An experimental drug, known as A-002, may be an effective treatment for preventing hardening of the arteries, according to a report in The Lancet.

A-002 works by blocking specific enzymes (natural proteins that trigger activity in the cells of the body) known to cause plaque build-up, or "atherosclerosis," in arteries of the heart and elsewhere.

Dr. Robert S. Rosenson, from the University of Michigan, Ann Arbor, and his colleagues studied whether giving A-002 would affect the amount of one such enzyme in patients' blood. By doing this, the researchers were able to determine whether A-002 is likely to have a beneficial effect on heart disease.

The study featured 393 patients with stable heart disease who were randomly assigned to receive either A-002 at one of four doses or an inactive "placebo," twice daily for 8 weeks. There was no difference in side effects between patients treated with A-002 and those given placebo.

On average, levels of this particular enzyme fell by 86.7 percent in the patients who took A-002, compared with a drop of just 4.8 percent in the placebo group, the report shows. Moreover, as the dose of A-002 increased, so did the reduction in patients' blood levels of the enzyme.

This effect suggests that "A-002 might be an effective anti-atherosclerotic agent," the authors write.

"Furthermore," they add, "combined use of A-002 with a statin (such as Zocor, Lipitor, or Mevacor) may have complementary benefits."