While
protease inhibitors (PIs) as a class are known cause elevated blood lipid levels
-- which may increase the risk of cardiovascular disease -- not all drugs in this
class have an equally detrimental effect.
Atazanavir
vs Other PIs
As described in a presentation at the 8th International
Congress on Drug Therapy in HIV Infection last month in Glasgow, Belgian researchers
conducted a study comparing the impact of atazanavir
(Reyataz), fosamprenavir (Lexiva),
and lopinavir/ritonavir (Kaletra)
on lipid profiles in patients matched for baseline triglyceride and cholesterol
levels.
The study
compared patients taking the various PIs: 55 patients in a comparison between
atazanavir and fosamprenavir, both boosted with ritonavir
(Norvir); 56 patients in a comparison between atazanavir/ritonavir and lopinavir/ritonavir;
and 87 patients in a comparison between fosamprenavir/ritonavir and lopinavir/ritonavir.
All groups were similar with regard to use of other antiretroviral drugs and lipid-lowering
medications.
Median values for triglycerides, total cholesterol, and high-density
lipoprotein (HDL or "good") cholesterol at baseline and median changes
12 months after starting the 3 PIs (all in mg/dL) are shown in the table below:
In
conclusion, the researchers wrote, "In patients with similar baseline lipid
profiles, boosted fosamprenavir and lopinavir provided a comparable increase in
triglycerides and total cholesterol, while atazanavir led to a reduction of these
two parameters. Change in HDL cholesterol was similar for the 3 drugs."
Is
a Switch Enough?
However,
a second study presented at the conference suggested that simply switching to
atazanavir may not be enough to adequately reduce the risk of cardiovascular disease.
Italian
researchers conducted a retrospective observational analysis of 222 patients aged
35-69 years who switched to atazanavir for any reason. The mean age was 45 years,
63% were male, 58% were smokers, 10% were diabetic, and 18% had been prescribed
medication for high blood pressure. Data were collected from clinical records
at the time of the switch and during follow-up. The researchers then calculated
cardiovascular risk scores, reflecting the 10-year risk of major cardiovascular
events.
Results
Prior to switching to atazanavir, 66% of patients were treated with another PI-based
regimen (79% ritonavir-boosted), while 34% were on NNRTI-based therapy.
The mean follow up time on atazanavir-containing regimens was 13 months.
8% of the patients were prescribed atazanavir alone, while 92% received ritonavir-boosted
atazanavir.
Total cholesterol fell by an average of median 13.3 mg/dL (P = 0.013).
HDL cholesterol and triglyceride levels also fell significantly.
However, the mean cardiovascular risk score increased by 0.04% (P = 0.12).
"Our
data show that treatment switch to atazanavir caused significant reductions in
total cholesterol, HDL, and triglycerides levels," the researchers wrote.
"[N]evertheless, this did not translate into significant changes in a cardiovascular
risk score based on the Italian population. Switch strategies should be accompanied
by changes in other preventable cardiovascular risk factors."
12/01/06
References
S
De Wit, B Poll, C Nescoi, and others. Atazanavir has a better impact on lipid
profiles than fosamprenavir and lopinavir in patients matched for baseline triglycerides
and cholesterol. 8th Congress on Drug Therapy in HIV Infection (HIV8). Glasgow.
November 12-16, 2006. Abstract P127.
M Colafigli, S Di Giambenedetto,
L Bracciale, and others. Improvement of lipidic metabolism does not change the
cardiovascular risk score in 13 months of observation of patients switched to
atazanavir-based regimen. HIV8. Abstract 128.
Prior to switching to atazanavir, 66% of patients were treated with another PI-based
regimen (79% ritonavir-boosted), while 34% were on NNRTI-based therapy.