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Experts Divided on Vytorin Cancer Risk

Nov 13, 2008 | Parker Waichman Alonso LLP

Vytorin was the subject of a heated debate at the annual meeting of the American Heart Association in New Orleans yesterday.  At issue was the controversial drug's potential cancer risk.  While some heart experts on a panel discussing the issue tried to ease concerns about Vytorin and cancer, others said the drug's various issues of safety and effectiveness warrant more investigation.

Vytorin is a combination of the statin Zocor and the cholesterol-lowering drug Zetia.  Vytorin has been under the microscope since the ENHANCE study was released in January.   That study showed that Vytorin was ineffective in preventing clogged arteries, and might actually increase plaque in some users. When ENHANCE was vetted during the annual meeting of the American College of Cardiology in March, doctors there recommended that it be used only as a last resort. “Our strongest recommendation is that people need to go back to statins,” said panel member Dr. Harlan Krumhotz.

Vytorin took another hit over the summer, when the SEAS study was released.  SEAS was designed to see if the drug helped people with aortic stenosis avoid heart attacks.  Not only did SEAS show that Vytorin offered no additional heart attack prevention, but Vytorin patients enrolled in the study had higher rates of cancer than those taking a placebo. In the trial, 102 patients taking Vytorin developed cancer, compared with 67 taking the placebo. Of those, 39 people taking Vytorin died from their cancer, compared with 23 taking placebo. Researchers conducting the study said that while those numbers don’t prove a definitive cancer link, they were “statistically significant”, meaning the odds were less than 5 percent that they were the result of chance.

Merck and Schering-Plough, the makers of Vytorin, have tried to downplay concerns about the drug's possible cancer risks, calling it an anomaly.  The companies based that claim on an analysis conducted by Richard Peto, an Oxford University statistician.  Peto pooled data from two much larger ongoing studies of Vytorin and said they showed that the cancer risk was a statistical fluke. He called the contention that Vytorin could cause cancer “bizarre”.

Reuters.com is now reporting that at yesterday's meeting, experts were not able to reach a consensus regarding Vytorin and cancer.  Some cautioned against judging Vytorin too soon, and said worries about cancer were unwarranted.   "There is no news here other than undue alarm being raised by some about treatments that may well produce further benefits in terms of reducing the risks of heart attacks and strokes," said Rory Collins, an Oxford University researcher.

According to Reuters, Collins is currently leading another Vytorin study called IMPROVE-IT.  That study is funded by Merck and Schering-Plough.

Others, however, were more concerned.  "I think it is impossible to be completely certain, based upon what we currently know, that there isn't a cancer signal" with Vytorin.  Allen Taylor, a cardiologist with Washington Hospital Center in Washington, D.C.  According to Reuters, Taylor said that until ongoing large trials definitely prove the safety and effectiveness of the Zetia component of Vytorin, he would only prescribe the drug to patients who had no other alternative.