Vioxx

WHITEHOUSE STATION, N.J. -- While some suppliers are racing to fill the vacuum left by the recall Of Merck's Vioxx, a cox-2 inhibitor pulled off the market because of its link with an increased risk of heart disease, it does not appear that concerns over Vioxx's safety will carry over to Pfizer's cox-2 inhibitors Celebrex and Bextra.

An NDCHealth database found that 32 percent of current U.S. Vioxx prescription holders had been taking the drug for more than 18 months, the time frame in which Merck cited that individuals would be at risk for increased cardiovascular events.

In fact, by all accounts, the majority of patients seeking a new arthritis remedy were given Celebrex or Bextra, representing a significant boost of cox-2 inhibitor prescriptions to Pfizer.

Indeed, following the Vioxx recall last month, Pfizer was no stranger to the press, relaying that long-term studies of Celebrex found no similar link between the use of its cox-2 inhibitor and the risk of heart attacks.

"Each cox-2 inhibitor has a distinct chemical structure, and we would not expect them to have the same side-effect profile, stated Dr. Joe Feczko, Pfizer's president of worldwide development. "The data we've accumulated over time demonstrate that Celebrex does not increase the risk of serious cardiovascular events in patients with arthritis and pain, even at higher-than-recommended doses."

And doctors have no plans of abandoning cox-2 inhibitors as a first line of treatment for rheumatoid arthritis. "No matter how you shake it, it doesn't appear that you're seeing the same sort of risk [associated with Celebrex]," commented Arthur Kavanaugh, a spokesman for the American College of Rheumatology and a professor at the University of San Diego. And although there are no long-term studies that would support a similar assertion for Bextra, there likewise are no clinicals linking the newer cox-2 inhibitor to an increased risk of heart disease.

Within 24 hours of Merck's Sept. 30 announcement, about 2.4 percent of the 1.2 million Vioxx prescription holders, as measured by NDCHealth, had received new prescriptions for alternative therapies. Of those active prescriptions, 58 percent had moved to either Celebrex or Bextra, and 33 percent received a,.prescription for nonsteroidal anti-inflammatory drugs.

Still, long-term concerns connecting cox-2 inhibitor use with an increase in heart disease linger because the simple fact is, the loss or a $5.3 billion prescription drug category is something the chain drug industry can ill afford.

Indeed, the pharmacy line item on drug store balance sheets has taken quite a few knocks in the last few years. The market for prescription-only hormone replacement therapies took a substantial hit following the news linking HRT use to an increased risk of breast cancer. And while the recent Claritin and Prilosec OTC switches represented sales boons on the OTC side, the gain was mitigated by the loss of prescription volume for the entire class of drugs and an increase in the number of chain drug competitors for those products.

The Vioxx recall may very well follow the same pattern as Bayer's Baycol recall did three years ago. When Baycol was lifted from the market, there were five other statin options that did not carry the same health risks as Baycol.

That's good news for pharmacists because even as some portion of the $1.8 billion worth of Vioxx dispensed in the United States last year will be lost to OTC alternatives--such as a combination of an NSAID like ibuprofen with a proton-pump inhibitor like Prilosec OTC to help manage heartburn symptoms sometimes common with the use of NSAIDs--the majority of that share accretion will fall back to Celebrex.

The Vioxx recall is bad news for pharmaceutical companies with cox-2 inhibitors in development, including Novartis Prexige, which already has been delayed Food and Drug Administration approval once. Those formulations now will face an additional hurdle of showing they are not linked to heart disease. with the new [applications] that come, there is always gong to be a question," Kavanaugh said. "People are going to be very suspicious [of new cox-2 inhibitors] until you get a very large body of data [showing no adverse risks]. The bar was just raised incredibly high."

Teva Pharmaceutical also suffers a loss from the recall. The company in late 2003 filed for approval to market a generic version of Vioxx.

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