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Increase in Risks is Found in Study

Posted on: Tuesday, 4 January 2005, 03:00 CST

Pfizer Inc. said it found an increased risk of heart attacks and strokes for patients taking high dosages of its top-selling arthritis painkiller Celebrex, the same problem that led to the withdrawal of its one-time competitor Vioxx.

The company said it has no plans to remove Celebrex from the market, but the disclosure Friday sent Pfizer's shares tumbling because of fears that it could cripple sales of what had been the most-prescribed drug for treating arthritis.

Acting Food and Drug Adminis-tration Commissioner Lester Crawford said the government is advising physicians to consider prescribing drugs other than Celebrex to their patients.

"We're leaving open all regulatory decisions as we move forward. But we do not have a decision on the fate of the product," Mr. Crawford said during a news briefing. "We do have great concern about this product (Celebrex) and the class of products."

Doctors already have been inundated with phone calls from worried patients and say they will curtail writing prescriptions for the drug.

Shares of Pfizer, a member of the Dow index and the world's largest pharmaceutical maker, fell $3.23, or 11.15 percent, to $25.75 in late afternoon trading on the New York Stock Exchange. The decline wiped out almost $25 billion of Pfizer's market value.

The drug industry already has been under fire for numerous high- profile debacles: Merck & Co.'s withdrawal of Vioxx; the failure of Chiron Corp. to deliver half the country's flu vaccines; and disclosures that drug companies had stifled negative clinical trial data from studies examining anti-depressant use in children.

Both Celebrex and Vioxx are a type of drug called cox-2 inhibitors. Vioxx was pulled from the market in September because a study found it doubled patients' risk of heart attack and strokes.

National Institutes of Health Direc-tor Elias Zerhouni said that he ordered a full review of the more than 40 agency-supported studies involving cox-2 inhibitors.

News of the increased heart risk for patients using Celebrex came in one of two long-term cancer prevention trials.

The National Cancer Institute, which was conducting the study for Pfizer, said patients in the clinical trial taking 800 milligrams of Celebrex had a 3.4 times greater risk of cardiovascular events compared to a placebo. For patients in the trial taking 400 milligrams of Celebrex, the risk was 2.5 times greater. The average duration of treatment in the trial was 33 months.

In the 2,000-patient study, 15 individuals taking 400 milligrams, 20 patients taking 800 milligrams and 6 patients on placebo suffered either a cardiac-related death, heart attack or stroke.

The study was intended to show whether Celebrex could prevent precancerous growths called polyps in patients that had already had at least one such growth.

A separate cancer study done by Pfizer found no increased heart risk with patients taking 400 milligrams of Celebrex per day.

Pfizer Chairman and Chief Executive Hank McKinnell, who takes Celebrex, told CNN's Paula Zahn that he plans to continue using the drug.

Dr. Joseph Feczko, the president of worldwide development for Pfizer, noted that the results in the trial finding increased risk of heart attacks were not consistent with the other cancer prevention trial or with a "large body of data" that the company had collected.

Dr. Feczko said in an interview later in the day that sales of Celebrex will continue because "it has not shown in totality that it increases the risk of heart attacks."

He said Pfizer still hadn't seen the data from the NCI study so he couldn't speculate on how the two trials could have such different outcomes. He added that the company was still planning to go ahead with a previously announced study to see whether Celebrex could help patients at high risk of heart attacks.

Finding patients to participate in such a study will be challenge because doctors are now saying patients at high risk of heart attacks should avoid taking Celebrex.

Dr. Garret A. FitzGerald, who has been critical of cox-2 inhibitors, said he doesn't believe Pfizer should take Celebrex off market but has to work hard to find the appropriate patient population for the drug. Cox-2s were developed to be gentler on the stomach than older pain relievers called nonsteroidal anti- inflammatory drugs, such as naproxen, that are associated with gastrointestinal problems. But unlike Vioxx, Celebrex was never statistically proven to decrease the risk of ulcers. It also doesn't reduce pain better than older drugs.

"The challenge for Pfizer now is to show why this drug should be chosen," said Dr. FitzGerald, a cardiologist at the University of Pennsylvania.

Dr. FitzGerald said Pfizer's huge marketing push behind the drug accounted for its dramatic use. Last year, Pfizer spent $87.6 million to advertise Celebrex, according to TNS Media Intelligence/ CMR. It recently launched a new campaign for the drug and placed full-page ads in newspapers touting Celebrex's safety in the wake of the Vioxx recall.

Those safety claims might cause problems for Pfizer. Citing recent company statements, including a Nov. 4 press release touting the drug's safety, U.S. Rep. Joe Barton, R-Texas, and U.S. Rep. John Dingell, D-Mich., asked Pfizer on Friday for documents regarding Celebrex and Bextra, the company's other cox-2 inhibitor. They want to know what information Pfizer had about the NCI study when it made the safety statements.

They also want to understand how the data safety monitor board that reviewed the ongoing trial in September and October could have determined to proceed with the study only to have it stopped two months later.

Meanwhile, Consumer Group Public Citizen called on the FDA to ban both Celebrex and Bextra.

Dr. FitzGerald said he believed the news also has implications for cox-2 inhibitors such as those under development at Merck and Novartis.

"I think the trial concludes the controversy about whether there is a class effect of these drugs. Now there is clear evidence of it," said Dr. FitzGerald. "You would need to believe the earth is flat if you thought this was just a coincidence."

For the first nine months of the year, worldwide sales of Celebrex more than doubled from a year earlier to $2.3 billion, accounting for 6 percent of Pfizer's total sales of $37.6 billion during that period.

Source: Augusta Chronicle, The

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