Effectiveness, durability, and safety of darunavir/ritonavir in HIV-1-infected patients in routine clinical practice in Italy: a postauthorization noninterventional study

Current antiretroviral (ARV) therapy for the treatment of human immunodeficiency virus (HIV-1)-infected patients provides long-term control of viral load (VL). Darunavir (DRV) is a nonpeptidomimetic protease inhibitor approved for use with a ritonavir booster (DRV/r). This study evaluated the effectiveness of DRV/r in combination with other ARV agents in routine clinical practice in Italy. In this descriptive observational study, data on utilization of DRV/r, under the conditions described in the marketing authorization, were collected from June 2009 to December 2012. Effectiveness (VL <50 copies/mL), tolerability, and durability in four patient groups (two DRV/r-experienced, one ARV-experienced DRV/r-naïve, and one ARV-naïve) were analyzed. Secondary objectives included immunological response, safety, and persistence/discontinuation rates. In total, 875 of 883 enrolled patients were included in the analysis: of these, 662 (75.7%) completed the follow-up until the end of 2012 and 213 (24.3%) withdrew from the study earlier. Initial DRV dose was 600 mg twice daily (67.1%) or 800 mg once daily (32.9%). Only 16 patients (1.8%) withdrew from the study due to virological failure. Virological response proportions were higher in patients virologically suppressed at study entry versus patients with baseline VL ≥50 copies/mL in each ARV-experienced group, while there was no consistent difference across study groups and baseline VL strata according to baseline CD4(+) cell count. CD4(+) cell count increased from study entry to last study visit in all the four groups. DRV/r was well tolerated, with few discontinuations due to study-emergent nonfatal adverse events (3.0% overall, including 2.1% drug-related) or deaths (3.0% overall, all non-drug-related); 35.3% of patients reported ≥1 adverse events. These observational data show that DRV/r was effective and well tolerated in the whole patient population described here. The DRV/r-containing regimen provided viral suppression in a high percentage of patients in all groups, with low rates of discontinuation due to virological failure.