CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

1091 Development and Evaluation of Tasso-M50 Method for Dried Blood Viral Load Detection Daniel S Rosenbloom 1 , Brad R. Evans 1 , Brian Squadroni 1 , Jennifer Nguyen 1 , Livio Azzoni 2 , Erin Coppola 1 , Guoxin Wu 1 , Jill W. Maxwell 1 , Jessicamarie Morris 2 , Kenneth Lynn 3 , Paul Zuck 1 , Pablo Tebas 3 , Karam Mounzer 4 , Luis J. Montaner 2 , Bonnie Howell 1 1 Merck Research Laboratories, Rahway, NJ, USA, 2 Wistar Institute, Philadelphia, PA, USA, 3 University of Pennsylvania, Philadelphia, PA, USA, 4 Philadelphia FIGHT, Philadelphia, PA, USA Background: At-home blood collection would enable HIV VL assessment for intensive monitoring without frequent access to a clinic – such as for PrEP programs, perinatal or breastfeeding pediatric monitoring, discordant couples, or participation in ART interruption studies. We present the development and qualification of a scalable, high-throughput PCR method using dried blood collected in Tasso-M50 cartridges. Methods: We developed a dried blood assay ("M50 assay") with samples from 21 people with HIV (5% female, 67% African American, mean age 51 years, NCT03588715). At clinic visits (mean 20.5), we collected a) capillary blood in two 4-well Tasso-M50 devices and b) matched plasma samples (pVL). Between visits, participants self-collected in two devices that were mailed back. Automated RNA extraction and duplicate RT-qPCR reads with dual LTR/GAG FAM-labeled primers were performed (up to 16 M50 PCR reads per timepoint, sourced from 400 uL blood collection). DNase treatment was used in a subset of samples collected during suppressive ART. Assay performance was tested on separate M50 samples prepared from RNA diluted into whole blood. Results: M50 assay PCR reagents/instruments were qualified on plasma samples (94% concordance to reference lab), and M50 VL was comparable between home- and clinic-collected samples. In the separate performance test, the M50 assay had 99.5% specificity and an estimated 95% limit of detection of 150 c/mL if all 16 reads from 2 devices are used. However, 64% of clinic visits with undetected pVL had median M50 read ≥ 200 c/mL, due to cell-associated HIV: M50 VL of these discordant samples correlated with total cellular HIV DNA (r = 0.95) and was stable on suppressive therapy (mean slope –3.1% per week [95% CI –8.4 to +2.3%]). DNase reduced M50 VL while preserving detectability of RNA standards, suggesting that ~28% of the stable M50 background is contributed by DNA and the remainder by RNA. Conclusion: We introduce and qualify a new assay for total HIV burden in dried whole blood with an at-home sampling device. Discordant samples with high M50 VL and negative pVL are stable over time and reflect contributions from intracellular viral DNA and RNA. Home sampling of total HIV burden may be able to monitor new infections in prophylaxis-directed studies, assess changes in residual cell-associated virus in cure-directed studies, or detect viral rebound after correcting for the stable on-therapy signal.

