When PCRM member Nancy Tufford began taking Vioxx in January 2002,
she had no idea that Merck, the drug’s manufacturer, was
betting her life on a misleading animal experiment. The drug giant—eager
to keep a profitable drug on the market—had decided to rely
on tests showing that Vioxx was safe in mice, rats, and monkeys,
while ignoring mounting evidence that the drug was dangerous to
humans.
The healthy and active Minneapolis resident first took the
painkiller after injuring her shoulder at the local YMCA and stuck
with it because it seemed to help her arthritis. A little over
a year later, Tufford began experiencing fatigue and shortness
of breath. A nonsmoker who had no symptoms or history of heart
problems before taking Vioxx, Tufford was diagnosed with congestive
heart failure in the summer of 2004.
An estimated 140,000 Americans developed heart and vascular
disease from Vioxx. What makes Tufford’s case unusual is
that she—with help from PCRM—is taking Vioxx’s
manufacturer to court over its reliance on misleading animal tests.
Tufford is a plaintiff in a PCRM lawsuit against Merck & Co.
filed in July in the Superior Court of New Jersey. The suit charges
that the New Jersey-based pharmaceutical maker wrongfully relied
on animal tests while ignoring more applicable human data.
The PCRM case is believed to be the first time a U.S. pharmaceutical
company has been sued specifically for relying on animal tests.
A top-selling painkiller, Vioxx was pulled off the market in fall
2004, after results from a clinical study showed that the drug
doubled the risk of stroke and heart attack in humans.
Drug Safety?
• More than 100,000 Americans die each year from adverse
reactions to approved drugs. This is the fifth leading cause of
death in the United States.
• More than 90 percent of drugs that appear safe in animal
tests fail in human studies.
• More than half of all approved drugs will be withdrawn
or relabeled for serious or lethal effects in humans.
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Animal Tests Led Merck Astray
PCRM cardiologist and medical researcher John J. Pippin,
M.D., F.A.C.C., testified before Food and Drug Administration and
Institute of Medicine committees on drug safety and released a
major report on the failure of animal tests to predict Vioxx’s
dangers.
According to Dr. Pippin, Merck disregarded and suppressed
human risk data that began appearing in 1996—and continued
to do so after its own study in 2000 showed that Vioxx was linked
to five times the heart attack risk of naproxen, an older anti-inflammatory
drug. Merck used data from animal tests to make a case for keeping
its blockbuster drug on the market.
Nine of 11 studies on mice and rats had shown Vioxx or other
COX-2 inhibitors to be safe for animal hearts and blood vessels.
In fact, six different animal studies—in four different species—showed
Vioxx was actually protective against heart attacks and vascular
disease. One researcher went so far as to suggest that Vioxx be
considered a treatment for human cardiovascular disease, based
on these animal tests.
Monkey tests were a special problem. After human studies indicated
that Vioxx was more dangerous than another painkiller, naproxen,
Merck used experiments on African green monkeys to try to show
that Vioxx wasn’t the problem. The monkey tests showed that
Vioxx was neutral for the heart, while naproxen seemed to have
a special heart-protective effect. Merck’s falsely optimistic
animal tests led the company to disregard the deadly problems emerging
in humans.
PCRM’s lawsuit charges that Merck was well aware of the
limitations of animal testing—that animal experiments are
often inconsistent, species-dependent, and not useful in predicting
drug safety or efficacy in humans.
Vioxx Reflects Larger Problem
Because most animals don’t suffer from heart attacks, hypertension,
and other cardiovascular problems, Merck and other drug companies
have used artificial methods to attempt to mimic heart disease
in animals. In the study on African green monkeys, Merck researchers
used electrical shocks to damage the animals’ veins and arteries
and induce blood clotting.
The end result of such tests was a large collection of unreliable
data. In this respect, Vioxx is not unique. Many other drugs have
appeared safe in animal tests but proved dangerous in humans. Rezulin,
a diabetes drug, appeared safe in rats, but caused fatal liver
failure in humans. The opposite scenario is also common. Penicillin,
for example, was discovered in 1929 but not used until a decade
later because of its ineffectiveness in curing infected rabbits.
If it had been tested in cats, guinea pigs, or hamsters, penicillin
would likely have been abandoned as toxic.
Merck erred in not doing adequate post-market surveillance of
patient reactions, says Dr. Pippin. And the company should have
conducted in vitro tests using human cells and tissues,
along with extensive computer modeling, rather than animal tests.
PCRM’s lawsuit charges Merck with knowing of these methods
but failing to employ them.
“Merck was wrong to rely on data from mice, rats,
and African green monkeys when faced with compelling evidence that
human patients were at risk,” says Dr. Pippin. “Animal
trials didn’t predict that Nancy Tufford would develop heart
disease from Vioxx, but human trials clearly did. Until we stop
using animal tests to gauge the safety of human drugs, disasters
like Vioxx are inevitable.”
PCRM president Neal D. Barnard, M.D. |
PCRM attorney Dan Kinburn |
Muhammad Mamdani, Pharm.D., M.A., M.P.H., lead author of human-based
study linking Vioxx to congestive heart failure |
PCRM cardiologist and medical researcher John J. Pippin, M.D.,
F.A.C.C. |
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