Background: Treatment-naïve, HIV-1-infected individuals with high viral load and/or low CD4 count may be difficult to treat. In two Phase 3 studies of fixed-dose combination bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) vs. dolutegravir comparators, there were no treatment differences between arms for subgroups with HIV-1 RNA >100,000 copies (c)/mL or CD4 < 200 cells/ µL at baseline. No participant failed with resistance. To further characterize efficacy of B/F/TAF, we analyzed pooled results from these trials for those with high HIV-1 RNA or low CD4 count at baseline.
Methods: Treatment-naïve, HIV-1-infected adults were randomized 1:1 to receive blinded treatment with B/F/TAF (50/200/25 mg) vs. dolutegravir/abacavir/lamivudine (DTG/ABC/3TC) (study 1489) or DTG (50 mg) + F/TAF (200/25 mg) (study 1490). Participants were recruited in North America, Europe, and Australia. To evaluate the efficacy of B/F/TAF specifically in these populations, we conducted a per-protocol (PP) analysis, which included participants randomized who received ≥1 dose of study medication but excluded those without on-treatment results in the week (W) 48 window (unless discontinued for lack of efficacy) or who had low medication adherence (< 2.5th percentile). We present W48 virologic responses by FDA snapshot algorithm for participants with baseline HIV-1 RNA >100,000 c/mL or CD4 count < 200 cells/µL using the PP analysis set.
Results: 629 adults were randomized in study 1489 (B/F/TAF n=314, DTG/ABC/3TC n=315) and 645 in study 1490 (B/F/TAF n=320, DTG+F/TAF n=325). Pooled, 198 participants (PP analysis set) had baseline HIV-1 RNA >100,000 copies/mL (B/F/TAF n=103/634 [16%], DTG/ABC/3TC n=46/315 [15%], DTG+F/TAF n=49/325 [15%]), and 132 (B/F/TAF n=73/634 [12%], DTG/ABC/3TC n=27/315 [9%], DTG+F/TAF n=32/325 [10%]) had baseline CD4 count < 200 cells/µL. For both high VL and low CD4 subgroups, rates of participants with HIV-1 RNA < 50 c/mL at W48 were similarly high for B/F/TAF, DTG/ABC/3TC, and DTG+F/TAF (table). No participant failed with resistance to any components of study drug.
Conclusions: B/F/TAF demonstrated potent viral suppression with no treatment-emergent resistance in treatment-naïve adults with high baseline HIV-1 RNA or low CD4 count. These data provide further evidence that B/F/TAF is an appropriate treatment for a wide range of patients, including late presenters who have been historically more difficult to treat.

Baseline HIV-1 RNA >100,000 c/mLB/F/TAF (n=103)DTG/ABC/3TC (n=46)DTG + F/TAF (n=49)
HIV-1 RNA < 50 c/mL99% (102/103)98% (45/46)98% (48/49)
HIV-1 RNA ≥ 50 c/mL1% (1/103)2% (1/46)2% (1/49)
Discontinued due to lack of efficacy000
Baseline CD4 count <200 cells/µLB/F/TAF (n=73)DTG/ABC/3TC (n=27)DTG + F/TAF (n=32)
HIV-1 RNA < 50 c/mL99% (72/73)96% (26/27)100% (32/32)
HIV-1 RNA ≥ 50 c/mL1% (1/73)4% (1/27)0
Discontinued due to lack of efficacy000
[Week 48 Outcomes by Baseline HIV-1 RNA >100,000 c/mL and CD4 count <200 cells/ ┬ÁL (PP Analysis Set)]

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