Pfizer Warns of Risks From Its Painkiller: Bextra

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October 16, 2004

 

 

Pfizer Warns of Risks From Its Painkiller

By REED ABELSON

 

Pfizer warned doctors yesterday that one of its best-selling

painkillers, Bextra, might increase the risk of heart attack or stroke

in coronary artery bypass surgery patients. The announcement comes

just two weeks after Merck removed from the market its painkiller,

Vioxx, which is in the same class of medicines as Bextra, because a

study showed that the risk of heart attacks doubled for patients who

had taken Vioxx 18 months or longer.

 

Pfizer said a clinical study involving more than 1,500 patients showed

that those who had undergone bypass surgery and had taken Bextra

intravenously and orally were at higher risk for heart attacks. An

initial study last year raised similar concerns in the same kinds of

patients.

 

The painkillers known as COX-2 inhibitors, which include Bextra and

Vioxx, have been widely prescribed to people with arthritis. Merck's

decision to withdraw Vioxx cast suspicion on the safety of drugs in

that class. Now Pfizer's warning is sure to fuel the debate about the

overall safety of these drugs for all patients.

 

Officials of the Food and Drug Administration said yesterday that the

agency would convene a panel of independent experts in January to

discuss these issues. Regulators abroad have also indicated plans to

review COX-2 drugs.

 

Pfizer said it was already conducting research into whether Bextra

increases the risk of heart attacks in people taking the drug for

chronic pain. The company also issued a warning yesterday about an

extremely rare and potentially fatal skin reaction to Bextra.

 

In addition to Bextra, Pfizer also makes Celebrex, the best-selling

COX-2 drug on the market. Bextra is the company's new and

faster-acting version of Celebrex.

 

Pfizer says there is no evidence that its drugs have problems similar

to Vioxx because they are chemically different. Although Bextra is not

approved for use for surgery patients, Pfizer said its studies had

shown that general surgery patients - as opposed to bypass patients -

are not at higher risk for heart attacks.

 

But some doctors say this group of drugs may work in a way that

increases the risk of heart problems for some patients, and they point

to this latest information as additional reason for concern.

 

" There are serious questions to be addressed here, " said Dr. Garret A.

FitzGerald, a University of Pennsylvania cardiologist and

pharmacologist who raised concerns about the painkillers in The New

England Journal of Medicine this month.

 

But Dr. FitzGerald also emphasized that these drugs are useful for

certain patients. " We absolutely shouldn't yank these drugs as a

class, " he said.

 

Other doctors also expressed concerns about the new information from

Pfizer. " It's going to require a lot of really serious looks, " said

Dr. David Campen, a rheumatologist for Kaiser Permanente in

California, a major health network, who has also been involved in

research on some of these drugs.

 

Millions of people have taken these drugs for pain and chronic

conditions like rheumatoid arthritis, and sales of these three drugs -

Vioxx, Celebrex and Bextra - exceeded $6 billion last year.

 

Regulators in Europe are expected to make a decision as soon as next

week about whether to take any action on the drugs. The F.D.A.'s

expert panel will review whether Celebrex and Bextra are safe, Dr.

Sandra Kweder, acting director of the administration's office of new

drugs, said in an interview yesterday.

 

While no study of either drug analyzed by the agency so far has been

cause for concern, Dr. Kweder said, the agency is not sure it has all

the information it needs. The agency is aware of the two studies

involving the intravenous form of Bextra, but " it's unclear what the

relationship is with the oral form, " she said.

 

Other recent studies suggesting that all COX-2 inhibitors may have

safety problems are still being analyzed by the agency, she said.

Uncertainty over the safety of drugs is not uncommon, Dr. Kweder said,

and that is " something we have to take into account with regard to

every decision we make about marketing a new drug and every decision

we make about withdrawal of a drug. "

 

But some doctors say because the benefits of COX-2 drugs are so

unclear, the advantages of taking one of these painkillers may not

outweigh these risks.

 

" You have to treat people who are high risk conservatively, " Dr.

Campen said.

 

The F.D.A. will take this into account, Dr. Kweder said. She also

noted that neither Celebrex nor Bextra had been proved to be any

better than older medicines like ibuprofen at guarding against stomach

bleeding, a benefit often cited with these drugs, and neither had been

proved to be any better at relieving pain than older drugs.

 

The agency will have to balance the risks and benefits of these drugs.

" That's what we're going to ask the advisory committee to do, " she said.

 

Since the Vioxx withdrawal, Pfizer has been emphatic in distancing its

drugs from Vioxx and playing down concerns about higher risk for heart

attack and stroke. The company says it is even conducting research

into whether Celebrex might reduce the risk of such events.

 

Many doctors have said it is critical that research be conducted to

settle this issue. " It's a trial long overdue, " said Dr. Eric J.

Topol, chairman of cardiovascular medicine at the department at the

Cleveland Clinic, who said the information about what happened in

bypass patients was " very worrisome. "

 

Dr. FitzGerald criticized Pfizer for not making this latest

information public more quickly since the company had completed the

study in the spring. Pfizer said it could not have released this

information earlier because it had to analyze the information.

 

" I thought we took a rather extraordinary step, " said Dr. Mitch

Gandelman, a Pfizer executive, who said the company released the

information before it normally would to quickly share it with

doctors.Pfizer officials emphasized that the news about Bextra does

not implicate Celebrex.

 

Shares of Pfizer's fell 58 cents, to close at $28.50 yesterday,

although the shares had been down even more sharply earlier in the day.

 

Gardiner Harris contributed reporting for this article.

 

Copyright 2004 The New York Times Company