Impact of preexisting nucleos(t)ide reverse transcriptase inhibitor resistance on the effectiveness of bictegravir/emtricitabine/tenofovir alafenamide in treatment experience patients

INTRODUCTION: Few clinical trials and cohort studies have evaluated the efficacy of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in people with HIV (PWH) with preexisting M184V/I or other nucleos(t)ide reverse transcriptase inhibitor (NRTI) resistance-associated mutations (RAMs). Real-world data are also scarce. METHODS: Retrospective review of treatment-experienced patients who started B/F/TAF in a cohort of PWH. HIV-RNA less than 50 copies/ml was analyzed at 48 weeks in an intention-to-treat (ITT) analysis (missing=failure) and per protocol analysis (patients with missing data or changes for reasons other than virological failure were excluded). Results were compared in patients with and without previous NRTI-RAMs. RESULTS: Five hundred and six PWH were included (16.2% women). Median age and time with HIV infection were 52.3 and 18.9 years, respectively. At baseline, viral load was less than 50 copies/ml in 440 patients (86.6%). Overall, 69 (13.6%) participants had documented preexisting NRTI-RAMs: 57 (11.2%) M184V/I and 30 (5.9%) tenofovir RAMs. In the ITT analysis, 83% (420/506) had HIV-RNA less than 50 copies/ml [82.2% (359/437) and 88.4% (61/69) in persons without and with NRTI-RAMs, respectively (P = 0.2)]. In the per protocol analysis 94.2% (420/445) had HIV-RNA less than 50 copies/ml [94.4% (359/380) vs. 93.8% (61/65); P = 0.2]. A total of 61 participants were excluded from the per protocol analysis (23 missing data, 19 discontinued B/F/TAF because of toxicity, 13 for other reasons, and 6 died). CONCLUSION: Switching to B/F/TAF is well tolerated and effective in the real-world setting, even in patients with preexisting NRTI RAMs, such as M184V and RAMs conferring resistance to tenofovir. These results confirm the robustness of this combination.