P-376. The US REGAL Cohort: A Retrospective Real-world Study of the Effectiveness and Tolerability of the Antiretroviral Treatment Regimens DTG/3TC Compared to BIC/FTC/TAF in Older Persons Living with HIV

Abstract Background Older persons living with human immunodeficiency virus (PLHIV) have more age-related comorbidities than the general population and greater potential for polypharmacy and drug-drug interactions with their antiretroviral treatment (ART). Data comparing the real-world effectiveness of the two-drug dolutegravir/lamivudine (DTG/3TC) and three-drug bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) regimens is limited in older PLHIV. Methods To assess the real-world effectiveness of switching to DTG/3TC versus BIC/FTC/TAF in older PLHIV, we conducted a retrospective chart review among people aged ≥50 years on ART who were virologically suppressed with ≥24 weeks of follow-up in the United States (US). Index date was defined as DTG/3TC or BIC/FTC/TAF initiation date. Results Among 326 PLHIV across 5 study sites, 165 were on DTG/3TC and 161 were on BIC/FTC/TAF. PLHIV were on average aged 61 years (23.6% aged >65 years), 76.3% male gender, 38.3% non-White, 15.7% Hispanic/Latinx ethnicity, and diagnosed with HIV an average of 19 years before index date. Clinical characteristics were similar between groups at index date (Table 1). A high burden of age-related comedications and comorbidities was observed. A total of 97.2% of PLHIV reported non-ART comedications. Approximately 64% of PLHIV reported ≥3 comorbidities; cardiac disorders (77.5%), metabolic and nutritional disorders (46.9%), and psychiatric disorders (40.4%) were most common. Prior virological failure was reported in 6.5% of PLHIV on DTG/3TC and 17.3% of PLHIV on BIC/FTC/TAF. Total follow-up was 356.6 and 435.8 person-years in DTG/3TC and BIC/FTC/TAF groups, respectively. Approximately 20% of PLHIV had 240 weeks of follow-up. Virological failure was reported for 1 PLHIV in each group. The incidence rate of virological failure was 0.28 (95% confidence interval [CI]: 0.01, 0.59) and 0.23 (95% CI: 0.01, 0.48) per 100 person-years for DTG/3TC and BIC/FTC/TAF, respectively over the study period. No treatment-emergent resistance was reported. Conclusion In older, virologically suppressed PLHIV with significant burden of age-related comorbidities and comedications in the US, switching to either two-drug DTG/3TC or three-drug BIC/FTC/TAF maintained long-term viral suppression without resistance. Disclosures Onyema Ogbuagu, MA, FACP, FIDSA, Gilead Sciences, Inc.: Advisor/Consultant|ViiV: Advisor/Consultant Jeremy Fraysse, MS, GSK: Stocks/Bonds (Public Company)|ViiV Healthcare: Stocks/Bonds (Private Company) Jennifer Kuretski, DNP, APRN, NP-C, AAHIVS, Gilead Sciences: Speaker|ViiV: Speaker Gustavo Verdier, BSc, BPharm, MBA, ViiV Healthcare: Employee Cynthia Firnhaber, MD, MS, DTM&H, MERCK: Advisor/Consultant|MERCK: Grant/Research Support Emilio Letang, MD, MPH, PhD, GSK: Stocks/Bonds (Public Company)|ViiV Healthcare: Employee Cassidy Henegar, PhD, MSPH, ViiV Healthcare: Employee|ViiV Healthcare: Stocks/Bonds (Public Company) Rebecca Glassman, MD, Gilead: Advisor/Consultant Deanna Merrill, PharmD, MBA, AAHIVP, ViiV Healthcare: employee Carly Rodriguez, PhD, Viiv Healthcare: Services via contract research organization Richard Grove, MSc, GSK: Stocks/Bonds (Public Company) Paula Peressini López, PhD, ViiV Healthcare: Financial payments to conduct the study Bryn Jones, MBChB, GSK: Stocks/Bonds (Public Company)|ViiV Healthcare: Employee Julie Priest, MSPH, GSK: Stocks/Bonds (Public Company)|ViiV Healthcare: Employee