Source: Hong Kong Med J  |  Posted 6 years ago

By Norra MacReady

PRAGUE, CZECH REPUBLIC -- May 2, 2005 -- Vytorin (ezetimibe/simvastatin) is more effective than atorvastatin for reducing the level of atherogenic particles in serum above and beyond its effect on low-density lipoprotein (LDL) cholesterol, according to a poster presentation made here at the 75[^]th[] European Atherosclerosis Society Congress.

Investigators examined the effect of the 2 regimens on the ratio of apolipoprotein (Apo) B to Apo A-1. Apo B is a proatherogenic particle, while Apo A-1 is an antiatherogenic particle and the major Apo component in high-density lipoprotein (HDL) cholesterol.

Some epidemiological studies have suggested that the Apo B/Apo A-1 ratio is a good predictor of coronary heart disease risk, said investigators led by Christie M. Ballantyne, MD, Director, Atherosclerosis and Lipid Laboratory, Baylor College of Medicine, Houston, Texas, United States.

Data came from the Vytorin versus Atorvastatin (VYVA) trial, a randomised, double-blind, 6-week study that compared the lipid-modifying efficacy and safety of the ezetimibe/simvastatin combination product to that of atorvastatin at 4 dose levels equivalent to 10 mg, 20 mg, 40 mg, and 80 mg of the statin. Patients in the atorvastatin group were randomised to doses of 10, 20, 40, or 80 mg.

The analysis included 927 patients in the atorvastatin group and 923 in the ezetimibe/simvastatin group.

Patients were stratified according to baseline LDL cholesterol level -- 130-159 mg/dL; 160-189 mg/dL; and 190 mg/dL or greater. They were further divided according to their baseline triglyceride levels -- < 200 mg/dL or 200 mg/dL or greater.

Patients taking the combination product experienced an average 45% decrease in the Apo B/Apo A-1 ratio, which was significantly more than the 39% decrease seen in patients on atorvastatin.

Significant differences were observed at all dose levels, but were greatest at the highest statin dose equivalent. At that dose level, patients in the combination-therapy group experienced a 50% reduction in the ratio, compared to 43% among patients taking atorvastatin.

Similarly, ezetimibe/simvastatin was associated with an average reduction of 43% in Apo B levels across all doses, significantly greater than the 38% reduction among patients taking atorvastatin. Here again the greatest effects were seen at the highest dose levels, with a 48% reduction and 44% reduction recorded for patients on the combination product and atorvastatin, respectively.

Drug treatment also reduced non-HDL cholesterol, but once again the combination product proved more effective than atorvastatin alone, with reductions of 49% and 42%, respectively.

The combination product proved to be more effective than atorvastatin regardless of baseline triglyceride levels, the investigators said.

These findings suggest that combination therapy produces significant improvement in a range of atherogenic particles, they concluded.

[Presentation title: Evaluation of Ezetimibe/Simvastatin Versus Atorvastatin on Atherogenic Ratios of Non-HDL-c/HDL-C and Apo B/Apo A-1. Poster W16-P045]