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Celebrex is the third in a family of popular prescription
painkillers to be linked to a higher incidence of heart attacks. This
follows the Sept. 30, 2004 removal of
Vioxx from the market and the later
revelation that
Bextra also presents an increased health risk.
The news concerning Celebrex, a top-selling medication
used largely by
arthritis sufferers and manufactured by Pfizer Inc., emerged
from a study sponsored by the National Cancer Institute, which was testing
the effect of Celebrex on certain tumors. What it discovered instead was
that patients who took Celebrex were more than twice as likely to suffer
heart attacks. (The cancer study was halted.)
More than 26 million people have taken Celebrex, whose
2004 sales will likely exceed $3 billion.
Celebrex, Bextra (also a Pfizer product) and Vioxx, made
by Merck & Co., are all COX-2 anti-inflammatory drugs. Merck withdrew
Vioxx from the market after its own study showed that Vioxx patients
suffered roughly twice the number of heart attacks and strokes. A deluge of
lawsuits followed the drug’s withdrawal by people who claim to have
suffered severe heart attacks and stroke, many of them represented by Kline
& Specter.
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Some five weeks after Vioxx was pulled from the market,
the
American Heart Association released a study showing that patients who
took Bextra were – similar to those who took Vioxx – more than twice as
likely to suffer heart attacks or strokes. Pfizer has not removed Bextra
from the market, saying more tests are necessary.
In the Celebrex test, patients took daily does of 400 and
800 milligrams to see if the drug could reduce certain tumors. But what the
study discovered was that the patients using Celebrex had 2.5 times the risk
of suffering a cardiovascular event as opposed to patients given a placebo.
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Background: Celebrex, Vioxx and Bextra all work by
inhibiting a protein called COX-2 that has been linked to inflammation.
Celebrex and Vioxx were both introduced in 1999 and instantly became
top-selling drugs for Merck and Pfizer, respectively. Pfizer, the world’s
largest drug maker, introduced Bextra in the United States in 2001, also to
robust sales.
"This does not bode well for COX-2 inhibitors in
general," Ira Loss, an analyst at Washington Analysis, told the Reuters
news agency.
While Merck removed Vioxx from the market, Pfizer has been
reluctant to follow suit with its COX-2 products. The company had insisted
after the removal of Vioxx that its Celebrex was safe and it has continued
to advertise and market the drug.
In fact, on the same day (Dec. 17) that the
National
Cancer Institute released its ominous study, Pfizer issued a statement that
Celebrex was not shown to increase heart risk in a second study similar to
that which turned up problems with Vioxx.
Congress Examining
The Vioxx withdrawal has prompted Congress to examine how
the FDA monitors the risks of medicines. The Senate Finance Committee held a
Nov. 18 hearing where FDA reviewer David Graham said the agency is incapable
of protecting the U.S. against another drug with risks such as Vioxx.
Senate Finance Committee Chairman Charles Grassley intends
to introduce legislation to make the FDA's Office of Drug Safety more
independent. The committee oversees U.S. government health- insurance
programs that pay for drugs, giving it a stake in the FDA's performance,
Grassley said in November.
The House Energy & Commerce Committee, which oversees
FDA, also have said they are scrutinizing the agency's performance.
Vioxx and Celebrex were supposed to be gentler on the
stomach because they targeted the Cox-2 enzyme that is involved with pain.
Older painkillers can cause stomach irritation by interfering with Cox-1, a
related enzyme.
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