Unpublished Zetia Studies Show Risks of Side Effects

Zetia Can Cause Liver Damage When Taken With Other Statins

In a December 21, 2007 article, "Data About Zetia Risks Was Not Fully Revealed", New York Times (NYT) reporter Alex Berenson broke the story that Merck and Schering-Plough had conducted several studies of Zetia which, in fact, raised the possibility that Zetia can cause liver damage when used long-term with other statins -- but that the drug companies opted not to publish the results of those Zetia studies.

In preparation for his December 2007 Zetia article, the Times' reporter Alex Berenson spoke to a drug company representative and some medical doctors about his discovery of unpublished research about Zetia and liver-related side effects.

"You don’t want to have data missing," said Dr. Bruce Psaty, a professor of medicine and epidemiology at the University of Washington. "When there have been adverse effects, when the benefits don’t look impressive, those are the trials that historically don’t make it to press."

"We keep telling people we want to practice evidence-based medicine, and what we keep finding out is that much of the evidence is obscured," said Dr. Harlan Krumholz, a cardiologist at Yale, when told about the previously undisclosed studies. "There is important evidence, but it’s not in public view. It's hidden from investigators."

Some evidence of Zetia risks can be found in a 2005 Dear Doctor letter addressed to healthcare professionals in Canada. No corresponding letter was addressed to healthcare professionals in the US.

A Schering executive, when asked by a reporter about the unpublished [Zetia] studies, confirmed their existence. But the executive, Dr. Robert J. Spiegel, said the companies had not considered the [Zetia] studies scientifically important enough to publish their findings. Some may eventually be published, he said. "We’re pretty comfortable that people don’t have trouble tolerating Zetia," said Dr. Spiegel.

In his December 2007 NYT article Mr. Berenson points out that although most of the studies about Zetia in which Merck and Schering have published the results covered periods of only 12 weeks — not enough time for liver problems to develop in most patients, the F.D.A.'s documents show that Merck and Schering conducted several other long-term trials of Zetia without releasing their findings.

Together those studies cover several thousand patients who took Zetia along with statins for one to two years. The statins include Lipitor and Crestor, as well as Zocor, which is usually prescribed generically as simvastatin and is the statin used in the Vytorin pill.

The companies' own published studies have generally played down the risk of liver problems. But Dr. Mark Stolk, a gastroenterologist in the Netherlands, last year reported two cases of patients who had developed hepatitis, a liver disease, after taking Zetia alongside Lipitor. One of the patients has since died, Dr. Stolk said in an interview last month. While Zetia is safe for most patients, doctors should carefully monitor patients for liver damage, he said. "I think other cases will emerge," he said.

What does the FDA have to say about this news reporter's discovery of unpublished studies suggesting that Zetia can cause serious liver injury when taken with statins? Mr. Berenson tells us: "The agency did not respond to requests for comment."

Read more about Zetia on our Zetia and Vytorin Information Page >>