Adherence and forgiveness of two modern ART regimens: lamivudine/dolutegravir and emtricitabine/tenofovir alafenamide/rilpivirine.

Introduction: Few data are available about the forgiveness of two-drug (2DR) or low-barrier three-drug antiretroviral regimens. The aim of this study is to evaluate the real-life forgiveness of lamivudine/dolutegravir (3TC/DTG) and emtricitabine/tenofovir alafenamide/rilpivirine (FTC/TAF/RPV).

Methods: A two center retrospective observational study enrolled all people with HIV (PWH) treated with 3TC/DTG or FTC/TAF/RPV. Adherence was measured as the proportion of days covered (PDC) by drug supply. Binary logistic regression was applied to test the impact of baseline variables and adherence on the achievement of virological suppression.

Results: 1258 adult PWH were enrolled, 368 in 3TC/DTG and 890 in RPV/F/TAF. Most were males (71 %), with median age of 51 years (IQR 43-58 years) and median CD4 nadir of 305 cells/mcL (IQR 132-485). The median cohort follow-up totaled 4558 persons/year. Median adherence, as calculated from PDC, was of 0.98 (IQR 0.93-1). Irrespective of the treatment group, a PDC as low as 0.8 was sufficient to obtain HIV-RNA below 200 copies/mL in almost all study participants. The same adherence value also allowed the achievement of HIV-RNA below 50 copies/mL in > 90% of study participants. PDC (P < 0.0001), Italian origin (P < 0.0001) and male sex (P = 0.038) significantly correlated to the achievement of < 200 copies/mL.

Conclusions: In this study, we found a similar and high grade of forgiveness in the INSTI-based 2-drug regimen 3TC/DTG and in the NNRTI-based 3-drug regimen FTC/TAF/RPV.