(NaturalNews) An expert panel from the American College of Cardiology has recommended that doctors stop prescribing the cholesterol-lowering drugs Zetia and Vytorin and stick with the older, proven class of cholesterol drugs known as statins.
"Our strongest recommendation is that people need to go back to statins," said Dr. Harlan Krumholz of Yale University, speaking on behalf of the panel before the college's Chicago meeting.
Among their reasons for coming to consensus that the drugs should no longer be used, the panelists cited lack of evidence that they lengthen patients' lives and lack of knowledge about potential risks.
"We all believe in the primary responsibility as a physician to do no harm," said panel member Joseph Messer, a Chicago cardiologist. "Since we do not know whether that harm could come from this drug, I think it is incumbent upon us to use it in a very conservative manner."
The panel was convened after Merck and Schering-Plough, which distribute the drugs in a joint venture, released the long-delayed results of a study into their effectiveness known as Enhance. Enhance found no evidence that heart disease patients treated with Vytorin lived any longer or had any fewer cardiovascular events than patients treated with a statin alone.
Vytorin is a combination of the statin Zocor (generic name simvastatin) and the newer cholesterol drug Zetia (generic name ezetimibe).
Because Zetia reduces LDL ("bad") cholesterol by a different mechanism than statins do, doctors enthusiastically embraced the combination Vytorin drug as a way to bring LDL levels much lower than would be possible with Zocor alone. Together, Zetia and Vytorin have pulled in $5 billion per year for manufacturers Merck and Schering-Plough.
Zetia lowers LDL levels by hampering the intestine's ability to absorb dietary cholesterol, while statins accelerate the filtering out of LDL cholesterol from the blood.
Krumholz said that because the effects of statins are well-known, doctors should stick to those drugs instead of the unproven Zetia and Vytorin.
"We know statins are good drugs and we know they reduce risks. We believe in general to get to a $5 billion-a-year drug, there was a lot of premature use of ezetimibe before the statin option had been exhausted," he said.
In contrast to statins, the risks of Zetia and Vytorin are not well-studied or well-known, Krumholz emphasized.
"We do not know. This is a new drug with a novel mechanism - first in class. We do not have outcomes studies," he said
No large-scale studies have ever been conducted into the safety of Zetia and Vytorin, in particular whether they raise the risk of heart attacks and strokes. The first such study is due to be completed in 2012.
The Enhance study and the panel's recommendations should have wider ramifications in the way that doctors approach heart health and new drugs, the panelists said.
The panelists noted that many doctors assumed that just because Zetia and Vytorin lowered LDL cholesterol, they must be improving heart health. But this assumption appears to have been faulty, as the mechanism by which cholesterol is lowered may be just as significant as the size of the cholesterol decrease.
"Drugs are complex compounds with an array of biological effects. Knowing how they affect lipids does not tell us how they affect people," Krumholz said.
Enhance "reminds us to look at the trial endpoint and how (drugs) affect patients and not to just look at the numbers," panelist Rick Nishimura of the Mayo Clinic agreed.
Following the panel's recommendations, shares of Merck fell 15 percent, while shares of Schering-Plough dropped 26 percent.
The two companies had previously been accused of intentionally delaying the release of the Enhance results in order to preserve their profits, and of concealing evidence that Zetia may lead to liver damage.