sequences were used. After removing low quality sequences or those lacking assay target regions, 53,503 HIV-1 and 68 HIV-2 sequences remained to assess assay target region percent identity. Results: Across the cohort m-PIMA™ HIV-1/2 Detect test detected 264/274 (96.4%) samples. Mean (min-max) VL of the panel was 3.93 (2.18-6.14) log copies/mL. Among samples with HIV VL >1000 copies/mL (VL > limit of detection of the m-PIMA™ HIV-1/2 Detect) 219/222 (98.6%) were detected. At least one panel member from each subtype/CRF and all URFs were detected. In silico analysis found only 2/53,503 (0.0037%) HIV-1 (both group O) and 1/68 (1.47%) HIV-2 (subtype F) accessions with mutations in target regions which would reduce % identity below 90%, considered the threshold to ensure detection. Conclusion: POC testing is a critical tool to identify HIV infections around the world. Here, we demonstrate that the m-PIMA™ HIV-1/2 Detect POC assay detects each of the major circulating HIV strains as well as rare divergent strains. In silico analysis predicted that m-PIMA™ HIV-1/2 Detect would detect the majority of HIV-1 and HIV-2 strains. These data indicate that this assay can detect the full range of HIV viral diversity. 1090 HIV & HCV Screen Rates for Hospitalized PWUD Are Heterogeneous & Suboptimal Across 11 US Hospitals Leo K. Westgard 1 , Taisuke Sato 1 , Finlay Pilcher 2 , Emily D. Grussing 3 , Jessica P. Ridgway 4 , Ayesha Appa 5 , Jaimie P. Meyer 6 , Uriel R. Felsen 7 , Luara Marks 8 , Kinna Thakarar 9 , Brian T. Montague 10 , Ank Nijhawan 11 , William S. Bradford 12 , Ellen Eaton 12 , Alysse G. Wurcel 1 , for the PWUD Care Workgroup (PCW) 1 Tufts Medical Center, Boston, MA, USA, 2 University of Vermont, Burlington, VT, USA, 3 Tufts University, Boston, MA, USA, 4 University of Chicago, Chicago, IL, USA, 5 University of California San Francisco, San Francisco, CA, USA, 6 Yale University, New Haven, CT, USA, 7 Albert Einstein College of Medicine, Bronx, NY, USA, 8 Washington University in St Louis, St Louis, MO, USA, 9 Maine Medical Center, Portland, ME, USA, 10 University of Colorado Anschutz Medical Campus, Aurora, CO, USA, 11 University of Texas Southwestern Medical Center, Dallas, TX, USA, 12 University of Alabama at Birmingham, Birmingham, AL, USA Background: To end the HIV and HCV epidemics, people who use drugs (PWUD) need more robust opportunities for HIV and hepatitis C virus (HCV) testing, confirmation of infection and linkage to care. While inpatient hospitalizations are an essential opportunity to test PWUD for HIV and HCV there is limited research on rates of inpatient testing for HIV and HCV among PWUD and no data comparing testing rates between hospitals or parts of the country. This primary aim of this study is to quantify aggregate testing rates across a cohort of U.S. hospitals and hospital systems. Secondarily, we aim to explore how HIV consent requirements impact testing rates. Methods: Eleven hospital sites were included in the study. Nine established a cohort of inpatient encounters from 1/1/2020 to 4/1/2022 tied to the presence of ICD-10 drug use diagnosis codes (Table 1). Two sites (CT and TX) identified inpatient cohorts from the same study period using Addiction Medicine consults. The unit of analysis was hospitalization. Data collected included: the number of hospitalizations, HIV antigen/antibody tests, HCV antibody tests, and HCV viral loads. HIV and HCV testing rates and positivity were derived as a percentage of total PWUD hospitalizations. All sites detailed their HIV screening and consent policies, where consent requires either written or oral patient approval. The impact of state consent requirements on screening was analyzed using a Student's t-test comparing hospitals with and without these mandates. Results: We included 65,276 hospitalizations of PWUD at across 11 hospitals. Sites had an average HIV screening rate of 40.08% (SD = 23.29%) and an average HCV Ab screening rate of 31.58% (SD = 15.14%), with widespread heterogeneity in screening rates across facilities. HIV screening rates did not significantly differ between states that require consent and those that did not (p-value = 0.389). Average test positivity across hospitals was 4.5% for HIV tests and 41.4% for HCV tests. Conclusion: In a study of 11 hospitals and hospital systems across the U.S., we found suboptimal HIV and HCV testing rates during inpatient encounters for PWUD. Testing rates for HCV were lower than those for HIV, with widespread heterogeneity across hospitals, regardless of consent requirements. Hospitalizations are a missed opportunity to offer HIV and HCV testing. As treatment (HIV) and cure (HCV) are necessary to end these epidemics, understanding and overcoming barriers to HIV and HCV testing need to be prioritized. The figure, table, or graphic for this abstract has been removed.

Poster Abstracts

1092 Declines in HIV Testing and Diagnoses: Unanticipated Consequences of Trump Adm 2019 Title X Policy Jennifer Sherwood , Elise Lankiewicz, Deborah Stenoien, Nathan Roberson, Brian Honermann, Greg Millett amfAR, New York, NY, USA Background: In 2019 the Trump administration instituted a regulation (hereinafter the Policy) which required that all Title X funded family planning clinics have financial and physical separation of abortion services from other health services and disallowed providers from referring clients for abortion. In response, 32% (1,280) of all Title X funded sites left the program. This exodus led to declines in Title X client numbers and contraception provision, however the Policy's impact on HIV testing and diagnoses has yet to be examined. Methods: This secondary analysis uses public data from Title X Family Planning Annual Reports (2016-2021) and CDC HIV surveillance reports (2016-2021) to examine the Policy's impact on: 1) HIV testing at Title X clinics by region, and 2)

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