Atazanavir/Ritonavir
versus Efavirenz: Retrospective Review of a Large US Cohort An
especially attractive feature of the protease inhibitor atazanavir
(Reyataz) is that it is taken once daily. However, ritonavir-boosted
atazanavir (ATZ/r) is not currently recommended by the US DHHS guidelines
for treatment-naive patients. Currently
there are limited data on ATZ/r use in ARV-naïve subjects, and there are
no data comparing ATZ/r to another once daily regimen like efavirenz
(EFV; Sustiva). This
study is a retrospective review of all ARV-naive patients at Thomas Street Health
Center in Houston, Texas started on ATZ/r or EFV. The
primary endpoint was the proportion of subjects with HIV RNA <400 copies/mL
through week 48; planned secondary assessments included CD4 count and bilirubin
changes (in ATZ/r patients). Twenty-four week results were reported at the 16th
International AIDS Conference in Toronto last week.
Results 
48 patients on ATZ/r and 340 patients on EFV were included in this study.
The baseline demographic characteristics were similar including age, gender, and
ethnicity.
Median CD4 cell count was 135 cells/mm3 for the ATZ/r group and 163 for the EFV
group.
Median HIV viral loads were 295,267 and 270,230 copies/mL, respectively.
At 24 weeks, 58% of ATZ/r and 58% of EFV patients had viral load <400 copies
/mL by ITT (P=1.0), the mean CD4 cell count increase from baseline was 135 cells/mm3
for ATZ/r and 87 cells/mm3 for EFV (p= 0.042).
Multivariate analyses found no difference between groups.
Among the ATZ/r group, 20/28 (71%) of patients with VL<400 had a bilirubin
?1, compared to only 4/12 (33%) of those with persistent viral loads (p=0.001).
Based
on these findings, the authors conclude, "In this study in ARV-naïve
HIV-Infected subjects, ATZ/r and EFV have similar virologic response rate through
24 weeks." "Patients
with treatment failure demonstrate less elevated bilirubin values than patients
with viral suppression, suggesting bilirubin levels as a marker of drug exposure
(likely due to adherence)." "This
study supports the use of ATZ/r in ARV-naïve subjects, though prospective
controlled studies are needed to confirm these results." Baylor
College of Medicine, Infectious Diseases, Houston, United States, Baylor College
of Medicine, Medicine, Houston, United States, Thomas Street Health Center, Pharmacy,
Houston, United States. 08/22/06 Reference
R
Andrade, R Cartin-Ceba, T Zerai, and others. Boosted-atazanavir versus efavirenz:
a retrospective review of two common once a day regimens in treatment-naïve
patients from a large county clinic in Houston. 16th International AIDS Conference.
August 13-18, 2006. Toronto, Canada. Abstract CDB0490. Articles
on Atazanavir (Reyataz)
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