Simplification of Antiretroviral Treatment from Darunavir/Ritonavir Monotherapy to Darunavir/Cobicistat Monotherapy: Effectiveness and Safety in Routine Clinical Practice.

Our aim was to evaluate the effectiveness and safety of darunavir/cobicistat (DRV/c) monotherapy as an antiretroviral treatment simplification strategy in HIV-infected patients already on suppressive darunavir/ritonavir (DRV/r) monotherapy in routine clinical practice. We conducted a retrospective multi-centre study including all adult patients switched from DRV/r monotherapy to DRV/c monotherapy while HIV-1 RNA was <50 copies/mL and who had at least one follow-up visit. The primary endpoint was the percentage of patients remaining free of treatment failure (TF), defined as discontinuation of monotherapy for any reason, including loss of follow-up. Virological failure (VF) was defined as a confirmed HIV-1 RNA ≥50 copies/mL or any change in the regimen after a single determination with HIV-1 RNA ≥50 copies/mL. Changes in renal function parameters and lipid profile were also evaluated. Factors associated with VF were analysed using Cox regression. In this study, 173 subjects were included. The median (IQR) time of follow-up was 58 (50-67) weeks. Overall, 90% of patients remained free of TF during follow-up. Ten (6%) patients discontinued DRV/c monotherapy for non-virological reasons and eight (5%) developed VF. No DRV-related mutations were identified in patients with VF. A decrease in triglyceride levels (p=0.006) and estimated glomerular filtration rate (p=0.005) were observed during follow-up. The presence of blips and CD4+ nadir <100 cells/mm3 were predictors of VF. In conclusion, switching to DRV/c monotherapy seems to be safe and effective in routine clinical practice in HIV-infected patients undergoing suppressive DRV/r monotherapy.