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)


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.