Exploratory analysis for the evaluation of lopinavir/ritonavir-versus efavirenz-based HAART regimens in antiretroviral-naive HIV-positive patients: results from the Italian MASTER Cohort.

OBJECTIVE: This retrospective longitudinal cohort study compared the virological
and immunological responses to highly active antiretroviral therapy containing
either efavirenz or lopinavir/ritonavir in previously antiretroviral-naive
HIV-infected patients.
PATIENTS AND METHODS: A total of 472 patients were selected (348 efavirenz and
124 lopinavir/ritonavir). The primary endpoint of this study was virological
success (HIV RNA <50 copies/mL). The immunological response was assessed on the
basis of either CD4+ T cell count variations (absolute and percentage) with
respect to baseline values or categorical endpoints (defined as either a CD4+ T
cell increase of > or =1;50 cells/mm(3) at week 24 or of > or =1;75 cells/mm(3)
at week 48).
RESULTS: At intention-to-treat (ITT) analysis, the adjusted odds ratio of
virological success for patients who started lopinavir/ritonavir, compared with
those who started efavirenz, was 0.54 (95% CI: 0.33-0.89, P = 0.016) at week 24
and 0.40 (95% CI: 0.33-0.89, P = 0.002) at week 48. However, patients receiving
lopinavir/ritonavir had a more pronounced CD4+ T cell recovery, demonstrating
both a mean absolute and percentage increase up to week 48 (MANOVA P < 0.0001).
CONCLUSIONS: Although comparisons of drug efficacy in non-randomized studies
should be viewed with caution, from a virological point of view
efavirenz-containing regimens performed as well (on-treatment analysis) or better
(ITT analysis) than those containing lopinavir/ritonavir. In contrast,
immunological outcome appeared to favour lopinavir/ritonavir.