NEW YORK (AFP) - Drugs giant Merck and Co. shares plunged nearly 10 percent as the Wall Street Journal said the firm had fought for years to minimize the risks in its blockbuster pain drug Vioxx.
Merck shares plummeted 3.03 dollars, or 9.68 percent, to finish at 28.28 dollars.
The Wall Street report intensified fears about a mass of litigation mounting up against the group.
Merck faces hundreds of lawsuits after announcing a global withdrawal of Vioxx on September 30, prompted by a study showing it increased the risk for strokes and heart attacks.
According to the Journal, internal Merck e-mails and marketing materials along with interviews with outside scientists showed it had fought to keep safety concerns from destroying the drug's commercial prospects.
By 2000, one e-mail suggested Merck recognized that something about Vioxx was linked to an increased heart risk, the paper said.
Merck research chief had e-mailed colleagues March 9, 2000, saying cardiovascular events "are clearly there," it said, even as the firm publicly rejected any increased intrinsic risk.
New York-based credit rating agency Standard and Poor's warned it may downgrade Merck, placing the firm's top notch AAA rating on "CreditWatch" with negative implications.
The agency affirmed its A-plus short-term corporate credit and commercial paper ratings on Merck.
"The actions reflect Standard and Poor's increasing concern about the magnitude of possible litigation against Merck after its withdrawal of COX-2 inhibitor Vioxx," Standard and Poor's credit analyst Arthur Wong said.
"The drug, which generated roughly 2.5 billion dollars in annual sales, was taken off the market after studies showed an increased risk of cardiovascular events among patients. Merck estimates that 20 million patients have taken Vioxx in the US."
Separately, it said, the US Food and Drug Administration had recently asked for extra safety and efficacy data on Arcoxia, Merck's second-generation COX-2 inhibitor and one of its few near-term product prospects, further delaying marketing approval.
Standard and Poor's said it planned to meet with Merck's management to discuss the firm's "long-term ability to retain its credit strength" before deciding on the rating action.

11/01/2004 - 21:44 GMT - AFP