Zetia, Vytorin Problems Continue With Latest Study

In the latest blow to popular cholesterol drugs Vytorin and Zetia, new research indicates that the medications may be less effective than older drugs in reducing the buildup of cholesterol in arteries, and were actually associated with more heart attacks and other heart-related incidents.

The new study, known as the ARBITER-6 HALTS, was presented Sunday at an American Heart Association conference, and published online by the New England Journal of Medicine. The research compared the use of Abbott Laboratories’ older cholesterol drug Niaspan (niacin) to Merck & Co.’s Zetia (ezetimibe), which is also contained in Vytorin in combination with the generic cholesterol drug simvastatin.

Researchers from Johns Hopkins University found that use of Zetia failed to reduce the amount of buildup in arteries when compared to Niaspan. In addition, Zetia users were found to experience more cardiovascular problems, though the number of adverse events was not large enough to reach any conclusions about a causal connection.

This is the second study in the last two years that has cast doubt on the effectiveness of Zetia and Vytorin. A prior study from last year found that Vytorin worked no better than taking simvastatins alone, which is available as a much cheaper generic.

In this latest study, researchers looked at data involving 363 patients with a high risk of heart disease. People who took Niaspan were found to have a 2% reduction in plaque buildup in the arteries, while there was no change for those on Zetia. In addition, the study was canceled early due to the high amount of heart attacks suffered by Zetia users. Nine Zetia-users suffered heart attacks during the study, compared to only two on Niaspan. As a result, only 208 participants completed the entire study.

While researchers admit that the study is limited due to the small sample size, they point out that the results reinforce the findings of the previous study, raising further questions about whether the drugs provide any benefit over older medications. However, there are two other, much larger studies currently underway which researchers say may give more concrete data.

Merck & Co. and Schering-Plough, which jointly market Vytorin, paid $5.4 million in penalties in July to resolve state investigations into their alleged attempts to hide data which showed that Zetia and Vytorin were not as effective as advertised. They also paid $41.5 million to settle a Vytorin class-action lawsuit brought by users over the same charges.

The lawsuits alleged that the two companies illegally withheld the results of a clinical trial known as ENHANCE. In January 2008, after delaying and stalling, Merck and Schering-Plough released data from the study, which demonstrated that Vytorin provided no significant medical benefits over taking Zocor alone.

Questions were raised about the companies’ actions months before the data was released, when the drug makers indicated that they wer going to change the ENHANCE study’s measure of effectiveness a year and a half ater the study had been concluded. These actions also led to a congressional investigation into whether the drug makers were trying to manipulate scientific data.