New Vytorin Study Results on the Way

Washington, DCAnother study is set to be released regarding the effectiveness of Vytorin, a drug that combines ezetimibe (known by the brand name Zetia) and simvastatin (known by the brand name Zocor). Whether the study will confirm previous findings that question the effectiveness of combining Zetia and Zocor is not known. Some previous studies have failed to show that the two drugs combined are more effective than Zocor alone or Zocor and a different statin.

The next study to potentially shed light on the risks and benefits of Vytorin is the IMPROVE-IT trial. Results of the trial will reportedly be announced at the American Heart Association’s annual scientific sessions, November 17. The trial investigated the cardiovascular outcomes - including death related to any cardiovascular event, non-fatal stroke or non-fatal coronary event (such as heart attack) - of using Vytorin as compared with using Zocor alone in approximately 18,000 patients.

According to Forbes (8/12/14), there has been controversy around both the use of Vytorin and the IMPROVE-IT trial. Vytorin was approved without clinical trials that showed there was a benefit to adding Zetia to Zocor. Meanwhile, the results of the IMPROVE-IT trial have been delayed repeatedly.

Critics are concerned that studies have not proven that the combination of Zetia and Zocor is any more effective than Zocor alone, while some studies have shown that other statins are more effective than Zetia when combined with Zocor.

The ARIBTER 6-HALTS trial (Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol 6-HDL and LDL Treatment Strategies in Atherosclerosis) was stopped early because an interim analysis showed that niacin was more effective than Zetia when combined with Zocor. Researchers noted that Niacin is “superior to ezetimibe for patients taking statins.”

That finding built on a previous trial, the ENHANCE trial, published in the New England Journal of Medicine (4/3/8), which found that adding Zetia to the highest dose of Zocor did not increase Zocor’s effectiveness.

According to Forbes (4/11/8), along with concerns that ENHANCE did not show Zetia added any benefits to Zocor were concerns that Merck had the information earlier but did not release it. The article notes that the study was published two years after the final patient ended the study.

Zetia has been proven to lower LDL cholesterol. But it has not been proven to have an impact on mortality rates, according to researchers, nor has it been definitively proven to be more effective than Zocor alone when the two drugs are combined.