Zetia and Vytorin Information: The
controversy about cholesterol-lowering drugs and their potential failure
A controversial study showing that the blockbuster cholesterol-lowering
drug Vytorin failed to slow the buildup of artery plaques more than a
cheaper statin is certain to provoke questions among heart patients
taking Vytorin or its sister drug Zetia. USA TODAY asked Steven Nissen,
the Cleveland Clinic's chief of cardiology, and Roger Blumenthal of the
Johns Hopkins Ciccarone Center for the Prevention of Heart Disease and
the American College of Cardiologyprevention committee, for some
answers.
Q: Why was the study controversial?
A: The two drugs are among the most widely used of all prescription
medicines. Yet, although the drugs have been shown to reduce
cholesterol, their manufacturers acknowledge that they've never been
shown to prevent heart attacks or other life-threatening events. Lipitor
and other statin drugs, in contrast, have demonstrated their
effectiveness in many studies.
A congressional committee said in December it will investigate
allegations that the companies that make the drugs, Merck and
Schering-Plough, delayed releasing data from the study, completed in
April 2006.
Q. What's the difference between cholesterol-lowering statins and
Vytorin and Zetia?
A. Statins block the formation of bad cholesterol, or LDL, in the liver,
while Zetia blocks its absorption in the intestines. Vytorin is simply
Zetia combined with a statin called Zocor, which is now available in
generic form as simvastatin. About 60% of patients who take Zetia take
it with Zocor as Vytorin.
Q: Who participated in the study?
A: The study involved 720 patients with very high levels of cholesterol
from an inherited form of heart disease. The study was designed to prove
that Vytorin could slow the growth of plaque in carotid arteries
supplying the brain more than simvastatin alone.
Q: What were the findings?
A: The researchers found that even though Vytorin dramatically reduced
bad-cholesterol levels, it did not slow the growth of artery blockages
more than generic Zocor. "It's certainly not an alternative to high
doses of statins, which we know work," Nissen says.
Q: Are other studies in the works?
A: Three bigger studies are underway that will test whether Vytorin can
prevent heart attacks, strokes and other events in thousands of
patients. The results from those studies won't be released until 2011.
Q: How can it be that a drug that dramatically lowers bad cholesterol
doesn't reduce plaques?
A: The answer isn't clear. Some drugs are simply more effective than
others. Statins may reap their benefits not just by lowering bad
cholesterol but also by raising good cholesterol and fighting artery
inflammation. Zetia and Vytorin, which work differently, only lower bad
cholesterol.
Sometimes drugs do everything that's asked of them and still fail to
perform. Pfizer's experimental drug torcetrapib dramatically raised good
cholesterol, as doctors had hoped it would. But lab tests don't tell the
whole story. Unfortunately, the drug had deadly side effects that killed
its chances of approval.
Q: How do the drugs' manufacturers explain their failure in this study?
A: Lee Davies, a spokesman for the two firms' joint venture, says the
patients presented a major challenge, partly because their cholesterol
was so high. Also, most of them had already been treated with statins,
making it harder to see any additional benefit.
Q: What's the bottom line for patients?
A. Zetia and Vytorin should not be used as first-line drugs, Blumenthal
says. They're most useful for patients who aren't getting all the help
they need from statins and for those who can't tolerate statins' side
effects, including liver problems
Thanks to, Steve Sternberg, USA TODAY
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