Merck's new pain reliever drug Arcoxia, which was proposed as a successor to Vioxx, was rejected by a federal health advisory panel.
The news came out just after the market closed. Merck shares fell in after-hours trading.
A Food and Drug Administration drug safety expert earlier told the panel that the drug may increase substantially the risk of stroke and heart attack and is no more effective for pain relief than other medicines in the same class.
"What you're talking about is a potential public health disaster," Dr. David Graham told the outside experts before the vote. Graham was a leading critic of Vioxx, a related drug also known as rofecoxib.
"We could have a replay of what we had with rofecoxib," Graham said.
Merck is seeking the FDA's approval to sell Arcoxia, also known as etoricoxib, to treat the signs and symptoms of osteoarthritis. Merck, based in Whitehouse Station, N.J., withdrew Vioxx in 2004 after the drug was linked to a higher risk of stroke and heart attack when compared with dummy pills.
Seeks Final Decision
The FDA is not required to follow the recommendations of its advisory committees, but the agency usually does. Merck hopes the FDA will make a final decision by month's end.
Arcoxia is the first drug of its class to go before the FDA for approval since Merck withdrew Vioxx.
"We at Merck believe etoricoxib represents a valuable treatment option for patients with osteoarthritis. We would like to emphasize there is more long-term safety data" for etoricoxib than there is for any other nonsteroidal anti-inflammatory drugs, or NSAIDs, said Peter Kim, president of Merck's research laboratories.
An estimated 21 million people in the United States suffer from osteoarthritis. NSAIDs are a common treatment. Arcoxia and Vioxx are types of NSAIDs called Cox-2 inhibitors, developed to be gentler on the stomach.
The FDA said this week that new NSAIDs that increase the risk of stroke and heart attack should not win approval if safer alternatives are available.
"The idea should not be we need new drugs. The idea should be we need better drugs," said Martha Solonche, the advisory panel's patient representative.
In evaluating Arcoxia and all other drugs from that class, the FDA said it would focus on the risks to the cardiovascular system.
NSAIDs deserve approval only if they fill a need for a particular group of patients for whom there are no relatively safer options, the FDA said in a memorandum released this week. The FDA does not doubt Arcoxia works for osteoarthritis.
Celebrex Still Sold
The only Cox-2 inhibitor still sold in the United States is Pfizer's Celebrex. The New York company withdrew another of the drugs, Bextra, in 2005.
Merck said the cardiovascular risk of Arcoxia was comparable to another older NSAID, diclofenac, based on the results of a study that enrolled nearly 35,000 patients. Arcoxia causes more high blood pressure than the older drug.
Graham, the FDA drug safety expert, and other critics believe it would have been more fair to compare other NSAIDs, such as naproxen, sold as Aleve and under other names. They contend diclofenac raises heart risks; Merck disputes that.
Diclofenac is widely used worldwide. In the U.S., however, it accounts for just 5 percent of the market for prescription NSAIDs.
Based on smaller and shorter studies, Merck said the cardiovascular risk of Arcoxia was consistent with that posed by other NSAIDs, but greater than that posed by naproxen. The company sells Arcoxia in 63 other countries.
In the U.S., the safety of Cox-2 inhibitors has drawn scrutiny from regulators, drug companies, academics, lawmakers, advocacy groups and the media in the wake of Vioxx's withdrawal.
Graham told a Senate committee in 2004 that the FDA had fumbled its handling of Vioxx and mishandled safety problems with five other widely used drugs.
If the FDA were to approve Arcoxia, Merck said it had no immediate plans to advertise the drug on television. Merck's ad campaign for Vioxx included TV spots that featured Olympic ice skater Dorothy Hamill.