Thyroid-hormone mimic lowers LDL.

A compound in a new class of potential anti-cholesterol drugs has passed an early test in people, researchers report.

The drug would mimic thyroid hormone, which reduces blood concentrations of low-density lipoproteins (LDL), or bad cholesterol. But the hormone also raises the risk of heart arrhythmia, osteoporosis, and muscle damage, so researchers have attempted to create a stand-in that would avoid the side effects.

John D. Baxter of the University of California, San Francisco and his colleagues at the firm Karo Bio in Huddinge, Sweden, recently tested, in more than a dozen people the performance of a compound labeled KB2115.

After 2 weeks of treatment, some volunteers receiving the drug had lowered their LDL concentrations by 40 percent.

Unlike thyroid hormone, the experimental drug had no effect on heart rate, and the volunteers' heart rhythms remained in the normal range, Baxter says.

In animals, moreover, a related compound enhances the effects of a currently available cholesterol-lowering statin drug, the researcher found. This may mean that, in people a lower, safer dose of the statin taken with a thyroid-hormone mimic would be as potent as a higher dose is by itself, Baxter notes.--B.H.