Studies leave verdict on Celebrex risk unclear

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Studies leave verdict on Celebrex risk unclear

Wednesday, February 02, 2005

Federal officials continue to sift through data in a major cancer-prevention

trial that pointed to heart attack and stroke risks associated with the use

of the popular anti-inflammatory . medication Celebrex, made by Pfizer Inc.

A clearer picture of the risks seen in the study, which was sponsored by the

National Cancer Institute and suspended in December, is not expected until

spring, according to a Cancer Institute spokeswoman.

In a new development, Pfizer acknowledged on Monday that an earlier clinical

trial in 1999 to determine whether Celebrex could treat Alzheimer's disease

found that almost four times as many patients taking Celebrex for a year

suffered heart problems as those taking a placebo.

In the Cancer Institute trial, federal officials hope to determine if there

was something about the people in the study that made them particularly

susceptible to heart attacks or strokes. Their findings also might provide

clues to why a different but similar anti-cancer study involving Celebrex

showed no heart problems.

Eventually, they hope to have enough information to help doctors and

patients determine their own risks if they continue to take the popular

anti-arthritis medication.

Celebrex, unlike its former chief competition, Vioxx, made by Merck & Co.

Inc., remains on the market, although Pfizer did stop advertising it in

mid-December.

News of the risks associated with Celebrex came three months after Vioxx was

pulled from the market. Celebrex, Vioxx and Pfizer's Bextra, all COX-2

anti-inflammatory drugs, have been linked to cardiovascular problems.

On Jan. 24, Public Citizen called on the Food and Drug Administration to

pull both Celebrex and Bextra from the market because of cardiovascular

risks.

Preliminary results reported by the Cancer Institute showed that people in

the Celebrex anti-cancer study who were taking the drug had on average a

2.5-fold increase in major or nonfatal heart attacks or strokes compared to

people taking an inert placebo pill.

The Cancer Institute's press office recently provided the Kalamazoo Gazette

with additional information on the clinical-trial results. According to the

Cancer Institute, participants in its study were divided into three groups:

679 people who took the placebo; 685 who took 200 milligrams of Celebrex

twice daily; and 671 who took 400 mg twice daily.

Investigators found six " cardiovascular events " -- primarily heart attacks

or strokes -- in the placebo group (0.9 percent of all participants), 15

" events " in the 200 mg group (2.2 percent) and 19 " events " in the 400 mg

group (2.8 percent).

The risks associated with Celebrex, however, are made murky by the results

of yet another Celebrex anti-cancer study, this one sponsored by Pfizer,

that showed no cardiovascular risks.

The same independent safety-and-monitoring board that found a 2.5-fold

increase in risk in the Cancer Institute trial did not find any added risk

of cardiovascular events in the Pfizer study. The Pfizer trial used the same

heart-event measures and the same safety-monitoring board that the Cancer

Institute trial.

Recommended doses of Celebrex are 100 to 200 milligrams daily for

osteoarthritis and 200 to 400 mg daily for rheumatoid arthritis. Celebrex is

also approved for a rare condition called familial adenomatous polyposis in

doses up to 800 mg per day.

At this point, people who take Celebrex or Bextra should check with their

physicians about continuing or discontinuing use of the popular drugs.

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