WHO: B.F. Studies `Urgently� Needed

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Bird Flu Studies `Urgently' Needed to Test Tamiflu, WHO Says

March 18 (Bloomberg) -- More studies are ``urgently'' needed to 

determine how bird flu patients can be best treated with oseltamivir, the 

antiviral drug marketed by Roche Holding AG as Tamiflu, the World Health 

Organization said.

Tamiflu is approved to treat seasonal flu. No direct clinical trial evidence 

shows the medicine is effective in treating people infected with the lethal 

H5N1 avian influenza virus because no such studies have been 

conducted, the Geneva- based United Nations health agency said 

yesterday.

``Because the optimal dosage has not been resolved by clinical trials, 

and because H5N1 infections continue to have a high mortality rate, 

prospective studies are needed urgently to determine optimal dosing and 

duration of treatment,'' the WHO said in a statement on its Web site.

The WHO and governments around the world are stockpiling Tamiflu for 

use as a prophylactic against any potential influenza pandemic. The 

medicine is also one of several drugs being used to treat patients with 

H5N1, which health officials worry may mutate into a form that's more 

contagious to humans.

Since 2003, H5N1 has killed at least 98 of 177 people infected, the WHO 

said on March 13.

There is limited evidence suggesting that some oseltamivir can reduce the 

duration of viral replication and improve prospects of survival, provided it 

is given within 48 hours following symptom onset, according to the 

WHO's fact sheet on avian flu, published on the Internet. Prior to an H5N1 

outbreak in Turkey earlier this year, most patients were detected and 

treated late in the course of illness, it said.

Turkish Data

Roche said last week it has data from 21 patients in Turkey who took the 

drug after being infected with H5N1. Four of the patients were given the 

drug ``very, very late'' and died, David Reddy, head of Roche's pandemic 

task force, said. The remaining patients recovered and were discharged 

from the hospital.

``The evidence for effectiveness of oseltamivir in human H5N1 disease is 

based on virological data from in vitro, animal models, and limited human 

studies and extrapolation from the results of trials in patients with 

ordinary human influenza, '' the WHO said.

Optimal treatment of H5N1 cases using oseltamivir may be different than 

recommended for seasonal flu, the WHO said in the statement yesterday. 

For seasonal flu, it is recommended that adults take 75 milligrams of 

oseltamivir twice a day for five days.

In H5N1 cases, it is possible that severely ill patients might benefit from 

taking the medicine for seven to 10 days or given as much as 300 

milligrams a day, the WHO said, adding that ``prospective studies are 

required.''

Higher Doses

Gastrointestinal side effects in particular may increase with higher doses, 

particularly above 300 milligrams a day, the WHO said. There is no 

adequate data on the use of oseltamivir in pregnant women, it said.

``Animal toxicology studies do not indicate direct or indirect harmful 

effects with respect to pregnancy or fetal development,'' the WHO said. 

``Decisions to use oseltamivir in pregnant women should be made on a 

case by case basis where the potential benefit to the mother justifies the 

potential risk to the fetus.''

Basel, Switzerland-based Roche said on March 16 it will use 15 partners, 

including Sanofi-Aventis SA and Clariant AG, to increase production of 

Tamiflu by 33 percent by year's end.

Based on the current manufacturing capacity, it will take a decade to 

produce enough oseltamivir to treat a fifth of the world's population, 

according to the WHO.

To contact the reporter on this story:

Jason Gale in Singapore at  j.gale@bloomberg.net

Last Updated: March 17, 2006 23:14 EST

http://www.bloomberg.com/apps/news?

pid=10000087&sid=aI8r6k310BL4&refer=top_world_news#

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	Bird Flu Studies `Urgently' Needed to Test Tamiflu, WHO Says March 18 (Bloomberg) -- More studies are ``urgently'' needed to determine how bird flu patients can be best treated with oseltamivir, the antiviral drug marketed by Roche Holding AG as Tamiflu, the World Health Organization said. Tamiflu is approved to treat seasonal flu. No direct clinical trial evidence shows the medicine is effective in treating people infected with the lethal H5N1 avian influenza virus because no such studies have been conducted, the Geneva- based United Nations health agency said yesterday. ``Because the optimal dosage has not been resolved by clinical trials, and because H5N1 infections continue to have a high mortality rate, prospective studies are needed urgently to determine optimal dosing and duration of treatment,'' the WHO said in a statement on its Web site. The WHO and governments around the world are stockpiling Tamiflu for use as a prophylactic against any potential influenza pandemic. The medicine is also one of several drugs being used to treat patients with H5N1, which health officials worry may mutate into a form that's more contagious to humans. Since 2003, H5N1 has killed at least 98 of 177 people infected, the WHO said on March 13. There is limited evidence suggesting that some oseltamivir can reduce the duration of viral replication and improve prospects of survival, provided it is given within 48 hours following symptom onset, according to the WHO's fact sheet on avian flu, published on the Internet. Prior to an H5N1 outbreak in Turkey earlier this year, most patients were detected and treated late in the course of illness, it said. Turkish Data Roche said last week it has data from 21 patients in Turkey who took the drug after being infected with H5N1. Four of the patients were given the drug ``very, very late'' and died, David Reddy, head of Roche's pandemic task force, said. The remaining patients recovered and were discharged from the hospital. ``The evidence for effectiveness of oseltamivir in human H5N1 disease is based on virological data from in vitro, animal models, and limited human studies and extrapolation from the results of trials in patients with ordinary human influenza, '' the WHO said. Optimal treatment of H5N1 cases using oseltamivir may be different than recommended for seasonal flu, the WHO said in the statement yesterday. For seasonal flu, it is recommended that adults take 75 milligrams of oseltamivir twice a day for five days. In H5N1 cases, it is possible that severely ill patients might benefit from taking the medicine for seven to 10 days or given as much as 300 milligrams a day, the WHO said, adding that ``prospective studies are required.'' Higher Doses Gastrointestinal side effects in particular may increase with higher doses, particularly above 300 milligrams a day, the WHO said. There is no adequate data on the use of oseltamivir in pregnant women, it said. ``Animal toxicology studies do not indicate direct or indirect harmful effects with respect to pregnancy or fetal development,'' the WHO said. ``Decisions to use oseltamivir in pregnant women should be made on a case by case basis where the potential benefit to the mother justifies the potential risk to the fetus.'' Basel, Switzerland-based Roche said on March 16 it will use 15 partners, including Sanofi-Aventis SA and Clariant AG, to increase production of Tamiflu by 33 percent by year's end. Based on the current manufacturing capacity, it will take a decade to produce enough oseltamivir to treat a fifth of the world's population, according to the WHO. To contact the reporter on this story: Jason Gale in Singapore at j.gale@bloomberg.net Last Updated: March 17, 2006 23:14 EST http://www.bloomberg.com/apps/news? pid=10000087&sid=aI8r6k310BL4&refer=top_world_news#