CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

461 VIROLOGICAL RESPONSE TO ANTIRETROVIRAL TREATMENT IN AN EASTERN EUROPEAN COHORT STUDY Radko Avi , Merit Pauskar, Heli Rajasaar, Eveli Kallas, Ene-Ly Jõgeda, Pilleriin Soodla, Irja Lutsar, Kristi Huik, for the Estonian HIV Positive Patients Database Univ of Tartu, Tartu, Estonia Background: Viral suppression (VS) of first line combined ART (cART) ranges from 53–80% in North America and Western Europe. However, corresponding data from Eastern Europe is not available. We evaluated virological response to first line ART and defined factors that influence this response. Methods: All patients participating in the Estonian HIV cohort study (E-HIV) who initiated cART between 2000 and 2014 were included. Primary VS was achieved if two consecutive viral loads (VLs) were below 400 c/ml after initiation of cART. Virologial failure (VF) was defined by two consecutive VLs over 400 c/ml or a major treatment regimen switch after primary VS. Hazard ratios (HR) were calculated using Cox proportional hazard models or Breslow test as appropriate. Results: Of a total of 4507 patients in the E-HIV, 3396 (61%men) met the study criteria and were followed-up for a median of 2.4 years; a total of 7890 person-years. Overall, 1325 patients were lost to follow-up. At initiation of cART the median age was 30 years (IQR 26–32), CD4 count 211 (124–230) cells/µl, and VL 4.9 (4.3–4.8) log10 copies/ml. In total, primary VS was achieved in 58% (95% CI:56%–60%) of patients (1967/3396). At months 6, 9, and 12 after cART initiation, VS was achieved in 40% (1363/3396), 46% (1567/3396) and 49% (1667/3396) of patients, respectively. Overall, the VF occurred in 25% of patients (492/1967) - 12% (236/1967), 21% (413/1967) and 24% (472/1967) at year 1, 3, and 5 after VS achievement, respectively. Intravenous drug use (IDU) as the transmission route (adjusted HR [aHR] 0.87, 95% CI:0.76–0.99), higher VL at cART initiation (aHR per log10 0.80, 95% CI:0.77–0.84), earlier calendar year of HIV diagnosis (aHR per year 0.96, 95% CI:0.95–0.97), and HCV seropositivity (aHR 0.73, 95% CI:0.64–0.84) decreased the probability of achieving VS. Female gender and IDU route were associated with an increased risk of VF (aHR 1.84, 95% CI:1.43–2.38, and 1.40, 95% CI:1.04–1.90, respectively), while older age at cART initiation and later calendar year of HIV diagnosis were related to a reduced risk of VF (aHR per year 0.96, 95% CI:0.94–0.97, and aHR per year 0.95, 95% CI:0.91–0.99, respectively). Conclusion: In the first large cohort study of the Eastern European HIV epidemic, we showed that the overall virological response to cART is comparable to the lower end of rates in Western countries. Our results indicate that special strategies are needed for younger patients, the HCV co-infected, females, and IDUs in order to reduce cART failure. 462 DURABILITY OF NNRTI BASED REGIMENS AFTER 7 YEARS OF TREATMENT IN RURAL UGANDA Mastula Nanfuka 1 , Zishan Cui 2 , Stephen Okoboi 1 , Josephine Birungi 1 , Pontiano Kaleebu 3 , Julia Zhu 2 , Samuel Tibengana 1 , David Moore 4 1 The AIDS Support Organization, Kampala, Uganda, 2 BC Cntr for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada, 3 Med Rsr Council, Entebbe, Uganda, 4 Univ of British Columbia, Vancouver, British Columbia, Canada Background: Most ART programs in low-income countries in Africa have predominantly used NNRTI-based regimens with limited access to routine viral load (VL) testing. For individuals who have maintained long term adherence to first line therapy and have been documented to have a suppressed VL on at least one occasion, it is unknown how frequently treatment failure would arise over the long-term. We measured the incidence of virologically defined failure among individuals who have been successfully treated on first line NNRTI based regimens for nearly seven years in rural Uganda. Methods: We analyzed data from a prospective cohort study of participants who had been on NNRTI based first line ART for ≥4 years and had a measured VL <1000 copies/mL at enrollment and followed up for an additional three years. All were clients of TASO in Jinja, Uganda. We collected clinical and behavioural data every six months and samples for VL testing were drawn annually. The main outcome of interest was VL > 1000 copies at 36 months after