FDA Holds Up Wyeth Drug

Updated from 9:20 a.m. EDT

Wyeth (WYE Quote) watched its shares drop sharply after U.S. regulators said they want another clinical trial for the menopause-symptoms treatment Pristiq.

The drugmaker said the Food and Drug Administration is asking for more information about Pristiq's potential risks of liver and cardiovascular side effects, adding that a clinical trial would take a year or more.

By late morning, the stock was down $4.36, or 7.8%, to $51.64 on trading that was already double the average daily volume for the past three months. The announcement provoked criticism from several analysts about a drug whose approval they had expected.

Wyeth was scheduled to hear from the FDA on Monday on Pristiq, one of seven drugs that the company had predicted would reach the market within the next 18 months. On Tuesday morning, Wyeth said the FDA had granted conditional approval for Pristiq, meaning it wasn't ready to fully sign off on the drug.

The company didn't provide an exact timetable for the new clinical trial. The FDA also asked Wyeth to answer questions about "certain chemistry, manufacturing and controls deficiencies" before it approves the drug. Wyeth didn't provide details.

A spokesman said Wyeth had no announcement on whether the FDA's decision would affect its 2007 earnings. If the drug had been approved, it would have been launched later in the year and would have had "little impact" on this year's revenue, he said.