Study Casts Doubts on Vytorin, Zetia
Cholesterol-Lowering Drugs May Not Reduce Plaque Buildup
Jan. 15, 2008 -- Disappointing results from a long-awaited trial of the best-selling cholesterol drug Vytorin drew mixed reactions from some of the nation's leading cardiologists.
Vytorin, which combines the unique cholesterol drug Zetia with the traditional statin drug simvastatin, was found to be no better than simvastatin alone for reducing plaque buildup in the carotid arteries. The carotid arteries run through both sides of the neck to the brain.
In fact, patients taking Vytorin actually had slightly more plaque buildup during the trial than those taking simvastatin alone.
The findings were revealed Monday morning in a news release issued by the drug companies Merck and Schering-Plough, which jointly market Vytorin and Zetia.
In an interview with WebMD, cardiologist Steven E. Nissen, MD, called the results "a stunning reversal for Zetia and Vytorin."
Nissen is chairman of the department of cardiovascular medicine at the Cleveland Clinic, and is a past president of the American College of Cardiology.
"Zetia works only by blocking the absorption of cholesterol, but it has not been shown to produce any health benefits," he says. "I have been skeptical of these drugs from the beginning because I wasn't sure that Zetia's mechanism of cholesterol lowering would produce the same benefits that we see with statins."
But P.K. Shah, MD, who directs the cardiology department at Cedars-Sinai Medical Center in Los Angeles, tells WebMD that the trial results do not mean that the millions of patients taking Zetia or Vytorin derive no benefit from the drugs.
"I don't think this is a call for a moratorium on Zetia. That would be overreaching," he says. "This was a small study and it is not the last word."
(Do you take Zetia? Will you talk to your doctor now? Tell us about it on WebMD's Cholesterol Support Group board.)
Congressional Probe of Zetia, Vytorin Research
The release of the results came just weeks after the announcement of a congressional investigation into the drug companies' actions surrounding the study, which ended nearly two years ago.
In addition to delays in presenting the results, critics had accused the companies of attempting to change the endpoints of the study, known as the ENHANCE trial, in an effort to present the results in a more favorable light.