March 18, 2009

Heart Disease Drug Falls Short

A drug designed to treat atherosclerosis may do just the opposite.

Atherosclerosis "“ when plaque builds up in the inner lining of the arteries, also known as hardening of the arteries "“ can lead to heart attack or stroke. Previous animal studies have shown blocking the ACAT enzyme, which is involved in cholesterol accumulation, with ACAT inhibitors can prevent the development of atherosclerosis. But a new study reveals the ACAT inhibitor, pactimibe, falls short.

Researchers examined nearly 900 patients with a family history of high cholesterol "“ a risk factor for atherosclerosis. All patients received treatment with a standard lipid-lowering therapy, but only half were administered pactimibe, while the other half received a placebo.

After six months, patients treated with pactimibe showed an increase of low-density-lipoprotein cholesterol (LDL), or "bad" cholesterol, of 7.3 percent, compared to just 1.4 percent in patients who received the placebo. High levels of LDL cholesterol will cause plaque build-up in the arteries, leading to atherosclerosis. Researchers also measured patients' carotid intima-media thickness (CIMT), a measurement of the thickness of the inner wall of a major artery.

"In patients with [a family history of high cholesterol], pactimibe had no effect on atherosclerosis as assessed by changes in maximum CIMT compared with placebo but was associated with an increase in mean CIMT as well as increased incidence of major cardiovascular events," the authors wrote.

Authors add the results of this study do not bode well for the future development of pactimibe or other ACAT inhibitors.

SOURCE: The Journal of the American Medical Association, 2009;301:1131-1139