1023. Suppressed Switch to Bictegravir/Emtricitabine/Tenofovir Alafenamide vs. Dolutegravir/Lamivudine: Virologic Failure and Durability
Authors: Pierone Gerald , Fusco Jennifer S , Brunet Laurence , Sension Michael , Dunbar Megan , Gruber Joshua , Dieterich Douglas , Fusco Gregory P 
Published: November 2023

Abstract

Background
In the US, two common single-tablet regimens for HIV treatment are bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) and dolutegravir/lamivudine (DTG/3TC). We sought to compare B/F/TAF and DTG/3TC in virologically suppressed, treatment-experienced people with HIV in the OPERA® cohort.

Methods
All treatment-experienced adults with HIV switching to B/F/TAF or DTG/3TC (01Aug2020-30Jun2022) with a viral load (VL) &lt; 200 copies/mL at switch and ≥1 follow-up VL were included. Confirmed virologic failure (VF) was defined as 2 consecutive VL ≥200 copies/mL or regimen discontinuation following a VL ≥200 copies/mL; VL ≥50 copies/mL was used in a sensitivity analysis. Discontinuation was defined as any regimen modification or a treatment gap &gt;45 days. Incidence rates (Poisson regression) and hazard ratios (Cox proportional hazard models) were estimated with inverse probability of treatment weights (IPTW) to adjust for race, payer, CD4 count and eGFR at baseline. Covariate balance was assessed with standardized mean differences; values ≤0.10 indicated adequate balance.

Results
On B/F/TAF, 3713 individuals were followed for a median of 16 months (interquartile range: 11, 22). On DTG/3TC, 2327 individuals were followed for a median of 15 months (10, 21). The distribution of key characteristics differed between groups; balance was achieved with IPTW (Table 1). VF≥200 incidence rates per 100 person years were low (B/F/TAF: 1.7; DTG/3TC: 2.1); risk with B/F/TAF was not statistically different than with DTG/3TC (HR≥200: 0.84 [95% CI: 0.59, 1.18]). VF≥50 incidence rates were higher, but risk did not differ between groups (HR≥50: 1.04 [0.86, 1.26]; Fig 1). All-cause regimen discontinuation was less likely with B/F/TAF than DTG/3TC (HR: 0.83; 95% CI: 0.73, 0.94; Fig 2). Treatment-related discontinuation (i.e., last VL ≥200 copies/mL, adverse diagnosis, side effect, lab abnormality) was identified in 6% of B/F/TAF and 9% of DTG/3TC discontinuers.

Conclusion
In this real-world US cohort, virologically suppressed individuals switching to B/F/TAF were less likely to discontinue their regimen than those switching to DTG/3TC. VF was infrequent and no statistical difference was observed in the risk of VF between regimens over the study duration.

Disclosures
Jennifer S. Fusco, BS, Epividian, Inc.: Salary|Epividian, Inc.: Ownership Interest|Epividian, Inc.: Stocks/Bonds Laurence Brunet, PhD, Epividian, Inc.: Salary|Epividian, Inc.: Stocks/Bonds Michael Sension, MD, Gilead: Advisor/Consultant|Gilead: Honoraria|Viiv: Advisor/Consultant|Viiv: Grant/Research Support|Viiv: Honoraria Megan Dunbar, PhD, Gilead: Employment Joshua Gruber, PhD, Gilead Sciences, Inc: Employee|Gilead Sciences, Inc: Stocks/Bonds Douglas Dieterich, MD, Abbvie: Advisor/Consultant|Abbvie: Honoraria|Gilead: Advisor/Consultant|Gilead: Honoraria|Merck: Advisor/Consultant|Merck: Honoraria Gregory P. Fusco, MD, MPH, Epividian, Inc.: Board Member|Epividian, Inc.: Ownership Interest|Epividian, Inc.: Stocks/Bonds