The US Justice Department wants to know more about a crucial Vytorin study, the results of which were concealed for more than a year. Known as ENHANCE, the study found that Vytorin was no more effective at preventing clogged arteries than less expensive statin drugs. The Justice Department probe is just one of many looking into the way ENHANCE was handled.
Vytorin, which was developed and marketed jointly by Merck and Schering-Plough, was approved for use by the Food & Drug Administration (FDA) in 2004. Since it came on the market, Vytorin sales have reached $5 billion per year. Vytorin is a combination of cholesterol-lowering Zetia and the statin Zocor. Statins like Zocor reduce the amount of cholesterol produced by the liver, while Zetia lessens the amount of cholesterol in food that is absorbed in the intestines. High cholesterol levels put a person at risk of developing clogged arteries – a major risk factor for heart attacks and strokes. Doctors and Vytorin users were led to believe that the drug would effectively reduce both sources of cholesterol, thereby lessening the amount of plaque build up in the arteries, as well as the risk of having heart attacks and strokes.
But the ENHANCE study, which was released on January 14, showed that Vytorin and Zetia were ineffective in preventing clogged arteries, and might actually increase plaque in some users. In spite of the findings, Merck and Schering-Plough delayed releasing ENHANCE for more than a year – something critics of the company have likened to fraud. In addition, the companies attempted to change the study’s endpoint – the main result it was meant to measure – after it was completed. It is generally accepted that for a clinical trial to be effective, a study’s endpoint must be set at its beginning and remain unchanged. In December 2007, in response to the ENHANCE delays and the attempt by Merck and Schering-Plough to change the endpoint, Congress initiated an investigation of the ENHANCE study. The companies dropped their attempt to change the ENHANCE endpoint shortly thereafter.
In its regular quarterly filing with the Securities and Exchange Commission, Schering-Plough said it received “requests for information” from an unspecified number of U.S. attorneys’ offices. The information requests involved the company’s handling of ENHANCE. Vytorin was already the subject of a Congressional investigation, as well as probes by several state attorneys’ general.
Last month, the House of Representatives Energy and Commerce Committee released some Schering-Plough documents that raised disturbing questions about the way ENHANCE as handled. Those documents related to a meeting held in November 2007 where ENHANCE was discussed. According to The Wall Street Journal, the minutes of that meeting suggested that outside consultants had recommended that the companies change the ENHANCE endpoint.
But other documents released by the Congressional Committee disputed the minutes. After receiving the minutes, James Stein, a cardiac-imaging expert at the University of Wisconsin who was present at the November meeting, wrote in an email to a Schering-Plough scientist: “It was my understanding that there were no minutes or transcript of this meeting.” He also told a company scientist in an email: “We did not vote on this….It was the decision of the company to change the endpoint.”