CROI 2020 Abstract eBook

Abstract eBook

Poster Abstracts

978 PUBLICLY FUNDED HIV PrEP IN BRITISH COLUMBIA: PROGRAM RETENTION AND NEW HIV DIAGNOSES

August 2018. During PS interviews, public health staff asked men who have sex with men (MSM) and transgender persons who have sex with men (TGSM) if they were taking PrEP. We used name, date of birth and sex to match STI PS data to public health HIV surveillance data to identify persons diagnosed with HIV after their interview. We calculated the incidence of HIV diagnoses per 100 person years in PrEP users and non-users and used Cox proportional hazard regression, adjusting for age and race/ethnicity, to assess the risk of HIV diagnosis based on past PrEP use. We included PrEP use status, race, Latinx ethnicity, age, and bacterial STI diagnoses in multivariate analysis. MSM and TGSMwithout an identified HIV diagnosis were administratively censored on August 31, 2018. We reviewed HIV PS interview records for PrEP users who were diagnosed with HIV to assess if they were taking PrEP at the time of their diagnosis. Results: The median time from PS interview to HIV diagnosis or censoring was 14 months (IQR 6 to 23 months). Five (0.4%) of 1206 people who reported PrEP use at the time of their STI diagnoses and 97 (3%) of 2162 persons who were not using PrEP were diagnosed with HIV infection (p<0.001). HIV incidence was lower among PrEP users than nonusers (0.02 vs. 0.09 cases per 100 person- years, aHR 0.16, 95% CI 0.06 to 0.45). Other factors associated with incident HIV diagnosis included age <20 years (aHR 1.76, 95% CI 0.68 to 4.54), Black race (aHR 1.21, 95% CI 0.60 to 2.45), and Latinx ethnicity (aHR 2.13, 95% CI 1.30 to 3.51). All five PrEP users diagnosed with HIV after their STI PS interview reported discontinuing PrEP prior to their HIV diagnosis. Conclusion: Based on current use in King County, PrEP is highly effective, reducing HIV incidence by 84% among MSM and transgender persons. Our findings highlight PrEP discontinuation as a key challenge limiting the effectiveness of PrEP, and the elevated risk of HIV among young and minority MSM and TGSM diagnosed with STI. 980LB TFV-DP IN DBS FOR PREGNANT/POSTPARTUM ADOLESCENT AND YOUNG WOMEN ON PrEP IN AFRICA Peter L. Anderson 1 , Lynda Stranix-Chibanda 2 , Sharon Huang 3 , Sybil Hosek 4 , Deborah Kacanek 3 , Teacler Nematadzira 2 , Frank Taulo 5 , Violet Korutaro 6 , Clemensia Nakabiito 7 , Masebola Masenya 8 , Kathryn Lypen 9 , Nahida Chakhtoura 10 , Hans M. Spiegel 11 , Benjamin H. Chi 12 , for the IMPAACT 2009 team 1 University of Colorado Anschutz Medical Campus, Aurora, CO, USA, 2 University of Zimbabwe, Harare, Zimbabwe, 3 Harvard University, Cambridge, MA, USA, 4 John H. Stroger Jr. Hospital of Cook County, Chicago, IL, USA, 5 Malawi College of Medicine- Johns Hopkins University Research Project, Blantyre, Malawi, 6 Baylor College of Medicine Children's Foundation, Kampala, Uganda, 7 Makerere University, Kampala, Uganda, 8 Wits Reproductive Health and HIV Institute, Johannesburg, South Africa, 9 FHI 360, Durham, NC, USA, 10 National Institute of Child Health and Human Development, Bethesda, MD, USA, 11 DAIDS, NIAID, Rockville, MD, USA, 12 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Background: Pregnant/postpartum adolescent girls and young women (AGYW) in Africa are one of the populations at highest risk for HIV acquisition; yet, pharmacokinetic (PK) data for pre-exposure prophylaxis (PrEP) remains limited. Intracellular tenofovir-diphosphate (TFV-DP) concentration in red blood cells, measured via dried blood spots (DBS), has been used to monitor cumulative PrEP adherence in many settings. Methods: The first phase of IMPAACT 2009 evaluated PK characteristics of daily oral PrEP (FTC 200mg/TDF 300mg) among pregnant/postpartum AGYW (16-24 years) in Malawi, South Africa, Uganda, and Zimbabwe. Daily FTC/ TDF was administered under direct observation for 12 weeks in two groups: pregnant AGYW starting at 14-24 weeks gestation (pregnancy) or 6-12 weeks after delivery (postpartum). Weekly TFV-DP was measured from DBS using a validated liquid chromatography-tandemmass spectrometry assay. TFV-DP distributions were determined at 12 weeks and groups compared with the Wilcoxon test. Population PK models were fit to estimate half-life and steady state concentrations. Results: FromMarch to June 2019, we enrolled 20 pregnant (median gestational age: 18 wks) and 20 postpartum (median time after delivery: 7 wks) women at a median age of 20 years (IQR:19,22). Of 3360 doses, 3348 (>99%) were directly observed. TFV-DP accumulated with a half-life of 15.3 days (95%CI: 12.8,17.8) in pregnancy and 18.0 days (95%CI: 15.3,20.7) postpartum, with steady state achieved by 8-10 weeks in both groups. Median TFV-DP was 965 fmol/punch (IQR: 691,1166) in pregnancy vs 1406 fmol/punch (IQR: 1053,1859) postpartum (p=0.006). Predicted median TFV-DP was 890 fmol/ punch (IQR: 704,1143) in pregnancy vs 1418 fmol/punch (IQR: 1179,2139) postpartum (Figure). Two fetal demises (unrelated to study agent), two

