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US: FDA accused of negligence over diabetes drug
By Joanne Laurier
26 May 2007
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The US federal Food and Drug Administration (FDA) has come
under sharp criticism this week for its inaction over the diabetes
drug Avandia. The FDA apparently failed to implement the recommendation
made several months ago by its own experts that the widely prescribed
drug should carry the strongest possible warning on its label.
In a floor statement placed in the Senate record on Thursday,
Senator Charles Grassley, Republican of Iowa, said that some FDA
staff members had advised that the prescribing information for
the medicine should include a caution framed by a black box, the
most serious type of alert.
On May 21, the prestigious New England Journal of Medicine
(NEJM) published a report linking Avandia, made by the
British company GlaxoSmithKline, to an increased risk of heart
attack and heart-related death.
Grassley complained that top officials in the FDA said they
wanted to postpone making any decisions about the drug until the
completion of an ongoing study slated to continue for at least
two more years. The FDAs own evaluation of Avandia suggests
that as many as 60,000 to 100,000 heart attacks may be linked
to its use since it came on the market eight years ago. Grassley
contends that the number of heart attacks possibly linked to the
drug could be as high as 20 a day.
NEJM reported on the results of a study on the blockbuster
pharmaceutical used to treat type 2, or adult-onset, diabetes
by the Cleveland Clinics Steven Nissen and Kathy Wolski.
The analysis, which pulled together a review of more than 40 existing
clinical studies of Avandia, suggested that the drug raises the
risk of heart attack by 43 percent and cardiovascular death by
64 percent.
Its a huge risk, Dr. Nissen said in an interview,
estimating that tens of thousands of people have had
heart attacks as a result of taking the medication.
Since 1999, it is estimated that 6 million people in the US
have used the drug, with some 1 million Americans currently taking
it. Last year, Avandia was one of Glaxos top-selling drugs,
with worldwide sales of more than $3 billion.
Although Glaxo disputed the results of the Cleveland Clinic
study, its own reviews showed the drug increased the risk
of heart attack by 30 percent, according to the Associated
Press, information the company submitted to the FDA in 2005. It
should be noted that any increase in heart attack risk is significant
because two thirds of diabetics die of heart-related problems.
But the company also presented a study that it said established
that Avandia was no riskier than other medication to treat diabetes.
Concerns about the drug date back to 2000, when a letter was
written to the FDA by Dr. John B. Buse, chief of endocrinology
at the University of North Carolina and currently president-elect
of the American Diabetes Association. In the communication, Buse
cited a worrisome trend in cardiovascular deaths and severe
adverse events among patients using the drug. He also accused
the company of blatant selective manipulation of data
in marketing the product.
Dr. Nissen said the cardiovascular risk has been present since
the drugs launching. There were, he said, an excess number
of cardiovascular events in the registry data given to the FDA
during the initial approval process. Although those events
did not reach statistical significance, the data were all going
the wrong way. He added: If I had been a member of
the FDA advisory panel that reviewed this drug in 1999, I would
have voted against approval and would have asked for more studies
to assess cardiovascular risk.
Among the first doctors to raise concerns about the cardiovascular
safety of Mercks Vioxx, Dr. Nissen publicly voiced questions
about Avandia in a letter published last December in the British
medical journal, the Lancet. The researchers letter
took note of increased cardiovascular problems in a 5,000-patient
clinical study sponsored by Glaxo. The pharmaceutical company
had underwritten the trial in an effort to expand use of the drug
to include not only treatment but also prevention of diabetes.
The results were staggering: in the trial, patients taking
Avandia had 66 percent more heart attacks, 39 percent more strokes
and 20 percent more deaths from cardiovascular-related events
compared with placebo. The outcome, wrote Dr. Nissen, virtually
precludes the possibility of an overall benefit and suggests an
unexpected mechanism for harm.
Rezulin, another drug in the same class as Avandia, was withdrawn
from the market in 2000 because it caused liver problems.
In the May 21 New England Journal of Medicine editorial,
Drs. Bruce Psaty and Curt Furberg observed: During the market
life of rosiglitazone [Avandia], tens of millions of prescriptions
for the drug have been written for patients with type 2 diabetes.
Insofar as the findings of Nissen and Wolski represent a valid
estimate of the risk of cardiovascular events, rosiglitazone represents
a major failure of the drug-use and drug-approval processes in
the United States.
The editorial pointed out that on May 10, the Senate passed
the Food and Drug Administration Revitalization Act, noting that
none of its provisions [in regard to the drug approval process]
would necessarily have identified the cardiovascular risks of
rofecoxib [Vioxx] or rosiglitazone [Avandia] in a timely fashion.
Attorneys representing Avandia users say that Glaxo could potentially
face tens of billions of dollars in liability. Pharmaceutical
analyst Mark Purcell of Deutsche Bank said that parallels
would inevitably to drawn to the ongoing Vioxx litigation,
which could assume as much as $10 billion in liability for Merck.
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