NEW YORK (Reuters) - Pfizer Inc. on Friday said its
popular Celebrex arthritis drug more than doubled the risk of heart attack
in a large cancer-prevention trial, a setback that comes just weeks after
Merck & Co. recalled its similar Vioxx drug due to heart safety risks.
Shortly after the Celebrex news, the New England Journal
of Medicine carried a letter in which Vanderbilt University cardiologists
questioned the safety of Pfizer's newer arthritis drug, Bextra, and
recommended doctors not prescribe it.
Shares of Pfizer, a component of the Dow Jones industrial
average, fell 11.1 percent following the double blast of bad news.
Merck recalled Vioxx on Sept. 30 after a study found that
long-term use of the drug doubled the risk of heart attack and stroke.
Both Celebrex and Vioxx belong to a class of drugs known as COX-2
inhibitors, as does Bextra.
"It is now a fair question to ask whether Celebrex and
Bextra could be removed from the market," Prudential Equity Group analyst
Tim Anderson said in a research report.
Some analysts have estimated Merck faces tens of billions
of dollars in potential future liability claims from former users of
Vioxx. Anderson said Pfizer must be concerned about its own legal risk if
Celebrex and Bextra remain on the market.
"This does not bode well for COX-2 inhibitors in general,"
Ira Loss, an analyst at Washington Analysis, said of the Celebrex trial.
"The sense had been that Celebrex is somehow different from the others."
Dr. Richard Hayes, a cardiologist at New York University, told Reuters,
"This raises my concern about Celebrex and all the COX-2 inhibitors, so I
will no longer be prescribing any of them."
A Pfizer spokesman said the company has no plans to pull
Celebrex off the market. It is one of the drugmaker's biggest products,
with 2003 sales of $1.9 billion. Bextra had sales last year of $687
million.
The U.S. Food and Drug Administration said it was
reviewing the new Celebrex data and will determine "appropriate action."
Meanwhile, it urged doctors to consider alternative treatments.
Pfizer shed almost $24 billion in market capitalization,
its stock closing down $3.23 to $25.75 on the New York Stock Exchange and
dragging down the Dow Jones industrial average as well as other
pharmaceutical stocks. Pfizer is off almost 30 percent this year.
MORE TROUBLE FOR COX-2s
Pfizer said the Celebrex trial, sponsored by the National
Cancer Institute involved patients taking 400-milligram and 800-milligram
daily doses of the drug to prevent tumors known as adenomas that grow from
glandular tissue. High doses of the anti-inflammatory drug were being
tested on the theory that inflammation is a cause of cancer.
Vioxx and Celebrex both work by selectively blocking a
protein called COX-2 that has been linked to inflammation. They were both
launched in 1999 and quickly became top-selling drugs, helped by massive
television and print advertising.
Pfizer also said on Friday that Celebrex was not shown to
increase heart risk in a second long-term trial designed to see if the
drug could prevent colon polyps. Negative findings in a similar trial led
to the withdrawal of Vioxx.
New York-based Pfizer said National Cancer Institute
officials decided to halt the Celebrex trial on adenomas after confirming
"an approximately 2.5-fold increase" in the risk of fatal or non-fatal
heart attack in patients taking the drug, compared with patients taking a
placebo.
Pfizer Chief Executive Officer Hank McKinnell on Friday
told CNBC television he does not believe the continuing negative news on
COX-2 drugs, including Celebrex and Bextra, will spell their eventual
demise.
"I don't believe they're doomed," he said, arguing that
older standard painkillers cause ulcers and gastrointestinal bleeding that
kill 16,500 Americans each year and that the COX-2 pills are gentler on
the stomach.
Amid concerns about the safety of all COX-2 inhibitors
after the Vioxx withdrawal, Pfizer plans to begin a major new trial next
year to verify the heart-safety of Celebrex in arthritis patients who have
had a recent heart attack.
The company has also defended Bextra's safety, although
Pfizer's newer treatment raised the risk of stroke and heart attack in two
small clinical trials of patients taking it after coronary bypass surgery.
In other fallout from the Celebrex news, Moody's Investors
Service on Friday said it revised Pfizer Inc.'s outlook to negative from
stable but affirmed its long-term debt ratings.
