Merck, Schering-Plough stocks fall following Vytorin advisory

KENILWORTH and WHITEHOUSE STATION, N.J. Stock prices for Merck and Schering-Plough fell sharply Monday after the American College of Cardiology physicians advised doctors to stop prescribing Vytorin because it is not as effective as other drugs in slowing down atherosclerosis.

The recommendation followed discussion of the ENHANCE trial, which showed that Vytorin, a combination of Merck’s Zocor (simvastatin) and Merck and Schering-Plough’s Zetia (ezetimibe), was no more effective than Zocor alone in treating people genetically disposed to having high cholesterol.

The recommendation came despite theoretical explanations provided by Merck of why Vytorin did not lower LDL cholesterol more than simvastatin alone. One explanation suggested the trial’s imaging technology was not sensitive enough to show the difference between Vytorin and Zocor. The other explanation says that patients with the genetic condition were so extensively pretreated by lipid-lowering therapy before they took Vytorin that they would not be significantly affected by it.