FDA: Vytorin Unlikely to Up Cancer Risk

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Latest Statement From FDA Reverses Earlier Findings on the Cholesterol-Lowering Drug

By Bill Hendrick
WebMD Health News

Reviewed By Louise Chang, MD

Dec. 22, 2009 -- The FDA today backed off a 2008 statement describing a possible link between use of the cholesterol-lowering drug Vytorin and cancer, saying any connection is unlikely but shouldn't be ruled out.

Vytorin is a combination of two cholesterol-lowering drugs, Zocor, from Merck, and Zetia, from Merck and Schering-Plough.

The FDA said in August 2008 that preliminary results from a large clinical trial indicated that Vytorin was possibly implicated with an increased risk of cancer and cancer-related deaths in people who took it compared to people who took a placebo.

The agency said today it issued the new statement after reviewing data from that trial (known as the SEAS trial) and two ongoing large clinical trials.

The SEAS trial involved 1,873 patients with a narrowed or obstructed aortic valve of the heart; its goal was to determine if lowering the amount of LDL "bad" cholesterol with Vytorin would reduce the number of major adverse cardiovascular events. The FDA said today it found no lower overall cardiovascular risk with patients on Vytorin.

The preliminary findings of the two ongoing trials known as the SHARP trial and IMPROVE-IT trial, which include over 20,000 participants, showed no increased risk of cancer. Although there were more deaths in the Vytorin groups, the finding wasn't statistically significant. The FDA notes that when the SHARP and IMPROVE-IT trials are completed, it will further analyze the data for cancer risk.

The agency said that while it's unlikely there's an association between Vytorin or Zetia and cancer, "at this time an association cannot be definitively ruled out."

The FDA said it is not advising doctors or consumers to stop using any of the three medications but will continue to evaluate the clinical benefits and potential risks of Vytorin and Zetia compared to other cholesterol-lowering drugs it has approved.

The FDA said it issued today's update because:

• Animal studies have not found an association between Zetia and an increased incidence of cancer.
• A large body of data indicates that Zocor is not associated with increased cancer risk, but that long-term data on Zetia is not sufficient to definitely rule out a cancer risk.
• Risk of cancer in the SEAS trial did not increase consistently over time with longer use of Vytorin, which would have been expected of a drug that caused cancer or promoted the growth of pre-existing cancers.
• The reported increase in cancer and cancer-related deaths in the SEAS trial was the result of combining a wide variety of cancer types together, making it "biologically less likely that a single drug" increases the risk of a wide variety of cancer types.
• When the SEAS trial results were compared with data from the two other large studies, no consistent pattern showed up of increased cancer risk among people being treated with Vytorin.
• The SEAS study wasn't designed to evaluate cancer risk but instead was performed after the fact and without necessary statistical corrections.

The FDA says the SHARP and IMPROVE-IT trials will provide more information in the future to further assess cancer risk with Zocor and Zetia. The SHARP trial is expected to end in 2010 and the IMPROVE-IT study in 2012.

SOURCES: News releases, FDA.

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