K.Junine Toy 1 , Cora L. Keeney 1 , Jason Trigg 1 , Wendy W. Zhang 1 , Paul Sereda 1 , Viviane D. Lima 1 , Mark Hull 1 , Katherine Lepik 1 , Martin St-Jean 1 , David M. Moore 1 , Silvia Guillemi 1 , Rolando Barrios 1 , Nancy Yu 1 , Julio S. Montaner 1 1 British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada Background: In January 2018, a province-wide HIV pre-exposure prophylaxis (PrEP) programwas launched in British Columbia (BC), Canada, to complement the existing publicly-funded HIV treatment as prevention strategy. BC residents were eligible to receive publicly-funded emtricitabine-tenofovir DF through the centralized BC Centre for Excellence in HIV/AIDS program if they were at risk of HIV acquisition according to BC PrEP Guidelines. We sought to evaluate program retention and the rate of new HIV diagnoses. Methods: Individuals enrolled in the BC PrEP program between 1-Jan-2018 and 30-Jun-2019 were characterized by clinical, demographic, and prescriber characteristics. For those who initiated PrEP, we determined program status at end of follow-up (31-Aug-2019). Multivariate logistic regression was used to evaluate factors associated with program non-retention (defined as >6 month lapse beyond expected PrEP refill date). Rate of new HIV diagnoses in the cohort was calculated. Results: In the first 18 months, 4648 individuals applied for PrEP and 4570 enrolled in the program [98%male, median age 33 years (Q1-Q3, 27-44)]. Most participants (90%) qualified based on an HIV Incidence Risk Index (HIRI) for MSM Score of ≥10 [median 19 (Q1-Q3, 15-25)]. The majority of participants (83%) resided in Greater Vancouver and received care at sexual health clinics (47%), HIV-focused clinics (23%) or general practice/other settings (30%). Of the 4451 participants who initiated PrEP, 84%were retained in the program as of 31-Aug- 2019 (See Figure 1). Factors associated with program non-retention were higher HIRI-MSM score [adjusted OR 1.29 (95% CI, 1.12-1.48) per 10 score increment] and prescriber-reported on-demand PrEP use [adjusted OR 4.09 (95% CI, 3.01- 5.55)] but not age, urban vs. rural location, or provider antiretroviral treatment or PrEP prescribing experience. Among participants who initiated PrEP, there were 8 HIV seroconversions in 4141 person years of follow-up, including 6 persons with >30 day lapse in PrEP medication prior to HIV diagnosis. Overall, new HIV diagnosis rate was 0.19 per 100 person years (95% CI, 0.08-0.38). Conclusion: In the context of a publicly funded, centrally distributed PrEP program, retention was high at 18 months, and the rate of new HIV diagnoses low relative to the expected rate for individuals reporting these risk behaviours. Persons with higher HIRI-MSM score were at increased risk of program non- retention, and thus may benefit from enhanced support.

Poster Abstracts

979 POPULATION-LEVEL EFFECTIVENESS OF PrEP AMONG MSM AND TRANSGENDER PERSONS WITH STI

Jade Pagkas-Bather 1 , Christine M. Khosropour 2 , Matthew R. Golden 2 , Julia C. Dombrowski 2 1 University of Chicago, Chicago, IL, USA, 2 University of Washington, Seattle, WA, USA Background: HIV PrEP is highly efficacious, but its effectiveness may be limited by poor adherence or discontinuation. Few studies have evaluated PrEP effectiveness outside of specific clinics or healthcare organizations. Methods: We conducted a retrospective cohort study using King County, Washington STI partner services (PS) interview data collected January 2014 to

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