Durability of lopinavir/ritonavir monotherapy in individuals with viral load ≤50 copies/ml in an observational setting

OBJECTIVE: The main objective is to evaluate the efficacy and durability of Lopinavir-ritonavir monotherapy (LPV/r-MT) in virologically-controlled HIV-positive individuals switching from combination antiretroviral therapy (cART). METHODS: Criteria to be included in this observational study were to have initiated for the first time LPV/r-MT after >=2 consecutive HIV-RNA ≤50 copies/mL achieved on a >=3 drugs-including regimen. The main end-points were time to virological rebound (VR, defined in two ways: time of first of two consecutive viral load (VL)>50 and >200 copies/ml); time to discontinuation/intensification and time to experience either a single VL >200 copies/ml or discontinuation/intensification (=treatment failure-TF). Individuals' follow-up accrued from the date of starting LPV/r-MT to event or last available VL. Kaplan-Meier curves and Cox regression analysis were used. RESULTS: 228 individuals were included; median age: 46 (IQR: 40-50) years, 36% females, 36% IDU, 25% HCV-co-infected. Median CD4 at nadir: 215 cell/mm3 (IQR:116-336); at baseline: 615 cell/mm3 (IQR: 436-768). By 36 months from switching to LPV/r-MT, the proportion of individuals with VR (confirmed VL>200 cp/ml) was 11% and with TF was 35%. In the multivariable Cox model the factors associated with a lower risk of TF was the duration of viral suppression <50 copies/mL prior to baseline (ARH=0.92, 95% CI:0.85-0.99, p=0.024, per 6 months longer) and having LPV/r as part of last cART (ARH=0.45, 95% CI:0.21-0.95, p=0.037) . CONCLUSIONS: In daily clinical practice, we confirm a relatively safe approach of simplification to LPV-MT in selected population with long-lasting virological control.