enrollment. We compared factors associated with virologic failure (VF) at 36 months using Wilcoxon Rank Sum, Chi square and Fisher’s Exact Test. Results: We enrolled 503 participants (75.9% females) with a median age of 45years and median duration of ART of 6.8years (Q1-Q3 = 6.0 -7.6 years). A total of 69.0% of participants were receiving nevirapine, lamivudine and zidovudine at enrollment , 22.5%were receiving efavirenz, lamivudine and zidovudine and 8.6%were receiving other regimens. After three additional years of follow up, 3.0% (15) died, 0.6% (3) were lost to follow up, 1.0% (5) voluntarily withdrew. Of the 479 who were followed up for 36 months and with complete information, 2.5% (12) had VL ≥ 1000 copies/mL, of whom 83% (10) had an enrollment VL <50 copies/mL and 1.7% (2) had VL between 50-500 copies. VF was inversely associated with reporting never missing pills (41.7% of failure patients vs. 72.8% non-failure patients p=0.034). There were differences in distribution of the previous ART regimens before enrollment (p=0.005), but there were no clear associations with specific regimens. There was no association between having a VL>50 copies/mL at enrollment and later VF (p=0.160). Conclusion: Incidence of VF among individuals who had been taking ART for nearly 7 years was very low in the subsequent three years. NNRTI-based regimens appear to be very durable among those with good adherence 463 LONG-TERM VIRAL SUPPRESSION DURING INITIAL ANTIRETROVIRAL THERAPY IN HANOI, VIETNAM Junko Tanuma 1 , Shoko Matsumoto 1 , Sebastien Haneuze 2 , Cuong Do Duy 3 , Thanh Thuy Pham Thi 3 , Dung T. Nguyen 4 , Kinh V. Nguyen 4 , Shinichi Oka 1 1 Natl Cntr for Global Hlth and Med, Tokyo, Japan, 2 Harvard Univ, Boston, MA, USA, 3 Bach Mai Hosp, Hanoi, Vietnam, 4 Natl Hosp for Trop Diseases, Hanoi, Vietnam Background: Achieving viral suppression is key in the global strategy to end the HIV epidemic. However, the levels of viral suppression have yet to be described in many resource- limited settings. Methods: Analyses were conducted with a longitudinal dataset from a cohort of adult HIV-infected individuals who initiated ART in two large hospitals in urban Hanoi, Vietnam from October 2007 to April 2013 and whose viral load was measured every 6 months until April 2015. The time to treatment failure from ART initiation was analyzed using two endpoints: (1) the virologic failure (VF) defined as having an HIV viral load of ≥1000 copies/mL during first-line ART and (2) a combined clinical endpoint that included death, loss to follow-up, and a change in antiretroviral drugs due to lack of efficacy or identification of VF, whichever occurred first after 6 months of first-line ART. The mean CD4 count and mean CD4 count change trajectories were estimated using linear regression with the outcome as a function of time. Factors related to the time to VF and impaired early immune recovery, which was defined as not attaining an increase of 100 cells/µl in CD4 counts at 24 months, were further analyzed. Results: In 1806 eligible participants, 225 were identified as having VF with a median of 50 months of first-line ART. The combined clinical endpoint was noted in 313 individuals, which included 225 VFs, 36 deaths, 50 loss to follow-ups, and 2 changes of ART for lack of efficacy. The viral suppression rate at 12 months was 95.5% and 80% for thresholds of 1000 and 50 copies/mL, respectively. The survival without VF was maintained above 90% until 42 months and was 86% at 5 years and 78% at 10 years. The mean change of CD4 count was 155 cells/µl in the first year and 255 cells/µl at 24 months and 164 out of 1013 failed to achieve early immune recovery. A younger age (hazard ratio [HR] 0.75, vs. <30), HCV-antibody positivity (HR 1.43), and d4T-containing regimens (HR 1.4, vs. AZT) were associated with earlier VF. Factors associated with impaired early immune recovery included the male sex (odds ratio [OR] 1.78), HCV-antibody positivity (OR 1.72), d4T-based regimens (OR 0.51, vs. AZT), and NVP-based regimens (OR 0.53, vs. EFV) after controlling for baseline CD4 counts. Conclusion: Durable high-rate viral suppression was noted in the cohort of patients on initial ART in Vietnam. Our results indicated that the 90% target of viral suppression could be achieved in Vietnam.

Poster and Themed Discussion Abstracts

CROI 2017 194