Viro-immunologic response to ritonavir-boosted or unboosted atazanavir in a large cohort of multiply treated patients: The CARe study

Maria Mercedes Santoro, Ada Bertoli, Patrizia Lorenzini, Adriano Lazzarin, Roberto Esposito, Giampiero Carosi, Giovanni Di Perri, Gaetano Filice, Mauro Moroni, Giuliano Rizzardini, Pietro Caramello, Renato Maserati, Pasquale Narciso, Antonietta Cargnel, Andrea Antinori, Carlo Federico Perno

Research output: Contribution to journalArticlepeer-review


Currently, comparative data able to define the potency of boosted versus unboosted atazanavir in highly pretreated HIV-infected patients are limited. Specifically, in clinical practice it is very important to establish whether atazanavir-boosting with ritonavir warrants potency and efficacy that overcome the profile of unboosted drug. For this reason, our goal was to evaluate viro-immunologic determinants of response to atazanavir, in unboosted ATV400 or boosted ATV300/r formulation, from baseline to week 48 in highly pretreated HIV-infected patients enrolled in a prospective observational Italian study. Data from 354 patients included in an atazanavir "Early Access Program" (AI424-900) with baseline viremia 500 copies per milliliter or more and with an available virologic follow-up were examined using as-treated analysis. Of these, 200 (56.5%) and 154 (43.5%), respectively, received regimens containing ATV300/r or ATV400. Virologic success (VS) was defined as reaching viremia of less than 500 copies per milliliter during follow-up. Estimated median time to VS was 8 weeks in the ATV300/r group and 13 weeks in the ATV400 group. Proportion of patients achieving VS was higher in the ATV300/r group than in ATV400 group at week 12 (66% versus 47%), as well as at week 48 (86% versus 64%). At multivariate Cox regression, receiving ATV300/r dosing was independently associated with increased probability of achieving VS [adjusted hazard ratio (AHR): 1.57; 95% confidence interval (CI): 1.19-2.06]. Conversely, CDC stage C, higher baseline viral load, and more experience with protease inhibitors (PIs) were associated with poorer virologic response. In an unselected population of highly pretreated HIV-infected individuals, receiving atazanavir as part of antiretroviral regimen results in effective virologic response and immunologic recovery. The antiviral efficacy of atazanavir is greater when boosted with low-dose ritonavir.

Original languageEnglish
Pages (from-to)7-16
Number of pages10
JournalAIDS Patient Care and STDs
Issue number1
Publication statusPublished - Jan 1 2008

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Leadership and Management
  • Nursing(all)


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