Healthy Skepticism Library item: 130

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Publication type: news

Hensley .
Pfizer Says Study Shows Heart Risk From Celebrex: Shares Sink 11% on News
Wall Street Journal 2004 Dec 17

Full text:

Pfizer Inc. said a government-sponsored study of its arthritis drug Celebrex in cancer prevention found a significant risk of cardiovascular problems, an unanticipated result that raises new questions about the safety of the popular drug.

Patients taking Celebrex had a risk of a major cardiovascular event that was two-and-a-half times greater than the risk for patients taking placebo. That level of risk appeared even greater than the one found in patients taking Vioxx in a similar trial that led Merck & Co. to withdraw Vioxx in late September. That study, called Approve, detected a doubling of risk of heart attacks and strokes in patients taking the daily pill longer than 18 months.

The Celebrex results “are unexpected,” Pfizer said in a news release, and run counter to a second cancer study which hasn’t found an increased risk of problems. Pfizer said it had no plans to withdraw Celebrex from the market.

The Food and Drug Administration said late Friday that physicians should consider prescribing drugs other than Celebrex while the agency continues to review information showing an increased risk of cardiovascular events.

Acting FDA Commissioner Lester M. Crawford said the FDA was notified Thursday night of results of the two clinical trials. He said the FDA is still reviewing information from those trials and other information about Celebrex. He said physicians who believe their patients would still benefit from Celebrex should prescribe the lowest possible dose.

Meanwhile, the National Institutes of Health said Friday it has suspended colon cancer studies involving Celebrex, which belongs to a class of drugs called Cox-2 inhibitors. Also, NIH Director Elias Zerhouni said in a statement that NIH would immediately review other federal studies involving all Cox-2 drugs, including one that is aimed at treating Alzheimer’s disease.

Pfizer shares sank in 4 p.m. trading on the New York Stock Exchange, falling $3.23, or 11%, to $25.75.

Colon Cancer Study

The worrisome study of Celebrex, called the Adenoma Prevention with Celecoxib trial, involved patients taking high doses of Celebrex—400mg and 800mg daily — to see if the drug could prevent colon cancer. The National Cancer Institute, which sponsored the study, stopped giving patients Celebrex after learning of the increased risk to patients during a review of the data. Recommended doses of Celebrex are 100mg to 200mg a day for osteoarthritis pain and swelling and 200mg to 400mg for rheumatoid arthritis symptoms, Pfizer said.

“These new data in Celebrex users should send a strong message to patients and clinicians that its use should be strongly restricted in patients with a diagnosis of coronary artery disease or its risk factors such as high blood pressure, high cholesterol, diabetes or a family history” said A. Mark Fendrick, a professor of medicine at the University of Michigan in Ann Arbor. “Data from other drugs in the Cox-2 inhibitor class — Vioxx and Bextra — had already raised a warning signal about their use in people at risk for heart attacks and strokes. People on either Celebrex or Bextra should talk to their doctor immediately about the risk and benefit of the drug for them.”

Pfizer Chief Executive Henry McKinnell said in a statement, “Pfizer is taking immediate steps to fully understand the results and rapidly communicate new information to regulators, physicians and patients around the world.” (See Pfizer’s statement.13)

Bextra Warning Label

Pfizer’s other Cox-2 drug, Bextra, was recently given a new FDA label warning of increased risk of heart attack and blood clots in patients who recently had coronary bypass surgery.

Separately, Researchers at Vanderbilt University School of Medicine have recommended that physicians stop prescribing the painkiller Bextra over concerns that the drug may raise the risks of heart attacks and strokes. Writing in the Dec. 23 edition of the New England Journal of Medicine, researchers said they recommend “that clinicians stop prescribing valdecoxib except in extraordinary circumstances.”

“It appears as though there’s a problem with Cox-2 inhibitors as a class of drugs,” says Michael Fleming, president of the American Academy of Family Physicians and a practicing physician in Shreveport, La. “But the fact is we just don’t know.” Dr. Fleming says he’s “concerned equally” about Bextra and Celebrex and would “think twice” about prescribing either to patients who haven’t used them yet. More study needs to be done on both of them, he says.

Scott Zashin, clinical assistant professor at the University of Texas Southwestern Medical School, says he is no longer prescribing Bextra to patients who have not already taken it, but he may continue to prescribe Celebrex to some patients.

Celebrex appears to be the least likely of the drugs to cause heart problems, Dr. Zashin says. As for the study results announced by Pfizer on Friday, he says, “I’m not sure you can take a lot of information from this other than saying [that] more study is needed and to use caution,” he says.

Prescriptions in Bextra and Celebrex rose sharply after the Vioxx recall. Prescriptions for Celebrex increased by 40% in the two months after Vioxx was removed from the market on the last day of the third quarter.

‘Big Enough Pipeline’

Pfizer can sustain any potential hit from health risks related to Celebrex, said Ted Parrish, co-portfolio manager of the Henssler Equity Fund. “We think that Pfizer has a big enough pipeline to sustain a hit like this if they were to have to withdraw Celebrex from the market,” he said in an interview on CNBC Friday

In the third quarter, Celebrex sales rose 14% to $797 million, accounting for about 6% of the company’s $12.83 billion in revenue; Bextra sales rose 37% to $324 million in the quarter.

Celebrex was Pfizer’s fourth-best selling drug in the third quarter, behind cholesterol-reducer Lipitor, blood-pressure treatment Norvasc and antidepressant Zoloft.

In 2007, some $14 billion of company revenue from current bestsellers, including both Zoloft and Norvasc, will be open to competition from generics. Earlier this month, the company reiterated its intent to submit 20 medicines or patent-protected reformulations of existing medicines for marketing approval by the end of 2006.