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Are any COX-2 inhibitors safe? The FDA does an about-face on Bextra

I am glad right now that the only thing I am suffering from is a common head cold, thanks to my two toddlers wanting to “share.” If I had arthritis like my grandmother did, I would really be starting to worry. It seems that even after the talk of using “black box warnings” from this past February’s hearings at the FDA, today, the FDA asked Pfizer [1] to pull Bextra [2] (valdecoxib), another beleaguered Cox-2 inhibitor, from the market today as part of a broad-ranging Public Health Advisory on the entire class of NSAIDs.

In making this announcement, the FDA cited inadequate information on possible heart risks from long-term use of the drug as well as “life-threatening” skin reactions, including deaths. The regulatory agency also called for the strongest warning possible on Pfizer’s other arthritis product, Celebrex. These decisions come about six months after rival drugmaker Merck & Co. pulled its blockbuster arthritis drug Vioxx off the market, also due to safety concerns.

In calling for a stronger warning on Celebrex labels, the FDA cited increased risk of cardiovascular “events” and gastrointestinal bleeding and said all similar drugs should have label warnings.

Pfizer said it “respectfully disagreed” with the FDA decision and it plans to hold talks with the agency about returning Bextra to the market.

What is particularly interesting in this case is that the FDA went against the advice of a panel of doctors and scientists, which in February concluded that Bextra was beneficial enough to justify its sale. Bextra, generated $1.29 billion in sales for New York-based Pfizer last year, 2.4 percent of total revenue. Celebrex brought in $3.3 billion, or 6.3 percent.

Cox-2 Class

Celebrex, Bextra and Vioxx are part of a class of drugs known as Cox-2 inhibitors. The medicines are designed to target the body’s production of Cox-2, an enzyme linked to pain and swelling, while sparing a related enzyme that helps protect the stomach from complications such as ulcers and bleeding. They sold for as much as $2 a pill, compared with pennies for generic painkillers such as aspirin.

Like the Merck drug Vioxx, the two Pfizer drugs are COX-2 inhibitors that work to prevent the internal bleeding associated with drugs like aspirin. Merck withdrew Vioxx last fall after studies showed it had twice the risk of heart attack and stroke compared with patients who took a placebo for 18 months. In a statement, the FDA also said it would “carefully review” any proposal to put Vioxx back on the market.
Bextra already carried a warning highlighted in a black box on its label about its link to skin reactions. One of those reactions, known as Stevens-Johnson, may cause a rash, blisters or red splotches on the skin and persistent fever. The FDA determined that the skin and cardiovascular risks together were enough to justify the drug’s withdrawal.

“No added advantage and a special risk is what led us to the change with Bextra,” Steve Galson, acting director of the FDA’s center for drug evaluation and research, said on a conference call.