Switching
from Lopinavir/Ritonavir to Unboosted Atazanavir Lowers Lipids Antiretroviral
therapy with certain protease inhibitors (PIs), in particular ritonavir
(Norvir), can raise blood lipid (cholesterol
and triglyceride) levels, potentially increasing the risk of cardiovascular
disease. Atazanavir (Reyataz),
a newer PI, is less likely to cause elevated lipids. The
international SWAN study (BMS097) was conducted to determine whether switching
from lopinavir/ritonavir (Kaletra)
to unboosted atazanavir
without ritonavir would improve lipid profiles while maintaining virological
suppression. The
study included participants taking PI-based regimens who had HIV RNA levels below
50 copies/mL and no prior virological
failure while using PIs. Subjects were randomly assigned to remain on their
current PI or switch to 400 mg once-daily unboosted atazanavir, while continuing
the same background nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs).
Patients who used tenofovir (Viread)
as one of their NRTIs used 300/100 mg atazanavir/ritonavir once daily. An
analysis presented at the recent XVI International AIDS Conference in Toronto
included 153 patients who were taking lopinavir/ritonavir at the start of the
study, with a mean prior therapy duration of 79 weeks. Results 
Efficacy results at 48 weeks are shown in the following table (treatment failure
was defined as viral rebound or discontinuation of therapy for any reason):
Efficacy
results
at 48 weeks | Switch
to atazanavir | Continued
lopinavir/ritonavir | | Viral
rebound (above 50 copies/mL) | 11%
(11/100) | 9%
(5/53) | | Treatment
failure for any reason | 26%
(26/100) | 28%
(15/53) |
Rates of viral rebound and CD4 changes
were similar in the two arms.
New-onset gastrointestinal symptoms of any grade were reported in 2% of subjects
on atazanavir and 13% on lopinavir/ritonavir (P < 0.01); 3% and 8%,
respectively, used anti-diarrhea drugs.
Improvements in lipid parameters were observed in the atazanavir switch arm.
Elevated non-HDL cholesterol was observed in 4% of patients in the atazanavir
arm and 17% in the lopinavir/ritonavir arm (P < 0.0001).
Participants in the atazanavir arm used less lipid-lowering agents (8% vs 21%;
P < 0.05).
Rates of serious adverse events and treatment discontinuations were similar in
the two arms: -
Serious adverse events: 12% vs 11%;
- All discontinuations: 17% vs 19%;
-
Discontinuations due to adverse events: 6% in both arms;
- Grade 3 or 4 ALT
elevations: 3% vs 2%.
1% of subjects taking atazanavir discontinued due to jaundice.
Conclusion "Simplification
to an unboosted atazanavir-based regimen provided comparable antiretroviral efficacy
and improvements in plasma lipids, compared to subjects who continued on lopinavir/ritonavir,"
the researchers concluded. "Both treatment arms were generally safe and well
tolerated, with subjects on atazanavir reporting less gastrointestinal symptoms."
09/01/06 Reference
J
M Gatell, T Branco, L Sasset, and others. Efficacy and safety of atazanavir (ATV)
based HAART in virologically suppressed subjects switched from lopinavir/ritonavir
(LPV/RTV) treatment. XVI International AIDS Conference. Toronto, August 13-18,
2006. Abstract THPE0123/18432.
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