Objectives: Analysis of bictegravir/emtricitabine/tenofovir alafenamide (BFTAF) efficacy and safety in virologically-suppressed people living with HIV (PLWH) in clinical practice. Patients and methods: Retrospective cohort study including adult treatment-experienced and virologically suppressed PLWH, switched to BFTAF from June 2019 to June 2021. Efficacy and safety were evaluated as virological failure (VF=2 consecutive HIV-RNA>50 copies/mL or a single HIV-RNA>400 copies/mL) and treatment failure (TF=VF or discontinuation for any reason) until data freezing (August 2022). Results: 1040 PLWH included, 67.8% switched from elvitegravir/cobicistat/FTAF. VF occurred in 4.2% (n=44), with incidence rate of 1.63 per 1000 person-months of follow-up (PMFU) and probability at 24-30 months of 3.8%-4.0%, respectively. Out of the 44 VF, in 75% virological re-supression was achieved while maintaining BFTAF. Discontinuation occurred in 15% after a median time of 13.5 months of follow-up, with incidence rate of 5.67 per 1000 PMFU, and probability at 24-30 months of 11.9%-15.3%, respectively. Main discontinuation reasons were simplification (51.3%) and toxicity (21.8%, involving CNS in half of cases). TF occurred in 18.6% with incidence rate of 7.01 per 1000 PMFU after a median time of 13.6 observation months; probability at 24-30 months was 14.8%-18.4%, respectively. Conclusions: BFTAF proved effective and well tolerated in clinical practice.

Background: Antiretroviral therapy reduces systemic inflammation and immune activation, but not to levels like HIV-negative. Limited drug penetration within tissues has been argued as potential mechanism of persistent inflammation. Data on the role of inflammation on plasma/intracellular (IC) pharmacokinetics (PK) of ARV drugs through to downregulation/expression of cytochrome P450 3A/membrane transport proteins are limited. Aim of this study was to investigate the correlation between inflammation markers and plasma/IC PK of different ARVs regimen in HIV-positive patients. Methods: We included in the study ART-treated HIV+ pts switching to 3 different ARV regimens: 1) DTG-based dual-therapy plus boosted-PIs, 2) DTG-based triple-therapy without PIs, 3) DRV/c-based triple-therapy. Plasma and IC ARV drugs concentration means at the end of dosing interval (T0), IM on samples concomitantly with ARV PK determination: sCD14, CRP, IL-6 and LPS were analysed. Results: 60 samples from pts included in the switching study were used for measuring plasma and IC concentrations of HIV drugs. No significative differences between CRP, sCD14, IL-6 and LPS values in 3 arms of therapy were observed. Significant correlation was observed between tenofovir plasma concentrations and sCD14 (p<0.001), DRV plasma concentration and sCD14 (p=0,07) and DRV IC/plasma ratio and Log10 IL-6 concentrations (p=0.04). Furthermore, in 24 pts on DTG-TT, we observed a negative trend between DTG IC concentrations and sCD14 (p=0.09). Conclusions: Our preliminary data support the hypothesis of lower IC concentrations of DRV and DTG in pts with higher plasma IM, suggesting an interplay between HIV drug penetration and persistent inflammation in cART-treated HIV-positive patients.