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A prescription drug that is on the verge
of being approved by the Food and Drug Administration (FDA)
should
not be allowed on the market because it raises
serious safety concerns
and may not be effective,
Public Citizen said today.
The drug, tegaserod (called Zelmac by
its maker, Novartis Pharmaceuticals) is designed to treat
constipation-predominant Irritable Bowel Syndrome (IBS). However,
the drug was associated with a three-
fold increase in the rate of ovarian cysts in women
in clinical trials compared to a placebo. Studies in rats
also showed that the drug unequivocally causes ovarian cysts.
A copy of the petition is available at
http://www.citizen.org/hrg/publications/1561.htm
Further, it is unclear
if the drug is effective, the petition notes. None
of the three pivotal trials demonstrated efficacy according
to the original protocol. Even after Novartis altered the
parameters of the trial, lowering the threshold for efficacy,
just one of the two remaining trials showed some efficacy,
and that was modest.
And while tegaserod is to be marketed
for constipation-predominant IBS, many of the patients in
the trials were not constipated, the petition says.
Added Dr. Elizabeth Barbehenn, research
analyst with Public Citizen,
"If the
FDA approves this drug, it may well have to be withdrawn because
of the high probability of seeing more cases of ovarian cysts
once the drug reaches the less-carefully monitored and less
healthy population at large."
The petition reminds the FDA of Lotronex,
a drug that also was designed to treat IBS (diarrhea- predominant
type) but had to be pulled from the market shortly after being
approved because of serious adverse effects also known prior
to approval.
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