CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

for 10 minutes for reverse transcription, and shifted to 68ºC for 40 minutes for LAMP reaction. Sybr-green fluorescence signal was recorded in real time. Results: HCG124 and HCDN-G3 primer sets detected HCV RNA in 109/116 HCV positive serum samples and in 8/9 HCV positive blood samples in less than 40 minutes. This new RT-LAMP system has a sensitivity level of 94% and 100% specificity. The limit of detection of the present system is 550 - 1000 IU/mL, lower than WHO recommended limit for HCV POC testing (3000 IU/mL). Real time measurements could be substituted by a single end-point measurement at 40 minutes using a portable fluorescent reader at POC. Conclusion: RT-LAMP system has showed to be highly sensitive and specific for molecular detection of HCV from less than 50 µL blood sample, easily collected by capillary punction and without a prior RNA purification step. Within less than 50 minutes, an active HCV infection can be detected at POC, implementing screening strategies among vulnerable populations as a crucial step towards HCV elimination goal. Prevalence and Resistance Profiles of “Unusual” HCV Subtypes in Italy Collins Ambe Chenwi 1 , Velia Chiara Di Maio 2 , Mohammad Al Khatib 1 , Elisabetta Teti 3 , Ada Bertoli 1 , Stefania Paolucci 4 , Nicola Coppola 5 , Teresa Pollicino 6 , Bianca Bruzzone 7 , Omar El Khalili 1 , Sohaib Khan 1 , Massimo Puoti 8 , Maurizio Zazzi 9 , Francesca Ceccherini-Silberstein 1 , for the HCV Virology Italian Resistance Network Vironet C 1 University of Rome Tor Vergata, Rome, Italy, 2 Bambino Gesu Children's Hospital, Rome, Italy, 3 Hospital of Rome Tor Vergata, Rome, Italy, 4 IRCCS Policlinico San Matteo Foundation, Pavia, Italy, 5 University of Campania Luigi Vanvitelli, Naples, Italy, 6 University of Messina, Messina, Italy, 7 IRCCS AOU San Martino-IST, Genoa, Italy, 8 ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy, 9 University of Siena, Siena, Italy Background: Recent data show that "unusual" hepatitis C virus (HCV) subtypes have lower responses to direct-acting antivirals (DAAs) compared to most prevalent subtypes. We aimed to investigate the prevalence and resistance profiles of "unusual" HCV subtypes in Italy. Methods: Clinical and virological data of "unusual" HCV genotype (GT)/ subtypes (defined as GT1 non-1a/b, GT2 non-2a/b, GT3 non-3a, GT4 non-4a/d) were analyzed within the Italian VIRONET-C database. Subtype assignment was confirmed by phylogenetic analyses on NS3±NS5A±NS5B sequences. The prevalence of resistance associated substitutions (RASs) was evaluated according to Sorbo et al 2018 list. Results: Out of 3554 individuals with an available NS3±NS5A±NS5B sequence, 282 (8%; median age [IQR], 73 [57-81]years; 58% males) were infected with "unusual" subtypes (GT1g/i/l=3/1/2; GT2c/j=247/2; GT3b/g/h/k=1/1/8/1; GT4c/i/l/m/n/o/r/v=1/1/1/1/3/5/3/1). Subtype distribution varied according to ethnicity, with GT2c and GT3h most prevalent in Italians (88-100%), other "unusual" GT3 in Asians (75%), and "unusual" GT1 and GT4 in Africans (78%). 206 individuals (73%) were DAA-naïve, while 76 were DAA-failures (27%), in particular 36 with a recommended regimen (22 glecaprevir/pibrentasvir and 14 sofosbuvir/velapatasvir±ribavirin). The patients infected with GT3 unusual subtypes were more prone to failure (91%, 10/11) followed by GT4 (44%, 7/16), GT2 (23%, 58/249) and finally GT1 (17%, 1/6). All failed patients (except one with GT4n) displayed at least one RAS in at least one protein (Figure 1). The number of RASs in each protein varied by GT, subtype and treatment exposure. Overall, NS5A-RASs were most prevalent, with complex patterns in both DAA naïve and failures, NS3-RASs were less prevalent but present in all GT3 failures, while NS5B-RAS were rare and present across GT2-GT3-GT4, with variable patterns. NS5A-RASs at position 93 (H/F/S) were detected only at failure in GT3h/k and GT4o/v. Few patients had NS3-RASs, only at failure (3/3 GT3h:80R or 158V; 4/24 GT2c:56Y/H±168V/A). Conclusion: In this Italian setting, GT1-GT4 unusual subtypes were frequent, predominated by GT2c in Italians, and with failure rates highest within GT3. Most DAA-failures carried complex NS5A-RAS patterns, some conferring high-level of resistance. These results advise for closer surveillance and further studies to better characterize the impact of "unusual" HCV subtypes on DAA efficacy.

