High Hopes for Merck, Schering-Plough

Future Prospects

How far can Vytorin go? A lot will depend on whether several more years of patients' experience and more clinical trials produce outcomes that propelled sales of the market leaders. It also will depend on whether doctors believe there's a difference between Vytorin and the statin class of cholesterol drugs such as Lipitor and Crestor.

Although the Zocor component of Vytorin is a statin, the Zetia component acts in a different way. Statins work in the liver to cut bad cholesterol; Zetia works in the digestive tract, reducing the amount of cholesterol that the body absorbs.

Clearly, the bar for Vytorin's growth has been set higher. That's why investors yawned last week when Schering-Plough and Merck presented a study showing Vytorin did a better job of lowering cholesterol than did Lipitor at different doses. The reason: Analysts said they had already seen similar data.

As with Crestor, Vytorin now must show analysts and doctors that it can improve clinical outcomes; lowering bad cholesterol is no longer enough.

What may capture their attention is several clinical trials sponsored by Merck and Schering-Plough. One trial is testing the bad cholesterol-lowering ability of Vytorin vs. placebo in patients with chronic kidney disease. It will measure if the drug has a beneficial impact on heart attacks and/or strokes and how fast predialysis patients reach end-stage renal disease.

Another trial will examine Vytorin vs. placebo in assessing death and injury of patients with aortic stenosis, a disorder that obstructs the heart valve leading to the aorta, the main artery, restricting blood flow to the body.

A third test will compare Vytorin vs. Zocor to see if the combination pill does a better job in reversing the plaque-related thickening of the carotid arteries in patients with high cholesterol. A buildup of plaque in these two arteries, which carry blood to the brain, increases the risk of a stroke. And a fourth trial will look at Vytorin vs. Zocor in reducing death, heart attacks and other major coronary events among patients with a variety of heart-related problems.