Bextra

NEW YORK -- Pfizer may end up being the winner in all of the controversy swirling around cox-2 inhibitors through a complicated formula of addition by subtraction.

Gone from the market are Vioxx and now Bextra--the Food and Drug Administration asked Pfizer to cease sales last month--leaving only Celebrex as the remaining cox-2 inhibitor on the market.

There was a significant portion of cox-2 users who were assumed to have stopped using arthritis pain remedies altogether until the dust surrounding cardiovascular safety concerns was resolved.

While the new black-box warnings that Celebrex will be required to carry may give many arthritis sufferers pause, they will be having that risk-versus-benefit conversation with their doctors. Consequently, sales ought to funnel back to Celebrex slowly throughout this year as more physicians become comfortable with cox-2 therapy in light of the latest contraindication.

"There are Bextra [prescriptions] switching into Celebrex [already]," reported Pat Kelly, president of Pfizer U.S. Pharmaceuticals, two weeks after Bextra's removal. "There is also switching from [non-steroidal anti-inflammatory drugs] to Celebrex going on in the market again, which is a good thing, he said. All of this movement pre-dates the actual addition of warning labels, after which Pfizer again will be able to communicate with doctors about Celebrex's benefits.

For the first quarter ended in March, Pfizer reported $265 million in sales of Celebrex, down 53 percent compared with last year. or all of 2004, according to IMS Health data, sales of Celebrex were up 7 percent to $2.7 billion.

Of course, Celebrex will not be the only cox-2 inhibitor on the market for too long. We respectfully disagree with the agency's position regarding the overall benefit/risk profile of Bextra," stated Karen Katen, vice chairman at Pfizer. "We will continue to stay in close contact with regulatory agencies around the world to take appropriate measures as required."

Bextra's cardiovascular risk could not be differentiated from other NSAIDs, Pfizer reported. However, the FDA concluded that the additional, increased risk of rare but serious skin reactions associated with Bextra warranted the request of withdrawal.

It should be easier to get Bextra back on the market once Pfizer satisfies any concerns the FDA has. Bextra never has been recalled formally--the FDA requested Pfizer cease sales, and Pfizer obliged.

And Merck is expected to pursue getting. Vioxx back on the market, as well as its new drug application for Arcoxia, which once was expected to be its cox-2 heir of Vioxx.

However, because Vioxx was recalled officially in September, any approval process to get Vioxx back on the market may take an extended period of time, as the FDA most likely will require additional clinical trials during its review. Similarly, the approval hurdle has been raised for the two cox-2 inhibitors furthest along in development: Arcoxia and Novartis' Prexige. Analysts once predicting peak sales in excess of $2 billion, now are not including any Prexige sales in their forecast models of Novartis.

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