NY subpoenas Merck and Schering-Plough over Vytorin

CHICAGO (Reuters) - New York Attorney General Andrew Cuomo has subpoenaed Merck & Co and Schering-Plough Corp for documents and information to see whether the companies hid the results of a study on their cholesterol drug Vytorin.

The move, announced on Saturday, came one day after U.S. regulators said they would review the study, called Enhance, which showed Vytorin worked no better than a generic in preventing the build-up of arterial plaque.

The U.S. Food and Drug Administration said it was not advising doctors to stop prescribing Vytorin, but shares of the two companies fell on Friday as news of the review unnerved investors.

The two stocks have fallen more than 20 percent since the results of the study were released on January 14, triggering a debate over Vytorin's value.

Cuomo said the investigation would review the marketing of Vytorin and also the sale of the companies' stocks to investors before the study's negative results were disclosed.

"We will investigate and, when appropriate, hold accountable drug companies for engaging in irresponsible and deceptive conduct and any deceitful marketing of prescription drugs," Cuomo said in a statement on Saturday.

"Drug companies are on notice that concealing critical information about life-saving prescription drugs, profiting at the expense of patients' health, and wasting taxpayer dollars, is simply unacceptable."

Vytorin combines the widely used generic Zocor with a newer cholesterol-fighting pill called Zetia. 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 did a better job of reducing "bad" LDL cholesterol.