FDA reviewing Vytorin cholesterol drug

By Lisa Richwine

WASHINGTON (Reuters) - U.S. regulators said on Friday they would review whether to take action over Merck & Co Inc's and Schering-Plough Corp's popular cholesterol drug Vytorin after a study showed it was no better than a generic in preventing the build-up of fatty plaque.

The Food and Drug Administration said it had not yet received a final report on the study, called Enhance. The agency's review of Vytorin will take about six months after final results are received, the FDA said.

In the meantime, patients with questions about the Enhance study should talk with their doctors, the FDA advised.

"At this time, it is not clear why the lower levels of LDL cholesterol in the patients who took Vytorin did not lead to lesser amounts of plaque compared to patients treated with simvastatin alone," an FDA statement said.

Simvastatin is the generic name for Zocor. Vytorin combines Zocor with a newer cholesterol-fighting pill called Zetia.

The FDA review puts an even bigger spotlight on a debate over Vytorin's value in the wake of the Enhance results early last week and concern over a long delay in releasing the data.

Major medical groups, prominent cardiologists and U.S. lawmakers have weighed in, while prescriptions for the drug have slipped.

Merck shares closed down 3.6 percent at $47.79 on the New York Stock Exchange. They had earlier fallen as much as 14 percent.

Shares of Schering-Plough, which had dropped as much as 13 percent, closed down 5.7 percent at $19.02, also on the NYSE. The two stocks have fallen more than 20 percent since the results of the study were first released.

"The FDA is attempting to buy time so noise can be filtered out and cooler heads can look at the Vytorin data, but it is unlikely even the FDA will be able to draw clear conclusions," said Viren Mehta, principal at Mehta Partners.

"For a clear picture, we will need to wait for outcomes data (data on heart attack and stroke risk) from larger Vytorin trials" due by 2010 or 2011, Mehta said.

Merck and Schering-Plough sell Vytorin and Zetia in a joint venture, and the products have combined annual sales of about $5 billion.

The Enhance study examined Vytorin against Zocor alone in patients with a rare genetic predisposition to dangerously high cholesterol levels. Vytorin failed to halt the clogging of neck arteries better than Zocor alone, but it did a better job of reducing "bad" LDL cholesterol.

Beyond Vytorin, the FDA said it also would review "whether any changes to FDA's current approach to drugs that lower LDL cholesterol are warranted." High LDL is commonly believed to be a major risk factor for heart disease.

FDA officials cautioned the public not to overreact to the Enhance study by turning away from cholesterol-lowering drugs.