1264. Durability and effectiveness of fostemsavir in heavily treatment-experienced people with HIV

Abstract Background Paired with other active antiretrovirals (ARVs), fostemsavir (FTR) may offer heavily treatment-experienced (HTE) people HIV (PWH) options for continuing effective treatment. Durability and effectiveness of FTR-containing regimens in routine clinical care the United States were assessed. Methods Electronic health record data from OPERA® cohort used to identify adults initiating between 2JUL2020 (FDA approval) 1SEP2021. Eligible PWH followed first FTR prescription (baseline) until discontinuation, death, loss follow up, or study end (28FEB2022). was assessed as frequency discontinuation. Virologic outcomes at 6 12 months (±3 months) included suppression (viral load [VL] < 50 copies/mL), virologic failure (2 consecutive VL ≥200 copies/mL 1 + discontinuation within 120 days after suppression), viral blips (1 ≥50 preceded by VLs copies/mL). Analyses stratified baseline (bVL copies/mL; bVL Results Overall, 86 initiated 50: 30; ≥50: 55), median up 10.8 (IQR: 6.8, 15.3). Compared ≥50, those older more likely be white have lived longer (Table 1). Over 20% discontinued 2). Most (82%) discontinuations switches alternative regimens; remaining ARV interruptions (no ARVs > 45 days). Among 50, most maintained (6 months: 74%; 82%; Figure). during period assessed, 33% suppressed months, 36% 48% achieved any time over entire (Figure). In either group, ≤5 experienced blip, though proportion multiple low. Conclusion Despite a heterogenous population diverse regimens, HTE remained on end. half period. infrequent, although limited this early evaluation real-world use. Disclosures Ricky K. Hsu, MD, Gilead: Honoraria|Merck: Honoraria|ViiV: Advisor/Consultant|ViiV: Grant/Research Support|ViiV: Honoraria Laurence Brunet, PhD, AIDS Healthcare Foundation: Client my employer|EMD Serono: employer|Gilead Sciences: employer|Janssen: employer|Merck & Co: employer|TheraTechnologies: employer|ViiV Healthcare: employer Jennifer S. Fusco, BS, Co.: Cassidy Henegar, MSPH, GlaxoSmithKline: Stocks/Bonds|ViiV full-time employee Vani Vannappagari, MBBS, MPH, ViiV I am full receive GlaxoSmithKline stock part compensation package|ViiV Stocks/Bonds Andrew Clark, Employee|ViiV Gerald Pierone, Jr., Support|GSK-VIIV: Support Gregory P. employer|EMD: Support|Gilead employer|Theratechnologies: employer.