Switching from a Non-Protease inhibitor-Based Regimen To the Fixed Dose Combination of Darunavir/Cobicistat/Emtricitabine/Tenofovir Alafenamide in Clinical Practice.

Background: The primary objective of this study was to estimate the proportion of people living with HIV (PLWH) who switched from a non-protease inhibitor (PI)-based regimen [integrase strand transfer inhibitor (InSTI)-based or non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen] to darunavir, cobicistat, emtricitabine, tenofovir alafenamide (D/C/F/TAF).

Methods: This was a retrospective study on PLWH treated with a non-PI regimen in January 2017, who switched to D/C/F/TAF or to another antiretroviral therapy (ART) within November 2019. Follow-up was from the start date of D/C/F/TAF until the last available visit or discontinuation for any reason of this regimen. Virological failure (VF) was defined as 2 consecutive HIV-RNA values >50 copies/mL. Characteristics were reported as median (interquartile range) or frequency (%). A univariate Poisson regression model was used to measure the incidence rate of switch to D/C/F/TAF. Changes in laboratory parameters during D/C/F/TAF were assessed by univariate mixed linear models.

Results: Overall, 3076 PLWH were included; 83% were male, median age at ART switch was 50 (42-56) years and median time on ART was 5.2 (0.3-13.0) years. PLWH had a median follow-up of 4.76 (3.70-6.38) years; during 17,099 person-years of follow-up (PYFU), 423/3076 (14%) participants discontinued the non-PI-based regimen and 106/423 (25%) switched to D/C/F/TAF, with an overall incidence rate of switch to D/C/F/TAF of 6.2 per 1000-PYFU (95% CI: 5.0-7.4). Among PLWH who switched to D/C/F/TAF, the ongoing regimen was based on NNRTIs in 37 (35%) and on InSTIs in 69 (65%). Main reasons leading to switch to D/C/F/TAF included neuropsychiatric adverse events (37%), VF (26%) and Kaposi sarcoma progression (5%).

Conclusion: In the last years, a non-negligible proportion of patients on an NNRTI- or an InSTI-based regimen switched to D/C/F/TAF.