An experimental class of drugs shows promise as a new way to lower the "bad" cholesterol that can lead to heart attacks.
A man-made antibody -- similar to the immune system proteins that fight infections -- lowered LDL cholesterol by about 70% when combined with a statin, according to a small, early trial published Wednesday in The New England Journal of Medicine.
Many heart disease experts are enthusiastic about the drugs, which will be featured prominently at the American Heart Association's Scientific Sessions that begin Saturday in Chicago.
"This is a new era of novel therapies," says William Zoghbi, president of the American College of Cardiology, who wasn't involved in the study.
The drop in cholesterol is "significant" and "much more than we usually see" with other types of drugs, Zoghbi says.
The preliminary study involved 92 patients whose cholesterol wasn't improving with statins. In addition to taking atorvastatin pills, sold as Lipitor, patients got injections of the new drugs, known as monoclonal antibodies, every two weeks.
Significantly, the new drugs haven't yet been shown to actually reduce heart attacks or deaths, says cardiologist Cam Patterson, a professor at the University of North Carolina-Chapel Hill.
And while the drugs caused few side effects in this study, doctors will need to conduct larger trials to show they're really safe, he says.
The intravenous drugs could also prove to help people who can't tolerate statins because of side effects such as muscle pain, says Robert Eckel, past president of the American Heart Association, who wasn't involved in the new research.
"This is a promising step forward, especially for the most difficult patients to treat," says Eckel, a professor at the University of Colorado Anschutz Medical Campus.
Unlike statins, which prevent the liver from making cholesterol, the new drugs target the process by which the liver takes LDL out of circulation, Patterson says.
An enzyme called PCSK9 prevents the body from getting rid of LDL, leaving it in the bloodstream, where it can damage the arteries, he says. The new antibodies block this enzyme.
The study was funded by the drugs' developers, Sanofi and Regeneron Pharmaceuticals. Amgen and Pfizer also are developing similar drugs, Patterson says.
If successful, the drugs could be a boost for the drug industry, now that statins are available generically, Patterson says.
Although man-made antibodies are widely used to fight cancer, they haven't previously had success in heart disease.
Man-made antibodies used in cancer, such as Erbitux and Avastin, cost several thousand dollars a month.
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