibitors of HIV-1 Strains in Taiwan Sui-Yuan Chang 1 ; Chien-Ching Hung 2 1 National Taiwan University, Taipei, Taiwan; 2 National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan Background: Integrase inhibitor in combination with 2 nucleoside reverse-transcriptase inhibitors has been shown to be effective treatment options for antiretroviral(ARV)- naive HIV-1-infected patients. In Taiwan, raltegravir was first introduced in 2009 as a regimen of second line ARV and a pilot study by our laboratory in 2011 revealed that there was no HIV-1 strains harboring integrase inhibitor-related major genetic mutations among the 160 analyzed specimens from treatment-naive patients. In this study, we aimed to determine the prevalence of integrase inhibitor-related genetic mutations after the implementation of regulations on the prescription of HAART to ARV-naive patients by the Taiwan Centers of Disease Control (CDC) on 1 June 2012, by which raltegravir can only be used in combination with zidovudine/lamivudine in ARV-naive patients or with other ARVs in treatment-experienced patients. Methods: Genotypic resistance assays were performed in the HIV strains from ARV-naïve patients seeking HIV care at the designated hospitals around Taiwan from June 2012 to December 2013. Resistance mutations to integrase inhibitors were identied using the HIVdb program of the Stanford University HIV Drug Resistance Database. Phylogenetic tree was constructed to determine the relationship between the resistant strains identified. Results: Of the 1087 HIV-1 strains included for analysis, the majority were subtype B (82.9%) and CRF01_AE (6.5%). The overall prevalence of TDR to integrase inhibitors was 6.0% (n=65), which includes 56 HIV-1 strains of subtype B, 5 CRF01_AE and 4 CRF07_BC. The prevalence of TDR to integrase inhibitors increased from 6.8% in the third quarter of 2012, peaked at 9.4% in the first quarter of 2013, and gradually declined to 3.3% in the last quarter of 2013. Among the identified II-related genetic mutations, Q148K and N155S were found in 41.5% (n=27) and 29.2% (19) of the integrase inhibitor-resistant strains, respectively. Other mutations identified include T66A (n=2), E92Q/KV (9), E138K (2), Y143C/R/S (5), P145R (4), E157Q (4), and R263K (3). Phylogenetic analysis showed that there was no clustering observed among these resistant sequences. Conclusions: In Taiwan, the prevalence of TDR to integrase inhibitors recently increased to 6.0%, which was temporally related to the implementation of regulations on the use of antiretroviral drugs in ARV-naïve patients. 609 Integrase Resistance Correlates of Response to Dolutegravir (DTG) Through 48Weeks Background: Phenotypic and genotypic correlates of antiviral response (AR) derived from clinical investigation characterize an antiretroviral’s (ART) ability to inhibit HIV. The VIKING-3 and VIKING-4 (V3/4) studies examined DTG 50mg twice-daily in patients with resistance to multiple ART’s, including integrase inhibitors (INI). Baseline Integrase (IN) genotypes and phenotypes were assessed to identify correlates to AR. Methods: In both studies DTG 50mg BID was given through Day 8 as functional monotherapy followed by optimization of background regimen. V3 data only was used for deriving correlates to AR. Day 8 categories for AR as change from Baseline in HIV-1 RNA were pre-defined as Full (>1.0 log 10 ), Intermediate (0.5-1.0 log 10 ) or No response (<0.5 log 10 ). IN resistance tests were performed by Monogram BioSciences. Baseline DTG fold change (FC) phenotypic cut-offs for Day 8 AR were examined using non-linear logistic regression modeling. For IN genotypic correlates, incidence of resistance-associated mutations and co-incidence of mutation pairs at Baseline were examined. Multivariate logistic regression Cindy L. Vavro ; Jenny Huang; Mounir Ait-Khaled GlaxoSmithKline, Research Triangle Park, NC, US

Poster Abstracts

384

CROI 2015