were eligible for the study. SOF/VEL treatment was started within 36 hours of delivery. Paired maternal blood and breast milk were obtained at 2 or more pharmacokinetic (PK) visits. VEL, SOF and GS-331007 concentrations in plasma and breast milk were measured using validated UPLC-MS/MS assays (LLOQ 5 ng/mL for VEL in plasma and breast milk and SOF/007 in plasma; 1 ng/mL for SOF/007 in breast milk). The infant daily dose was calculated using drug concentrations in the milk and considering that the amount of milk ingested by an exclusively breastfed infant is 150 mL/kg/day and reported relative to the adult dose normalized to 70 kg weight and the child dose normalized to 13 kg weight. Data were summarized using descriptive statistics. Results: Four participants were enrolled with a median (range) age of 29.5 years (27-36); 3 white, 1 multiple races; all were multiparous with median (range) weight of 69 kg (58-88) and median creatinine of 0.5mg/dL range (0.5-0.6). The participants had their first PK visit within 24 hours of initiating SOF/VEL and had 2 to 7 PK visits each yielding a total of 17 paired samples for analysis occurring a median (range) time of 1.99 days (0.19-6.13) after treatment start. VEL and GS-331007 were quantifiable in all paired samples; SOF was quantifiable in 9 breast milk and 7 plasma samples due to its short half-life (Table). SOF, GS-331007, and VEL concentrations in the breast milk were lower than maternal plasma concentrations. The estimated infant daily dose from breastmilk is less than 0.7% of the daily dose in an adult and a child adjusted to weight. Conclusion: Based on our findings, exposure to SOF/VEL via breastmilk is minimal and reassuring for infant safety and low potential for development of HCV resistance with perinatal transmission. Clinicians should consider expedited HCV treatment in the postpartum period during breastfeeding to improve linkage to HCV care.

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Validation of a Point-of-Care Test Based on RT-LAMP for HCV Detection by Capillary Sampling Sonia Arca-Lafuente 1 , Cristina Yépez-Notario 2 , Pablo Cea-Callejo 3 , Violeta Lara Aguilar 1 , Celia Crespo-Bermejo 1 , Luz Martín-Carbonero 4 , Ignacio De los Santos 5 , Verónica Briz 1 , Ricardo Madrid 3 1 Institute of Health Carlos III, Madrid, Spain, 2 Universidad Pablo de Olavide, Sevilla, Spain, 3 Complutense University of Madrid, Madrid, Spain, 4 La Paz University Hospital, Madrid, Spain, 5 Hospital Universitario de La Princesa, Madrid, Spain Background: Every year, 1.5 million people suffer a new infection by HCV, and nearly 58 million people worldwide live with a Hepatitis C chronic infection [World Health Organization (WHO), June 2022]. To overcome the underdiagnosis of HCV among hard-to-reach population and accomplishing WHO's target of Hepatitis C virus (HCV) elimination by 2030, it is essential to develop new rapid and easy-to-use molecular diagnostic systems with similar performance values to the gold standard qRT-PCR. Loop-Mediated Isothermal Amplification (LAMP) arises as a promising tool for point-of-care (POC) molecular detection of viral diseases. In this work, we have validated a new diagnostic tool based on fluorescent reverse transcriptase (RT) LAMP technique, detecting HCV RNA directly from capillary blood samples in less than 50 minutes. Methods: 125 samples from HCV infected patients [116 serum samples (genotypes 1 to 4) and 9 fresh blood samples], 27 individuals who tested negative for HCV but positive for HIV, and 11 healthy controls were analysed. Serum was collected from 50 µL of blood samples by 5 min centrifugation, incubated in lysis buffer for 10 min, and then mixed with RT-LAMP reagents. RT-LAMP reactions were run in parallel with two different primer sets: HCG124, a set of 9 primers designed to detect HCV genotypes 1, 2, or 4; and HCDN-G3, a set of 6 specific primers for genotype 3. Reaction mix was first incubated at 45ºC

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