Last Updated: 2007-03-19 13:00:47 -0400 (Reuters Health)

NEW YORK (Reuters) - Morgan Stanley said on Friday that AstraZeneca's cholesterol fighter Crestor did not significantly reduce plaque in the carotid artery in a clinical trial, missing a potential opportunity to distinguish itself from rival medicines.

Jami Rubin, an analyst for Morgan Stanley, drew her conclusions from an abstract, or brief summary, of the highly awaited METEOR trial sponsored by AstraZeneca. Specific data from the trial are slated to be presented on March 25 at a major medical meeting in New Orleans.

The study, which compared Crestor to placebo, was designed to show whether the drug reduces plaque in the carotid artery in asymptomatic patients with high cholesterol deemed at low risk of heart disease. Previous Crestor studies in patients with more serious atherosclerosis, or arterial plaque buildup, had demonstrated impressive regression.

Rubin said the unexpected Crestor result could play to the advantage of two other cholesterol medicines co-marketed by Merck & Co. and Schering-Plough Corp., even though Crestor cut levels of bad LDL cholesterol by 50 percent, raised good cholesterol by 8 percent and halted plaque progression.

"While there is still good news here for Crestor, we view this as even better news for Schering-Plough and Merck's Vytorin and Zetia as investors were worried that a definitively positive atherosclerosis study would impair Vytorin's relative competitive positioning," Rubin said a research note.

Schering-Plough shares closed up 41 cents, or 1.8 percent, at $23.49 on the New York Stock Exchange. Merck shares closed off 10 cents at $43.09 on the NYSE.