109. Preexisting Resistance and Week 48 Virologic Outcomes After Switching to B/F/TAF in African American Adults with HIV

BACKGROUND: The BRAAVE 2020 study is evaluating the safety and efficacy of switching to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) among virologically suppressed Black adults with HIV. At Week (W) 24, 0.6% (2/328) on B/F/TAF vs 1.8% (3/165) who stayed on their baseline 3 drug regimen (SBR) had HIV-1 RNA ≥ 50 c/mL demonstrating noninferiority of B/F/TAF. Here, resistance analyses and virologic outcomes at W48 are described. METHODS: Enrollment criteria permitted prior treatment failure, except on an INSTI-containing regimen, and allowed documented resistance to NNRTIs, PIs and/or NRTIs, except for K65R/E/N, ≥ 3 thymidine analog mutations (TAMs), or T69-insertions; primary INSTI resistance (-R) was excluded. Preexisting drug resistance was assessed with historical genotypes and proviral DNA genotyping. B/F/TAF outcomes were determined by last on-treatment HIV-1 RNA through W48. RESULTS: Altogether, 495 participants enrolled (B/F/TAF n=330, SBR n=165). Preexisting primary NRTI-R, NNRTI-R, and PI-R substitutions were observed in 14% (70/495), 21% (102/495), and 13% (62/495), respectively. M184V/I and TAMs were detected in 10% (51/495) and 7% (34/495), respectively. Primary INSTI-R was detected post-randomization in 2% (11/495); all continued on study and were included in efficacy analyses. At W24, 163 in the SBR group switched to B/F/TAF (SBR to B/F/TAF). W48 outcomes were determined for 489 participants who had ≥ 1 post-switch HIV-1 RNA measurement: 99% (324/327) in the B/F/TAF and 100% (162/162) in the SBR to B/F/TAF groups had HIV-1 RNA < 50 copies/mL at their last study visit, including 100% (68/68) with NRTI-R (50 of whom had archived M184V/I and post-switch data), and 100% (11/11) with INSTI-R (Table). No participant had treatment emergent resistance to study drugs. Table. BRAAVE 2020 Preexisting Resistance and Virologic Suppression at Week 48 (Last On-treatment Observation Carried Forward Analysis) [Image: see text] CONCLUSION: Preexisting resistance was common among virologically suppressed Black adults in BRAAVE 2020, notably M184V/I, TAMs, and NNRTI-R. High rates of virologic suppression were maintained through 48 weeks of B/F/TAF treatment and there were no failures with de novo resistance, indicating that B/F/TAF is an effective treatment option for virologically suppressed people with HIV with or without preexisting resistance to NNRTIs, PIs, or non-tenofovir NRTIs. DISCLOSURES: Kristen Andreatta, MSc, Gilead Sciences (Employee, Shareholder) Michelle L. D’Antoni, PhD, Gilead Sciences (Employee, Shareholder) Silvia Chang, Masters, Gilead Sciences (Employee, Shareholder) Aiyappa Parvangada, MS Computational Biology, Gilead Sciences (Employee) Christiana Blair, MS, Gilead Sciences (Employee, Shareholder) Sean E. Collins, MD, MS, Gilead Sciences (Employee) Kirsten L. White, PhD, Gilead Sciences, Inc. (Employee, Shareholder)