- WASHINGTON (UPI) -- Governments
hurriedly stockpiling the anti-viral drug Tamiflu should beware of relying
on the medication for protection against avian influenza, a U.S. preparedness
official has warned.
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- Experts have long said Roche's Tamiflu is not a cure
for the avian flu, but the drug is thought to help slow the severity or
spread of the disease in the event of an outbreak in humans. Governments
have rushed to order stocks, prompting a worldwide run on the drug and
criticism of the company for its apparent refusal to share the Tamiflu
patent with generic drug makers in this time of potential emergency.
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- The assessment might be overly optimistic, however, Dr.
Michael Osterholm, director of the Center for Infectious Disease Research
and Policy at the University of Minnesota in Minneapolis, told reporters
Tuesday.
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- "I believe that anti-viral drugs really represent
a tool -- a limited tool," said Osterholm, who also is associate director
of the National Center for Food Protection and Defense, an agency within
the Department of Homeland Security. "What we don't know is if Tamiflu
will work."
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- Tamiflu and similar drugs can mitigate flu severity and
slow disease spread -- if it is taken within 24 hours to 48 hours of infection.
The drug has been shown to have some effectiveness against H5N1, the viral
strain that has sickened more than 120 persons and killed more than 60
in Southeast Asia.
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- Studies have suggested Tamiflu has some effectiveness
against H5N1, but little real-world data show whether it is effective in
infected humans, Osterholm said.
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- H5N1 replicates more rapidly and infiltrates a wider
range of lung cells than do other more common flu forms when they enter
the body. The aggressive infection sets off a rapid and massive release
of chemicals, which attack the immune system and destroy it.
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- One key -- but as-yet-unanswered -- question about the
drug is whether it needs to be given earlier or in higher-than-usual doses
in avian flu cases.
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- "Frankly we just don't know," Osterholm said.
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- Limited animal studies have suggested Tamiflu must be
administered before infection even occurs in order to be effective, he
added.
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- The federal government has announced plans to increase
its Tamiflu stores, from 2 million to more than 12 million doses. The drug
is on back order from Roche, because dozens of other governments also have
requested the drug.
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- "It's being sold right now as almost the Cipro of
post-9/11," said Osterholm, referring to mass purchases of the antibiotic
ciprofloxacin, after mailed anthrax attacks killed 5 people in the United
States in the fall of 2001.
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- "Tamiflu is designed to be active against all clinically
relevant influenza viruses and key international research groups have demonstrated,
using animal models of influenza, that Tamiflu is effective against the
avian H5N1 strain circulating in the Far East," William M. Burns,
chief executive officer of Roche's pharma division, said in a statement.
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- Regarding the criticism that the company has refused
to suspend its Tamiflu patent so generic drug makers could help fill stockpile
orders, Roche spokesman Terrence Hurley said the company has not refused
official requests to do so.
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- "To date, we have been approached by just one country
in the Far East, and are having conversations with them right now,"
Hurley told UPI.
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