Efficacy and safety of boosted atazanavir-containig antiretroviral regimens in real life: results from a multicentre color study.

BackgroundAtazanavir (ATV) has demonstrated high efficacy and safety in both treatment-naı¨ve and treatment-experienced patients. Some comparative data are available on the durability of ritonavir-boosted(ATV/r) and unboosted formulations, but there are no data on clinicians’ motivations for choosingone or another in everyday practice. The aim of this study was to evaluate the long-term efficacy ofboosted and unboosted ATV in a cohort of treatment-experienced patients.MethodsAll patients included in the study were enrolled in an observational cohort within the SurveillanceCohort Long-Term Toxicity Antiretrovirals (SCOLTA) Project. Data on CD4 cell count, HIV viral load,metabolic parameters and adverse events of grade 3–4 are collected through an on-line system everysix months. The duration of treatment with ATV was evaluated using the Kaplan–Meier curve andboosted and unboosted regimens were compared using the log-rank test.ResultsA total of 509 patients starting ATV as a component of their antiretroviral therapy were enrolled inthe SCOLTA Project at the time of the study. Boosted ATV was received by 379 patients (74.5%) while130 (25.5%) were treated with the unboosted formulation. The last therapeutic regimen did notinfluence the choice of ATV formulation. The mean observational time was 23.9 months. At the endof follow-up, 58.5% of patients on unboosted ATV and 58.1% of patients on ATV/r continued thetreatment and no statistically significant differences were observed for ATV durability between theformulations or among the single causes of therapy interruption.ConclusionsOur results suggest that, in unselected clinical settings, ATV-containing antiretroviral therapy isdurable and safe in both its formulations.