The study, called Enhance, was designed to explore whether Zetia increases the effectiveness of Zocor at preventing heart attack by keeping plaque from building up in the arteries. It's an important question for Merck and Schering-Plough because there's never been a study showing their combo prevents heart attacks, strokes or deaths any better than Pfizer's Lipitor or generic Zocor.
If the news were good, the companies would rush it out, but delay doesn't bode well, Forbes points out this week. "It starts to raise suspicion," Allen Taylor, head of cardiology at Walter Reed Army Medical Center, tells the mag. "The more time it takes, the more you start to naturally wonder what is wrong."
Reasons to be suspicious: The trial wasn't listed clinicaltrials.gov until asked by Forbes about its absence. The drugmakers say that it was an oversight because the study began before the industry listed every study online. Also, clinical trial experts often recommend that outside researchers conducting a study, not a company, control the computerized database created to analyze study results. In this case, that database is held by Schering-Plough.
In explaining the delays, the drugmakers point to difficulties reading some 30,000 artery pictures of 1,000 patients, who received Zocor or Vytorin. Ultrasound pictures were taken of arteries in their thighs and necks. If adding Zetia, the key ingredient in both drugs, was good for arteries, Vytorin patients would have less plaque than those who just got Zocor, Forbes notes. The patients have a genetic disorder that causes high cholesterol.
"This has been time consuming and taken longer than originally anticipated because during the analysis, observations of variability in some of the data were detected as part of the validation/data review procedures" the statement reads. "Such potentially confounding observations are not unusual in studies of this kind."
"It is critically important for researchers to take the appropriate time and rigor to conduct clinical trials, analyze data and report study results. The Enhance trial is complex and is being conducted with great care," says John Kastelein, a professor of medicine and chairman, Department of Vascular Medicine, Academic Medical Center, Amsterdam, Netherlands, in the statement. And as he tells Forbes, "I certainly want it finished. There are all sorts of conspiracy theories that are not good for my reputation."