So far, the results from three different studies have proved
insufficient to determine a definite link between the cholesterol-lowering drug
Vytorin and an increased risk of cancer.
Last week, the New England Journal of Medicine issued a statement
encouraging doctors and patients to use the drug with caution until more
conclusive evidence is available.
Vytorin is a drug manufactured by combining Merck’s Zocor, a
long-prescribed statin, and Schering-Plough’s Zetia, a newer and different type
of cholesterol-lowering drug.
Questions about Vytorin’s relationship to an increased
cancer risk first emerged last July, when Dr. Terje Pederson of Oslo, Norway
noticed a greater number of cancer cases among patients taking Vytorin as part
of a study than among those taking placebo pills. The study, originally intended to determine
whether Vytorin could halt damage to the heart’s aortic valve, also showed that
Vytorin made no difference in the number of heart attacks, strokes, or
surgeries related to valve damage.
In reponse to Pederson’s findings, researchers at Oxford University reviewed the results of two of their own Vytorin studies and found
not higher cancer rates, but higher cancer death
rates, among Vytorin users.
Sir Richard Peto, a cancer epidemiologist leading one of the
Vytorin-sponsored studies, deemed the Oxford reviews inconclusive.
In Pederson’s study, 105 Vytorin users developed cancer,
while only 70 patients developed cancer while taking a placebo. Cancer-related deaths were higher in all
three studies, with a combined 134 cancer deaths on Vytorin versus 92 among
placebo users.
Still, some doctors, such as Dr. Douglas Weaver of the
American College of Cardiology (ACC), argue that Vytorin may be useful for
people with high cholesterol, who have had problems getting other drugs to
work.
The U.S. Senate has recently asked the ACC to account for
the money it receives from American pharmaceutical companies such as
Merck. There is some worry that doctors
receiving funding from these companies are more likely to disregard warnings
about the drugs they manufacture.
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